GUTFREUND Yoram (ISRAEL) (Fellow)
KNUDSEN Eric I. (Host)
Department of Neurobiology, Stanford University School of Medicine, Stanford, USA
Utilizing transgenic mice to study taste coding

Attending to behaviorally relevant stimuli is a fundamental process in an animal's interaction with its environment. Typically, attending to stimuli effects processes of perception, memory and learning. An important problem in cognitive neuroscience is to understand the neural basis of these effects. Barn owls in their natural habitat rely for survival on attending precisely and swiftly to auditory, as well as to visual, stimuli. Thus neuronal investment in such processes is expected to be significant. Barn owls have been used extensively and successfully as a model system for studying auditory localization and learning. This research has provided a wide base of knowledge concerning the manner in which auditory information is processed, represented and adjusted. However, in all previous experiments the owls have been anesthetized and immobilized. The major novelty of the proposed research is to perform such studies on awake behaving animals. This will enable us to address a whole range of new questions relating to cognitive processes.

Recently developed techniques allow stable extra-cellular recordings in awake, moving animals. These have been used successfully in a wide variety of species, including songbirds (Dave et al., Science, 1998, 282:2250-2254). The general strategy of the proposed study is to apply one of these techniques to the barn owl auditory localization pathway. This will allow us to identify and study signals which are involved in attentional processes including those which induce and guide experience-dependent plasticity.

The experiments will involve implanting electrodes in the midbrain auditory localization pathway and measuring single unit activity while the barn owl performs the task of orienting to stimuli (visual, auditory or bimodal). Experiments will be performed in normal owls, owls with previously altered sensory experience and owls that are at a transition state where two auditory maps coexist. By manipulating the locations of the stimuli relative to the receptive field of the recording site and relative to the gaze orientation it will be possible to identify and study signals which are associated with attention processes and/or learning.