Neuroscience 2 Exam 3 Review

Neuroscience 2 Exam 3 Review - Neuroscience 2 Exam 3 Review...

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Neuroscience 2 Exam 3 Review Ventromedial Versus Lateral Descending Pathways from UMNs in the Brain to LMNs in the Ventral Horn of the Spinal Cord: Name of Tracts, Origin, Terminations, and Functions Functions Medial Vestibulospinal o Origin: Medial Vestibular Nucleus o Termination: Ventro-Medial o Function: Position head and neck so we maintain equilibrium (Vestibulo-collic Reflex) Lateral Vestibulospinal o Origin: Lateral Vestibular Nucleus o Termination: Ventro-Medial o Function: Position limbs to maintain equilibrium (Vestibulo-spinal Reflex) Pontine Reticulospinal o Origin: Pontine Reticular Formation o Termination: Ventro-Medial o Function: Fasiculates the anti-gravity muscles (tone) always active and enhances the stretch reflex Medullary Reticulospinal o Origin: Medullary Reticular Formation o Termination: Ventro-Medial o Function: Shuts down anti-gravity muscles Tectospinal o Origin: Superior Colliculus of Midbrain o Termination: Ventro-Medial o Function: Control head and neck for orientating in space, turn head towards objects of interest Rubrospinal o Origin: Red Nucleus of Midbrain o Termination: Ventro-Lateral o Function: Controls voluntary movement of upper limbs (not-postural lateral) Organization of Interneurons in Spinal Cord (functional significance of location, axon trajectory, and termination in ventromedial versus lateral pathways) Medial Interneurons o Synapse with LMNs to axial muscles o Terminate over many segments o Bilateral o Get input from medial pathways Posture and gross input Lateral Interneurons o Synapse with LMNs to distal muscles o Short axons o Remain ipsilateral o Get input from lateral pathways General Function Dichotomy of Lateral and Ventromedial pathways (Results of Lawerence and Kuypers Lesion Studies) They found that when moving a pen with hand, wrist, mouth, and foot, showed unique characteristics that were maintained in all locations No matter which muscles are activated, the representation is still there Classification based on where axons travel in the spinal cord Ventromedial pathways are for posture and gross movements Lateral pathways are for fine, discrete movements of distal muscles
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Function of Vestibulospinal and Cervicocollic Reflexes When head and body rotate or tilt, the lateral and medial vestibular pathways cause contraction of limb and neck muscles that oppose the motion and return body to vertical o EX) Right Fall reflexes extend right arm and tilt the head left o EX) Pitch Forward reflexes cause upward rotation of the head, both arms and legs are flexed Characteristics of Spasticity and Two Treatments for it (dorsal Rhizotomy and Baclofen Pump) Hypertonus with unidirectional resistance to stretch Treatment o Dorsal Rhizotomy Identifies, targets, and destroys damaged nerves that don’t respond to GABA o Baclofen Pump Baclofen is pumped into the body to mimic the effects of GABA Spinal Cord Lesions: Signs and Symptoms During Initial Period (Spinal Shock) and 2
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This note was uploaded on 04/07/2008 for the course ES/OT 343 taught by Professor Youakim during the Spring '07 term at SUNY Buffalo.

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Neuroscience 2 Exam 3 Review - Neuroscience 2 Exam 3 Review...

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