1. Auditory feedback in the Bengalese finch animal model
By Jake McGrath
Program in Neuroscience
Department of Zoology & Physiology

2. auditory feedback: humans
Delayed Feedback
Musicians and auditory feedback
Choral Speech
Useful in cases of stuttering (Kalinowski & Saltuklaroglu, 2003)

3. Animal model: Bengalese Finch
Establishment of the Bengalese Finch Animal Model
Deafening reveals necessity for active auditory feedback in songbirds
Most sensitive songbird to changes in auditory feedback (Woolley & Rubel, 1997)

4. Previous studies Deafening studies and effects on bird song
Reversible changes in auditory feedback
Use of gas to produce change in auditory feedback
(Yamada & Okanoya, 2003)

5. Current research: My project
Utilization of gasses to change auditory feedback
Heliox (Helium 70% + Oxygen 30%): research in progress
Sulfox (Sulfur Hexafluoride 70% + Oxygen 30%): soon underway
Our Goals:
Understand the role of auditory feedback in vocal control
Instructive: change in vocal output is specific to feedback error
Permissive: change in vocal output is not specific to feedback error
(pushing pitch down with gas is novel…)  this for instructive vs. permissive.
Also define composition of gas.

6. Establishing atmospheric change
Testing for chamber saturation – the “click test”
Heliox – increase in the speed of sound due to lower density

7. Song sequence stereotypy
Song syntax is variable, but with a specific set of possible transitions a b a
c d e f f g h h h h h b a a c d e f f g
10 kHz
0 kHz
500 ms
then seque to left panel of blue blocks on slide with same text as bullet above

8. Song Sequence stereotypy cont.
No change in syntax when singing in heliox
Contrasts with previous results (Yamada & Okanoya, 2003) a b a
c d e f f g h h h h h b a a c d e f f g
10 kHz
0 kHz

9. Did heliox raise pitch? The Bengalese Finch song:
Harmonic “stacked note”:
10 kHz
0 kHz

10. POWER IN harmonic NOTES
Ratio of high frequency (6th harmonic) to low frequency (2nd harmonic)
Prediction: Ratio high/low will be greater in heliox
Initial results indicate opposite change *

11. SUMMARY
Despite change in feedback induced by heliox, no change in syntax
Reveals active role in online vocal control based on auditory feedback
Counterintuitive opposite change suggests active compensation
to overcome error
Consistent with recent results from other groups
(Sober & Brainard, 2009)

12. Relevance Importance of auditory feedback
Bengalese finch: an important animal model
Compensation suggests auditory feedback plays an instructive role in vocal output
Heliox and sulfox experiments will continue in Summer 2011
Future research will investigate the neural mechanisms underlying sensorimotor integration to shape vocal behavior

13. ACKNOWLEDGEMENTS INBRE Jonathan Prather, Ph. D.
Margaret Flanigan, Ph. D.
Sean Reid

14. Questions?