Motor Systems 1 Spinal Reflexes 2 Central Pattern

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Motor Systems 1. Spinal Reflexes 2. Central Pattern Generators in spine and brainstem 3.

Motor Systems 1. Spinal Reflexes 2. Central Pattern Generators in spine and brainstem 3. Motor Cortex and Basal Ganglia

Central Pattern Generator Locomotion, chewing, swallowing, breathing, etc.

Central Pattern Generator Locomotion, chewing, swallowing, breathing, etc.

Central Pattern Generator Properties 1. Multiple neurons -- not a simple reflex loop 2.

Central Pattern Generator Properties 1. Multiple neurons -- not a simple reflex loop 2. Motor patterns produced by different combinations of neurons or recruitment of neurons 3. CPGs have oscillatory activity 4. Defined by “fictive locomotion” 5. CPGs localized in brainstem/spinal cord by transections 6. Properties modulated by central or peripheral input 7. CPGs not necessarily conserved across species (but properties of neurons are conserved across species).

Walking

Walking

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The Generation of Spinal Motor Programs for Walking Rhythmic Oscillation

The Generation of Spinal Motor Programs for Walking Rhythmic Oscillation

The Generation of Spinal Motor Programs for Walking

The Generation of Spinal Motor Programs for Walking

Walking

Walking

Central Pattern Generator: Lamprey swimming http: //www. life. umd. edu/biology/cohenlab/lamprey. mpeg_1. mpeg

Central Pattern Generator: Lamprey swimming http: //www. life. umd. edu/biology/cohenlab/lamprey. mpeg_1. mpeg

Lamprey Spinal Cord Rhythmic pattern Fictive Movement Fictive movement: Cord “swims” in absence of

Lamprey Spinal Cord Rhythmic pattern Fictive Movement Fictive movement: Cord “swims” in absence of sensory input, muscles

Lamprey Spinal Network

Lamprey Spinal Network

Walking

Walking

Walking

Walking

Swimming vs. Walking: Swimming = fast, traveling wave (hips, shoulders wiggle) Walking = slow,

Swimming vs. Walking: Swimming = fast, traveling wave (hips, shoulders wiggle) Walking = slow, standing wave (hips, shoulders stay in line) Change in pattern -> change in locomotion

Locomotion in spinal cat localized to spinal cord

Locomotion in spinal cat localized to spinal cord

Decerebrate Cat walks on all four limbs if stimulated Fictive walking: note contribution of

Decerebrate Cat walks on all four limbs if stimulated Fictive walking: note contribution of afferent feedback Fictive Movement

Isolated Neonatal Rat spinal cord

Isolated Neonatal Rat spinal cord

Central Pattern Generator Control of CPG output Locomotion, chewing, swallowing, breathing, etc.

Central Pattern Generator Control of CPG output Locomotion, chewing, swallowing, breathing, etc.

Descending Modulation of CPG

Descending Modulation of CPG

Descending Modulation of CPG stimulate midbrain

Descending Modulation of CPG stimulate midbrain

Central Pattern Generator Properties 1. Multiple neurons -- not a simple reflex loop 2.

Central Pattern Generator Properties 1. Multiple neurons -- not a simple reflex loop 2. Motor patterns produced by different combinations of neurons or recruitment of neurons 3. CPGs have oscillatory activity 4. Defined by “fictive locomotion” 5. CPGs localized in brainstem/spinal cord by transections 6. Properties modulated by central or peripheral input 7. CPGs not necessarily conserved across species (but properties of neurons are conserved across species).