Certain animals such as dolphins, bats and owls are well known for using sound signals to detect and classify objects in their environment underwater or in the dark. The auditory mechanisms for localizing and acoustically identifying objects remain poorly understood, but comparing the binaural inputs of timing and intensity cues from the two ears usually is considered a critical necessity. This project is to develop a biologically inspired model of binaural reception and processing of bioacoustic signals for auditory localization and identification, and test it using echolocating dolphins. The research emphasizes how the physical structure of the head contributes to the ability of dolphins to spatially resolve features of objects based on their acoustic images. The computational model combines a self-organizing neural network with a signal processing model of dolphin hearing, to represent available spatial acoustic information. Experiments related to localization and acoustic imaging are simulated and used to predict the results of behavioral tests with dolphins. Results will provide the first quantitative description of dolphin sonar localization and imaging that incorporates a neurally plausible approach. This project is a Minority Research Planning Grant, which will have an impact by fostering the career of a young minority scientist. It also provides opportunities for cross-disciplinary training of graduate and undergraduate students, including those from under-served minorities, in combining math, physics, neurobiology, psychology and engineering.
