Owl location

Question 1

Do owls use vision to hunt

Answer 1

No! They could do it in the dark/struck the leaf if it rustled (not the mouse)

Question 2

Is aud. map caluclated in cochlea?

Answer 2

No, cochlea only has amplitude and frequency.
Aud Map calculated higher up (ICX)

Question 3

Knudsen Konishi magnet coil experiment (basic finding?)

Answer 3

localize sound with audio and head turning, not visual

Question 4

Facial ruff, explain directions

Answer 4

Ears asymmetrical, right ear does upward sounds, left ear does downward sounds
RUFF = (RU, right up)

Question 5

how is elevation and azimuth calculated owls

Answer 5

Elevation by ILD (ruff), Azimuth by ITD (ONGOING disparity, not on/offset)

Question 6

Basic Path for owls

Answer 6

N. magno/angularis TO
N. laminaris TO
ICC TO
ICX TO
Optic Tectum

Question 7

Where is aud map first seen

Answer 7

ICX
EXCLUSIVELY BINAURAL tuned to COMBO OF ITD AND ILD

Question 8

ICX Receptive Field

Answer 8

ICX neurons have receptive field for ITD/ILD, azimuth and elevation “best area”
HAVE SURROUND INHIBITION = SPATIAL SHARPENING

Question 9

Parallel Pathway evidence in owls

Answer 9

Lidocaine numbing to angularis only disrupted ILD, left ITD alone because parallel in mangocellularis

Question 10

Delay Lines, explain what this does

Answer 10

To code ITD, delay lines coming from IPSILATERAL MAGNOCELLULARIS going to the LAMINARIS
Coincidence detector in laminaris

Question 11

Where is phase locking

Answer 11

in n. magnocellularis NOT IN ANGULARIS, Phase locking to encode ITD precisely

Question 12

Describe N. laminaris coincidence detector

Answer 12

ITD for multiple frequency bands
mulitple coindice detector
this is so when get to IC, map of ITD

Question 13

Phase ambiguity, why problem/how solve

Answer 13

If pure tone, time it takes to get to other ear becomes simultaneous,
FIRE AT 0TD, +/- PERIOD
Solved because IXC SUMS OVER FREQS and most natural sounds complex

Question 14

Convergence of what from ICC to ICX?

Answer 14

Same ITD over all freqs gets averaged
NO FREQ CODING IN ICX, only ITD and ILD
ICC had freq and ITD

Question 15

What area controls head-turning orientation

Answer 15

Optic Tectum is sensoritmotor, takes in visual and auditory senses and puts out motor signals

Question 16

Aligning auditory map how?

Answer 16

Visual info drives the alignment, computed from ITD/ILD

Question 17

Results of plugging ear in localization and in juvenile owls

Answer 17

Plug right ear = think sound is LOWER because left ear louder
vice versa for left
IN JUVENILES - adjust to these abnormal cues because VISION GUIDES AUDITORY, learn to correct it
If blinders placed over eyes, never correct

Question 18

Describe prism orienting behavrios throughout experiment

Answer 18

0 days = normal to aud/visual stimulus
Day 1 = visual affected immediately, aud not
Day 42 = visual and aud both affected
Post removal = visual normal, aud still affected
VISION DRIVES AUD, aud takes time to adjust

Question 19

Describe Optic Tectum receptive field shifts

Answer 19

OT has a receptive field of vis/aud
Visual part shifts first, like orienting behavior
Then aud shifts later in prism experience

Question 20

Critical period for ITD calibration in OT

Answer 20

If juveniles had experience with prisms, then they shift their ITD later too
Adults without experience don’t shift their Aud receptive field, need exposure as juvenile

Question 21

Where does the ITD shift occur

Answer 21

ITDs change in the ICX
ICC normal
It’s how the synapses from the ICC connect to the ICX

Question 22

Describe how the ITD shift occurs over time

Answer 22

During beginning phase, there’s a “TRANSITION” period where ICX is tuned to both NORMAL and AFFECTED ITD values
Then later, they are fully shifted to AFFECTED ITD tuning

Question 23

Anatomical shifts in ICX ITD Tuning

Answer 23

New synapses use NMDA Receptors
Old synapses use AMPA Receptors
GABA synapses SUPPRESS OLD tuning