The subcortical motor centres

This chapter looks more closely at some of the subcortical motor centres that play a peripheral or an auxiliary role in the standard view: primarily the basal ganglia, the cerebellum, and the superior colliculus; also several brainstem centres. These all play a significant role in motor control and between them receive inputs from the majority of cortical areas. The colliculus serves as an example of a centre that in mammals is often dominated by the cortex. The cortical action may be direct or may involve a strong inhibitory pathway through the basal ganglia. The standard view assigns even quite simple actions to the motor cortex, although comparable actions can be controlled in our vertebrate ancestors by the midbrain tectum which corresponds to the mammalian superior and inferior colliculi. The interactive view has information about movements going to most parts of the cortex, and has all cortical areas contributing to motor control through phylogenetically old centres. For most cortical areas, we must still learn how their motor outputs influence our actions.