Professor, Department of Biology
Member & Co-Director, ION
Ph.D. State University of New York, Downstate Medical Center
B.S. University of California, Irvine
Research Interests: Coding and integration of sensory information; neuroethology
Overview: The goal of my research program is to understand how we get perception from physical stimuli. To address this broad question, my laboratory uses electrophysiological, anatomical, behavioral, and computational modeling methods to study spatial hearing in the barn owl, a nocturnal predator that can hunt solely by means of auditory cues. Not only is the barn owl a good auditory predator, but its midbrain contains a retina-like map of auditory space. The neurons that compose this map have spatial receptive fields, like visual neurons, and are arrayed topographically so that each neuron represents some point in auditory space. Using this auditory space map, my lab has been analyzing the auditory system's ability to resolve and image the sounds from a particular source in the presence of echoes and other competing sounds.
Human Auditory Detection and Discrimination Measured with the Pupil Dilation Response.
J Assoc Res Otolaryngol. 2019 Dec 02;:
Authors: Bala ADS, Whitchurch EA, Takahashi TT
In the standard Hughson-Westlake hearing tests (Carhart and Jerger 1959), patient responses like a button press, raised hand, or verbal response are used to assess detection of brief test signals such as tones of varying pitch and level. Because of its reliance on voluntary responses, Hughson-Westlake audiometry is not suitable for patients who cannot follow instructions reliably, such as pre-lingual infants (Northern and Downs 2002). As an alternative approach, we explored the use of the pupillary dilation response (PDR), a short-latency component of the orienting response evoked by novel stimuli, as an indicator of sound detection. The pupils of 31 adult participants (median age 24 years) were monitored with an infrared video camera during a standard hearing test in which they indicated by button press whether or not they heard narrowband noises centered at 1, 2, 4, and 8 kHz. Tests were conducted in a quiet, carpeted office. Pupil size was summed over the first 1750 ms after stimulus delivery, excluding later dilations linked to expenditure of cognitive effort (Kahneman and Beatty 1966; Kahneman et al. 1969). The PDR yielded thresholds comparable to the standard test at all center frequencies tested, suggesting that the PDR is as sensitive as traditional methods of assessing detection. We also tested the effects of repeating a stimulus on the habituation of the PDR. Results showed that habituation can be minimized by operating at near-threshold stimulus levels. At sound levels well above threshold, the PDR habituated but could be recovered by changing the frequency or sound level, suggesting that the PDR can also be used to test stimulus discrimination. Given these features, the PDR may be useful as an audiometric tool or as a means of assessing auditory discrimination in those who cannot produce a reliable voluntary response.
PMID: 31792632 [PubMed - as supplied by publisher]