GuenonBrodmann area 10 is a subdivision of the frontal lobe of the guenon defined on the basis of cytoarchitecture. Brodmann-1909 did not regard it as cytoarchitecturally homologous to his human frontopolar area 10. Distinctive features (Brodmann-1905): compared to Brodmann area 9-1909, the multiform layer (VI) of area 10 shows an unusual organization of cells into trains oriented parallel to the cortical surface that are separated from one another by narrow cell-free fiber bundles; less marked differences are an overall thinner cortical thickness and a somewhat thicker molecular layer (I). Compared to Brodmann area 6-1909, area 10 has a subtle but clearly present internal granular layer (IV); layer 3b of the external pyramidal layer (III) is weakly developed and composed of medium sized pyramidal cells; and the internal pyramidal layer (V) is more developed. Human vs. nonhumanPrefrontal white matter, strongly associated with neotenous acceleration of neural maturation and particularly notable in BA10, shows the largest difference between human and nonhuman. Gray matter shows no significant difference, which suggests accelerated genetic expression and neotenous maturation of BA10 played a key role in human brain evolution. Morphological comparisonsCasts taken from the inside of skull of 'Flo', the female Homo floresiensis designated LB1, revealed significant enlargement of Brodmann's area 10, a brain region thought responsible for planning. This neuromorphological feature is unique to H. floresiensis. By relative size, this area is much more prominent in Flo than in chimpanzees, or even in modern humans. This finding is compatible with earlier primate research, which suggests robust gorillas have less frontal cortex white matter than their gracile cousins, the chimpanzees, just as relatively robust humans appear to have relatively less development of BA10 compared to H. floresiensis. Prefrontal white matter, strongly associated with neotenous acceleration of neural maturation and particularly notable in the BA10 of hominids, shows the largest difference between human and nonhuman mammals. Gray matter shows no significant difference, suggesting accelerated genetic expression and neotenous maturation of BA10 played a key role in human brain evolution. FunctionAlthough this region is quite extensive in humans, its exact function is still poorly understood. Koechlin & Hyafil have proposed that processing of 'cognitive branching' is the core function of the frontopolar cortex1. Cognitive branching enables a previously running task to be maintained in a pending state for subsequent retrieval and execution upon completion of the ongoing one. Many of our complex behaviors and mental activities require simultaneous engagement of multiple tasks, and they suggest the anterior prefrontal cortex may perform a domain-general function in these scheduling operations. However, other hypotheses have also been proffered, such as those by Burgess et al.2. See alsoReferences
External links
| | ||||||||||||||||||||||||||||||||