Muscle and Cricket

Question 1

3 cats of movement

Answer 1

reflexive, rhythmic, and voluntary

Question 2

Muscle fiber and axon

Answer 2

Each fiber has SINGLE axon

Question 3

Hierarchy for motor neurons

Answer 3

basal ganglia/cerebllum modulate
upper motor neuron in stem
lower motor in fibers

Question 4

Alpha motor neurons and input

Answer 4

innervate extrafusal, generate force
input from interneurons, muscle spindle, and upper motor neurons brain

Question 5

Muscle spindle

Answer 5

in parallel with extrafusal
Ia sensory afferent around it, INFO ABOUT MUSCLE LENGTH

Question 6

Monosynaptic myotatic reflex

Answer 6

Stretch reflex, knee-jerk
A force stretches the muscle
Ia axon sends info to alpha neuron which shortens muscle

Question 7

Gamma motor neurons

Answer 7

Adjust sensitivity
Resets length of spindle by contracting INTRAFUSAL fiber
So Ia can continue to glean information about length

Question 8

Golgi tendon organ

Answer 8

propioception
Monitor MUSCLE TENSION
In series with fiber
Ib afferents encode tension
Fire when stretched/tension/forced
reflex to Alpha motor

Question 9

Reverse myotatic Reflex

Answer 9

Protect from overload
Golgi Ib afferent inhibit Alpha motor neuron, lessen force

Question 10

Reciprocal Inhibition

Answer 10

Flexor inhibits extensior vice versa
Flexor crossed extensor reflex - step on tack
- Ipsilateral excite flexor, inhibit extensor
Contra excite extensor, inhibit flexor

Question 11

CPG in human motor system

Answer 11

Rhytmic behaviors, walking/swallowing/swimming
Start in brain, go down spinal cord, cut= don’t make it down

Question 12

Basal ganglia Loop

Answer 12

Initiate willed movements
Procedural learning

Question 13

Cerebellar Loop and Projections

Answer 13

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

Question 14

Lower Order corollary discharge

Answer 14

Control sensation
- Reflex inhibition in sea slug feeding
- Sensory filtration in cricket song deafening

Question 15

Higher Order Corollary Discharge

Answer 15

Sensory stability - shifting receptive fields
Sensorimotor Learning - bird song feedback

Question 16

3 cricket songs

Answer 16

Calling (positive phonotaxis), courtship, aggression

Question 17

Elements of cricket song in order small to big

Answer 17

Cycle - syllable (carrier frequency, syl rate)- chirp (chirp rate) - song

Question 18

Song production morphology

Answer 18

Wing stridulation
Scraper against file in CLOSING, harp amplified
Wing morphology determines cycles in pulse (file), how quickly wing close = pulse duration

Question 19

CNS of cricket

Answer 19

Song production motor neurons innervate wing in MESOTHORACIC Ganglion (3 thoracic)
6 abdominal ganglion act as spinal cord
Brain

Question 20

5 Ways to monitor motor neurons

Answer 20

Extracellular activity spikes of MUA
Intracellular spikes of MUA
Extracellular spikes of Neuron
Intraceullar Endplate potential of muscle cell
Extracellular Electromyogram EMG

Question 21

Two muscle for sound production

Answer 21

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

Question 22

Where song production triggered, what control what

Answer 22

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

Question 23

3 criteria for command neurons

Answer 23

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

Question 24

Post-Inhibitory Rebound

Answer 24

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

Question 25

Fictive Singing and what involved in CPG

Answer 25

Cut motor to wings
Induced by injecting cholinergic agonists in brain so can still record motor activity
Recorded with truncated abdominal nerve

A3 neuron is rhytmic with fictive singing
SPIKE 10MS BEFORE WING OPENER
HYPER IN PHASE WITH CLOSING

Question 26

Reset Experiment

Answer 26

Current inject in a neuron, see if CPG behavior resets, if it does, then part of the CPG

A3 current injection resets rhythm, A3 part of CPG

Question 27

Pulse Timer Network and Chirp Timer

Answer 27

A3/4, pulse period

Chirp Timer
A4/5 chirp duration and number pulse
A5/6 Chirp period

Question 28

Phonotaxis behavior path

Answer 28

Zigzag toward song, in direction that is LOUDEST

Question 29

Essential features of song for phonotaxis

Answer 29

5Khz
30 syls/second
Louder songs

Question 30

Why 5Khz?

Answer 30

Indirect route towards ipsi tympanum is longer than Direct ipsi tympanum
Indirect/direct same length contra
Extra distance is 3.5cm, half wavelength of 5khz sound (7cm)
Ipsi tympanum MAXIMIMALLY moves with 5khz sound (pushed and pulled from outside inside in rhythm with sound)
Contra tympanum MINIMALLY moves with 5Khz (outside push and inside pull cancel since same time)

Moves best for 5khz, resonates and sensory filters

Question 31

Aud nerve direction tuning

Answer 31

Directionally tuned auditory nerves for 5khz
Lowest db threshold for direct right 3:00, higher threshold at other directions like 2:00/4:00

Question 32

Aud to omega path and inhibition

Answer 32

Auditory nerves DO NOT CROSS MIDLINE
Synapse to ipislateral Omega neurons neuropile

Omega neurons on left/right inhibit each other
Reciprocal inhibition
In phase with syllables in song
Helps with direction selecitivty
Reciprocal inhibition ENHANCES differences in aud signal

Question 33

AN-1 neurons and path to brain

Answer 33

Ascending neurons EXCITED from auditory nerves
Inhibited by CONTRA Omega neurons
Also direction selecitve
If LAN fires more, female moves left
RAN, move right
Can change by hyperpolarizing left, even if left sound, moves right

Send signal to BNC-1,2
BNC-1/2 NO temporal pattern to song
AN-1/Omega DO HAVE temporal pattern

Question 34

BNC types for syllable rates

Answer 34

BNC-1 Low pass, low syl rate
BNC-2 High pass, high syl rate
BNC-2 Band pass, 30 syl/sec

Question 35

BNC-2 Firing

Answer 35

BNC-2 Activity MATCHED female behavior
Song recognition cell!

Needs simulatenous input BNC-1/2, their firing overlaps at 30 syls/second, AND gate

Question 36

Corollary Discharge in crickets

Answer 36

Desensitize auditory during loud aggression call

CD Interneurons output to prothoracic (AUD and Omega)
Spike with motor CLOSING
Not part of CPG (reset experiment no effect)
IT DOES RECEIVE EXCITATORY INPUT FROM CPG THOUGH! (COPY OF MOTOR COMMAND)!

Question 37

Primary Afferent Depolarization and CDI inhibition

Answer 37

Pre-synaptic Inhibitiojn
Depol pre-syn so that Ca less driivng force
Doesn’t release as much NT

CDI does this on Auditiory nerve afferent with wing CLOSING (when soud happens)
Reduces transmission of aud and omega
Also does IPSP on Omega with sound (post-syn inhibition)

So CDI does both pre and post syn inhibition on aud and omega

Sensory filtration
Reduce sensitivty DURING call, retain during non-call!

Question 38

Lateral and Ventromedial motor path

Answer 38

lateral - Goal directed voluntary, basal ganglia
Ventromedial - posture, locomotion, orientation and balance, cerebellar