* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Control of Movement
Neuroeconomics wikipedia , lookup
Aging brain wikipedia , lookup
Cognitive neuroscience of music wikipedia , lookup
Sensory substitution wikipedia , lookup
Eyeblink conditioning wikipedia , lookup
Embodied language processing wikipedia , lookup
End-plate potential wikipedia , lookup
Synaptic gating wikipedia , lookup
Endocannabinoid system wikipedia , lookup
Synaptogenesis wikipedia , lookup
Neuropsychopharmacology wikipedia , lookup
Central pattern generator wikipedia , lookup
Embodied cognitive science wikipedia , lookup
Molecular neuroscience wikipedia , lookup
Clinical neurochemistry wikipedia , lookup
Neuromuscular junction wikipedia , lookup
Anatomy of the cerebellum wikipedia , lookup
Microneurography wikipedia , lookup
Premovement neuronal activity wikipedia , lookup
Feature detection (nervous system) wikipedia , lookup
Motor cortex wikipedia , lookup
Neuroscience in space wikipedia , lookup
Sensorimotor Control of Behavior: Somatosensation Lecture 8 Somatosensation Sensory info from body Cutaneous senses exteroceptors touch / pain Kinesthesia interoceptors body position & movement ~ Somatosensory cortex S1 - Postcentral Gyrus Somatotopic Organization topographic representation of body Distorted Homunculus disproportionate amount of cortex for body parts high sensitivity: large cortical area ~ Somatosensory Cortex Formation of a Body Image Does not simply respond to sensory input Phantom Limbs after amputation also pain ~ PPC M1 S1 Kinesthesia Kinesthesia Body Position & Movement proprioception Joint information Pacinian corpuscles & Ruffini endings Muscle & tendon information changes in tension Golgi tendon organ muscle spindle fibers ~ Cutaneous Receptors Stretching of the skin Limited role in proprioception Ruffini Endings slow adapting population of neurons responding simultaneously ~ Cutaneous Receptors Role depends on location Anesthetize skin assess ability to detect passive movement Knee: no affect on proprioception Mouth, hands, & feet proprioception significantly reduced ~ Muscle Receptors Major role in proprioception Stretch receptors detect changes in tension 2 types of receptors Muscle spindles & Golgi tendon organs differences in threshold & location ~ Muscle-Spindle Receptors Muscle length detectors Parallel with extrafusal fibers Low threshold Monosynaptic stretch reflex Postural adjustments Muscle tonus Sensory neuron ---> alpha motor neurons monosynaptic excitation disynaptic inhibition ~ Dorsal + M S - + Ventral + + Golgi Tendon Organ Gauges muscle tension high threshold Stretch receptor safety mechanism controlled muscle contraction ~ Dorsal GTO Inhibits alpha motor neuron - Ventral + GTO: Function Inhibits muscle contraction Control of motor acts slow contraction as force increases e.g., holding an egg breaks if too much force Autogenic inhibition safety mechanism too much tension ---> damage ~ The Orienting Senses Orientation: The Vestibular System Position & motion of body in space critical for adaptive interaction largely unnoticed except unusual conditions motion sickness: nausea, dizziness Maintenance of balance & posture coordinating body position with other sensory information ~ Receptors for Orientation Inner ear Gravity detectors plane of reference Mechanoreceptors Vestibular Organs otocysts • saccule • utricle semicircular canals ~ Otocysts Liquid-filled “ear sacs” lined with hair cells contain otoliths “ear stones : direction of acceleration saccule: vertical movement utricle: horizontal movement ~ At rest tilted Direction of gravity Acceleration to right Semicircular Canals Rotary acceleration direction & extent of circular movement any direction 3 fluid-filled canals right angles to each other 1 for each major plane Movement causes fluid to circulate displaces cupula ~ Semicircular canals Ampulla Crista hair cells Utricle Cupula Vestibular Pathway Vestibulocochlear nerve (VIII) Some axons directly to cerebellum Most axons to medulla vestibular nuclei cerebellum, spinal cord, medulla & pons motor nuclei for eyes (III, IV, & VI) compensates for movement of head temporal cortex (dizziness) ~ Input to Vestibular System Other sensory information eyes trunk & neck limbs cerebellum Constant postural adjustments Maintains visual image fixed on retina maintains center of gravity during movement ~ Sensorimotor Integration Sensorimotor Integration Somatosensory cortex provides spatial coordinates Motor Cortex executes movements Results in meaningful behavior ~ Posterior Parietal Cortex - PPC Constructs spatial coordinates for behavior Apraxia inability to purposefully organize movements Left parietal apraxia bilateral inability to perform requested movements ~ Constructional apraxia - damage to PPC Spatial Neglect Contralateral neglect neglect of left side of body and world Damage to right PPC map of body & space destroyed ~