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| | [http://www.emc.maricopa.edu/faculty/farabee/BIOBK/cerebrum_1.gif Picture of Primary Motor Cortex] | | [http://www.emc.maricopa.edu/faculty/farabee/BIOBK/cerebrum_1.gif Picture of Primary Motor Cortex] |
| | == Background == | | == Background == |
| - | � Primary motor cortex is also called M1
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| - | � One of the principle areas involved in motor function
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| - | � Located in the frontal lobe of the brain along the precentral gyrus
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| - | � The role is to generate neural impulses that control the execution of movement
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| - | � Signals from M1 cross the body�s midline to activate skeletal muscles on the opposite side of the body
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| - | � The right hemisphere controls the left side of the body
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| - | � The left hemisphere controls the right side of the body
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| | == Somatotopic Representation == | | == Somatotopic Representation == |
| - | � Every part of the body is represented in the primary motor cortex
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| - | � Body part representations are arranged somatotopically
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| - | � The foot is next to the leg, next to the trunk, next to the arm, which is next to the hand
| + | == Damage to Primary Motor Cortex == |
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| - | � The amount of brain matter devoted to a particular body part represents the amount of control that the primary motor cortex has over that body part
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| - | � A lot of cortical space is devoted to complex hand and finger movements; therefore, they have larger representations in M1
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| - | == Corticospinal Tract ==
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| - | � Neurons in M1, supplementary motor area, and premotor cortex give rise to fibers of the corticospinal tract
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| - | � The corticospinal tract is the only direct pathway from the cortex to the spine
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| - | � This tract is composed of over a million fibers
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| - | � The fibers descend through the brainstem and cross to the opposite side of the body
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| - | � The fibers then continue to descend through the spine, terminating at the appropriate spinal levels
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| - | � This tract is the main pathway for control of voluntary movement in humans
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| - | == Damage to Primary Motor Cortex ==
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| - | � Lesions in the primary motor cortex result in paralysis of the contralateral side of the body
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| | == Works Cited == | | == Works Cited == |
| | [http://www.brainconnection.com/topics/?main=anat/motor-anat The Anatomy of Movement] | | [http://www.brainconnection.com/topics/?main=anat/motor-anat The Anatomy of Movement] |
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| | + | [http://en.wikipedia.org/wiki/Primary_motor_cortex Primary Motor Cortex] |
