Global optimization of cerebral cortex layout

Abstract

Functional areas of mammalian cerebral cortex seem positioned to minimize costs of their interconnections, down to a best-in-abillion optimality level. The optimization problem here, originating in microcircuit design, is: Given connections among components, what is the physical placement of the components on a surface that minimizes total length of connections? Because of unfeasibility of measuring long-range ''wire length'' in the cortex, a simpler adjacency cost was validated. To deal with incomplete information on brain networks, a size law was developed that predicts optimization patterns in subnetworks. Macaque and cat cortex rank better in this connection optimization than the wiring of comparably structured computer chips, but somewhat worse than the macroeconomic commodity-flow network among U.S. states. However, cortex wiring conforms to the size law better than the macroeconomic patterns, which may indicate cortex optimizing mechanisms involve more global processes.

Organization, development and function of complex brain networks

“…Thus, the minimization of this property might compete with global wiring length minimization. As a by-product, the short-distance preference for inter-area connections during spatial growth can lead to optimal component placement [75] without the need of a posteriori optimization. tasks and within different locations of the brain.…”

Natural world physical, brain operational, and mind phenomenal space–time

“…From a functional perspective, the spatiotemporal brain organization is necessitated by evolutionary pressure [78]: In the space-constrained skull, more computational efficiency is obtained by grouping together (space aspect) neurons with similar function and denser interactions on a particular time scale (temporal aspect), so that the overall number of interconnections is minimized [79][80][81]. Indeed in the course of the evolution of the brain, the number of neurons has considerably increased, whereas their connections have become less direct [79,82,83], thus minimizing costs of interconnection between neural sites, and yielding efficient communication between them [84][85][86][87].…”

“…Indeed, it would be rather inconvenient to fall asleep while crossing the road with hectic automobile traffic or try to go through a wall because it is not present subjectively at the phenomenal level 87 . Thus, the brain needs to contain (or construct) a 86 For similar argumentation and further discussion of this topic see Smythies [333].…”

“…Thus, the brain needs to contain (or construct) a 86 For similar argumentation and further discussion of this topic see Smythies [333]. 87 However, such situations can exist in some pathological conditions. For example, REM sleep behavior disorder (RBD) refers to a pathological condition in which the usual condition of muscular atonia is removed for the dreaming; MIND PHYSICAL WORLD BRAIN continuum of dynamic spatial-temporal patterns from a multisensory stream of neural events caused by the spatial-temporal patterns of the outside physical world.…”

Xenacoelomorpha: a case of independent nervous system centralization?

“…This condition constrains the geometry of the network, provided that energy consumption is efficient. The principle has been thoroughly analysed in the context of the arrangement of the Caenorhabditis elegans NS [111]; the rat olfactory cortex and the amygdala [113]; and the cat sensory and macaque visual cortex [114]. In fact, Cherniak [111] has shown that in C. elegans (or in H. sapiens), rstb.royalsocietypublishing.org Phil.…”