Final answer:
The motor control theory suggests that the CNS, particularly the motor cortex, facilitates higher control over basic reflexes through increased corticalization. The right motor cortex controls the left side of the body and vice versa, through the corticobulbar and corticospinal tracts. Reflex actions are quick and involve local connections within the spinal cord.
Step-by-step explanation:
The theory in question suggests that motor control originates in the central nervous system (CNS) and is associated with the increased corticalization leading to higher control levels over basic reflexes. Motor cortex organization reflects the musculature arrangement of the body, with motor cortex neurons located near neurons controlling adjacent parts. This organization facilitates precise voluntary movements. The cortex sends motor outputs through descending pathways like the corticobulbar and corticospinal tracts. Betz cells in the primary motor cortex synapse with lower motor neurons, with the corticobulbar tract responsible for movements on the same side of the body and the corticospinal tract mostly contralateral, influencing movements on the opposite side of the body. This indicates that the right motor cortex controls muscles on the left side, and vice versa.
The primary motor cortex’s principle output is to stimulate spinal neurons that, in turn, activate skeletal muscle contraction. Reflex actions are managed by faster local synaptic connections within the spinal cord, which can rapidly respond to sensory stimuli without direct brain involvement, although information about the reflex action is conveyed to the brain.