Moth Escape Behavior

Question 1

Receptive field

Answer 1

The part of the sensory field to which a neuron responds to (typically determined by recording AP from a neuron and stimulating different parts of the sensory field)

Question 2

Visual system flow of information

Answer 2

Retina → lateral geniculate nucleus → primary visual cortex (V1)

Question 3

Hierarchical flow of information in visual system (how is it a hierarchical flow?)

Answer 3

Many LGN cells define the receptive fields of a simple cell, many simple cells define the receptive field of a complex cell (multiple simple cells → one complex cell)

Question 4

Neural codes

Answer 4

How communication between neurons leads to behavior

Question 5

Rate code

Answer 5

As stimulus changes, rate of neuron firing changes (focused on # of spikes)

Question 6

Temporal code

Answer 6

Focused on timing of spikes (first-to-spike model) - timing of action potentials changes w/ stimulus quality

Question 7

Population code

Answer 7

Individual neurons are broadly selective (broadly tuned) but collectively as a population they convey information about a stimulus

Question 8

Basic escape circuit (general)

Answer 8

Sensors → sensory neurons → interneurons → motor neurons → muscles

Question 9

Bat calls (function)

Answer 9

Can be frequency modulated (FM) or constant frequency (CF), received echo of a call determines size and location of prey (only small portion of call is echoed back if prey is small)

Question 10

Moth response to presence of bat

Answer 10

Directional response (when intensity of bat call is low)
Erratic (when the intensity is high)

Question 11

Adaptations in moths to respond to bat calls

Answer 11

Moths have developed hearing to detect bat calls - located on the thorax, contains a tympanic membrane that is connected to two sensory neurons

Question 12

Stimulus parameters a moth needs to know

Answer 12

Frequency (is it a bat?)
Distance
Direction

Question 13

Response of auditory nerve to a bat echolocation pulse of increasing intensity (how is it encoded?)

Answer 13

Rate code - as stimulus intensity increases, # of spikes of action potentials increases

Question 14

Interaural differences (how are they encoded?)

Answer 14

The intensity differences between the two “ears” may be encoded by the difference in response magnitude (rate code) and latency (temporal code) - only when bat is far away (~100 ft)

Question 15

Neural circuit in moth

Answer 15

Tympanal organ → tympanal nerve → first order neurons (501, 504) → higher order neurons → connections to flight motor centers
First order neurons and higher order neurons make up the pterothoracic ganglion