| Parahippocampal gyrus | |
|---|---|
| Human brainstem anterior view (Gyrus parahippocampalis is #7, near center right.) | |
| Parahippocampal gyrus labeled at bottom center. | |
| Latin | gyrus parahippocampalis |
| MeSH | Parahippocampal+Gyrus |
The parahippocampal gyrus (Syn. hippocampal gyrus)[1] is a grey matter cortical region of the brain that surrounds the hippocampus. This region plays an important role in memory encoding and retrieval.
It has been involved in some cases of hippocampal sclerosis.[2]
Asymmetry has been observed in schizophrenia.[3]
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The anterior part of the gyrus includes the perirhinal and entorhinal cortices.
The term parahippocampal cortex is used to refer to an area that encompasses both the posterior parahippocampal gyrus and the medial portion of the fusiform gyrus.
The parahippocampal place area (PPA) is a subregion of the parahippocampal cortex that plays an important role in the encoding and recognition of scenes (rather than faces or objects). fMRI studies indicate that this region of the brain becomes highly active when human subjects view topographical scene stimuli such as images of landscapes, cityscapes, or rooms (i.e. images of "places"). The region was first described by Russell Epstein (currently at the University of Pennsylvania) and Nancy Kanwisher (currently at MIT) in 1998,[4] see also other similar reports by Geoffrey Aguirre[5][6] and Alumit Ishai.[7]
Damage to the PPA (for example, due to stroke) often leads to a syndrome in which patients cannot visually recognize scenes even though they can recognize the individual objects in the scenes (such as people, furniture, etc.). The PPA is often considered the complement of the fusiform face area (FFA), a nearby cortical region that responds strongly whenever faces are viewed, and which is believed to be important for face recognition.
Additional research has increased the probability that the right parahippocampal gyrus in particular has functions beyond the contextualizing of visual background. Tests by a California-based group led by Katherine P. Rankin indicate that the lobe may play a crucial role in identifying social context as well, including paralinguistic elements of verbal communication.[8] For example, Rankin's research suggests that the right parahippocampal gyrus enables people to detect sarcasm.
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