BIO 208 Lecture Notes - Lecture 5: Brainstem, Transcranial Magnetic Stimulation, Central Sulcus
19 Sep 2016
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Document Summary
Motor cortex: primary motor cortex (m1) participates in the execution of movement. Electrical stimulation in m1 evokes simple movements of the contralateral (opposite) side of the body. Electrical stimulation in pma and sma requires higher current strength and evokes more variable and complex movements than m1 stimulation: lateral pathways. Neurons in the motor cortex send their axons into corticospinal (pyramidal) tract. Pyramidal tract neurons descend into the brainstem and cross to the other side of the brain (pyramidal decussation) The axons continue down to terminate in the spinal cord. Damage to the lateral pathways disrupts movement of distal musculature, particularly independent (fractionated) finger movements. We name tracts by where they originate and where they terminate (ex: corticospinal: ventromedial pathways. Originates from the pontine reticular formation neurons. Originates from neurons in the medullary reticular formation. Together, these neurons receive inputs from the cortex and cerebellum and help control postural reflexes and axial musculature.
