Final answer:
Secondary motor cortices, including the premotor cortex and supplemental motor area, are involved in motor planning and receive input from the prefrontal cortex. They work alongside the primary motor cortex, which controls voluntary muscle movements, and integrative areas that coordinate complex motor actions.
Step-by-step explanation:
To qualify as secondary motor cortices, certain areas of the brain must be involved in the planning and execution of movements that are initiated by the prefrontal cortex. These regions do not directly elicit movement when electrically stimulated, but rather, receive projections from the prefrontal areas. The premotor cortex and the supplemental motor area are key components of the secondary motor cortices.
The primary motor cortex is responsible for the voluntary control of skeletal muscles and is organized topographically, represented by a motor homunculus, highlighting the motor control of body regions. Adjacent to the primary motor cortex are specialized planning centers like the frontal eye fields and Broca's area which control eye movement and speech production, respectively.
Integrative areas, such as the posterior parietal cortex, are known for processing sensory or motor information in complex ways, such as coordinating visual and motor functions to perform tasks like reaching for an object. These are part of the brain's intricate network that supports cognitive abilities and conscious execution of movements.