Introducing the brain: cerebellar contributions explored (Introduction)

by David Turell , Monday, February 24, 2020, 00:28 (1734 days ago) @ David Turell

Another paper:

https://www.sciencedirect.com/science/article/pii/S0896627313009963?dgcid=raven_sd_reco...

"Twenty-five years of discovery have converged to suggest that the majority of the human cerebellum is connected to cerebral association networks. The revelation that the cerebellum possesses prominent association zones has far-reaching implications for how we explore its function and also view mental disturbances that arise from network disruptions. The recognition of the cerebellum’s importance to cognition is also a remarkable story of scientific discovery. Initial insights arose from the unconventional thoughts of a unique interdisciplinary team (Henrietta Leiner, Alan Leiner, and Robert Dow) and an observation made serendipitously during an early neuroimaging study of human cognition. Modern anatomical techniques were necessary to give traction to the discovery while neuroimaging techniques able to broadly survey the brain were best suited to reveal a parsimonious map that connects the motor zones of the cerebellum to the newly discovered association zones.

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"In considering the large size of the cerebellum in primates and humans, adaptive arguments have been put forward in the context of motor function leaning on the dexterous hands of primates and consequences of full bipedalism in humans or, in the context of cognitive function, the extraordinary mental abilities of apes and humans . These notions assume that there has been direct selection for an increase in the size of the cerebellum. An alternative is that the selection has been for an overall increase in brain size and the cerebellum comes along as a byproduct.

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"As brain size increases from a mouse to a monkey to a human, the cerebellum’s size scales at a rate second only to that of the cerebral cortex. Moreover, recent neuronal counting studies using modern techniques demonstrate that there is a relatively fixed ratio between the numbers of neurons in the cerebellum and cerebrum across species."

Comment: The point is as we grew our big brain cerebrum the size of the cerebellum followed along in like fashion. The main point is that we are now finding it contributes to certain cognitive functions, the extent not fully understood as yet. Obviously our brain had to accommodate our dexterous hands and our bipedalism in concert with the developments.