Disengagement of Motor Cortex during Long-Term Learning Tracks the Performance Level of Learned Movements
| Autor: | Jeffrey E. Dahlen, Eun Jung Hwang, Madan Mukundan, Takaki Komiyama |
|---|---|
| Rok vydání: | 2021 |
| Předmět: |
Male
Action Potentials Medical and Health Sciences Mice Forelimb Disengagement theory Motor skill Research Articles Neurons education.field_of_study Hand Strength Movement (music) General Neuroscience Rehabilitation Motor Cortex multiple movement learning medicine.anatomical_structure Motor Skills Neurological Female mouse reaching movement consistency Single-Cell Analysis Psychology Motor learning Motor cortex Memory Long-Term 1.1 Normal biological development and functioning Population education Long-Term Basic Behavioral and Social Science Memory Underpinning research Behavioral and Social Science medicine Biological neural network Animals Learning motor cortex inactivation Neurology & Neurosurgery Psychology and Cognitive Sciences Neurosciences Brain Disorders Physical Rehabilitation Nonlinear Dynamics mouse motor cortex Neuroscience motor learning Psychomotor Performance |
| Zdroj: | The Journal of neuroscience : the official journal of the Society for Neuroscience, vol 41, iss 33 J Neurosci |
| Popis: | Not all movements require the motor cortex for execution. Intriguingly, dependence on motor cortex of a given movement is not fixed, but instead can dynamically change over the course of long-term learning. For instance, rodent forelimb movements that initially require motor cortex can become independent of the motor cortex after an extended period of training. However, it remains unclear whether long-term neural changes rendering the motor cortex dispensable are a simple function of the training length. To address this issue, we trained mice (both male and female) to perform two distinct forelimb movements, forward versus downward reaches with a joystick, concomitantly over several weeks, and then compared the involvement of the motor cortex between the two movements. Most mice achieved different levels of motor performance between the two movements after long-term training. Of the two movements, the one that achieved higher trial-to-trial consistency (i.e., consistent-direction movement) was significantly less affected by inactivation of motor cortex than the other (i.e., variable-direction movement). Two-photon calcium imaging of motor cortical neurons revealed that the consistent-direction movement activates fewer neurons, producing weaker and less consistent population activity than the variable-direction movement. Together, the motor cortex was less engaged and less necessary for learned movements that achieved higher levels of consistency. Thus, the long-term reorganization of neural circuits that frees the motor cortex from the learned movement is not a mere function of training length. Rather, this reorganization tracks the level of motor performance that the animal achieves during training. SIGNIFICANCE STATEMENT Long-term training of a movement reshapes motor circuits, disengaging motor cortex potentially for automatized execution of the learned movement. Acquiring new motor skills often involves learning of multiple movements (e.g., forehand and backhand strokes when learning tennis), but different movements do not always improve at the same time nor reach the same level of proficiency. Here we showed that the involvement of motor cortex after long-term training differs between similar yet distinct movements that reached different levels of expertise. Motor cortex was less engaged and less necessary for the more proficient movement. Thus, disengagement of motor cortex is not a simple function of training time, but instead tracks the level of expertise of a learned movement. |
| Databáze: | OpenAIRE |
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