Brain complexity: study results very incomplete (Introduction)

by David Turell , Friday, May 25, 2018, 19:48 (2162 days ago) @ David Turell

The critics point out that we really don't know much about the brain, because its overall activity is ignored when studying specific areas, and the whole brain is generally always active:

https://www.quantamagazine.org/neuroscience-critics-learn-how-brain-waves-link-to-speec...

"Poeppel and his co-authors carried on this tradition in a paper that appeared in Neuron last year. In it, they review ways in which overreliance on the “compelling” tools for manipulating and measuring the brain can lead scientists astray. Many types of experiments, for example, try to map specific patterns of neural activity to specific behaviors — by showing, say, that when a rat is choosing which way to run in a maze, neurons fire more often in a certain area of the brain. But those experiments could easily overlook what’s happening in the rest of the brain when the rat is making that choice, which might be just as relevant. Or they could miss that the neurons fire in the same way when the rat is stressed, so maybe it has nothing to do with making a choice. Worst of all, the experiment could ultimately be meaningless if the studied behavior doesn’t accurately reflect anything that happens naturally: A rat navigating a laboratory maze may be in a completely different mental state than one squirming through holes in the wild, so generalizing from the results is risky. Good experimental designs can go only so far to remedy these problems.

"The common rebuttal to his criticism is that the huge advances that neuroscience has made are largely because of the kinds of studies he faults. Poeppel acknowledges this but maintains that neuroscience would know more about complex cognitive and emotional phenomena (rather than neural and genomic minutiae) if research started more often with a systematic analysis of the goals behind relevant behaviors, rather than jumping to manipulations of the neurons involved in their production. If nothing else, that analysis could help to target the research in productive ways.

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"The auditory and speech motor activities did stay entrained, but only up to about 5 hertz. Once the audio changed faster than spoken language typically does, the motor cortex dropped out of sync. A computational model later confirmed that these results were consistent with the idea that the motor cortex has its own internal oscillator that naturally operates at around 4 to 5 hertz.

"These complex results vindicate the researchers’ behavior-linked approach in several ways, according to Poeppel and Assaneo. Their equipment monitors 160 channels in the brain at sampling rates down to 1 hertz; it produces so much neurophysiological data that if they had simply looked for correlations in it, they would have undoubtedly found spurious ones. Only by starting with information drawn from linguistics and language behavior — the observation that there is something special about signals in the 4-to-5-hertz range because they show up in all spoken languages — did the researchers know to narrow their search for meaningful data to that range. And the specific interactions of the auditory and motor cortices they found are so nuanced that the researchers would never have thought to look for those on their own."

Comment: The point is we need to look more at whole brain studies, not just specific areas.