Introducing the brain:neurons control muscle impulse control (Introduction)

by David Turell , Tuesday, April 19, 2022, 20:37 (736 days ago) @ David Turell

A new discovery:

https://medicalxpress.com/news/2022-04-exploring-role-motor-neurons.html

"...researchers from the Cognition and Actions Lab (UCLouvain Institute of Neuroscience, IoNS) made a surprising discovery. Dr. Gérard Derosière and Prof. Julie Duqué, in collaboration with Dr. David Thura (INSERM, Lyon) and Prof. Paul Cisek (University of Montreal), demonstrated that the activity of neurons projecting to the muscles involved in the execution of a chosen action was strongly amplified when subjects favored quick decisions.

"More important, they discovered that this amplification is present in other groups of neurons that project to muscles that are not at all involved in the execution of the chosen action.

"Another discovery was that the activity of a third type of neuron is rapidly reduced during the decision, which not only allows us to decide quickly but also to contract specific muscles quickly and thus move more quickly.

"'We've succeeded in demonstrating that motor system neurons not only control movement but also incite action," explains FNRS scientific collaborator Dr. Derosière. "While decision-making is commonly associated with the brain's prefrontal structures, located just above the eyes, our work shows the importance of the motor system in the speed of our choices and in impulsivity."

"Recent research on decision-making seemed to suggest that rapidly made choices were based on global changes in the activity of these neurons. However, this hypothesis remained speculative and it remained unclear how decision speed was regulated, because the tools used by scientists did not, until now, allow the activity of these neurons to be recorded accurately.

"The UCLouvain team had the idea of using an existing tool, transcranial magnetic stimulation, to establish more precise measurements. The subject is asked to perform a task that requires decision-making; at the same time, neurons in the motor cortex are stimulated and potentials in several muscles (up to nine!) are measured.

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"The result: the researchers were able to demonstrate, for the first time, an amplification of motor cortex activity in a context of impulsivity, but also an amplification of the potentials in the legs of a subject who moves his hands, even though his lower limbs perform no movement!

"What's the point of this research? Thanks to this study, we know that motor system neurons are directly involved in the regulation of decision speed in healthy subjects. But in addicts (alcoholics, for example), this regulation is disrupted: they decide impulsively and make bad choices. Studying the motor system's role in this context makes sense in the light of this discovery."

Comment: more evidence that our brain is designed to help us, but still allows us free will.