Lawrence C. Katz, Ph.D.
Olfactory Behaviors and the Brain
Summary: While humans interpret the world primarily through their well-developed visual and auditory senses, most other mammals use their acute sense of smell to detect predators, defend territory, recognize other individuals, and find food and mates. To accomplish these myriad functions, mammals are equipped with two distinct chemosensory organs: the main olfactory system, which detects airborne odors, and the vomeronasal system, which detects species-specific signals called pheromones. Until his recent death, Lawrence Katz's lab used the mouse as a model to examine how olfactory signals important for basic, built-in behaviors are encoded by these two distinct systems, and how the neural circuits they activate elicit species-specific behaviors.
Using brain-imaging techniques, we have visualized the representations of individual odorants and mixtures in space and time in the living brain. Advanced microscopy techniques have allowed us to visualize the microstructure of neuronal circuits in living mice and to follow changes in these circuits as animals learn new olfactory tasks. Electrophysiological recordings in awake, behaving animals are used to probe the relationships between real-world problems of odor discrimination and the behavior of neuronal ensembles. Recordings of brain activity, in conjunction with sophisticated chemical analytical techniques, have enabled us to uncover the special smells used by animals to communicate their identity and sex to other members of their species.
We are also continuing our investigations of circuit formation in the developing mammalian visual system, a widely studied model of developmental plasticity. In the search for innate molecular cues responsible for the initial development of cortical circuits, we have uncovered molecular correlates of visual processing streams in the mammalian brain.
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