Perirhinal cortex

Last updated
Perirhinal cortex
Details
Part of Cerebral cortex
Identifiers
Latin area perirhinalis
MeSH D000071039
NeuroNames 2425
NeuroLex ID nlx_anat_1005006
Anatomical terms of neuroanatomy

The perirhinal cortex is a cortical region in the medial temporal lobe that is made up of Brodmann areas 35 and 36. It receives highly processed sensory information from all sensory regions, and is generally accepted to be an important region for memory. It is bordered caudally by postrhinal cortex or parahippocampal cortex (homologous regions in rodents and primates, respectively) and ventrally and medially by entorhinal cortex.

Contents

Structure

The perirhinal cortex is composed of two regions: areas 36 and 35. Area 36 is sometimes divided into three subdivisions: 36d is the most rostral and dorsal, 36r ventral and caudal, and 36c the most caudal. Area 35 can be divided in the same manner, into 35d and 35v (for dorsal and ventral, respectively).

Area 36 is six-layered, dysgranular, meaning that its layer IV is relatively sparse. Area 35 is agranular cortex (lacking any cells in layer IV).

Function

The perirhinal cortex is involved in both visual perception and memory; [1] it facilitates the recognition and identification of environmental stimuli. Lesions to the perirhinal cortex in both monkeys and rats lead to the impairment of visual recognition memory, disrupting stimulus-stimulus associations and object-recognition abilities. [2]

The perirhinal cortex is also involved in item memory, especially in coding familiarity or recency of items. [3] Rats with a damaged perirhinal cortex seemed unable to tell novel objects from familiar ones—they were still more interested in exploring when novel objects were present, but examined the novel and familiar objects equally, unlike undamaged rats. Thus, other brain regions are capable of noticing unfamiliarity, but the perirhinal cortex is needed to associate the feeling with a specific source. [2]

The perirhinal cortex also receives a large dopaminergic input and signals the rewards that are associated with visual stimuli [4]

Damage to the perirhinal cortex has been shown to cause impairment in discriminating among object concepts when there is a high degree of visual semantic overlap among choices, such as between a hairdryer and a gun. [5] A growing body of evidence suggests that the perirhinal cortex protects against interference from low-level visual features. [6] The perirhinal cortex's role in the formation and retrieval of stimulus-stimulus associations (and in virtue of its unique anatomical position in the medial temporal lobe) suggest that it is part of a larger semantic system that is crucial for endowing objects with meaning.

Other animals

Primates

The monkey perirhinal cortex receives a majority of its input from high-level visual areas, whereas, in the rat, its inputs are primarily olfactory and, to a lesser extent, auditory. Outputs to orbitofrontal cortex and medial prefrontal cortex regions (such as prelimbic and infralimbic) have been described. Perirhinal cortex also sends output to a number of subcortical structures, including the basal ganglia, the thalamus, the basal forebrain, and the amygdala.

It also has direct connections with hippocampus region CA1 and the subiculum. Perirhinal cortex projects to distal CA1 pyramidal cells, overlapping the projections from entorhinal cortex. The same CA1 cells send return projections back to perirhinal cortex. Inputs from subiculum terminate in both superficial and deep layers.

Visual areas TE and TEO send and receive a significant reciprocal connection with perirhinal cortex. Weaker, but still significant, projections come from other parahippocampal regions and from the superior temporal sulcus. Other inputs include anterior cingulate and insular regions, in addition to prefrontal projections.

Rodents

Auditory inputs from temporal cortical regions are the primary inputs to rat 36d, with visual inputs becoming more prominent closer to the postrhinal cortical border. Area 36d projects to 36v and then to 35, which forms the primary output region of perirhinal cortex. Inputs to area 35 more strongly reflect olfactory and gustatory inputs from piriform and insular cortices, in addition to inputs from entorhinal cortex and frontal regions.

Related Research Articles

<span class="mw-page-title-main">Entorhinal cortex</span> Area of the temporal lobe of the brain

The entorhinal cortex (EC) is an area of the brain's allocortex, located in the medial temporal lobe, whose functions include being a widespread network hub for memory, navigation, and the perception of time. The EC is the main interface between the hippocampus and neocortex. The EC-hippocampus system plays an important role in declarative (autobiographical/episodic/semantic) memories and in particular spatial memories including memory formation, memory consolidation, and memory optimization in sleep. The EC is also responsible for the pre-processing (familiarity) of the input signals in the reflex nictitating membrane response of classical trace conditioning; the association of impulses from the eye and the ear occurs in the entorhinal cortex.

<span class="mw-page-title-main">Hippocampus</span> Vertebrate brain region involved in memory consolidation

The hippocampus is a major component of the brain of humans and other vertebrates. Humans and other mammals have two hippocampi, one in each side of the brain. The hippocampus is part of the limbic system, and plays important roles in the consolidation of information from short-term memory to long-term memory, and in spatial memory that enables navigation. The hippocampus is located in the allocortex, with neural projections into the neocortex, in humans as well as other primates. The hippocampus, as the medial pallium, is a structure found in all vertebrates. In humans, it contains two main interlocking parts: the hippocampus proper, and the dentate gyrus.

<span class="mw-page-title-main">Cingulate cortex</span> Part of the brain within the cerebral cortex

The cingulate cortex is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus. The cingulate cortex is usually considered part of the limbic lobe.

<span class="mw-page-title-main">Temporal lobe</span> One of the four lobes of the mammalian brain

The temporal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The temporal lobe is located beneath the lateral fissure on both cerebral hemispheres of the mammalian brain.

The entorhinal cortex (EC) is a major part of the hippocampal formation of the brain, and is reciprocally connected with the hippocampus.

An apical dendrite is a dendrite that emerges from the apex of a pyramidal cell. Apical dendrites are one of two primary categories of dendrites, and they distinguish the pyramidal cells from spiny stellate cells in the cortices. Pyramidal cells are found in the prefrontal cortex, the hippocampus, the entorhinal cortex, the olfactory cortex, and other areas. Dendrite arbors formed by apical dendrites are the means by which synaptic inputs into a cell are integrated. The apical dendrites in these regions contribute significantly to memory, learning, and sensory associations by modulating the excitatory and inhibitory signals received by the pyramidal cells.

<span class="mw-page-title-main">Subiculum</span> Most inferior part of the hippocampal formation

The subiculum is the most inferior component of the hippocampal formation. It lies between the entorhinal cortex and the CA1 subfield of the hippocampus proper.

<span class="mw-page-title-main">Parahippocampal gyrus</span> Grey matter region surrounding the hippocampus

The parahippocampal gyrus is a grey matter cortical region of the brain that surrounds the hippocampus and is part of the limbic system. The 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.

<span class="mw-page-title-main">Lobes of the brain</span> Parts of the cerebrum

The lobes of the brain are the major identifiable zones of the human cerebral cortex, and they comprise the surface of each hemisphere of the cerebrum. The two hemispheres are roughly symmetrical in structure, and are connected by the corpus callosum. They traditionally have been divided into four lobes, but are today considered as having six lobes each. The lobes are large areas that are anatomically distinguishable, and are also functionally distinct to some degree. Each lobe of the brain has numerous ridges, or gyri, and furrows, the sulci that constitute further subzones of the cortex. The expression "lobes of the brain" usually refers only to those of the cerebrum, not to the distinct areas of the cerebellum.

Theta waves generate the theta rhythm, a neural oscillation in the brain that underlies various aspects of cognition and behavior, including learning, memory, and spatial navigation in many animals. It can be recorded using various electrophysiological methods, such as electroencephalogram (EEG), recorded either from inside the brain or from electrodes attached to the scalp.

<span class="mw-page-title-main">Brodmann areas 35 and 36</span>

Brodmann area 35, together with Brodmann area 36, comprise the perirhinal cortex. They are cytoarchitecturally defined temporal regions of the cerebral cortex.

<span class="mw-page-title-main">Perforant path</span>

In the brain, the perforant path or perforant pathway provides a connectional route from the entorhinal cortex to all fields of the hippocampal formation, including the dentate gyrus, all CA fields, and the subiculum.

The rhinal cortex is the cortex surrounding the rhinal fissure, including the entorhinal cortex and the perirhinal cortex. It is a cortical region in the medial temporal lobe that is made up of Brodmann areas 28, 34, 35 and 36.

<span class="mw-page-title-main">Paralimbic cortex</span> Area of three-layered cortex

The paralimbic cortex is an area of three-layered cortex that includes the following regions: the piriform cortex, entorhinal cortex, the parahippocampal cortex on the medial surface of the temporal lobe, and the cingulate cortex just above the corpus callosum.

The trisynaptic circuit or trisynaptic loop is a relay of synaptic transmission in the hippocampus. The circuit was initially described by the neuroanatomist Santiago Ramon y Cajal, in the early twentieth century, using the Golgi staining method. After the discovery of the trisynaptic circuit, a series of research has been conducted to determine the mechanisms driving this circuit. Today, research is focused on how this loop interacts with other parts of the brain, and how it influences human physiology and behaviour. For example, it has been shown that disruptions within the trisynaptic circuit lead to behavioural changes in rodent and feline models.

<span class="mw-page-title-main">Hippocampus anatomy</span> Component of brain anatomy

Hippocampus anatomy describes the physical aspects and properties of the hippocampus, a neural structure in the medial temporal lobe of the brain. It has a distinctive, curved shape that has been likened to the sea-horse monster of Greek mythology and the ram's horns of Amun in Egyptian mythology. This general layout holds across the full range of mammalian species, from hedgehog to human, although the details vary. For example, in the rat, the two hippocampi look similar to a pair of bananas, joined at the stems. In primate brains, including humans, the portion of the hippocampus near the base of the temporal lobe is much broader than the part at the top. Due to the three-dimensional curvature of this structure, two-dimensional sections such as shown are commonly seen. Neuroimaging pictures can show a number of different shapes, depending on the angle and location of the cut.

Recognition memory, a subcategory of explicit memory, is the ability to recognize previously encountered events, objects, or people. When the previously experienced event is reexperienced, this environmental content is matched to stored memory representations, eliciting matching signals. As first established by psychology experiments in the 1970s, recognition memory for pictures is quite remarkable: humans can remember thousands of images at high accuracy after seeing each only once and only for a few seconds.

Chantal Stern is a neuroscientist who uses techniques including functional magnetic resonance imaging (fMRI) to study the brain mechanisms of memory function. She is the Director of the Brain, Behavior and Cognition program and a professor of Psychological and Brain Sciences at Boston University.After completing a degree at McGill University, she performed her doctoral research at Oxford University with Richard Passingham.

In psychology, associative memory is defined as the ability to learn and remember the relationship between unrelated items. This would include, for example, remembering the name of someone or the aroma of a particular perfume. This type of memory deals specifically with the relationship between these different objects or concepts. A normal associative memory task involves testing participants on their recall of pairs of unrelated items, such as face-name pairs. Associative memory is a declarative memory structure and episodically based.

References

  1. ↑ Murray EA, Bussey TJ, Saksida LM (2007). "Visual perception and memory: a new view of medial temporal lobe function in primates and rodents". Annual Review of Neuroscience. 30: 99–122. doi:10.1146/annurev.neuro.29.051605.113046. PMID   17417938.
  2. 1 2 Kinnavane L, Amin E, Olarte-Sánchez CM, Aggleton JP (November 2016). "Detecting and discriminating novel objects: The impact of perirhinal cortex disconnection on hippocampal activity patterns". Hippocampus. 26 (11): 1393–1413. doi:10.1002/hipo.22615. ISSN   1098-1063. PMC   5082501 . PMID   27398938.
  3. ↑ Davachi L (2004). "The ensemble that plays together, stays together". Hippocampus. 14 (1): 1–3. doi:10.1002/hipo.20004. PMID   15058475.
  4. ↑ Liu, Zheng; Richmond, Barry J. (2000-03-01). "Response Differences in Monkey TE and Perirhinal Cortex: Stimulus Association Related to Reward Schedules". Journal of Neurophysiology. 83 (3): 1677–1692. doi:10.1152/jn.2000.83.3.1677. ISSN   0022-3077.
  5. ↑ Martin, Chris B.; Douglas, Danielle M.; Man, Louisa Lok Yee; Newsome, Rachel N.; Park, Haley; Aslam, Hira M.; Barense, Morgan (2019-07-31). "Resolving cross-domain semantic interference among object concepts requires medial temporal lobe cortex". doi:10.31234/osf.io/d68jt.{{cite journal}}: Cite journal requires |journal= (help)
  6. ↑ Graham, Kim S.; Barense, Morgan D.; Lee, Andy C.H. (March 2010). "Going beyond LTM in the MTL: A synthesis of neuropsychological and neuroimaging findings on the role of the medial temporal lobe in memory and perception". Neuropsychologia. 48 (4): 831–853. doi:10.1016/j.neuropsychologia.2010.01.001.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.