Primary motor cortex

From Psy3241

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== Background ==
== Background ==
-
Primary motor cortex is also called M1
+
� Primary motor cortex is also called M1
-
One of the principle areas involved in motor function
+
� One of the principle areas involved in motor function
-
Located in the frontal lobe of the brain along the precentral gyrus
+
� 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
+
� 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
+
� 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  
+
â�¢ The right hemisphere controls the left side of the body  
-
The left hemisphere controls the right side of the body
+
� The left hemisphere controls the right side of the body
== Somatotopic Representation ==
== Somatotopic Representation ==
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Every part of the body is represented in the primary motor cortex
+
� Every part of the body is represented in the primary motor cortex
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Body part representations are arranged somatotopically
+
� 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 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
+
� 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
+
� A lot of cortical space is devoted to complex hand and finger movements; therefore, they have larger representations in M1
== Corticospinal Tract ==
== 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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� 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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� 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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� 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
+
� 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
+
� 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
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� This tract is the main pathway for control of voluntary movement in humans
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Lesions in the primary motor cortex result in paralysis of the contralateral side of the body
+
� Lesions in the primary motor cortex result in paralysis of the contralateral side of the body
== Works Cited ==
== Works Cited ==
 +
� The Anatomy of Movement: http:www.brainconnection.com/topics/?main=anat/motor-anat
 +
 +
� Wikkipedia: Primary Motor Cortex: http://en.wikipedia.org/wiki/Primary¬_motor_cortex

Revision as of 15:19, 24 April 2008


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

� Lesions in the primary motor cortex result in paralysis of the contralateral side of the body

Works Cited

� The Anatomy of Movement: http:www.brainconnection.com/topics/?main=anat/motor-anat

� Wikkipedia: Primary Motor Cortex: http://en.wikipedia.org/wiki/Primary¬_motor_cortex

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