grey matter
Grey matter (or gray matter) is a major component of the central nervous system
The central nervous system (CNS) is the part of the nervous system
In biology
Biology is the natural science that studies life and living organisms, ...
cortical
Cortex or cortical may refer to:
Science Anatomy
* Cortex (anatomy), the outermost or superficial layer of an organ
* Cortex (hair), the middle layer of a strand of hair
* Adrenal cortex, the portion of the adrenal gland that produces cortisol and ...
region of the brain
A brain is an organ
Organ may refer to:
Biology
* Organ (anatomy)
An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exist in organ systems.
A given organ's tis ...
that surrounds the hippocampus
The hippocampus (via Latin from Greek#REDIRECT Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece
Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its popul ...
and is part of the limbic system
The limbic system, also known as the paleomammalian cortex, is a set of brain
A brain is an organ
Organ may refer to:
Biology
* Organ (anatomy)
An organ is a group of Tissue (biology), tissues with similar functions. Plant life and anim ...
. The region plays an important role in memory
Memory is the faculty of the brain
A brain is an organ
Organ may refer to:
Biology
* Organ (anatomy)
An organ is a group of Tissue (biology), tissues with similar functions. Plant life and animal life rely on many organs that co-exis ...
encoding
In communication
Communication (from Latin
Latin (, or , ) is a classical language
A classical language is a language
A language is a structured system of communication
Communication (from Latin ''communicare'', mean ...
and retrieval. It has been involved in some cases of hippocampal sclerosis. Asymmetry has been observed in schizophrenia
Schizophrenia is a mental disorder
A mental disorder, also called a mental illness or psychiatric disorder, is a behavioral or mental pattern that causes significant distress or impairment of personal functioning. Such features may b ...
.
Structure
The anterior part of the gyrus includes the perirhinal andentorhinal
The entorhinal cortex (EC) is an area of the brain's allocortex, located in the medial temporal lobe
The temporal lobe is one of the four major lobes of the cerebral cortex
The cerebral cortex, also known as the cerebral mantle, is the outer ...
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 fusiform gyrus, also known as the ''lateral occipitotemporal gyrus'','' ''is part of the temporal lobe
The temporal lobe is one of the four major lobes of the cerebral cortex
The cerebral cortex, also known as the cerebral mantle, is the o ...
.
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 andrecognition
Recognition may refer to:
*Award, something given in recognition of an achievement
In science and technology
In computer science
*Pattern recognition, a branch of machine learning which encompasses the meanings below
Biometric
*Recognition of h ...
of environmental scenes (rather than faces). fMRI
Functional magnetic resonance imaging or functional MRI (fMRI) measures brain activity by detecting changes associated with blood flow
Hemodynamics American and British English spelling differences#ae and oe, or haemodynamics are the Fluid dynami ...
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"). Furthermore, according to work by Pierre Mégevand et al. in 2014, stimulation of the region via intracranial electrodes yields intense topographical visual hallucinations of places and situations. The region was first described by Russell Epstein and Nancy Kanwisher
Nancy Gail Kanwisher FBA (born 1958) is the Ellen Swallow Richards Professor in the Department of Brain and Cognitive Sciences at the Massachusetts Institute of Technology
Massachusetts Institute of Technology (MIT) is a private land-gr ...
in 1998 at MIT, 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
The fusiform face area (FFA, meaning fusiform, spindle-shaped face area) is a part of the human visual system (while also activated in people blind from birth) that is specialized for face perception, facial recognition. It is located in the Infer ...
(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 suggested 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
hippocampus
The hippocampus (via Latin from Greek#REDIRECT Greek
Greek may refer to:
Greece
Anything of, from, or related to Greece
Greece ( el, Ελλάδα, , ), officially the Hellenic Republic, is a country located in Southeast Europe. Its popul ...
. Parahippocampal gyrus labelled at bottom.
File:Gehirn, basal - beschriftet lat.svg, Basal view of a human brain.
File:Parahippocampal gyrus.jpg, Basal view of a human brain. Parahippocampal gyrus shown in yellow.
File:Slide4MIR.JPG, Close up of parahippocampal gyrus.
Parahippocampal - DK ATLAS.png, Parahippocampal gyrus, shown in right cerebral hemisphere.
File:Parahippocampal gyrus coronal sections.gif, Parahippocampal gyrus highlighted in green on coronal T1 MRI images
File:Parahippocampal gyrus sagittal sections.gif, Parahippocampal gyrus highlighted in green on sagittal T1 MRI images
File:Parahippocampal gyrus transversal sections.gif, Parahippocampal gyrus highlighted in green on transversal T1 MRI images
References
External links
* * https://web.archive.org/web/20090505072544/http://www2.umdnj.edu/~neuro/studyaid/Practical2000/Q35.htmTemporal-lobe.com An interactive diagram of the rat parahippocampal-hippocampal region
{{Authority control Hippocampus (brain) Gyri