Question

_________ assumes that Motor control is seen as a ""top-down"" meaning that the higher level exerts control over the levels under it. Lines of control do not cross and also the control cannot go from the bottom-up.

Answer 1

The 'top-down' approach refers to the higher cerebral levels controlling motor functions by sending commands through descending pathways, namely the corticobulbar and corticospinal tracts, from the primary motor cortex to the lower motor neurons.

Step-by-step explanation:

The concept being described assumes a "top-down" approach to motor control, which suggests that control begins at a higher cerebral level and influences the subsequent lower neural mechanisms.

This notion revolves around how the primary motor cortex sends motor commands through specific pathways to enact voluntary movements. The descending pathways, which include the corticobulbar and corticospinal tracts, are crucial for this process. Neurons from the primary motor cortex, particularly the Betz cells, synapse with lower motor neurons either in the brain stem or spinal cord, executing the control of muscles accordingly.

Top-down processing involves using prior knowledge and expectation to recognize and influence stimuli and movements. For example, this kind of processing is evident when we deliberately search for objects, like looking for yellow keys in places where they are likely to be found, based on past experience and logical deduction. The control is therefore deliberate and based on experience, distinguishing it from potential bottom-up processing that would instead rely on sensory inputs leading to motor responses.