Echolocating big brown bats perceive sonar images that have distance, or target range, as their primary dimension. Distances to objects are determined from the delay of echoes, but the bat's images also depict the locations of reflecting points within each object as the basis for representing target shape. Echoes from parts of objects arrive so close together that that they overlap to form an interference spectrum, and the bat determines the separation of the target's parts from the frequencies of notches in this spectrum. However, the distance to each part of the object is depicted in the images by transforming the pattern of notches into true delay estimates. The objective of the proposed research is to understand how spectral information about the small time separations of echoes from different parts of the same object is bound with spike-timing information about the overall delay of echoes for the distance to the object as a whole. In the auditory cortex, this binding process is based on temporal coincidences between spikes representing overall delay independent of the echo spectrum and spikes representing the delay of echoes that have spectral notches, thus serving as a model for temporal feature binding as a general perceptual phenomenon. The project consists of behavioral experiments to measure the width of the bat's time windows for binding spectral delay estimates to temporal delay estimates and neuropsychological experiments to trace the movement of information about the echo spectrum from one delay to another using the same acoustic stimuli as in the behavioral experiments. A biologically realistic computational model of echo processing will be used as a tool for linking the behavioral and physiological findings. ? ?

Agency
National Institute of Health (NIH)
Institute
National Institute of Mental Health (NIMH)
Type
Research Project (R01)
Project #
5R01MH069633-02
Application #
6836100
Study Section
Integrative, Functional and Cognitive Neuroscience 8 (IFCN)
Program Officer
Glanzman, Dennis L
Project Start
2003-12-15
Project End
2008-11-30
Budget Start
2005-01-01
Budget End
2005-11-30
Support Year
2
Fiscal Year
2005
Total Cost
$346,275
Indirect Cost
Name
Brown University
Department
Neurosciences
Type
Schools of Medicine
DUNS #
001785542
City
Providence
State
RI
Country
United States
Zip Code
02912
Knowles, Jeffrey M; Barchi, Jonathan R; Gaudette, Jason E et al. (2015) Effective biosonar echo-to-clutter rejection ratio in a complex dynamic scene. J Acoust Soc Am 138:1090-101
Simmons, James A (2014) Temporal binding of neural responses for focused attention in biosonar. J Exp Biol 217:2834-43
Simmons, James A (2012) Bats use a neuronally implemented computational acoustic model to form sonar images. Curr Opin Neurobiol 22:311-9
Bates, Mary E; Simmons, James A; Zorikov, Tengiz V (2011) Bats use echo harmonic structure to distinguish their targets from background clutter. Science 333:627-30
Simmons, James A; Megela Simmons, Andrea (2011) Bats and frogs and animals in between: evidence for a common central timing mechanism to extract periodicity pitch. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 197:585-94
Bates, Mary E; Simmons, James A (2011) Perception of echo delay is disrupted by small temporal misalignment of echo harmonics in bat sonar. J Exp Biol 214:394-401
Bates, Mary E; Simmons, James A (2010) Effects of filtering of harmonics from biosonar echoes on delay acuity by big brown bats (Eptesicus fuscus). J Acoust Soc Am 128:936-46
Hiryu, Shizuko; Bates, Mary E; Simmons, James A et al. (2010) FM echolocating bats shift frequencies to avoid broadcast-echo ambiguity in clutter. Proc Natl Acad Sci U S A 107:7048-53
Stamper, Sarah A; Bates, Mary E; Benedicto, Douglas et al. (2009) Role of broadcast harmonics in echo delay perception by big brown bats. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 195:79-89
Petrites, Anthony E; Eng, Oliver S; Mowlds, Donald S et al. (2009) Interpulse interval modulation by echolocating big brown bats (Eptesicus fuscus) in different densities of obstacle clutter. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 195:603-17

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