Barn Owl Lecture

Question 1

Named the experimenter which conducted the barn owl experiment with coil attached to its head

Answer 1

Knudsen and Konishi

Question 2

Name two aspects of the sound an owl must determine and state whether this axis is used for intensity or timing

Answer 2

• Azimuth (Horizontal) TIMING

- Elevation (Vertical) INTENSITY

Question 3

Where would you find the biaural cells?

Answer 3

In the inferior colliculus (ICX)

Question 4

Where does the interaural differences in time and intensity of sound originated before the space-spefici cells in ICX received it?

Answer 4

• Cochlear nuclei

Question 5

By which structures are time and intensity information processed?

Answer 5

Time - Nucelus Magnocellularis

Intensity - Nucleus Angularis

Question 6

The owl determines azimuth component of a sound by

Answer 6

ONGOING disparity

Question 7

Describe an experimental evidence which proves the use of ongoing disparity in detecting azimuth component of sound

Answer 7

Experiment conducted by Moiseff and Konishi

• They plugged the owl ears with miniature speaker to deliver the sound directly and independently
• By this, they could eliminate one of the parameters (either transient disparity or ongoing disparity)
• When they removed the transient disparity parameters, the owl would always flicked their head towards the horizontal position where the sound should’ve been in space
• When ongoing disparity excluded, the owl would not accurately detect where the sound suppose to be

Question 8

Which structure process the TIME and INTENSITY information?

Answer 8

Time = Nucleus Magnocellularis

Intensity = Nucleus Angularis

Question 9

Describe the properties of space specific cells and where it is found

Answer 9

• Found in ICX, BINAURAL
• They’re arranged topograhically forming a map of auditory space in ICX
• Each cells respond to different combination of ITD and ILD hence defining the neuron’s receptive field in space
• They have an inhibitory surrounding region which helps defining the receptive field

Question 10

Describe how space-specific cells helps in sound localisation. Present experimental evidence when necessary

Answer 10

• These neurons tunes the combination of incoming ITD and ILD
• They integrate these information to localise sound
• Lesion in specific areas of ICSX produced predictable behavioural sound localisation error

Question 11

Where are the ITD encoded and what features does this particular structure has?

Answer 11

ITD is encoded in Nucleus Laminaris

Cells in NL act as a coincidence detector (will only fire maximally when received input from both ears). It also provides delay lines to allow the two inputs to enter simultaneously