Temporal Pattern Recognition in Crickets

Question 1

Temporal sensory discrimination

Answer 1

Being able to distinguish between temporal elements of external stimuli (i.e. being able to tell whether someone is walking towards you or away from you)

Question 2

Lower vertebrates (frogs, fish, insects) acoustic patterns

Answer 2

Communication signals vary in their temporal structure (i.e. Morse code is based on timing) → pulse duration, pulse interval, combination of pulses

Question 3

Structure and location of auditory neurons

Answer 3

TH1-AC1 - receives information from surroundings → B-LC3, B-LI2, B-LI3, and B-LI4 (same side and contralateral side)

Question 4

Neural activity that results in a specific phonotactic (responding to sound) behavior

Answer 4

Crickets move in a particular direction based on the sound they hear
Experiment - crickets tethered to a styrofoam ball w/ pocket of air underneath to measure movement (speed, direction, pattern)

Question 5

Phonotactic behavior towards sound w/ more pulses or higher repetition rate

Answer 5

Sound has more pulses → cricket is drawn to the sound (i.e. speaker on the left has more pulses → cricket will go to the left)
Steering velocity decreases when other speaker pulses

Question 6

Neural mechanisms of the phonotactic behavior

Answer 6

B-LI4 are the best feature detectors (tuned to same pulse duration and pulse interval as the behavior)
Hierarchical flow of information from TH1-AC1 to B-LI4: TH1-AC1 (fastest spike latency) → B-LI2 → B-LC3 → B-LI3 → B-LI4 (slowest spike latency)

Question 7

Relative responses of phonotaxis and brain neurons

Answer 7

Heat map gets more specific/localized as info. flows from TH1-AC1 to B-LI4 → hierarchical flow of information
Peak response of B-LI4 at 20 ms intervals → correlates w/ behavior

Question 8

Specific feature inciting neuron response for auditory pathway

Answer 8

Preceding pulse interval (PI) important for B-LC3 neurons

Question 9

Response selectivity of B-LI4

Answer 9

Interaction between excitation and inhibition: PI response function was maximal at 20 ms → inhibition after the first pulse was ~17 ms

Question 10

Neural mechanisms of interval counting

Answer 10

Temporal summation of rebound inhibition and another EPSP