The forebrain is the part of the brain of vertebrates that has evolved into the elaborate cerebral hemispheres. Roughly half of all vertebrate species are bony fishes, yet we know very little about the forebrain structure of this important group. This project will clarify the identity of the neuronal fields in the two major anterior parts of the brain, the telencephalon and diencephalon, in bony fishes. Anatomical studies will follow four lines of approach. 1) Distribution of certain chemical markers will be studied by antibody binding, to identify regions that are comparable to similarly studied regions in the forebrain of other vertebrates. 2) Patterns of connections between forebrain and other brain regions will be determined by local uptake and neuronal transport of certain tracer substances. 3) The unusual development of the forebrain in these fish will be analyzed to better understand the origins and correspondences of certain structures with those found in other vertebrates. 4) Comparisons will be made among fish species that are closely related evolutionarily, but have diverse lifestyles and differentially developed sensory systems, to gain insight into the functional significance of specific regions of the forebrain. This work will provide a morphological foundation for physiological and behavioral studies, lead to better understanding of the organization and evolution of the vertebrate brain, and reveal new aspects of form and functional relations in the forebrain. It will be important to neuroscience in general, beyond just sensory, motor, or neuroscience, and perhaps important to brain modelers.
