Parahippocampal gyrus

Parahippocampal gyrus
File:Sobo 1909 630 - Parahippocampal gyrus.png Human brain seen from below. Parahippocampal gyrus shown in blue
Medial view of left cerebral hemisphere. Parahippocampal gyrus shown in orange.
Details
Latin	gyrus parahippocampalis
Identifiers
MeSH	A08.186.211.577.710
NeuroLex ID	Parahippocampal gyrus
Dorlands /Elsevier	g_13/14816442
TA
TH	{{#property:P1694}}
TE	{{#property:P1693}}
FMA	{{#property:P1402}}
Anatomical terminology [[[d:|edit on Wikidata]]]

The parahippocampal gyrus (Syn. hippocampal gyrus) is a grey matter cortical region of the brain that surrounds the hippocampus and is part of the limbic system. This region plays an important role in memory encoding and retrieval.

It has been involved in some cases of hippocampal sclerosis.

Asymmetry has been observed in schizophrenia.

Structure

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.

Function

Scene recognition

The parahippocampal place area (PPA) is a sub-region of the parahippocampal cortex that lies medially in the inferior temporo-occipital cortex. PPA plays an important role in the encoding and recognition of environmental scenes (rather than faces). 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, see also other similar reports by Geoffrey Aguirre and Alumit Ishai.

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 that is believed to be important for face recognition.

Social context

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. For example, Rankin's research suggests that the right parahippocampal gyrus enables people to detect sarcasm.

Additional images

• Parahippocampal gyrus animation.gif

  Animation. Parahippocampal gyrus shown red.

• Gray727 parahippocampal gyrus.png

  Medial surface of left cerebral hemisphere. Parahippocampal gyrus shown in orange.

• Human brain inferior-medial view description.JPG

  Human brain inferior-medial view. Parahippocampal gyrus labelled as #5

• Gehirn Frontalschnitt hippocampus.png

  Coronal section. Parahippocampal gyrus labelled at bottom center.

• 

  Coronal section of hippocampus. Parahippocampal gyrus labelled at bottom.

• 

  Basal view of a human brain.

• Parahippocampal gyrus.jpg

  Basal view of a human brain. Parahippocampal gyrus shown in yellow.

• Slide4MIR.JPG

  Close up of parahippocampal gyrus.

External links

• hier-146 at NeuroNames
• http://www2.umdnj.edu/~neuro/studyaid/Practical2000/Q35.htm
• Temporal-lobe.com An interactive diagram of the rat parahippocampal-hippocampal region