The intraparietal sulcus (IPS) is located on the lateral surface of the
parietal lobe
The parietal lobe is one of the four major lobes of the cerebral cortex in the brain of mammals. The parietal lobe is positioned above the temporal lobe and behind the frontal lobe and central sulcus.
The parietal lobe integrates sensory informa ...
, and consists of an oblique and a horizontal portion. The IPS contains a series of functionally distinct subregions that have been intensively investigated using both single cell neurophysiology in primates and human functional neuroimaging.
Its principal functions are related to perceptual-motor coordination (e.g., directing eye movements and reaching) and visual attention, which allows for visually-guided pointing, grasping, and object manipulation that can produce a desired effect.
The IPS is also thought to play a role in other functions, including processing symbolic numerical information, visuospatial working memory and interpreting the
intent
Intentions are mental states in which the agent commits themselves to a course of action. Having the plan to visit the zoo tomorrow is an example of an intention. The action plan is the ''content'' of the intention while the commitment is the ''a ...
of others.
Function
Five regions of the intraparietal sulcus (IPS): anterior, lateral, ventral, caudal, and medial
*
LIP
The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...
& VIP: involved in visual attention and
saccadic eye movements
* VIP & MIP: visual control of reaching and pointing
* AIP: visual control of grasping and manipulating hand movements
* CIP: perception of depth from stereopsis
All of these areas have projections to the frontal lobe for executive control.
Activity in the intraparietal sulcus has also been associated with the learning of sequences of finger movements.
The
dorsal attention network includes the intraparietal sulcus of each hemisphere. The intraparietal sulcus is activated during voluntary orientation of attention.
Understanding numbers
Behavioral studies suggest that the IPS is associated with impairments of basic
numerical magnitude processing and that there is a pattern of structural and functional alternations in the IPS and in the
PFC in
dyscalculia
Dyscalculia () is a disability resulting in difficulty learning or comprehending arithmetic, such as difficulty in understanding numbers, learning how to manipulate numbers, performing mathematical calculations, and learning facts in mathematics. ...
. Children with developmental dyscalculia were found to have less gray matter in the left IPS.
Studies have shown that electrical activity in a particular group of nerve cells in the intraparietal sulcus spiked when, and only when, volunteers were performing calculations.
Outside experimental settings it was also found that when a patient mentioned a number—or even a quantitative reference, such as "some more", "many" or "bigger than the other one"—there was a spike of electrical activity in the same nerve-cell population of the intraparietal sulcus that was activated when the patient was doing calculations under experimental conditions.
Additional images
File:Gray725 intraparietal sulcus.png, Lateral surface of left cerebral hemisphere, viewed from above.
File:OccCaptsLateral.png, Left cerebral hemisphere, viewed from the back. (Intraparietal sulcus visible at top center)
File:Cerebral Hemisphere Demonstration - Sanjoy Sanyal - Neuroscience Lab Fall 2013 (Cropped from 28m57s to 29m50s) Intraparietal sulcus.webm, Human brain dissection video (53 sec). Demonstrating position of the intraparietal sulcus of the left cerebral hemisphere
The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres ...
.
References
External links
Illustrations at ssc.uwo.ca
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Sulci (neuroanatomy)
Articles containing video clips
Parietal lobe