Intraparietal sulcus

Five regions of the intraparietal sulcus (IPS): anterior, lateral, ventral, caudal, and medial

• LIP & 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.{{Cite journal | last1 = Sakai | first1 = K. | last2 = Ramnani | first2 = N. | last3 = Passingham | first3 = R. E. | title = Learning of sequences of finger movements and timing: Frontal lobe and action-oriented representation | journal = Journal of Neurophysiology | volume = 88 | issue = 4 | pages = 2035–2046 | year = 2002 | pmid = 12364526| doi = 10.1152/jn.2002.88.4.2035 }}

The dorsal attention network includes the intraparietal sulcus of each hemisphere.{{cite journal | last1 = Fox | first1 = M.D. | last2 = Corbetta | first2 = M. | last3 = Snyder | first3 = A.Z. | last4 = Vincent | first4 = J.L. | last5 = Raichle | first5 = M.E. | year = 2006 | title = Spontaneous neuronal activity distinguishes human dorsal and ventral attention systems | journal = Proceedings of the National Academy of Sciences | volume = 103 | issue = 26| pages = 10046–10051 | doi=10.1073/pnas.0604187103| pmid = 16788060 | pmc = 1480402 | bibcode = 2006PNAS..10310046F | doi-access = free }} The intraparietal sulcus is activated during voluntary orientation of attention.{{cite journal | last1 = Corbetta | first1 = M. | last2 = Kincade | first2 = J. M. | last3 = Ollinger | first3 = J. M. | last4 = McAvoy | first4 = M. P. | last5 = Shulman | first5 = G. L. | year = 2000 | title = Voluntary orienting is dissociated from target detection in human posterior parietal cortex | journal = Nature Neuroscience | volume = 3 | issue = 3| pages = 292–297 | doi=10.1038/73009| pmid = 10700263 | s2cid = 52807698 }}

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.{{cite journal | doi = 10.1016/S1364-6613(02)02040-5 |author1=Ansari D. |author2=Karmiloff-Smith A. | year = 2002 | title = Atypical trajectories of number development: a neuroconstructivist perspective | journal = Trends in Cognitive Sciences | volume = 6 | issue = 12| pages = 511–516 | pmid=12475711|s2cid=1228615 }} Children with developmental dyscalculia were found to have less gray matter in the left IPS.{{cite journal |vauthors=Kucian K, etal | year = 2006 | title = Impaired neural networks for approximate calculation in dyscalculic children: a functional MRI study | journal = Behavioral and Brain Functions | volume = 2 | page = 31 | pmid = 16953876 | pmc = 1574332 | doi = 10.1186/1744-9081-2-31 | doi-access = free }}

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.{{Cite journal | last1 = Dastjerdi | first1 = M. | last2 = Ozker | first2 = M. | last3 = Foster | first3 = B. L. | last4 = Rangarajan | first4 = V. | last5 = Parvizi | first5 = J. | title = Numerical processing in the human parietal cortex during experimental and natural conditions | doi = 10.1038/ncomms3528 | journal = Nature Communications | volume = 4 | pages = 2528 | year = 2013 | pmid = 24129341| pmc = 3826627| bibcode = 2013NatCo...4.2528D }}

Numerical magnitude processing refers to the cognitive ability to understand and compare numbers. This assists in tasks that involve estimation, mathematical processes, and decision-making. The intraparietal sulci are made up of two parts, left and right. The right intraparietal sulcus is involved more in non-symbolic numerical tasks, which involve estimation and spatial reasoning. The left intraparietal sulcus focuses on symbolic numerical tasks, which involves understanding symbols and mathematical operations. Studies have demonstrated that the right intraparietal sulcus shows more activity during magnitude estimation and length comparison tasks. Researchers discovered that disrupted activity in the right intraparietal lobe using rTMS, (repetitive transcranial magnetic stimulation) resulted in participants having difficulties with performance in both the magnitude and length tasks. Studies have shown that children who show a larger change in brain activity in the left intraparietal sulcus tend to perform better at arithmetic tasks. This suggests that the left intraparietal sulcus plays an important role when it comes to numerical processing and mathematics.{{Cite journal |last=Dormal |first=Valérie |last2=Andres |first2=Michael |last3=Pesenti |first3=Mauro |date=2012-05-01 |title=Contribution of the right intraparietal sulcus to numerosity and length processing: An fMRI-guided TMS study |url=https://www.sciencedirect.com/science/article/abs/pii/S0010945211001638?casa_token=ejeBy0aeYPIAAAAA:SqJ57bM-G8gmFTRSUsmlvW63lUEwYx6rPav8qAyRkkli5moVKKEZbWNRkwgdZeB2Qt9UGjtswXCt |journal=Cortex |volume=48 |issue=5 |pages=623–629 |doi=10.1016/j.cortex.2011.05.019 |issn=0010-9452}}{{Cite journal |last=Bugden |first=Stephanie |last2=Price |first2=Gavin R. |last3=McLean |first3=D. Adam |last4=Ansari |first4=Daniel |date=2012-10-01 |title=The role of the left intraparietal sulcus in the relationship between symbolic number processing and children's arithmetic competence |url=https://www.sciencedirect.com/science/article/pii/S1878929312000412 |journal=Developmental Cognitive Neuroscience |volume=2 |issue=4 |pages=448–457 |doi=10.1016/j.dcn.2012.04.001 |issn=1878-9293|pmc=7005765 }}

Damage to the intraparietal sulcus (IPS) can make it difficult to represent and manipulate numerical quantities. Research completed by Ganor-Stern et al. investigated the involvement of the IPS in estimating the results of multi-digit multiplication problems.{{Cite journal |last=Ganor-Stern |first=Dana |last2=Gliksman |first2=Yarden |last3=Naparstek |first3=Sharon |last4=Ifergane |first4=Gal |last5=Henik |first5=Avishai |date=2020-07-01 |title=Damage to the Intraparietal Sulcus Impairs Magnitude Representations of Results of Complex Arithmetic Problems |url=https://www.sciencedirect.com/science/article/abs/pii/S0306452220303031 |journal=Neuroscience |volume=438 |pages=137–144 |doi=10.1016/j.neuroscience.2020.05.006 |issn=0306-4522}} In a computation estimation task, they compared a 24-year-old female (JD) with damage in the left IPS to an age-matched control group. During this estimation task, participants were presented with multi-digit multiplication problems accompanied by reference numbers. They were asked to estimate whether the exact answer to each problem was larger or smaller than the reference number. JD did not show the typical patterns of distance and size effects compared to control groups during this task. JD also had an atypical strategy in which she only used the approximated calculation strategy that involved rounding and calculating procedures. Most control participants used both a calculation strategy and the sense of magnitude strategy, which relies on an intuitive approximated magnitude representation of the results. The findings of this study suggest that damage to the IPS impaired JD’s representations of magnitude, which play an important role in everyday estimation tasks.

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.

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• [https://web.archive.org/web/20090405083407/http://psychology.uwo.ca/fmri4newbies/PrimeronCorticalSulci.html Illustrations at ssc.uwo.ca]

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Category:Sulci (neuroanatomy)

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Category:Parietal lobe