10.3 The Brain Motor Centers and the Descending Pathways They Control

Basal Nuclei

Nuclei deep in cerebral hemispheres that code and relay information associated with control of body movements; specifically, caudate nucleus, globus pallidus, and putamen

Brainstem Pathways (Extrapyramidal System)

Descending motor pathways that originate in the brainstem; associated with involuntary movements

Corticobulbar Pathway

Descending pathway having its neuron cell bodies in cerebral cortex; its axons pass without synapsing to region of brainstem motor neurons, and end in the brainstem

Corticospinal Pathways

Descending pathways that originate in the cerebral cortex; associated with producing voluntary movement, and decussate at the junction of the medulla oblongata and the spinal cord

Motor Cortex (Primary Motor Cortex)

Strip of cerebral cortex along posterior border of frontal lobe; gives rise to many axons descending in corticospinal and multineuronal pathways

Parietal-Lobe Association Cortex

Region of cerebrum involved in integrating inputs from primary sensory cortices, as well as higher-order cognitive processing and motor control

Premotor Area

Region of the cerebral cortex found on the lateral sides of the brain in front of the primary motor cortex; involved in planning and enacting complex muscle movements

Pyramidal System

Descending nervous system pathways that originate in the cerebral cortex, cross over the midline in the medulla, and control fine movements of the distal extremities

Somatosensory Cortex

Strip of cerebral cortex in parietal lobe in which neurons transmitting somatic sensory information synapse

Somatotopic Map

A representation of the different regions of the body formed by neurons of the cerebral cortex

Substantia Nigra

A subcortical nucleus containing dark-staining neurons that release dopamine and are important for suppressing extraneous muscle activity

Supplementary Motor Cortex

Region of the cerebral cortex found on the medial side of brain hemispheres in front of the primary motor cortex; involved in planning and enacting complex muscle movements