Which term is associated with motor control that includes inhibition and decreased excitability of motor units, leading to a reduction in spasticity?

• A. Inhibition
• B. Facilitation
• C. Irradiation
• D. Post contraction inhibition

Answer: (B)

In motor control, reducing spasticity hinges on inhibitory mechanisms that dampen the excitability of motor units. After a muscle contraction, there is a temporary suppression of motoneuron activity called post contraction inhibition. This inhibition lowers the responsiveness of the spinal reflex circuits and reduces muscle tone, helping to lessen spasticity. Among the options, post contraction inhibition best fits the description because it explicitly involves inhibition with a decreased excitability of motor units following contraction, leading to a reduced spastic response. Inhibition is a broad term and doesn’t specify the contraction-related timing, facilitation would increase excitability rather than reduce it, and irradiation describes the spread of force to adjacent muscles rather than a neural inhibitory process.