Institute of Neuroscience,
224, Huestis Hall,
University of Oregon,
Eugene, OR 97402
email: avinash at uoneuro.uoregon.edu
Post-doctoral Associate in the laboratory of Prof. T Takahashi, Institute of Neuroscience, University of Oregon. April 1997 to date.
The main part of my work has concentrated on the relationship between behavioral and neuronal discrimination of auditory space in the barn owl, Tyto alba . As two sound sources are moved further apart, the ability of the bird to resolve one from the other increases. The smallest discriminable difference, or the MAA in behavior is 3o. When the neurons in the mid brain were examined, however, a large distribution of neuronal performance was revealed. In such a case, how is the output of this diverse population of neurons combined to yield behavioral discrimination? We find that the behavioral discrimination ability of the owl is related to the average performance of neurons in the owl's midbrain (paper; poster). We find that auditory discrimination behavior is very closely predicted by a habituation-based model that takes into account both the firing rate of the population of midbrain neurons, as well as the variance in those firing rates.
Subsequently, the model developed to describe discrimination behavior in azimuth has also shown to hold true for discrimination in elevation (paper). This serves as an 'internal control', since elevation acuity in the barn owl is twice as poor as acuity in azimuth.
Earlier, I had developed a habituation based paradigm to investigate auditory behavior in the owl. The pupil of the owl dilates in response to the presentation of any salient sound ( paper (330 kB); ; poster(0.9 MB) ). This response habituates on repeated presentation of sound, and can then be recovered by the presentation of a novel sound stimulus. The amplitude of this recovered response can be compared to the population of habituated responses, yielding a measure of discrimination.
Using this behavior, I have looked at frequency and spatial discrimination of the barn owl. The minimal audible angles (MAA) of the owl have been measured for the first time. Spatial discrimination in azimuth (MAA = 3o) has been shown to be finer than that in elevation (MAA = 9o), in keeping with previously described neuronal measurements in the anesthetized owl.
At the present time, I am trying to extend behavioral techniques based on the habituation and recovery of the pupil dilation response to human subjects, with the long term aim of using this behavior as a diagnostic tool and as a substitute for other tools to psychophys of audition and vision.
Graduate student in the laboratory of Prof. Obaid Siddiqi at the Tata Institute of Fundamental Research, Bombay, India. August 1989 to April 1997. The research project comprised isolation and analysis of two olfactory mutations in Drosophila melanogaster, and an analysis of chemotaxis in the Drosophila larva.
Ph.D. in Molecular Biology, Tata Institute of Fundamental Research, Bombay, India, 1997.
M.Sc.(Honours School) Microbiology, Panjab University, Chandigarh, India. 1989
B.Sc.(Honours School) Microbiology, Panjab University, Chandigarh, India. 1987.
Ph.D. thesis: Olfactory reception in Drosophila melanogaster. Mumbai University, Mumbai, India. 1997.
M.Sc thesis: "Isolation of alkalophilic bacteria and characterization of carboxy-methyl-cellulases from two alkalophilic isolates". Panjab University, Chandigarh, India. 1989.
Tata Institute of Fundamental Research Competitive Scholarship for graduate studies, TIFR, Bombay, India. 1989-1997.
Gold medal, 1989, Panjab University (Ranked first in Honors School Masters Program).
Council of Scientific and Industrial Research (Department of Science and Technology, Govt. of India). Junior Research Fellowship (for Graduate Research), 1988. Declined.
