Motor orders leaving the cortex are by default inhibited by a signal produced by the Basal Ganglia. Only when the action is deemed worth pursuing, the basal ganglia stops inhibiting the motor signal, allowing it to reach the muscles. It is well known in psychology that motor actions are not…
(This is an excerpt from my book on Autism Spectrum Disorder, which you can purchase on http://amzn.to/2EPOcNZ)