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The lateral corticospinal tract is a descending motor pathway that begins in the cerebral cortex, decussates in the pyramids of the lower medulla [1] (also known as the medulla oblongata or the cervicomedullary junction, which is the most posterior division of the brain [2]) and proceeds down the contralateral side of the spinal cord.
Subacute combined degeneration of spinal cord, also known as myelosis funiculus, or funicular myelosis, [1] also Lichtheim's disease, [2] [3] and Putnam-Dana syndrome, [4] refers to degeneration of the posterior and lateral columns of the spinal cord as a result of vitamin B 12 deficiency (most common).
Of all the circuits, the motor circuit is the most studied due its importance to motor disorders. The direct pathway of the motor circuit is one in which projections from the cortex travel to the putamen directly to the internal segment of the globus pallidus (GPi also known as GP-Medial) or the substantia nigra, pars reticulata (SNr) and are then directed toward the ventral anterior nucleus ...
The symptoms observed in bvFTD are caused by dysfunction of the orbitofrontal cortex; thus these two neuropsychological tests might be useful in detecting early-stage bvFTD. However, as self-monitoring and somatic marker processes are so complex, it likely involves other brain regions.
UMNs are motor neurons that project from the cortex down to the brainstem or spinal cord. [18] LMNs originate in the anterior horns of the spinal cord and synapse on peripheral muscles. [18] Both motor neurons are necessary for the strong contraction of a muscle, but damage to an UMN can be distinguished from damage to a LMN by physical exam. [19]
Cortical stimulation mapping led to the development of a homunculus for the motor and sensory cortices, which is a diagram showing the brain's connections to different areas of the body. An example is the cortical homunculus of the primary motor cortex and the somatosensory cortex, which are separated by the central sulcus.
However, if blood flow cannot be increased or if doubled blood flow does not correct the problem, symptoms of cerebral hypoxia will begin to appear. Mild symptoms include difficulties with complex learning tasks and reductions in short-term memory. If oxygen deprivation continues, cognitive disturbances, and decreased motor control will result. [6]
A frequently occurring motor deficit is left-sided hemiparesis (in strokes affecting the motor cortex). A less common motor deficit in this population is dysphagia. [4] Patients with right hemisphere brain damage often display sensory deficits such as left neglect, in which they ignore everything in the left visual field. [5]