LAY ABSTRACT IBN-9808411 The goal of this project is to study the spontaneously bursting neuron in a neuroethological context. For the past 40 years, numerous investigators have exploited the large size of this neuron and have used it in studies of the cellular and molecular mechanisms that underlie such important neuronal functions as spontaneous burst generation, synaptic and hormonal modulation of burst generation, synthesis and cellular processing of neuropeptides, modulation of the strength of synaptic connections between neurons, and the effects of aging of neuronal function. Neuron R 15 has thus become one of the most widely studied neurons in the animal kingdom and as such is an exemplar of spontaneously bursting cells. Nevertheless, there is nothing known about how it is active in the intact animal. This study will determine the physiological and behavioral conditions under which R15, as well as the neurons that modulate its activity, are active in the intact, freely behaving animal. This information will serve as a key to interpreting the vast literature that has been amassed concerning R15's cellular properties over the years. In addition, the data from the intact animal concerning R15's physiological firing patterns will be used to design experiments that determine how the synaptic input to RI5 modulates its bursting properties. These experiments will combine recording from identified neurons in intact, behaving animals, with detailed analyses in the isolated nervous system of the biophysical mechanisms by which bursting of R15 is modulated. By using R15 as a canonical example of a bursting neuron, we expect to add significantly to our fundamental understanding of the role of spontaneous burstors in the function of neural circuits. An important feature of this study will be a pilot project that will be part of a NSF-sponsored undergraduate course in neuroethology at the Institute of Neurobiology in Puerto-Rico. In addition to providing the first comparative data for this well studied neuron, our project will establish a collaborative liaison between Columbia University and the faculty and trainees of the Institute in Puerto Rico that will extend into to the future as an ongoing relationship. It will expose students from this predominately minority institution to a broader range of neuroscience research than they would otherwise experience.
