Muscle and Cricket Flashcards
(38 cards)
3 cats of movement
reflexive, rhythmic, and voluntary
Muscle fiber and axon
Each fiber has SINGLE axon
Hierarchy for motor neurons
basal ganglia/cerebllum modulate
upper motor neuron in stem
lower motor in fibers
Alpha motor neurons and input
innervate extrafusal, generate force
input from interneurons, muscle spindle, and upper motor neurons brain
Muscle spindle
in parallel with extrafusal
Ia sensory afferent around it, INFO ABOUT MUSCLE LENGTH
Monosynaptic myotatic reflex
Stretch reflex, knee-jerk
A force stretches the muscle
Ia axon sends info to alpha neuron which shortens muscle
Gamma motor neurons
Adjust sensitivity
Resets length of spindle by contracting INTRAFUSAL fiber
So Ia can continue to glean information about length
Golgi tendon organ
propioception
Monitor MUSCLE TENSION
In series with fiber
Ib afferents encode tension
Fire when stretched/tension/forced
reflex to Alpha motor
Reverse myotatic Reflex
Protect from overload
Golgi Ib afferent inhibit Alpha motor neuron, lessen force
Reciprocal Inhibition
Flexor inhibits extensior vice versa
Flexor crossed extensor reflex - step on tack
- Ipsilateral excite flexor, inhibit extensor
Contra excite extensor, inhibit flexor
CPG in human motor system
Rhytmic behaviors, walking/swallowing/swimming
Start in brain, go down spinal cord, cut= don’t make it down
Basal ganglia Loop
Initiate willed movements
Procedural learning
Cerebellar Loop and Projections
Sequencing/timing complex movements
Procedural Learning
Intended movement from motor cortex via pons
Actual Movement from propioceptors in muscles (to inferior cerebellar peduncle)
= ERROR SIGNAL, Corrollary Discharge
Know if due to exafference = enviro
or reafferance = own movement
Lower Order corollary discharge
Control sensation
- Reflex inhibition in sea slug feeding
- Sensory filtration in cricket song deafening
Higher Order Corollary Discharge
Sensory stability - shifting receptive fields
Sensorimotor Learning - bird song feedback
3 cricket songs
Calling (positive phonotaxis), courtship, aggression
Elements of cricket song in order small to big
Cycle - syllable (carrier frequency, syl rate)- chirp (chirp rate) - song
Song production morphology
Wing stridulation
Scraper against file in CLOSING, harp amplified
Wing morphology determines cycles in pulse (file), how quickly wing close = pulse duration
CNS of cricket
Song production motor neurons innervate wing in MESOTHORACIC Ganglion (3 thoracic)
6 abdominal ganglion act as spinal cord
Brain
5 Ways to monitor motor neurons
Extracellular activity spikes of MUA
Intracellular spikes of MUA
Extracellular spikes of Neuron
Intraceullar Endplate potential of muscle cell
Extracellular Electromyogram EMG
Two muscle for sound production
M90 Wing closer
M99 Wing opener
in mesothoracic ganglion
Takes time to develop force to close, so song not instanetenous
Recicrpocal output to closer/openers
THESE MOTOR NEURONS HAVE RHYTMIC ACTIVITY IN PHASE WITH SONG
Where song production triggered, what control what
Brain go/no go
NO Song pattern info in brain, just a go signal
Trigger CPGs in ganglion which trigger muscles
CPG - pulse rate, chirp rate/duration
Muscles - pulse duration, cycles, carrier frequency
3 criteria for command neurons
Correlation - fire with behavior
Sufficiency - stimulate neuron = behavior
Necessity - inhibit neuron = NO behavior
Command neuron in brain gives GO signal, NO pattern info, just a plain go signal, not corr’d with song patterns
Post-Inhibitory Rebound
after inhibition, motor neurons spike in a rebound
Works in CPG for wing motor neurons in reciprocal way
GO singal goes to opener/closer, reciprocal inhibition and rebound