lecture 17

lecture 17 - Upper motor control Axons from the upper motor...

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Upper motor control Axons from the upper motor neurons descend to inFuence the local circuits in the brainstem and spinal cord that organize movements. Upper motor pathways include several brainstem centers and a number of cortical areas in the frontal lobe. Brainstem centers are especially important for postural control. Motor and premotor cortex are responsible for the planning and precise control of complex sequences of voluntary movements.
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Upper motor control
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The medial brain stem pathways modulates the action of MNs in the ventromedial area Medial pathways, primarily used to control axial muscles and proximal limbs. Vestibular nuclei- receive info from inner ear-project to medial regions of spinal grey matter-control axial muscles and proximal limbs. Called the vestibulospinal tract.
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The medial brain stem pathways modulates the action of MNs in the ventromedial area Superior colliculus- projects to medial cell groups in the cervical cord, inFuences neck muscles (colliculospinal tract).
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The medial brain stem pathways modulates the action of MNs in the ventromedial area Reticular formation- receives input from higher motor cortex, complicated network of circuits located in the core of the brainstem-from midbrain to medulla. Important for posture. Called the reticulospinal tract.
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Pathways from the Motor Cortex to the Spinal Cord • Direct pathway: lateral corticospinal tract controls distal Fne motor movements • Axons cross the midline to project on the opposite side •If the direct pathway is cut, leaving the indirect pathways intact, it will not affect the ability to walk, run, but will prevent the distal parts of their limbs from being used.
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Pathways from the Motor Cortex to the Spinal Cord Indirect pathway: postural adjustments, especially for axial and proximal muscles. • Ventral corticospinal tract (direct pathway) • Corticoreticulospinal tract (indirect pathway).
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Modulation of movement by the Basal Ganglia Does not project directly to the spinal cord, instead inFuence movements by regulating the activity of upper motor neurons. Basal ganglia is a large set of nuclei that lie deep within the cerebral hemispheres. 3-main nuclei- caudate, putamen, and the globus pallidus.
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lecture 17 - Upper motor control Axons from the upper motor...

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