Primary motor cortex
From Psy3241
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[[Category:Brain areas]] | [[Category:Brain areas]] | ||
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| + | [http://www.emc.maricopa.edu/faculty/farabee/BIOBK/cerebrum_1.gif Picture of Primary Motor Cortex] | ||
| + | == 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 | ||
| + | == 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 | ||
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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 | ||
| + | == Corticospinal Tract == | ||
| + | • 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 | ||
| + | == Damage to Primary Motor Cortex == | ||
| + | • Lesions in the primary motor cortex result in paralysis of the contralateral side of the body | ||
| + | == Works Cited == | ||
| + | [http://www.brainconnection.com/topics/?main=anat/motor-anat The Anatomy of Movement] | ||
| + | |||
| + | [http://en.wikipedia.org/wiki/Primary_motor_cortex Primary Motor Cortex] | ||
Current revision as of 15:43, 24 April 2008
Picture of Primary Motor Cortex
Contents |
Background
• Primary motor cortex is also called M1
• One of the principle areas involved in motor function
• Located in the frontal lobe of the brain along the precentral gyrus
• The role is to generate neural impulses that control the execution of movement
• Signals from M1 cross the body’s midline to activate skeletal muscles on the opposite side of the body
• The right hemisphere controls the left side of the body
• The left hemisphere controls the right side of the body
Somatotopic Representation
• Every part of the body is represented in the primary motor cortex
• Body part representations are arranged somatotopically
• The foot is next to the leg, next to the trunk, next to the arm, which is next to the hand
• 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
• A lot of cortical space is devoted to complex hand and finger movements; therefore, they have larger representations in M1
Corticospinal Tract
• Neurons in M1, supplementary motor area, and premotor cortex give rise to fibers of the corticospinal tract
• The corticospinal tract is the only direct pathway from the cortex to the spine
• This tract is composed of over a million fibers
• The fibers descend through the brainstem and cross to the opposite side of the body
• The fibers then continue to descend through the spine, terminating at the appropriate spinal levels
• This tract is the main pathway for control of voluntary movement in humans
Damage to Primary Motor Cortex
• Lesions in the primary motor cortex result in paralysis of the contralateral side of the body
