Hippocampus

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In the illustration above, the hippocampus is displayed by means of the blue colored structures.

 

Memory formation

The hippocampus is the structure of the brains that is most closely associated with memory formation. It is known as the repository for long-term memory and is involved in storing memories from long-term memory to permanent memory. The hippocampus also plays an important role in spatial orientation.

 

Context of memories and experiences

The hippocampus is closely involved in organizing that which you imagine with something in your mind. That is, the context of memories like they have been experienced. The hippocampus is very important to be able to connect experiences with other experiences in a kind of network of memories. Even for the sequence of your memories, the hippocampus is responsible.

Professor Howard Eichenbaum of Boston University: ‘The hippocampus helps us to represent items in the order in which they are experienced.’

 

Consequences of injury to the hippocampus

  • Inculcating / memory storage problems
  • Remembering / long term memory problems
  • Spatial disorientation
  • A specific form of agnosia

 

Classical symptoms of Alzheimer's disease: memory loss and disorientation, are associated with atrophy (decrease of tissue) of the hippocampus.

Atrophy of the hippocampus is also related to depression, bipolar disorder and schizophrenia.

 

An example from everyday life

In 1985 Clive Wearing, a British conductor, composer and musician, suffered a viral encephalitis, which caused major damage to the left and right hippocampus. Although his intellectual skills are intact, he has serious problems with his memory and he cannot create new declarative memories (consciously accessible factual knowledge).

He cannot enter into a conversation because he constantly forgets the previous sentence of the conversation. He cannot go outside because he does not know where he is, where he comes from and where he is going. Every day he wakes up as if awakened from a coma, unaware of where he is.

 

Resources

Professor Howard Eichenbaum Boston University: Hippocampus-and-Sequence-Learning

Bird and Burgess in 2008: review current literature on the role of the hippocampus in memory and spatial processing: http://www.nature.com/nrn/journal/v9/n3/full/nrn2335.html