What is the hippocampus? 

The hippocampus is located deep within the medial temporal lobe and has extensive connections, largely to cortical association areas including the sensory modalities. This widespread connectivity facilitates multimodal integration of sensory information, and likely contributes to the role of the hippocampus in generating memory and facilitating spatial navigation. The medial temporal lobes, particularly the hippocampus and the surrounding cortical regions, have been implicated as crucial facilitators in the formation of new declarative memories.

What is the evidence for hippocampal alterations?

High quality evidence suggests there are hippocampal grey matter reductions in people with chronic or first-episode schizophrenia compared to controls. Moderate to high quality evidence suggests first-degree relatives of people with schizophrenia also have reduced hippocampal volume. Moderate quality evidence suggests reductions in white matter integrity in the hippocampus, entorhinal gyrus, and parahippocampal gyrus in people with schizophrenia. Moderate to low quality evidence suggests increased hippocampal volume after treatment with second generation antipsychotics.

Moderate quality evidence suggests decreased activation in the hippocampus of people with schizophrenia during memory encoding and retrieval tasks. Moderate to low quality evidence suggests decreased activation in the parahippocampus during emotion processing tasks. There are also metabolic changes, with decreased hippocampal N-acetyl aspartate/creatine ratio in people with schizophrenia and in their first-degree relatives, and decreased hippocampal translocator protein in people with schizophrenia.

December 2019

Last updated at: 5:42 am, 18th December 2019
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NeuRA Libraries

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