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Unformatted text preview: BIPN100 Winter 2008 Dr. Fortes Ann Shih [email protected] OH: Mon 10 – 11 Café Roma Handout 4 Compare Sensory and Motor pathway comparison Tract Dorsal column Ventrolateral spinothalamic Corticospinal tract (pyramidal) Extrapyramidal tract function Fine touch, proprioception, vibration Nociceptors (pain), temperature and coarse touch Motor movement Motor movement Origin Sensory receptor go through dorsal root Sensory receptor go through dorsal root Prefrontal cortex, cerebellum, basal ganglia, brain stem for planning, origin from primary motor cortex Prefrontal cortex, cerebellum, basal ganglia, brain stem for planning, origin form primary motor cortex Travel step 1 Along dorsal column ipsilaterally up spinal cord (primary neuron) Synapse in dorsal horn (primary neuron) from cortex to thalamus for relay information from cortex to thalamus for relay information Travel step 2 In medulla oblongata and cross midline and up to thalamus (secondary neuron) Axon travel contralaterally up spinal cord to thalamus (secondary neuron) Most of the neuron synapse in medulla oblongata and decussate (cross midline) at pyramids Tract stay ipsilaterally to medulla oblongata outside of pyramidal tract to spinal cord Travel step 3 From thalamus to sensory cortex (tertiary neuron) From thalamus to sensory cortex (tertiary neuron) According to the target location, take the ventromedial tracts to trunk motor for posture or dorsolateral to limb for movement Decussate in spinal cord and according to the target location, as for pyramidal tract Sensory receptors: Mechanoreceptors – ion channels; respond to pressure, vibrations, sound, stretch EX:: increase in cytosolic osmolarity causes cell volume to increase, which stretches MB, activating mech-R Thermoreceptors – respond to temperature (cold or hot) and chemicals (chili oil, menthol/mint) (a) Cold receptors – respond to temp below 37C; Warm receptors respond to temp above ~45 Chemoreceptors – respond to chemical ligands that bind to the receptor (O 2 , CO 2 , pH, glucose) Photoreceptors – respond to light Nociceptors – respond to noxious stimuli, pain (Very hot/cold or very strong mechanical/chemical stimulus) Receptive fields Skin sensitivity increase if: 1. increase sensory neurons in that area and decrease convergence onto secondary sensory neuron...
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This note was uploaded on 04/14/2008 for the course BIPN 100 taught by Professor French during the Winter '07 term at UCSD.
- Winter '07