Beckman Fellow 1993-94

Mark E Nelson

Molecular & Integrative Physiology

Control of Sensory Acquisition in Weakly Electric Fish

A common goal of biological sensory systems is to acquire useful information for guiding or influencing behavior. Because the content and quality of incoming sensory signals are often critical to an animal's survival, many sensory systems have evolved complex mechanisms for actively controlling the sensory acquisition process to ensure that high quality data is being collected. The long-term objective of this research is to gain an understanding of the neural system. The mechanisms associated with sensory acquisition can be grouped into two broad categories: those dealing with the control of neural response properties in sensory processing pathways (adaptive signal processing aspects) and those dealing with the active positioning of peripheral sensory structures (motor control aspects). The objective of Professor Nelson's research is to gain an understanding of both types of mechanisms and the associated information processing principles.

The research proposed will investigate both adaptive signal processing and motor control aspects of sensory acquisition in the electrosensory system of weakly electric fish. Although this is a somewhat unusual sensory system, it provides an excellent opportunity to study both aspects of sensory acquisition simultaneously and it offers several technical advantages over more common vertebrate sensory systems, such as the visual and auditory systems. In these adaptive signal processing studies, the team will investigate neural mechanisms involved in the descending modulation of stimulus filtering properties in the electrosensory lateral line lobe (ELL). The motor control studies will quantify the behavioral strategy use by weakly electric fish when carrying out electrosensory discrimination tasks. Professor Nelson's team will make use of computer modeling and simulation techniques to elucidate underlying neural mechanisms and will use theoretical analysis to examine the sensory acquisition process from an information processing point of view.