Thalamus

 

The thalamus, the yellow section on the drawing above, is an important brain nucleus and is considered one of the intermediate brain, together with the pituitary gland and the hypothalamus. It is the most 'wired' portion of the brain.

 

Introduction

Foreword: The brain works together as a single unit. Brain functions are distributed throughout the brain regions and arise from the exchange between the regions. Nevertheless, symptoms can be identified per brain region.


Do you only want the short summary? Then follow this link.


Do you only want to read the possible symptoms per core group and per adjacent brain regions? Follow this link.

 

Do you want to know more about the anatomy, functions, and potential damage per core group? Then follow this link.

Thalamus: most wired part of the brain

The thalamus is an important relay station deep within the brain. Virtually all sensory information – such as what you see, feel, and hear – is transmitted via the thalamus to the cerebral cortex.

It helps to focus attention on important information and filter out less important stimuli.

It also assists with movement, memory, emotions, and with being conscious, awake, and alert.

It plays a role in akinetic mutism. This is a syndrome, a consequence of brain injury, in which the person speaks little or not at all (mutism) and moves little or not at all (akinesia). The person may follow you with their eyes but otherwise appears apathetic and does almost nothing of their own accord.

Thalamus is derived from the Greek word for hidden central inner chamber or bedroom; θάλαμος, because it lies deep within the brain and forms the 'central' chamber.

It is a deep-seated central nucleus in the brain

  • virtually all sensory information (except smell) enters it first
  • it distributes and organizes information before it goes to the cerebral cortex
  • it is in contact with almost all parts of the cortex via thousands of connections

You can therefore view the thalamus as the central inner chamber where information first enters and is forwarded

Senses

 l

Thalamus

(central inner chamber)

  l

Cerebral Cortex

 

Gateway to the Cerebral Cortex

The connections from the thalamus to the cerebral cortex return from the cortex to the thalamus.


This is called the thalamo-cortico-thalamic circuit. As a result, minor thalamic lesions can mimic cerebral cortex syndromes, and in some syndromes, the specialization of the cerebral hemisphere can be recognized.


As a gateway to the cerebral cortex, the thalamus has to transmit many sensory stimuli (except smell), but it must also filter stimuli, allowing healthy individuals to "shut off" certain stimuli. It is therefore one of the so-called "filters" (stimulus filters), a control center to help the brain focus on important and unimportant stimuli.

The main core groups of the thalamus and adjacent structures (in the diencephalon)

Important to know:

The thalamus works closely with other brain regions. The symptoms a person experiences may correspond to damage to a specific core group, but are often also determined by the cooperation between different brain networks.
The following anatomical terms explain the names of the core groups:

The image below is a schematic anatomical representation. The exact shape, size, and mutual boundaries of the core groups may vary slightly depending on the anatomical cross-section and the anatomical reference work.

 

Discussion of the image of the thalamus viewed from the side (lateral view) with the adjacent metathalamus

 

The image shows the main nuclear groups of the thalamus in a lateral view. The thalamus consists of various nuclear groups that receive, process, and transmit information to the cerebral cortex. Not all nuclear groups are fully visible from this view. Therefore, hidden or partially hidden structures are indicated with a curved gray arrow, while straight black arrows point to structures that are directly visible.

The lamina medullaris interna (Y-shaped white matter tract) divides the thalamus into different anatomical nuclear groups.

The intralaminar nuclei are located within this white matter tract. The midline nuclei lie directly along the third ventricle and are barely visible from a lateral view. The reticular nucleus forms a thin layer on the outside of the thalamus and plays an important role in regulating the information processed by the thalamus.

 

Located at the posterior side are the lateral knee-form body (LGN (Medial Geniculate Nucleus)) and the medial knee-form body (MGN (Medial Geniculate Nucleus)). Together, they form the metathalamus. The LGN processes visual information, while the MGN is involved in processing auditory information.

The illustration is based on the anatomical classification as described in Gray's Anatomy, supplemented and verified with Mai & Paxinos and Blumenfeld.

For each section, we elaborate on the following:

  • Where are the nuclei located?
  • From where do they receive information?
  • Where do they send information?
  • What do these nuclei do?
  • Possible consequences of damage
  • What do you notice about this in daily life?
  • Important to know
  • In-depth information for healthcare professionals
  • Anatomical references

 

The list is written in plain language (B1 level), but is based on authoritative anatomical and neurological literature, including Gray's Anatomy, Mai & Paxinos, and Blumenfeld. Where scientific insights are still developing, this is indicated in the text. In this way, we combine understandable explanations with current medical knowledge.

 

1. Anterior core group

Where is this core group located?

Located at the front (rostral) of the dorsal (back) thalamus. Forms an important node in the limbic network.

(The limbic network is responsible for understanding, regulating, and processing emotions)

 

Receives information from
Primarily the mammillary bodies (limbic network)

 

Sends information to
The cingulate gyrus

 

What does this core group do?

  • Helps form new memories
  • Helps remember events
  • Supports learning new information
  • Links memories to emotions.

 

Possible consequences of damage

  • Difficulty remembering new information
  • Forgetfulness - Problems remembering recent events
  • Sometimes difficulty remembering events chronologically
  • Sometimes difficulty learning
  • Sometimes difficulty remembering events in the correct order
  • Sometimes changes in motivation or emotions.

 

What do you notice about this in daily life?

New appointments or conversations are forgotten more quickly. Inability to encode information (anterograde amnesia) and memory disorders.

Important to know
Isolated damage is rare.
This core group is part of Papez's circle, a network in the brain that is important for pre-memory and emotions. They play a role in episodic memory (life events, the life story).

2. Mediodorsal core group (MD)

Where is this core group located?

The mediodorsal core group (MD) is located on the inside (medial) of the dorsal thalamus, directly next to the third ventricle.

 

Receives information from
Limbic structures and other parts of the brain

 

Sends information to
Brain areas involved in planning and decision-making

 

What does this core group do?

This core group works closely with the prefrontal cortex and plays an important role in so-called executive functions, such as organizing, maintaining an overview, weighing the consequences of choices.

  • Planning
  • Making decisions
  • Maintaining attention
  • Working memory (briefly remembering and using information)
  • Processing emotions (assessing emotions, adapting behavior to social situations, regulating emotional responses)
  • Social behavior
  • Weighing choices and their consequences.

 

Possible consequences of damage

Common consequences

  • difficulty planning and organizing
  • problems with concentration
  • easily distracted
  • difficulty making decisions
  • forgetfulness, especially regarding new information
  • reduced initiative

Occasional consequences

  • changes in social behavior
  • difficulty assessing appropriate behavior
  • reacting more flatly to emotions or, conversely, reacting more emotionally
  • difficulty maintaining an overview of complex tasks
  • sometimes changes in social behavior
  • a memory gap is sometimes filled with fabrications (anterograde amnesia). Forgetting the sequence (sequence amnesia). There is damage to executive functions: executive function disorders (executive function disorders)

 

What do you notice about this in daily life?

  • that it becomes harder to plan a day
  • that it takes longer to make choices
  • doing multiple tasks at once quickly becomes too much
  • that conversations are harder to follow when a lot of information is given at once
  • that appointments are forgotten more quickly
  • that others notice that you take less initiative or react differently in social situations

 

Important to know
Intelligence is usually retained, but it may become more difficult to apply knowledge effectively in daily life.

 

In-depth study for the professional

Akinetic mutism may occur when certain parts of the thalamus, particularly the paramedian thalamus (specifically the mediodorsal nucleus (MD) and parts of the intralaminar nuclei), are damaged on both sides.

This usually occurs due to a stroke in the supply area of ​​the paramedian thalamic arteries.

The thalamus plays three important roles in this process:

  1. Consciousness and alertness – The intralaminar nuclei are part of the ascending activating system (ARAS). Damage reduces mental activation.
  2. Motivation to act – The mediodorsal nucleus is connected to the prefrontal cortex and the limbic system. With damage, the inner urge to start speaking or moving often disappears.
  3. Initiating behavior – The thalamus forms a link in the fronto-thalamo-basal ganglia networks necessary to initiate voluntary actions.

The result is that a person appears awake and has the eyes open, but hardly speaks or moves spontaneously. The muscles are usually not paralyzed and language need not be severely impaired. The biggest problem is the failure of goal-directed behavior to get started.

 

3. Lateral dorsal core group (LD)

Where is this core group located?

The lateral dorsal core group (LD) is located on the upper side of the dorsal thalamus, directly behind the anterior core group. The LD is part of the limbic network and is connected via connections to, among others, the cingulate cortex and the hippocampus.

Assists with memory, spatial orientation, and attention.

  • Forming and retrieving memories
  • Orienting in space
  • Recognizing the environment
  • Focusing attention on important information
  • Combining spatial information with memories

Possible consequences of damage

Common consequences

  • Difficulty orienting oneself in a familiar environment
  • Problems with spatial memory
  • Difficulty maintaining an overview in an unfamiliar environment

Occasional consequences

  • Difficulty finding familiar routes
  • Reduced attention to spatial information
  • Mild problems remembering places or locations

 

What do you notice in daily life?

  • That it is more difficult to find your way in a familiar environment
  • That it takes longer to remember a new route
  • That you lose your bearings more quickly in a busy building, such as a hospital or shopping center
  • That you sometimes have to think about a route that used to come naturally.

Important to know
Damage to only the lateral dorsal core group is rare. Symptoms usually arise because other parts of the memory and orientation network are also damaged. As a result, the symptoms are often mild and can easily be overlooked.

4. Lateral posterior core group (LP)

Where is this core group located? It is located behind the LD - Lateral dorsal core group (see tab above at 4) and in front of the pulvinar (see tab below at 5).

 

What does this core group do? The LP (Lateral posterior core group) primarily helps the brain to give meaning to what you see, in cooperation with other brain regions.

 

  • Combining visual information with information from other senses
  • Focusing attention on important events in the environment
  • Recognizing the spatial position of objects
    Processing complex visual information
  • The cooperation of different brain regions during perception

 

Consequences of injury Damage can lead to difficulty maintaining an overview and visual attention.

Common consequences

  • Difficulty focusing attention on what you see
  • Problems processing complex visual information
  • Difficulty maintaining an overview in a busy environment
  • Difficulty with spatial orientation


Occasional consequences

  • Reduced eye-hand coordination during visual tasks
  • Difficulty estimating the location of objects

Sometimes reduced attention to stimuli on the opposite side of the room, especially with more extensive injury.

 

What do you notice in daily life?

  • It becomes harder to find something on a crowded table
  • Busy environments, such as a supermarket or station, become cluttered more quickly
  • It takes more effort to pick up an object you see lying there
  • You sometimes overlook something even though you are looking at it.

 

Important to know!

It is not a primary visual center. Damage to only the lateral-posterior core group is rare. Symptoms usually occur in conjunction with damage to other parts of the thalamus or the parietal cortex. As a result, the symptoms can vary from person to person.

Pulvinar

Where is this core group located?

It is the largest posterior part of the dorsal thalamus.

What does this core group do?

It assists with attention, complex visual processing, and information integration.

 

  • The pulvinar helps combine information from different senses, such as sight, hearing, and touch. This ensures that the brain gets a clearer picture of the environment.
  • The pulvinar helps the brain to quickly determine
    where your attention should go and to connect information from different brain regions.
  • Focusing and maintaining attention
  • Processing complex visual information
    The pulvinar works together with the visual parts of the brain. It receives information from the superior colliculi (a part of the midbrain).
  • It helps in processing visual reflexes
    It helps focus attention on important visual details such as color, shape, or location in a complex environment
    Recognizing objects and faces
    Combining information from different senses
    Orienting in space
    Filtering important and less important information
    Learning and remembering, especially regarding things we see and visual memories
    Processing emotional stimuli, particularly how we deal with emotions and how we connect with others.

Possible consequences of damage

Damage may lead to problems with attention and spatial orientation.

Common consequences

  • Difficulty focusing attention
  • Problems processing complex visual information
  • Difficulty maintaining an overview in a busy environment
  • Problems with spatial orientation
  • Slower processing of visual stimuli

 

Occasional consequences

  • Difficulty recognizing objects or faces in a busy environment
  • Reduced attention to stimuli on the opposite side of the room
  • Difficulty combining information from different senses
  • Problems with eye movements while searching for an object.

 

Damage to the pulvinar may disrupt visual reflexes, which may lead to problems focusing attention on important visual details.

Another part of the thalamus, the reticular nucleus of the thalamus, also likely helps the brain focus on the most important details of what you see.

 

What do you notice about this in daily life?

Difficulty finding an object in a busy environment

 

Important to know! The pulvinar works closely with multiple brain regions. Neglect and visual attention disorders may occur, but are usually more severe when the parietal cortex or other thalamic nuclei are also damaged.

  • Damage to the right pulvinar can cause left-sided spatial neglect / failure to notice (neglect).
  • Damage to the left pulvinar can cause word-finding difficulties.

Two specific nuclei: the pulvinar at the back of the thalamus and a nucleus in the middle at the bottom, the nucleus reticularis thalami, have partially overlapping functions:

 

Two  nuclei: the pulvinar at the back of the thalamus and a nucleus in the middle at the bottom, the nucleus reticularis thalami, have partially overlapping functions:

FUNCTION PULVINAR NUCLEUS RETICULARIS THALAMI
Attention regulation mostly visual general and modeling
Visual processing strongly involved supports visual attention
Integration of sensory information multisensory filters unwanted information
Role in consciousness less direct, more in perception crucial for alertness and focus

6. Ventral anterior core group (VA)

Where is this core group located? The Anterior side of the ventral thalamus.

The ventral anterior core group (VA) is located at the anterior side of the ventral thalamus, in front of the ventral lateral core group (VL). The VA primarily receives information from the basal ganglia and transmits it to the premotor cortex and the supplementary motor cortex.

Receives information from
The basal ganglia; especially the globus pallidus internus (GPi) and the substantia nigra pars reticulata (SNr)

 

Sends information to
Brain regions that prepare movements

 

What does this core group do?
It helps preparing and initiating voluntary movements.
It ensures that movements are properly prepared before they are executed.

  • Preparing movements
  • Planning goal-directed movements
  • Choosing the right movement

  • Initiating voluntary movements

  • Ensuring the smooth execution of sequential movements

     

The ventral anterior nucleus helps control movements via connections with the basal ganglia, which are the basal nuclei important for movement, balance, posture, and eye movements.

Possible consequences of damage Damage may lead to difficulty initiating movements.

Common consequences

  • Difficulty starting a movement
  • Slower movements
  • Less fluid movements
  • Difficulty planning sequential movements

Occasional consequences

  • Less spontaneous movements
  • Problems performing learned movements
  • Mild coordination problems with complex movements.

 

What do you notice about this in daily life?

Everyday activities start less smoothly.

  • It takes longer to start a movement
  • You start walking hesitantly
  • You have difficulty performing multiple movements in succession
  • Actions such as getting dressed or cooking take more time
  • Your movements feel less natural

 

Important to know! Muscle strength is usually preserved.

The VA does not directly control the muscles. This core group primarily assists in preparing and planning movements. Muscle strength is usually preserved, but initiating and organizing movements may be more difficult.

For healthcare professionals:

The VA receives afferent projections from the globus pallidus internus (GPi) and the substantia nigra parsreticulata (SNr). The efferent projections run mainly to the premotor cortex (BA6) and the supplementary motor area (SMA).

7. Ventral lateral core group (VL)

Where is this core group located?

Briefly: Behind the VA ventral anterior core group (see drop-down menu 6.) in the ventral thalamus.


In detail: The ventral lateral core group (VL) is located in the ventral part of the dorsal thalamus, directly behind the ventral anterior core group (VA) and in front of the sensory nuclei (VPL see 8. and VPM see 9.).

The VL forms an important link between the cerebellum, the basal ganglia, and the motor cortex.

Receives information from

  • The cerebellum (the main input comes from the
    nucleus dentatus of the cerebellum)
  • The basal ganglia

Sends information to

  • The primary motor cortex
  • Brain areas involved in performing voluntary movements

As a result, the VL helps to execute movements accurately and smoothly.

 

What does this core group do?

  • Performing voluntary movements
  • Ensuring movements proceed smoothly
  • Coordinating movements
  • Precisely controlling arm and leg movements
  • Adjusting movements during execution

 

The VL helps ensure that movements proceed smoothly, accurately, and are well-coordinated.

 

Possible consequences of damage

  • Less smooth movements
  • Coordination problems
  • Difficulty with precise movements

Common consequences:

  • Less smooth movements
  • Problems with coordination
  • Difficulty with precise movements
  • Slower execution of movements
  • Difficulty adjusting a movement during execution

Sometimes occurring consequences:

  • Mild balance problems
  • Difficulty with fine motor skills
  • Less fluent speech if other motor areas are also affected.

 

What do you notice about this in daily life?

  • Writing is less neat
  • A cup or glass is held less firmly
  • Fastening buttons or turning a key takes more effort
  • Movements are less fluid
  • Walking feels less smooth

 

Important to know

Isolated damage to the VL is rare. The symptoms depend on the size of the lesion and on other brain areas involved.

Muscle strength is often largely preserved, but movements may be performed with less precision and fluidity. The VL does not directly control the muscles.

This core group primarily helps to properly coordinate movements before the muscles are controlled by the motor cortex.

 

In-depth for healthcare professionals 

  • Dentate nucleus of the cerebellum (via the superior cerebellar peduncle)
  • Internal pallidum (primarily to specific VL subnuclei)

 

Main efferent connections

  • Primary motor cortex (M1; Brodmann area 4)
  • Premotor cortex
  • Supplementary motor cortex (SMA)

 

Clinical relevance
The VL plays a central role in the cerebello-thalamo-cortical and partly in the basal ganglia-thalamo-cortical circuits. Lesions may lead to ataxia, dysmetria, intention tremor, or impaired motor coordination, depending on the precise location and extent of the lesion.

 

Primary source

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice
    (most recent edition)

Additional Anatomical Resources

  • Mai & Paxinos – Atlas of the Human Brain
  • Blumenfeld – Neuroanatomy Through Clinical Cases

Supporting clinical literature

  • Recent neuroanatomical and clinical-neurological literature on the cerebello-thalamo-cortical and basal ganglia-thalamo-cortical networks.

8. Ventral posterolateral core group (VPL)

Where is this core group located?

Briefly: Behind the VL in the ventral thalamus.


In detail: The ventral posterolateral core group (VPL) is located in the posterior part of the ventral thalamus, directly behind the ventral lateral core group (VL) and next to the ventral posteromedial core group (VPM).

The VPL is the main sensory core for the trunk, arms, and legs

Receives information via the medial lemniscus and the spinothalamic tract.

Sensory pathways from trunk, arms, and legs.

 

Sends information to
The primary sensory cortex (somatosensory cerebral cortex)

Here, sensory information is consciously perceived and recognized.

 

What does this core group do?

The VPL ensures that sensory information from the body reaches the cerebral cortex, so that you can consciously feel what is happening.

  • Feeling touch
  • Perceiving pain
  • Feeling heat and cold
  • Recognizing vibrations
  • Sensing the position of arms and legs without looking
  • Recognizing where a touch occurs on the body /
    body posture (proprioception for balance)

 

Possible consequences of damage

Common consequences

  • Reduced sensation on the opposite side of the body
  • Reduced sensitivity to touch
  • Reduced sensitivity to pain or temperature
  • Reduced sensitivity to vibrations
  • Difficulty accurately feeling the position of an arm or leg without looking
  • Tingling or numbness


Occasional consequences

  • Burning or stabbing pain (thalamic pain) Central post-stroke pain (thalamic pain syndrome) usually arises from injuries to the posterolateral thalamus, in which the VPL is often involved.
  • Hypersensitivity to touch
  • Difficulty recognizing objects by touch, while muscle strength is normal

 

What do you notice about this in daily life?

  • You have a reduced sense of where your foot is while walking
  • You are less quick to notice if something is warm or cold
  • You drop things from your hand more easily without a clear reason
  • You have to look at your hands or feet more often to know exactly where they are
    Touch may feel different than before.

 

Important to know

Muscle strength usually remains normal.

The VPL only processes sensory information from the trunk, arms, and legs.

Sensory information from the face is processed by the ventral posteromedial core group (VPM) (expandable menu below).


Muscle strength is usually preserved. The problems mainly relate to sensation.

 

In-depth for healthcare professionals

Main afferent connections

  • Medium lemniscus
  • Spinothalamic tract
  • Trigeminothalamic tracts do not terminate in the VPL but in the VPM

 

Major efferent connections

  • Primary somatosensory cortex (S1; Brodmann 3, 1 and 2)

Clinical relevance


A lesion of the VPL typically causes
contralateral hemisensic loss of trunk and extremities. Depending on the extent and location of the lesion, disturbances may arise of:

  • fine touch
  • vibration sensation
  • proprioception
  • pain and temperature sensation.

In some patients, a central pain syndrome (Déjerine-Roussy syndrome) develops.

 

Primary source

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice
    (most recent edition)

Additional anatomical sources

  • Mai JK & Paxinos G. Atlas of the Human Brain
  • Blumenfeld H. Neuroanatomy Through Clinical Cases

Supporting literature

  • Recent neuroanatomical and clinical neurological literature on the somatosensory thalamus and central pain syndromes.

9. Ventral posteromedial core group (VPM)

Where is this core group located?

Briefly: Medially (in the middle) next to the VPL.
In detail: The ventral posteromedial core group (VPM) is located in the posterior part of the ventral thalamus, directly next to the ventral posterolateral core group (VPL).

The VPM is the main sensory core for the face. In addition, this core group also processes taste information.

Receives information via the trigeminothalamic pathways
(facial sensation) and the tractus solitarius (taste).

  • The sensory nerves of the face
  • The oral cavity
  • The tongue
  • The taste pathways

 

These pathways transmit information about:

  • Touch
  • Pressure
  • Pain
  • Temperature
  • The position of the jaw during chewing
  • Taste

VPM sends information to

  • The primary sensory cortex for the face
  • The taste cortex (gustatory cortex)

Here, sensory and taste information is consciously perceived.

 

What does this core group do? Helps with:

  • Feeling touch on the face
  • Perceiving pain in the face
  • Feeling warmth and cold on the face
  • Recognizing where a touch occurs on the face
  • Sensing the position of the jaw during chewing
  • Processing taste information

The VPM ensures that sensory and taste information from the face and mouth reaches the cerebral cortex, so that you can consciously perceive it.

 

Possible consequences of damage
Common consequences of damage:

  • Reduced sensation in the opposite half of the face
  • Reduced sensitivity to touch in the face
  • Reduced sensitivity to pain or temperature in the face
  • Numbness or tingling in the face
  • Reduced sense of taste

Occasional consequences of damage

  • Burning or stinging pain in the face (central facial pain)
  • Hypersensitivity to touch in the face
  • Difficulty feeling food properly in the mouth while chewing.

 

What do you notice about this in daily life?

  • You feel less well when your face is touched
  • Food or drink has less taste
  • You feel less well if there is still food in your mouth
  • Hot or cold food feels different
  • Shaving, brushing teeth, or applying makeup becomes more difficult because the sensation in the face has changed.

 

Important to know
The VPM processes sensation from the face, not from the arms or legs.
Isolated VPM lesions are rare. Central facial pain may occur when the posteromedial thalamusis is affected.

The VPM processes sensory information from the face and taste information.
Sensory information from the trunk, arms, and legs is processed by the ventral posterolateral core group (VPL), see the drop-down menu above.
Muscle strength in the chewing and facial muscles is usually preserved. The problems mainly relate to sensation and sometimes to taste.

 

In-depth information for healthcare professionals

Main afferent connections

  • Trigeminothalamic pathways (nucleus principalis and nucleus spinalis nervi trigemini)
  • Tractus solitarius via the parabrachial and thalamic projections (gustatory information)

Main efferent connections

  • Primary somatosensory cortex (facial representation; Brodmann 3, 1 and 2)
  • Gustatory cortex (insula and operculum frontoparietale)

 

Clinical relevance


A lesion of the VPM typically causes a contralateral sensory loss in the face. Depending on the extent and location of the lesion, disturbances may arise of:

  • fine touch
  • pain and temperature sensation
  • proprioception of the jaw
  • taste

Some patients develop central facial pain or other forms of neuropathic pain.

 

Primary resource

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice (most recent edition)

 

Additional anatomical resources

  • Mai JK & Paxinos G. Atlas of the Human Brain
  • Blumenfeld H. Neuroanatomy Through Clinical Cases

 

Supporting literature
Recent neuroanatomical and clinical neurological literature on the somatosensory and gustatory thalamus

10. Intralaminar Nuclei (CM/Pf)

Where is this group of nuclei located?

The intralaminar nuclei are located in the middle of the Y-shaped internal medullary lamina of the dorsal thalamus. The two most important nuclei are:

  • Centromedian nucleus (CM)
  • Parafascicular nucleus (Pf)

 

Receive information from
Due to their central location, they can connect information from different brain regions. They receive information from the reticular activating system, the basal ganglia, and spinothalamic systems.

  • The brainstem
  • The basal ganglia
  • The cerebellum
  • Other parts of the thalamus
  • Pain pathways from the body
 
The information concerns, among other things:
  • Alertness
  • Movement
  • Pain
  • Attention

 

Send information to

  • The cerebral cortex
  • The basal ganglia, especially the striatum
  • Other thalamic nuclei

 

Through this, they help various brain networks work together.

 

What do these nuclear groups do?

The intralaminar nuclei help the brain to notice important information and respond to it.

  • Maintaining attention
  • Staying alert
  • Processing pain stimuli
  • Initiating and supporting movements
  • Switching between different brain networks
  • Consciously perceiving important stimuli

 

Possible consequences of damage

Common consequences of damage

  • Reduced alertness
  • Problems with attention
  • Becoming fatigued more quickly
  • Difficulty processing information effectively
  • Reduced initiative

 

Occasional consequences of damage

  • Problems initiating movements
  • Changes in pain perception
  • Reacting more slowly to events
  • In case of extensive injury (bilateral lesions): reduced consciousness / severe disturbances of consciousness
  • Sometimes chronic pain.

 

What do you notice in daily life?

  • You are more easily distracted
  • It takes more effort to keep your attention focused on something
  • You get tired more quickly during conversations or reading
  • It takes longer for you to respond to something
  • You have less energy to start activities

 

Important to know
The centromedial (CM) and parafascicular (Pf) nuclei are the most important intralaminar nuclei.

Many textbooks describe them too simply as "nuclei for alertness." This is now outdated.

The centromedial nucleus (CM) and the parafascicular nucleus (Pf) also play an important role in attention, motor networks, pain processing, and consciousness.

 

The intralaminar nuclei do not regulate one single specific function. They help various brain regions work together.
As a result, symptoms can vary from person to person.

With a minor injury, symptoms are often mild, while more extensive injury can affect attention and consciousness.

 

In-depth for healthcare professionals
Main afferent connections

  • Ascending reticular activating system (ARAS)
  • Spinothalamic pathways
  • Globus pallidus internus
  • Cerebellar projections
  • Other thalamic nuclei

 

Major efferent connections

  • Diffuse projections to the cerebral cortex
  • Strong projections to the striatum (caudate nucleus and putamen)
  • Connections to other thalamic nuclei

 

Clinical relevance
The CM/Pf complexes play an important role within the thalamo-striatal networks. They are involved in attention, arousal, pain modulation, and motor control. Bilateral lesions can lead to severe disturbances of consciousness. Additionally, the centromedial nucleus is a recognized target for deep brain stimulation (DBS) in treatment-resistant epilepsy and is being investigated for movement disorders.

 

11. Midline cores

Where are these groups of nuclei located?

The midline nuclei are located directly next to the third ventricle, exactly in the center of the thalamus. They form a narrow row of small nuclei along the inner edge of the dorsal thalamus.


Due to their central location, they can connect information from different brain regions.

Receive information from

  • The limbic system (including the hypothalamus and hippocampus)
  • The brainstem
  • Other parts of the thalamus
  • The prefrontal cortex

 

This information concerns, among other things:

  • Emotions
  • Memory
  • Alertness
  • Motivation

The midline nuclei receive extensive connections from limbic structures, the reticular formation, and the prefrontal cortex. The precise connections differ per subnucleus.

Modern neuroanatomy shows that these nuclei form a connection between memory, emotions, motivation, attention, and arousal/alertness.

 

Send information to

  • The prefrontal cortex
  • The limbic system
  • Other parts of the thalamus
  • The nucleus accumbens and other parts of the basal forebrain

As a result, they help various brain networks work together.
Modern studies show that the midline nuclei form an important link between limbic and cognitive networks.

 

What do these core groups do?

The midline nuclei assist with:

  • Maintaining attention
  • Forming and retrieving memories
  • Processing emotions
  • Maintaining motivation
  • Consciously processing important information
  • The collaboration of different brain networks

The midline nuclei help the brain remember important information, process emotions and maintain attention.

 

Possible consequences of damage
Isolated damage is rare. Symptoms depend heavily on the size and location of the injury.

 

Common consequences

  • Difficulty remembering new information
  • Problems with attention
  • Easily distracted
  • Less initiative
  • Becoming mentally fatigued more quickly

Occasional occurring consequences

  • Changes in emotions
  • Reduced motivation
  • Difficulty processing information properly
  • In case of extensive injury: reduced consciousness.

 

What do you notice in daily life?
Someone with damage to these core groups may notice, for example, that:

  • You forget recent events more quickly
  • It is harder to follow a conversation
  • You are more easily distracted
  • It takes more effort to start something
  • You get tired more quickly after activities that require careful thought.

 

Important to know!

These nuclei are part of the limbic network.

The midline nuclei do not have a single clear task. They help various brain regions work together.

As a result, symptoms may vary from person to person.

A minor injury often causes mild symptoms, while more extensive injury can affect memory, attention, motivation, and awareness.

 

In-depth for healthcare professionals

Main afferent connections

  • Hippocampus (indirect via limbic circuits)
  • Hypothalamus
  • Reticular formation
  • Amygdala (indirect)
  • Mediodorsal and other thalamic nuclei
  • Prefrontal cortex

 

Main efferent connections

  • Medial prefrontal cortex
  • Anterior cingulate cortex
  • Nucleus accumbens
  • Hippocampal and parahippocampal networks
  • Other medial thalamic nuclei

 

Clinical relevance
The midline nuclei, together with the mediodorsal nucleus and the anterior nucleus group, form an important part of the limbic-thalamocortical networks. They play a role in episodic memory, attention, motivation, arousal, and emotional regulation.

Recent research shows that the nucleus reuniens, in particular, forms an important connection between the
hippocampus and the medial prefrontal cortex. This connection appears to be important for working memory, spatial memory, and cognitive flexibility.

Bilateral damage to the midline nuclei can lead to impairments of memory, attention, and consciousness.

 

Anatomical references

Primary source

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice (most recent edition)

Additional anatomical sources

  • Mai JK & Paxinos G. Atlas of the Human Brain
  • Blumenfeld H. Neuroanatomy Through Clinical Cases

 

Supporting literature

  • Recent neuroanatomical and functional MRI studies on the midline thalamus, limbic-thalamocortical networks, and the role of the nucleus reunion in memory and attention.

Many older textbooks state that the midline nuclei primarily "regulate consciousness." Nowadays, this is considered too limited a description. Modern neuroanatomy shows that these nuclei form a connection between memory, emotions, motivation, attention, and arousal.

12. Reticular nucleus

 

Where is this group of nuclei located?

The reticular nucleus (Thalamic Reticular Nucleus (TRN)) lies like a thin shell on the outside of the dorsal thalamus. The nucleus lies between the thalamus and the
internal capsule and encloses a large part of the outside of the thalamus.

Unlike the other thalamic nuclei, the reticular nucleus
is not located *inside* the dorsal thalamus, but directly surrounding it.

 

Receives information from both thalamo-cortical and cortico-thalamic connections.

  • The cerebral cortex
  • Other thalamic nuclei

 

This information concerns, among other things:

  • Sense
  • Movement
  • Seeing
  • Hearing
  • Attention

 

Sends information to

  • Other thalamic nuclei

The reticular nucleus does not send information directly to the cerebral cortex.
It helps other thalamic nuclei determine which information is forwarded and which is not.

 

What does this core group do?

It is the "gating network" within the thalamocortical circuits.
The reticular nucleus assists with:

 

  • Selecting important information
  • Suppressing less important stimuli
  • Focusing attention
  • Regulating the sleep-wake cycle
  • Coordinating the exchange of information between the thalamus and the cerebral cortex

The reticular nucleus acts as a control center. It helps the brain to focus on important information and temporarily suppress less important stimuli.

 

Possible consequences of damage
Isolated injuries of the TRN are rare.

Common consequences

  • Difficulty maintaining attention
  • Easily distracted
  • Problems filtering stimuli
  • Hypersensitivity to sounds or other stimuli
  • Disturbed sleep

Occasional consequences

  • Difficulty concentrating in a busy environment
  • Slower information processing
  • Changes in the sleep-wake cycle.

 

What do you notice in daily life?

Someone with damage to this core group might notice, for example, that:

 

  • You are more easily distracted by sounds or movements around you
  • It is difficult to follow a conversation in a busy room
    You have more trouble keeping your attention on a single task
  • You become overstimulated more quickly
  • You sleep less well or have trouble falling asleep.

 

Important to know!

The reticular nucleus does not send information directly to the cerebral cortex.

The reticular nucleus itself does not process sensation, movement, sight, or hearing.

It primarily helps to determine which information is important at that moment and needs to be forwarded to the cerebral cortex.

As a result, this core group plays an important role in attention, concentration, and sleep.

 

In-depth for healthcare professionals

Main afferent connections

  • Collaterals of thalamo-cortical projections
  • Collaterals of cortico-thalamic projections
  • Limited modulating input from cholinergic and monoaminergic systems

Main efferent connections

  • GABAergic projections to virtually all specific and associative thalamic nuclei

 

Important: the TRN does not project directly to the cerebral cortex.

 

Clinical relevance

The reticular nucleus consists almost entirely of GABAergic neurons and forms the most important inhibitory network of the thalamus.

It regulates the synchronization of thalamocortical activity and plays a role in:

  • selective attention
  • sensory filtering
  • sleep spindles during non-REM sleep
  • regulation of thalamocortical rhythms

TRN disorders are associated with, among others:

  • absence epilepsy
  • attention deficit disorders
  • schizophrenia
  • sleep disorders

For many of these conditions, the TRN is likely
one of several involved networks. The precise contribution is still being investigated.

 

Anatomical references

Primary source

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice (most recent edition)

Additional anatomical sources

  • Mai JK & Paxinos G. Atlas of the Human Brain
  • Blumenfeld H. Neuroanatomy Through Clinical Cases

Supporting literature

  • Recent neuroanatomical and neurophysiological literature on the nucleus reticularis thalami, GABAergic inhibition, thalamocortical networks, and attention and sleep regulation.

Anatomical note

The metathalamus and the epithalamus do not belong to the dorsal thalamus. They are included in this list nonetheless, because according to the anatomical atlases of Gray's Anatomy, Mai & Paxinos, and current clinical neurological knowledge of Blumenfeld, they are described together with the thalamus as parts of the diencephalon (interbrain).

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice
    (most recent edition)
  • Mai JK & Paxinos G. Atlas of the Human Brain
  • Blumenfeld H. Neuroanatomy Through Clinical Cases

13. Metathalamus (LGN and MGN) as anatomical part of the diencephalon

Where is the metathalamus located?

The metathalamus is located on the posterior-inferior side of the thalamus, directly beneath the pulvinar.

The metathalamus consists of two separate structures:

• Lateral knee-like body (LGN (Lateral Geniculate Nucleus))
• Medial knee-like body (MGN (MedialGeniculate Nucleus))

See the following drop-down menu.

Although the metathalamus is often described together with the thalamus, anatomically it does not belong to the dorsal thalamus. It forms a separate part of the diencephalon (interbrain).

13A. Lateral knee-shaped body (LGN)

Where is this nucleus located?

The lateral knee-shaped body (LGN) is located on the outside of the metathalamus, directly beneath the pulvinar. The LGN is the main relay station for vision.

 

Receives information from

  • The retina of both eyes

The information travels via the optic nerve and the optic pathways to the LGN, via the optic tract after partial crossing in the optic chiasm.

 

Sends information to

  • The primary visual cortex in the occipital cortex

Here, the information is further processed into what we consciously see.

 

What does this nucleus do?

The LGN helps with:

  • Transmitting visual information
  • Recognizing contrasts
  • Processing color
  • Processing motion
  • Focusing visual attention

The LGN is more than just a relay station. It also helps to select important visual information before it reaches the cerebral cortex.

 

Possible consequences of damage

  • Visual field loss on the opposite side
  • Difficulty processing visual information
  • Problems recognizing movement
  • Difficulty maintaining an overview while looking

 

What do you notice about this in daily life?

For example, you might notice that:

  • You do not see part of your surroundings
  • You miss people or objects on one side
  • Reading becomes more difficult
  • Busy images are difficult to take in

 

Important to know
The LGN does not enable seeing, but it ensures that visual information is properly prepared before it reaches the cerebral cortex.

13B. Medial knee-shaped body (MGN)

Where is this nucleus located?

The medial knee-shaped body (MGN) is located on the inside of the metathalamus, next to the LGN.

The MGN is the main relay station for hearing.

 

Receives information from

  • The auditory pathways from the brainstem
  • Especially from the inferior colliculus

This information concerns:

  • Pitch
  • Intensity
  • Direction of sound
  • Sound patterns

Sends information to

  • The primary auditory cortex in the temporal lobe

Here, sounds are consciously perceived and recognized.

 

What does this nucleus do?

The MGN helps with:

  • Transmitting sound information
  • Recognizing different sounds
  • Distinguishing speech from other sounds
  • Determining where sound comes from
  • Focusing attention on important sounds

 

Possible consequences of damage

  • Difficulty processing sounds
  • Difficulty understanding speech in a noisy environment
  • Problems recognizing sound sources
  • Impaired processing of complex sounds

A single lesion in the MGN usually does not cause complete deafness, because the auditory pathways are represented on both sides of the brain.

 

What do you notice about this in daily life?

For example, you might notice that:

  • You find it harder to follow conversations when there is a lot of background noise.
  • You have trouble determining where a sound is coming from.
  • Music sounds different or is harder to recognize.
  • It takes more effort to understand spoken language.

 

Important to know
The MGN ensures that sound information is properly prepared before it reaches the auditory cortex.
As a result, this nucleus helps in recognizing and understanding sounds.

 

In-depth for healthcare professionals
Lateral knee-shaped body (LGN)


Main afferent connections

  • Retina via the optic tract
  • Cortical feedback from the visual cortex
  • Reticular thalamic nucleus

 

Major efferent connections

  • Optical radiation
  • Primary visual cortex (V1)

 

Medium knee-shaped body (MGN)

Main afferent connections

  • Inferior colliculus via the brachium colliculi inferioris
  • Auditory brainstem nuclei
  • Reticular thalamic nucleus

Main efferent connections

  • Auditory radiation
  • Primary auditory cortex (Heschl)

 

Clinical relevance
The LGN forms the main thalamic relay of the visual system and consists of six stratified neuronal layers with separate processing of magnocellular, parvocellular, and koniocellular information.

The MGN forms the main thalamic relay of the auditory system and plays a role in temporal processing, auditory attention, and speech processing. Due to the bilateral organization of the auditory pathways, a unilateral MGN lesion usually does not lead to complete hearing loss.

 

Anatomical references

Primary source

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice (most recent edition)

 

Additional anatomical sources

  • Mai JK & Paxinos G. Atlas of the Human Brain
  • Blumenfeld H. Neuroanatomy Through Clinical Cases

 

Supporting literature

  • Recent neuroanatomical literature on the visual and auditory thalamus, corticothalamic feedback, and sensory information processing.

14. Epithalamus

Where is the epithalamus located?

The epithalamus is located above and behind the dorsal thalamus, against the roof of the third ventricle.

It forms a small but important part of the diencephalon.

What parts make up the epithalamus?

The epithalamus consists of four important parts. We discuss these in the following drop-down menus:

• Habenular nuclei (nuclei habenulares)
• Stria medullaris thalami
• Commissura habenularum
• Epiphysis (pineal gland) (follow link)

PLEASE NOTE! The epithalamus is not an independent functional center. These parts work closely together, but each has its own function and specialized task.

What does the epithalamus do?

The various parts of the epithalamus work together and assist in, among other things:

• processing emotions and motivation
• assessing reward and disappointment
• adjusting behavior based on previous experiences
• exchanging information between parts of the limbic system
• regulating the sleep-wake cycle via the pineal gland and the hormone melatonin
In addition, the epithalamus forms a connection between the limbic system, the brainstem, and other parts of the diencephalon.

 

Possible consequences of damage

The consequences depend on which part of the epithalamus is damaged.

• Damage to the habenular nuclei causes different symptoms than damage to the pineal gland.

• Damage to the stria medullaris thalami is different from damage to the commissura habenularum.

 

What do you notice about this in daily life?

The symptoms vary from person to person and depend on which part of the epithalamus is affected. When one part of the epithalamus functions less well (which is rare), you may notice, for example, that:

• You are less motivated to undertake activities.

• It is more difficult to cope with disappointments.

• You learn less effectively from past experiences.

• Your emotions change more quickly or are more difficult to control.

• Your day-night rhythm becomes disrupted when the pineal gland or its connections are also affected.

• You have difficulty adapting to changing situations.

• You are more sensitive to stress.

• You sometimes have difficulty concentrating.

 

Possible consequences of damage

The consequences depend on which part of the epithalamus is damaged.

• Damage to the habenular nuclei causes different symptoms than damage to the pineal gland.

• Damage to the stria medullaris thalami is different from damage to the commissura habenularum.

 

Important to know
The epithalamus is not part of the dorsal thalamus.

Nevertheless, it is often described together with the thalamus, because both structures are part of the diencephalon and are closely connected.

 

In-depth information for healthcare professionals
The epithalamus consists of multiple anatomical structures with different functions. The habenular nuclei form the most important neuronal component and are involved in limbic-mesencephalic circuits.

The stria medullaris thalami is the main afferent pathway to the habenula, while the commissura habenularum connects the two habenular nuclei.

The pineal gland is a neuroendocrine gland that produces melatonin and plays a role in regulating the circadian rhythm.

 

Anatomical references
Primary source
• Gray's Anatomy: The Anatomical Basis of Clinical Practice (most recent edition)

Additional anatomical sources
• Mai JK & Paxinos G. Atlas of the Human Brain
• Blumenfeld H. Neuroanatomy Through Clinical Cases

Supporting literature
• Recent neuroanatomical literature on the epithalamus, the habenular nuclei, and limbic networks.

14A. Habenular nuclei

Where are these nuclei located?

The habenular nuclei are located at the posterior-upper side of the thalamus, as part of the epithalamus. They lie just in front of the pineal gland and next to the third ventricle.

 

There are two habenular nuclei:

  • the medial habenular nucleus
  • the lateral habenular nucleus

Together, they form an important communication center between the limbic system, the brainstem, and other parts of the diencephalon.

 

Receive information from

The habenular nuclei receive information from various brain regions, including:

  • the limbic system
  • the hypothalamus
  • the basal forebrain
  • the prefrontal cortex (indirectly)
  • other parts of the diencephalon

 

This information concerns, among other things:

• emotions
• motivation
• reward
• stress
• behavior

 

A large part of this information reaches the habenular nuclei via the stria medullaris thalami.

 

Send information to
The habenular nuclei send information primarily via the retroflex fasciculus (hebenulo-interpeduncular tract) to:

• the brainstem
• the interpeduncular nucleus
• areas involved in the production and regulation of:

  1. dopamine
  2. serotonin
  3. noradrenaline

As a result, the habenular nuclei can exert influence on mood, motivation, and behavior.

 

What do these nuclei do?

The habenular nuclei assist with:

• processing disappointments
• adjusting behavior when things do not go well
• weighing rewards against disadvantages
• motivation
• processing stressful events
• influencing mood
• learning from experiences

 

 

A large part of this information reaches the habenular nuclei via the stria medullaris thalami.

The habenular nuclei help the brain determine whether an experience is positive or negative. Based on this, behavior can be adjusted.

 

Possible consequences of damage
Because damage to only the habenular nuclei is rare, symptoms can vary from person to person.

 

Possible consequences include:

• difficulty with motivation
• changes in mood
• difficulty learning from experiences
• changes in responding to reward or disappointment
• changes in emotional processing

In the case of more extensive injury, problems with attention or stress regulation may also arise.

There is limited data on single (isolated) habenular lesions in humans. Much knowledge comes from animal research and imaging studies.

 

What do you notice about this in daily life?

Someone with damage to these nuclei may notice, for example, that:

• It is more difficult to stay motivated.

• You learn less effectively from previous experiences.

• Disappointments affect you more strongly or, conversely, less strongly.

• It is more difficult to make choices based on previous experiences.

• Your mood changes more rapidly.

 

Because these symptoms may also occur in other brain disorders, it is often unclear whether the habenular nuclei alone are responsible.

 

Important to know
The habenular nuclei do not regulate emotions in isolation.

They help various brain regions involved in motivation, learning, mood, and the processing of reward and disappointment to work together.

Research into the precise functions of the habenular nuclei is still very much in development.

 

In-depth information for healthcare professionals

Anatomical classification
The habenula consists of:

• Medial habenular nucleus
• Lateral habenular nucleus

 

The two nuclei differ in connections, neurotransmitters, and functions.

Major afferent connections:
• Stria medullaris thalami
• Septal nuclei
• Hypothalamus
• Basal forebrain
• Limbic structures

 

Main efferent connections
• Retroflex fasciculus (habenulo-interpeduncular tract)
• Interpeduncular nucleus
• Dopaminergic areas (including ventral tegmental area)
• Serotonergic raphe nuclei
• Noradrenergic locus coeruleus (indirect)

 

Clinical relevance
The lateral habenula plays an important role in encoding negative reward predictions, aversive learning, and motivation. The medial habenula is more strongly involved in the connection with the interpeduncular nucleus and cholinergic regulation.

Functional MRI and connectivity studies suggest a role for the habenula in:

• depressive disorders
• addiction issues
• chronic pain
• anxiety disorders

However, there is not yet a complete consensus regarding the exact contribution of the habenula to these conditions.

Most data are derived from experimental and translational research.

 

Anatomical references

Primary source
• Gray's Anatomy: The Anatomical Basis of Clinical Practice (most recent edition)

Additional anatomical sources
• Mai JK & Paxinos G. Atlas of the Human Brain
• Blumenfeld H. Neuroanatomy Through Clinical Cases

Supporting literature
• Recent neuroanatomical and neuroscientific literature on the habenular nuclei, the retroflex fasciculus, limbic circuits, and the modulation of dopamine, serotonin, and noradrenaline systems

14B. Stria medullaris thalami (nerve pathway to the habenular nuclei)

What is stria medullaris thalami?

The stria medullaris thalami is a nerve pathway that carries information to the habenular nuclei.

Location
The nerve pathway runs along the upper inner side of the thalamus to the habenula.

Function
The stria medullaris transports information from various parts of the limbic system to the habenular nuclei.
As a result, this nerve pathway plays a role in the processing of emotions, motivation, and reward.

14C. Commissura habenularum (nerve connection between the habenular nuclei)

What is it?

The commissura habenularum is a nerve connection between the left and right habenular nuclei.

Location
The connection is located in front of the pineal gland, above the roof of the third ventricle.

Function
The commissure ensures that both habenular nuclei can exchange information with each other.

14D. Epiphysis (pineal gland)

See our special page on the pineal gland or epiphysis.

Brief summary

 

Why is the thalamus important?

If a core group does not function properly, it may lead to:

  • problems with movement
  • altered or diminished sensations
  • problems seeing or ignoring things
  • difficulty with thinking, planning, and memory
  • pain complaints that cannot be easily explained (such as thalamic pain)

Important to know

The thalamus contains more than fifty small nuclei.

The classification into fifteen nuclear groups helps to better understand the functions associated with complaints and to understand the structure and function of the thalamus.

 

The thalamus houses more than 50 distinct nuclei, which are organized into functionally diverse core groups. Each group is linked to specific symptoms that can occur upon injury. In the text above, we discuss in detail the consequences of injury to the most important core groups.

 

 

These nuclei function as relay stations, where information from other parts of the nervous system is transmitted to specific areas in the cerebral cortex. Important to know: The thalamus works closely with other brain regions. The symptoms mentioned on this page may correspond to damage to a specific core group, but are often also determined by the cooperation between different brain networks. In the text below, we discuss the symptoms per core group.

 

Anterior nuclei (front)

Help store new memories and learn things

Mediodorsal nucleus (MD)

Important for planning, making decisions, and executing plans

Lateral nucleus (LD)

Processes visual information and helps to recognize and see things

Lateral posterior nucleus (LP)

Processes visual information and helps to recognize and see things

Pulvinar (posterior center)

Important for visual attention, seeing movement, and linking information between different brain regions

Ventral anterior nucleus (VA)

Helps control movements via connections with the basal ganglia

Ventral lateral nucleus (VL)

Important for initiating and controlling voluntary movements

Ventral posterolateral nucleus (VPL)

Brings sensation from the body (such as touch, pressure, and posture) to the cerebral cortex

Ventral posteromedial nucleus (VPM)

Brings sensation from the face and taste to the cerebral cortex

Intralaminar nuclei (IL)

Give an ‘alarm’ and keep you awake and alert

Midline nuclei

Play a role in emotions, pain perception, and the autonomic nervous system (unconscious bodily functions)

Habenular nuclei (habenula)

Help with reward, motivation, and the dopamine regulatory system

Epithalamic nuclei (epithalamus)

Support the biological clock and the day-night rhythm

Geniculate bodies

Important for hearing (medial) and vision (dorsal)

Reticular nucleus

Thin layer surrounding the thalamus that regulates the flow of information and influences the rhythm of brain activity

 

 

The possible consequences of thalamic damage and by core group

Important to know

The thalamus works closely with other brain regions. The symptoms mentioned may be consistent with damage to a specific core group, but are often partly determined by the cooperation between different brain networks. Not everyone with thalamic damage experiences the same symptoms. Which symptoms arise depends, among other things, on:

• which core group is affected
• the extent of the injury
• whether one or more core groups are damaged
• which other brain regions are involved.

Many symptoms can also have another cause.

This list shows which symptoms can occur with damage to the thalamus or adjacent structures.

 

We elaborate on the following consequences:

• Memory
• Executive functions
• Attention and concentration
• Movement
• Changes in sensation and pain
• Vision
• Visual attention
• Hearing
• Sensory overstimulation
• Emotions
• Behavior
• Fatigue
• Reduced mental resilience
• Sleep
• Consciousness
• Language
• Spatial orientation

 

For each consequence, we refer to the explanation regarding the core groups of the thalamus as shown in the green drop-down menu above and the numbers in the image below:

 

Below you can find a summary table with the main function and symptoms

Possible consequences

Memory

Possible complaints:

  • Difficulty remembering new information

→ 1. AN - anterior core group, 2. MD - Mediodorsal nucleus

  • Forgetfulness

→ 2. MD Mediodorsal nucleus

  • Difficulty placing events in the correct order

→ 1. AN - anterior core group

  • Difficulty storing experiences properly 

→ 1. AN anterior core group

  • Mild memory problems

→ 11. Midline nuclei

 

Attention and concentration

Possible complaints:

  • Easily distracted

→ 2. MD - Mediodorsal nucleus

  • Difficulty maintaining attention

→ 2. MD - Mediodorsal nucleus

→ 5. Pulvinar

  • Difficulty multitasking

→ 5. Pulvinar

  • Slower information processing

→ 10 Intralaminar nuclei

 

Movement

Possible complaints:

  • Slower movement

→ 6.VA - ventral anterior nucleus

→ 7.VL - ventral lateral nucleus

  • Less fluid movements

→ 7.VL - ventral lateral nucleus

  • Coordination problems

→ 7.VL - ventral lateral nucleus

  • Difficulty initiating a movement

→ 6.VA - ventral anterior nucleus

  • Less precise movements

→ 7.VL - ventral lateral nucleus

 

Changes in sensation and pain

  • Numbness or tingling on one side of the body

→ 8.VPL - Ventral posterolateral nucleus

→ 9.VPM - Ventral posteromedial nucleus

  • Reduced sense of touch

→ 8.VPL - Ventral posterolateral nucleus

→ 9.VPM - Ventral posteromedial nucleus

  • Impaired sense of temperature

→ 8.VPL - Ventral posterolateral nucleus

→ 9.VPM - Ventral posteromedial nucleus

  • Impaired sense of pain

→ 8.VPL - Ventral posterolateral nucleus

→ 9.VPM - Ventral posteromedial nucleus

  • Burning or severe pain without a clear cause

→ 8.VPL - Ventral posterolateral nucleus

→ 9.VPM - Ventral posteromedial nucleus

 

Déjerine-Roussy syndrome / Thalamic pain syndrome

Thalamic pain occurs in the thalamus following a stroke (CVA).

The pain is then felt on the opposite side of the body from where the stroke occurred, i.e., in one half of the body.

The pain can be localized or felt over a larger area in the legs, arms, or face.

It involves burning, stabbing, pricking, and tingling sensations. Changes in the weather or certain movements or activities may worsen it.

Characteristics:

  • burning pain
  • stabbing or shooting pain
  • prickling or tingling sensations
  • pain in the arm, leg, and/or face on the opposite side of the body
  • pain upon light touch (allodynia)
  • excessive pain response (hyperalgesia)
  • aggravation by cold, heat, weather changes, movement, or stress

Read more on our page on pain.

 

Vision

Possible complaints:

  • Difficulty processing visual information 

→ 4. LP – Posterior lateral nucleus

→ 5. Pulvinar

  • Difficulty surveying a busy environment 

→ 5. Pulvinar

  • Difficulty recognizing important visual information among many other stimuli 

→ 5. Pulvinar

  • Visual field defect on the opposite side of the visual field 

→ 13a. LGN – Metathalamus (Lateral knee-shaped body)

 

Important to know

The thalamus does not enable us to see.

That primarily happens in the cerebral cortex at the back of the brain. However, the thalamus does help transmit and select visual information.

 

Visual attention

Possible complaints:

  • Difficulty focusing attention on an object or person

→ 5. Pulvinar

→ 5. Pulvinar

  • Becoming distracted more easily by movement in the environment

→ 5. Pulvinar
→ 4. LP – Posterior lateral nucleus

 

Important to know
Visual attention is different from being able to see well. The eyes may function normally, yet it is still difficult to focus attention on the correct visual information. This is not about sensory overload.

 

Hearing

Possible complaints:

  • Difficulty processing sound

→ 13b. MGN – Medial knee-shaped body (metathalamus)

  • Difficulty recognizing differences between sounds

→ 13b. MGN – Medial knee-shaped body (metathalamus)

  • Difficulty understanding speech clearly in a noisy environment

→ 13b. MGN – Medial knee-shaped body (metathalamus)
→ 12. Reticular nucleus
→ 5. Pulvinar

 

Important to know
Hearing itself may be normal, while the processing of sounds in the brain is still difficult.

 

Sensory Overstimulation

Important to know
Sensory overstimulation concerns the burden of sensory information ánd the reduced capacity to handle sensory stimuli as a result of brain injury. Consequently, ordinary stimuli, which previously posed no problem, may be perceived as too much or too intense.

The thalamus plays an important role in this, but works closely with other brain regions. Sensory overstimulation is usually not caused by a single brain region alone. On this page, we discuss ónly the role of the thalamus, the metathalamus, and the epithalamus.

! Other brain regions that may also play a role are not discussed in further detail on this page!

 

Possible effects:

  • Difficulty understanding speech clearly in a noisy environment.

→ 13b. MGN – Medial knee-shaped body (metathalamus)
→ 12. Reticular nucleus
→ 5. Pulvinar

 

Emotions

Possible symptoms:

  • Less control over emotions

→ 2. MD - Mediodorsal nucleus
→ 14A. Habenular nuclei

  • Reacting emotionally quickly

→ 2. MD - Mediodorsal nucleus

  • Showing less emotion than before.

→ 2. MD – Mediodorsal nucleus

  • Mood swings.

→ 2. MD – Mediodorsal nucleus
→ 14A. Habenular nuclei

  • Reduced motivation

→ 14A. Habenular nuclei

  • Difficulty coping with disappointments

→ 14A. Habenular nuclei

  • Experiencing less pleasure in activities that used to be fun

→ 14A. Habenular nuclei

 

Important to know
Emotions arise from the cooperation of different brain regions. The mediodorsal nucleus and the habenular nuclei play an important role in this, but work closely with, among others, the prefrontal cortex and other parts of the limbic system.

 

Behaviour

Possible complaints:

  • Taking less initiative

→ 2. MD – Mediodorsal nucleus

 

Important to know
Changes in behavior do not mean that a person's personality changes completely. Often, it involves subtle changes in initiative, planning, social interaction, and adapting to new situations.

 

Sleep

Possible symptoms:

 

Important to know
The sleep-wake rhythm is regulated by multiple brain regions. The pineal gland produces the hormone melatonin and is influenced by signals from various brain networks. The epithalamus plays a supporting role in this.

 

Consciousness and alertness

Possible symptoms:

 

Important to know
The intralaminar nuclei are part of a larger network involved in alertness and consciousness. Severe disturbances of consciousness usually only occur when multiple components of this network are damaged.

Fatigue

Possible symptoms:

 

Important to know
Fatigue after a brain injury is more than just ordinary tiredness. Many people find that their brains become exhausted more quickly and require more recovery time.

The thalamus plays an important role in alertness, attention, and information processing. However, mental fatigue is usually not caused by a single brain area alone. Various brain networks work together in this process.

In this list, we discuss only the role of the thalamus. Other brain regions that also contribute to mental fatigue are not further elaborated on this page.

 

Reduced Mental Capacity

What does mental capacity mean?

Mental capacity is the amount of effort the brain can handle before symptoms appear. After a brain injury, this capacity can decrease. As a result, activities that previously required little effort may now demand a lot of energy.

Mental capacity consists of various components.
Two important forms are cognitive capacity and sensory capacity:

1) Cognitive capacity

Possible effects:

  • Difficulty thinking for extended periods
  • Shorter ability to concentrate
  • Difficulty processing a lot of information at once
  • Making mistakes more quickly when a task takes longer
  • Difficulty performing multiple tasks simultaneously
  • Needing more breaks while thinking or working

Potentially involved core groups

→ 2. MD – Mediodorsal nucleus
→ 10. Intralaminar nuclei
→ 5. Pulvinar

 

2) Sensory Load

Possible effects:

  • Sound is quickly perceived as overwhelming.
  • Background noise consumes a lot of energy.
  • Light quickly becomes bothersome.
  • Busy images require a lot of effort.
  • Touch can quickly feel too intense.
  • It is difficult to sustain multiple stimuli at once.

A long recovery time is needed after a busy environment.

Possibly involved nucleus groups

→ 12. Reticular nucleus
→ 5. Pulvinar
→ 10. Intralaminar nuclei
→ 13a. LGN – Lateral knee-shaped body (metathalamus)
→ 13b. MGN – Medial knee-shaped body (metathalamus)
→ 8. VPL – Ventral posterolateral nucleus
→ 9. VPM – Ventral posteromedial nucleus

 

Important to know
Cognitive and sensory capacity often influence each other. Someone who has to process many sensory stimuli may subsequently be less able to concentrate or think for a shorter period. Conversely, prolonged mental exertion can cause someone to become more sensitive to sound, light, or other sensory stimuli.
Although these forms of capacity are related, they are not the same functions. It is therefore important to distinguish them from one another.

 

Other problems mentioned following injury to the thalamus

 

Reduced taste

→ 9. VPM – Ventral posteromedial nucleus

This problem is rare.

 

Language problems

Possible symptoms:

  • Difficulty finding a word (word-finding problems)

→ 2. MD – Mediodorsal nucleus
→ 4. LP – Posterior lateral nucleus
→ 5. Pulvinar

(occurs especially with damage to the left thalamus)

 

  • Speaking more slowly because the correct word is not found immediately

→ 2. MD – Mediodorsal nucleus
→ 5. Pulvinar

(especially left)

 

  • Using a wrong word when you actually mean something else

→ 2. MD – Mediodorsal nucleus
→ 5. Pulvinar

(less common)

 

(less common)

 

(rare, usually with more extensive or left-sided damage)

 

(this is usually a problem with information processing and not with language comprehension itself)

Word finding (anomia) is by far the most common language disorder following thalamic injury.

Language production (sentence formation and fluent speech) is affected much less frequently and usually only in cases of more extensive or left-sided lesions.

Language comprehension is even rarer as a direct result of an isolated thalamic lesion.

 

What do you notice about this in daily life?

For example, you may notice that:

  • a word is "on the tip of your tongue" but you can't get it out
  • you need more time to say something
  • conversations take more energy
  • you sometimes use a different word than you mean
  • you have trouble following a conversation when multiple people are talking at the same time
  • you lose the thread of a conversation more quickly

 

Important to know

The thalamus is not a language center. The main language areas are located in the cerebral cortex, primarily in the left hemisphere.

However, the thalamus does play an important role in the networks that support language.

As a result, problems may arise with finding words, speaking fluently, processing language.

These symptoms are often subtle and vary from person to person.

 

In-depth study for healthcare professionals (drop-down menu)

Thalamic aphasia is a relatively rare condition primarily described following lesions of the left thalamus, particularly the mediodorsal nucleus (MD), the pulvinar, and to a lesser extent the posterior lateral nucleus (LP).

The clinical picture often consists of word-finding difficulties (anomia), reduced verbal fluency, and semantic paraphasias, while articulation and repetition usually remain relatively well preserved.

Language comprehension disorders are generally mild and occur primarily with more extensive lesions or disruption of the thalamocortical language networks.

Current literature supports the idea that the language disorder is not caused exclusively by damage to a single thalamic nucleus, but rather by disruption of the connections between the thalamus and the frontal, temporal, and parietal language areas.

Executive functions (goal-directed action)

Possible complaints

  • Difficulty making a plan

→ 2. MD – Mediodorsal nucleus

  • Difficulty performing a task step by step.

→ 2. MD – Mediodorsal nucleus

  • Difficulty maintaining an overview

→ 2. MD – Mediodorsal nucleus

  • Difficulty setting priorities

→ 2. MD – Mediodorsal nucleus

  • Difficulty starting an activity

→ 2. MD – Mediodorsal nucleus
→ 6. VA – Ventral anterior nucleus (when initiating movements is also affected)

  • Difficulty completing an activity

→ 2. MD – Mediodorsal nucleus

  • Difficulty changing approach when something doesn't work

→ 2. MD – Mediodorsal nucleus

  • Less ability to solve problems

→ 2. MD – Mediodorsal nucleus

  • Reacting impulsively more quickly

→ 2. MD – Mediodorsal nucleus

  • Less ability to assess the potential consequences of a choice

→ 2. MD – Mediodorsal nucleus

 

What do you notice about this in your daily life?

See our special page about this issue.

For example, you may notice that:

  • it is harder to plan a day
  • cooking according to a recipe takes more effort
  • grocery shopping without a list becomes more difficult
  • you get stuck more easily when something unexpected happens
  • you need help more often to keep track
  • you start a task but do not finish it
  • it is harder to make choices

 

Important to know

Executive functions help you act in a goal-oriented manner. They enable you to plan, organize, make choices, solve problems, and adapt your behavior when a situation changes.

The mediodorsal nucleus plays an important role in this process because it works closely with the prefrontal cortex. Damage to this nucleus can make it more difficult to apply knowledge and skills in daily life, even if intelligence itself remains intact.

See our dedicated page on this issue.

 

In-depth study for healthcare professionals (drop-down menu)

The mediodorsal nucleus (MD) has extensive reciprocal connections with the prefrontal cortex, including the dorsolateral, orbitofrontal, and medial prefrontal regions. Through these connections, the MD contributes to executive functions such as working memory, cognitive flexibility, planning, decision-making, behavioral regulation, and goal-directed action.

Leases of the MD may lead to dysexecutive syndrome, in which patients have difficulty planning, organizing, taking initiative, and adapting behavior to changing circumstances. These disorders arise from disruption of the thalamo-prefrontal networks and not solely from damage to the MD itself.

Spatial orientation

For example:

  • difficulty finding one's way
  • difficulty maintaining an overview
  • difficulty with spatial attention

especially:

 

Here you can download a document by Emmanuel Carrera M.D. and Julien Bogousslavsky, M.D., containing more information about thalamus injury and behavior.

Thalamus and behavior

PDF – 709,5 KB 10322 downloads

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Resources

Cairns, H., RC Oldfield, JB Pennybacker, D. Whitteridge: akinetische mutisme met epidermoïd cyste op de 3e ventrikel . In: Brain . Volume 64, 1941, p 273-290.

Carrera, E., & Bogousslavsky, J. (2006). The thalamus and behavior: Effects of anatomically distinct strokes. Neurology, 66(12), 1817–1823. https://doi.org/10.1212/01.wnl.0000219679.95223.4c

Eyskens, E., Feenstra, L., Meinders, A., Vandenbroucke, J. P., & Van Weel, C. (1997). Codex Medicus (10e ed.). Maarssen, Nederland: Elsevier Gezondheidszorg.

File:Thalamus3.PNG - Wikimedia Commons. (2007, 20 januari). Consulted from https://commons.wikimedia.org/wiki/File:Thalamus3.PNG

Haaxma, R. (2013). Neurologie van cognitie en gedrag in hoofdlijnen. Houten, Nederland: Springer Media.

Herrero, M., Barcia, C., & Navarro, J. (2002). Functional anatomy of thalamus and basal ganglia. Child's Nervous System, 18(8), 386–404. https://doi.org/10.1007/s00381-002-0604-1

Hersenletsel uitleg (page on the thalamus)

Kuks, J. B. M., Snoek, J. W., Oosterhuis, H. G. J. H., & Fock, J. M. (2003). Klinische neurologie (15e ed.). Houten, Nederland: Bohn Stafleu van Loghum.

Palm, J. (2012). Omgaan met Hersenletsel. Assen, Nederland: Van Gorcum.

Schuurman, P. R., Bosch, D. A., Bossuyt, P. M., Bonsel, G. J., Van Someren, E. J., De Bie, R. M., . . . Speelman, J. D. (2000). A Comparison of Continuous Thalamic Stimulation and Thalamotomy for Suppression of Severe Tremor. New England Journal of Medicine, 342(7), 461–468. https://doi.org/10.1056/nejm200002173420703

Sherman, S. M. (2005). Thalamic relays and cortical functioning. Progress in Brain Research, , 107–126.https://doi.org/10.1016/s0079-6123(05)49009-3

Thalamus, consulted from: http://medicaltextbooksrevealed.s3.amazonaws.com/files/11185-53.pdf

Thalamus, consulted from:  http://zlab.rutgers.edu/modules/teaching/docs/Thalamus/Thalamus%20Lecture.pdf

Thalamus, consulted from: http://www.neuroanatomy.wisc.edu/coursebook/thalamus.pdf

Wikipedia: https://nl.wikipedia.org/wiki/Bestand:Thalamus3.PNG

Zesiewicz, T. A., Elble, R., Louis, E. D., Hauser, R. A., Sullivan, K. L., Dewey, R. B., . . . Weiner, W. J. (2005). Practice Parameter: Therapies for essential tremor: Report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology, 64(12), 2008–2020. https://doi.org/10.1212/01.wnl.0000163769.28552.cd

Anatomic resources:

  • Gray's Anatomy: The Anatomical Basis of Clinical Practice (meest recente editie)
  • Mai & Paxinos – Atlas of the Human Brain
  • Blumenfeld – Neuroanatomy Through Clinical Cases

"Thalamus3" by Original uploader was Albert Kok at nl.wikipedia - Originally from nl.wikipedia; description page is/was here.. Licence Public domain via Wikimedia Commons.