sensorimotor neurophysiology of active sensing overview dr. martha flanders
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Sensorimotor Neurophysiology of Active Sensing Overview Dr. Martha Flanders Department of Neuroscience University of Minnesota Receptors and Spinal Cord Dr. Steve I. Perlmutter Dept. of Physiology and Biophysics Univ. Washington Cerebral Cortex - PowerPoint PPT PresentationTRANSCRIPT
Sensorimotor Neurophysiology of Active Sensing
Overview
Dr. Martha Flanders Department of NeuroscienceUniversity of Minnesota
Receptors and Spinal Cord
Dr. Steve I. PerlmutterDept. of Physiology and Biophysics Univ. Washington
Cerebral Cortex
Dr. Stephen I. Helms TilleryHarrington Dept. of Bioengineering Arizona State University
Overview cortex
Brodal 1981 (after Brodmann and Vogt) Golgi stain - Nissl stain - Myelin stain
Schiebel et al. 1974
6 Layers 80% of neurons are excitatory pyramidal
1 Million Columns 0.5 mm wide processing modules
Receptive fieldsMovement fields
Population CodingSparse Coding
Overview dorsal column nuclei, cerebellum, thalamus and cortex
thalamussomatosensory cortex
Roberts and Hanaway 1970
brainstem(cerebellum)
Cortical sheet gray matter (neurons) white matter (axons)
Subcortical structures thalamus brainstem midbrain, pons medulla dorsal column nuclei cerebellum
Spinal cord
Overview receptors, spinal cord
Haines 1987
Iggo and Muir 1969
Neurons – deepAxons – more superficial
Dorsal - sensoryVentral – motor
7 – Intermediate Zone interneurons
8-10 – motor neuron cells axons exit via ventral root
Dorsal Root incoming sensory information
Overview efference copy
cortical subcortical spinal
efference copy
somatosensory feedback
motor output
targetstate
current state
sensory feedback
motor command
targetstate
currentstate
muscle activityforcemovement
efference copy
A) Input (motor error) = target state – current state
Brain learns mapping from A to B by comparing efference copy to sensory feedback
Comparison operations occur at many levels
Somatosensory feeback (tactile and proprioceptive) can be used to continuously guide an ongoing < - - - - - movement
AB
Overview neural comparison and cancellation
A. Comparison
B. Cancellation
Mid LeftRight
motor command
efference copy sensory input
motor output
leftear
right ear
PAD
Corinnewww.thepaintedparrot.com.au
Examples of Comparison
Sound localization in barn owl brainstem
Primary afferent depolarization in primate spinal cord
Overview neural comparison and cancellation
A. Spinal Cord
B. Brain
motor command
efference copy sensory input
motor output
inhibition
dorsal horn spinal cord
dorsal root ganglion
peripheralsensory afferents
PAD
muscle spindle tendon organ cutaneous
cerebral cortex
dorsal columnnuclei - medulla
Heiligenberg 1973
Object Localization in electric fish brainstem
Primary afferent depolarization in primate A. spinal cord
B. brainstem?
A. Extraction
B. Extrapolation
Time (ms) Time (ms)SFA
(*b)
(*f)
(*c)
(*e)
(*d)
(*a)
STD
Research questions aboutneural mechanism in primate somatosensory cortex
Overview neural feature extraction and extrapolation