Motor System

The extrapyramidal system is the system involved in execution of movement.

The planning area for movement is a region of the cortex anterior to the primary motor cortex.

In the somatosensory cortex homunculus, the neurons that initate movement in the [blank_start]leg and foot[blank_end] lie in the medial cortex and the neurons that initiate movement in the [blank_start]face and arm[blank_end] lie in the lateral cortex.

Which area is not represented with an increase in size in the somatosensory homunculus?

A single anterior horn cell (AHC) and all the muscle fibers it innervates is called a "motor unit."

Label Corticospinal tract

Neurons in the primary motor cortex initiate movement of the contralateral side of the body.

A lesion of the lateral corticospinal tract at the upper cervical cord results in [blank_start]ipsilateral[blank_end] weakness of the whole left side of the body. A lesion involving the corticospinal tract in the right hemisphere of the brain results in [blank_start]left-sided[blank_end] weakness.

Upper motor neuron lesions result in:

Which of the following is NOT a typical result of a lower motor neuron lesion?

Extrapyramidal motor system is similar to the pyramidal system in that both send projections to anterior horn cells in the spinal cord.

Nuclei in the extrapyramidal motor system include:

What is an autosomal dominant genetic disease that causes a loss of neurons in the caudate and putamen involved in the indirect pathway?

Hemiballismus is caused by:

Loss of dopamine from substantia nigra can result in which of the following clinical features?