Understanding the biophysical properties of single neurons and how they process information is fundamental to understanding how brain works. The long-term objective of this proposal is to contribute to understanding the logic of information processing in the dendrites of individual vertebrate neurons. We will utilize new tools, based on a recently developed high-resolution imaging technique with intracellular voltage-sensitive dyes, to examine two notable spatial aspects of dendritic integration; (a) processing of sensory information in two functional compartments of mitral cells of the olfactory bulb and (b) functional subdivisions of CA1 pyramidal neuron dendritic tree. An accurate description of interactions between excitatory and inhibitory components in different dendritic compartments of mitral and tufted cells should facilitate understanding of the process of signal integration in the olfactory bulb. Such an understanding would be an important step toward comprehension of neuronal mechanisms involved in sensory perception. The postulate that synaptic amplification of the backpropagating action potential is restricted to the site of synaptic input is based on computer simulation and indirect experimental evidence. This is an important hypothesis because spatially restricted changes in excitability could functionally subdivide a neuron; multiple functional compartments, in turn, have important implications for synaptic integration and plasticity. The results of this analysis will bear on the basic neuroscience of signaling.
