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The human brain's control of motor function is a mirror image in terms of connectivity; the left hemisphere controls the right hand and vice versa. This theoretically means that the hemisphere contralateral to the dominant hand tends to be more dominant than the ipsilateral hemisphere, however this is not always the case [ 2 ] and there are ...
Control of more central axial and girdle muscles comes from the anterior corticospinal tract. [3] Damage to different parts of the body will cause deficits, depending on whether the damage is above (rostral) or below (caudal) the pyramidal decussation. Damage to the body above the pyramidal decussation will cause contralateral motor deficits.
As speech is a very complex motor control task, the specialised fine motor areas controlling speech are most efficiently used to also control fine motor movement in the dominant hand. As the right hand is controlled by the left hemisphere (and the left hand is controlled by the right hemisphere) most people are, therefore right-handed.
The second, the ipsilateral pathway, allows for the transmission of information along the same side of the body (i.e., the left side of the body to the left hemisphere). [ 15 ] In a healthy individual, when a hand is stimulated by touch, there is increased brain activity in the contralateral hemisphere, and decreased activity in the ipsilateral ...
The arm and hand motor area is the largest, and occupies the part of precentral gyrus between the leg and face area. These areas are not proportional to their size in the body with the lips, face parts, and hands represented by particularly large areas due to the comparative enrichment and density of motor receptor in these regions.
The major function of this pathway is fine voluntary motor control of the limbs. The pathway also controls voluntary body posture adjustments. corticobulbar tract: from the motor cortex to several nuclei in the pons and medulla oblongata: Involved in control of facial and jaw musculature, swallowing and tongue movements.
The motor neuron sends an electrical impulse to a muscle. When the neuron in the cortex becomes active, it causes a muscle contraction. The greater the activity in the motor cortex, the stronger the muscle force. Each point in the motor cortex controls a muscle or a small group of related muscles. This description is only partly correct.
Consequently, the left side of the forebrain mostly represents the right side of the body, and the right side of the brain primarily represents the left side of the body. The contralateral organization involves both executive and sensory functions (e.g., a left-sided brain lesion may cause a right-sided hemiplegia).