Introducing the brain: even our white matter is different (Introduction)

by David Turell , Thursday, June 17, 2021, 20:55 (1037 days ago) @ David Turell

A description of how our white matter is larger adn how it differs:

https://science.sciencemag.org/content/372/6548/1265?utm_campaign=toc_sci-mag_2021-06-1...

"...the cerebral cortex is only a few millimeters thick, so the relative neglect of the rest of the brain below the cortex has prompted the term “corticocentric myopia”. Other regions relevant to behavior include the deep gray matter of the basal ganglia and thalamus, the brainstem and cerebellum, and the white matter that interconnects all of these structures. On page 1304 of this issue, Zhao et al. present compelling evidence for the importance of white matter by demonstrating genetic influences on structural connectivity that invoke a host of provocative clinical implications.

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"White matter occupies about half of the adult human brain, and some 135,000 km of myelinated axons course through a wide array of tracts to link gray matter regions into distributed neural networks that serve cognitive and emotional functions. The human brain is particularly well interconnected because white matter has expanded more in evolution than gray matter, which has endowed the brain of Homo sapiens with extensive structural connectivity. The myelin sheath, white matter's characteristic feature, appeared late in vertebrate evolution and greatly increased axonal conduction velocity. This development enhanced the efficiency of distributed neural networks, expanding the transfer of information throughout the brain. Information transfer serves to complement the information processing of gray matter, where neuronal cell bodies, synapses, and a variety of neurotransmitters are located. The result is a brain with prodigious numbers of both neurons and myelinated axons, which have evolved to subserve the domains of attention, memory, emotion, language, perception, visuospatial processing, executive function, and social cognition.

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"The emerging recognition of white matter and its contribution to human behavior will advance medicine as well as neuroscience. Considering both environmental and genetic factors clarifies the structure and function of normal and abnormal tracts, and this knowledge promises in turn to improve the diagnosis and treatment of people in whom white matter dysfunction may be disturbing neurobehavioral capacity. Moreover, the understanding of AD and many disabling neuropsychiatric disorders may be transformed by a focus on microstructural pathology in myelinated tracts. Broadly, a more detailed understanding of the relationships between white matter and behavior will surely expand knowledge of the brain. A complete portrait of the structural basis of cognition and emotion cannot neglect the white matter because it interacts so intimately with its gray matter counterpart."

Comment: The main point is the enormous connectivity between the brain parts which allows to to have the thinking capacity we have. Had to be designed.