Final answer:
The indirect pathway of cortical motor signal transmission results in decreased excitation of the thalamus by the basal ganglia, leading to less stimulation of motor cortical areas and subsequently decreased motor activity.
Step-by-step explanation:
The indirect pathway of cortical motor signal transmission involves a series of neural circuits within the basal ganglia that ultimately modulate the activity of the thalamus, which is a pivotal structure involved in relaying motor signals to the cerebral cortex. When the indirect pathway is activated, it results in decreased excitation of the thalamus. This reduction of thalamic activity leads to less stimulation of the motor areas of the cerebral cortex. Consequently, there is a reduction in motor activity initiated by the cortex. This pathway contrasts with the direct pathway, which facilitates increased motor activity by providing more excitation to the thalamus. The end result of the activation of the indirect pathway is less motor activity, which manifests as slowed or reduced movements, such as those observed in conditions like Parkinson's disease.