Inferior parietal lobule

Structure

It is divided from rostral to caudal into two gyri:

• One, the supramarginal gyrus (BA 40), arches over the upturned end of the lateral fissure; it is continuous in front with the postcentral gyrus, and behind with the superior temporal gyrus.
• The second, the angular gyrus (BA 39), arches over the posterior end of the superior temporal sulcus, behind which it is continuous with the middle temporal gyrus. In males, the inferior parietal lobule is significantly more voluminous in the left hemisphere compared to the right. This extreme asymmetry is not present in females and this may contribute to cognitive differences between the sexes.

In macaque neuroanatomy, this region is often divided into caudal and rostral portions, cIPL and rIPL, respectively. The cIPL is further divided into areas Opt and PG whereas rIPL is divided into PFG and PF areas.

Function

Inferior parietal lobule has been involved in the perception of emotions in facial stimuli, | display-authors = 8 and interpretation of sensory information. The Inferior parietal lobule is concerned with language, mathematical operations, and body image, particularly the supramarginal gyrus and the angular gyrus.

Clinical significance

Destruction to the inferior parietal lobule of the dominant hemisphere results in Gerstmann's syndrome: left–right confusion, finger agnosia, dysgraphia and dyslexia, dyscalculia, contralateral hemianopia, or lower quadrantanopia. Destruction to the inferior parietal lobule of the non-dominant hemisphere results in topographic memory loss, anosognosia, construction apraxia, dressing apraxia, contralateral hemispatial neglect, contralateral hemianopia, or lower quadrantanopia.

In other animals

Functional imaging experiments suggest that the left anterior supramarginal gyrus (aSMG) of the human inferior parietal lobule exhibits an evolved specialization related to tool use. It is not currently known if this functional specialization is unique to humans as complementary experiments have only been performed with macaque monkeys and not apes. The habitual use of tools by chimpanzees makes the uniqueness of the human aSMG an open question as its function may have evolved prior to the split from our last common ancestor.

Additional images

|Image:Gehirn, lateral - Hauptgyri beschriftet.svg|Lateral view of a human brain, main gyri labeled. |File:Slide2HAN.JPG|Cerebrum. Lateral view. Deep dissection. |File:Slide3HAN.JPG|Cerebrum. Lateral view. Deep dissection. |File:Slide4HAN.JPG|Cerebrum. Lateral view. Deep dissection. |File:Inferior Parietal - DK ATLAS.png|Inferior parietal lobule, right hemisphere view. |File:Inferior parietal lobule coronal sections.gif|Inferior parietal lobule highlighted in green on coronal T1 MRI images |File:Inferior parietal lobule sagittal sections.gif|Inferior parietal lobule highlighted in green on sagittal T1 MRI images |File:Inferior parietal lobule transversal sections.gif|Inferior parietal lobule highlighted in green on transversal T1 MRI images

References

General

• {{cite journal | last1 = Peeters | first1 = R.

References

1. (2011). "The Brain from top to bottom".
2. (December 1999). "Sex differences in the inferior parietal lobule". Cerebral Cortex.
3. (1982-01-10). "Intrinsic connections and architectonics of posterior parietal cortex in the rhesus monkey". The Journal of Comparative Neurology.
4. (2003). "Journal of Neurology, Neurosurgery & Psychiatry".
5. {{harvnb. Peeters. Simone. Nelissen. Fabbri-Destro. 2009