CDS Lecture Series

Friday, May 10, 2002, 2:00 p.m.

Cynthia Moss
Department of Psychology
Institute for Systems Research
University of Maryland at College Park

Audiomotor integration for spatially-guided behavior in the echolocating bat

The sonar systems of echolocating bats operate through continuous interaction between perception and motor control. The bat actively probes the environment by producing ultrasonic vocal signals that reflect from objects in the path of the sound beam. The bat uses information contained in returning echoes to determine the direction, distance, size and possibly the shape of sonar targets. In turn, the spatial information obtained from sonar echoes guides the aim of the bat's head, direction of its flight path and the acoustic features of its subsequent sonar signals. Many species of bat use echolocation to hunt small insect prey in the dark, a daunting perceptual task, given the acoustic environment in which the bat must operate. To successfully intercept insect prey and avoid obstacles, the bat's sonar system must compute the three-dimensional positions of multiple auditory objects, which are continuously changing with respect to the bat as it flies. The bat's spatial perception of the auditory scene guides its selective control over the acoustic features of its vocalizations, which in turn yield new patterns of sonar echoes that are used to update its behavior. My talk will focus on perception and action for spatially-guided behavior in the echolocating bat. I will present data from insect capture studies that detail the bat's control over its flight path, head aim and sonar vocalizations. The data from these studies reveal distinct temporal patterns in the bat's sonar signal production that occur with target selection and interception, as well as obstacle avoidance. In addition, I'll describe neurophysiological studies of the superior colliculus of the bat, a midbrain structure implicated in orienting behavior. In particular, I will present data suggesting that the superior colliculus of the echolocating bat shows specializations to support audiomotor integration for acoustic orientation by sonar.

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