Adaptive Plasticity in Barn Owl Tectum

1
Adaptive Plasticity in Barn Owl Tectum
Bartlett D. Moore IV DeBello Lab, Winter 2003
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Barn owl
Midbrain Sound Localization Pathway
Optic tectum (OT)
-20
Retinotopic visual input
Inferior colliculus (IC)
0
-20
0
-20
0
20
20
20
40
40
60
40
60
60
Ascending Interaural Timing Difference
(ITD) information
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Adaptive Plasticity of Auditory Tuning
normal
adaptive
Normalized Response
-16 -8 0 8 16
Interaural Time Difference (ITD)
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Question

• Adult owls do not adapt to large prismatic
  displacement.
• However, adult owls can adapt to small prismatic
  displacements. Perhaps the amount of adult
  plasticity depends on quality of learning
  environment.
• Will adult owls adapt to large prismatic
  displacements when provided live mice daily?

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Methods
16 Speakers

• Auditory spatial receptive field mapping from
  free field sound stimulation from 16 speaker
  locations, each 4 apart.
• Visual receptive field mapping by projecting hand
  held stimuli onto tangent screen

64
owl
6
Sound Equalization
Speaker 1 microphone
Speaker 2 microphone
Speaker 3 microphone
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Deep Tectum Responses
Raster plot
Speaker Location
Right 24
Center (0)
Left 24
time (s)
Stimulus duration
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Superficial Tectum
Raster and PSTH
Speaker 16
Speaker locations
Speaker 8
Speaker 1
time (ms)
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Spatial tuning curve
Raw firing rates
VRF
Right 32
Left 28
Center (0)
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Conclusions

• Free field speaker array in combination with
  visual tangent screen is an excellent technique
  for measuring auditory-visual receptive field
  alignment.
• No evidence of significant adaptive shift in the
  adult studied after 22 days of prism experience
  in aviary with live mice.

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• Thanks to
• Dr. Will DeBello
• Odell Austin Collins
• the Birds