Luisa Scott, Ph.D. - US grants

DESCRIPTION:(adapted from applicant?s abstract) The addition of new neurons into an established neural pathway may facilitate behavioral plasticity but also require training to be behaviorally adaptive. In adult songbirds, species differences in the extent of neuronal incorporation correlate with differences in song degradation after adult deafening, and the aim of the proposed experiments is to test further this relationship between neuron addition and behavioral plasticity. First, an antimitotic agent will be used to attenuate neuron addition and then determine if this attenuates behavioral change after deafening. Second, behavioral plasticity after deafening will be prevented by lesioning a specific part of the avian song system, and it will be determined if this manipulation also attenuates the addition of new vocal motor neurons. Third, adult-generated neurons will be labelled with bromodeoxyuridine and in situ hybridization will be used to determine if the expression of NMDA receptor mRNAs in these neurons recapitualtes maturational changes associated with periods of enhanced plasticity during development. These experiments will elucidate how the addition of new neurons in adulthood affects behavior, and will shed light on the consequences of endogenously and exogenously promoted neurogenesis and neuronal recruitment in humans.

[unreadable] DESCRIPTION (provided by applicant): Principal neurons of the medial superior olive (MSO) compute sound location from interaural time disparities (ITDs) introduced by the physical separation of the ears. In turn, they encode horizontal sound location in their rate of action potential (AP) firing. It is not fully understood how MSO neurons' intrinsic electrical properties combine with their highly structured morphology (ie., channel expression/distribution) to support this submillisecond computation, particularly in the face of high frequency firing found in auditory brainstem pathways. Recent work shows AP backpropagation into the soma and dendrites is downregulated developmentally such that somatic APs are small in electrically mature neurons. Experiments in this grant will explore the mechanisms and functional significance for the electrical segregation of AP signaling from synaptic integration using immunohistochemistry and slice electrophysiology techniques. Results will uncover how the membrane properties of MSO neurons help to surmount the unique computational challenges associated with encoding brief sound localization cues embedded in high frequency signals. [unreadable] [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): Principal neurons of the medial superior olive (MSO) compute sound location from interaural time disparities (ITDs) introduced by the physical separation of the ears. In turn, they encode horizontal sound location in their rate of action potential (AP) firing. It is not fully understood how MSO neurons' intrinsic electrical properties combine with their highly structured morphology (ie., channel expression/distribution) to support this submillisecond computation, particularly in the face of high frequency firing found in auditory brainstem pathways. Recent work shows AP backpropagation into the soma and dendrites is downregulated developmentally such that somatic APs are small in electrically mature neurons. Experiments in this grant will explore the mechanisms and functional significance for the electrical segregation of AP signaling from synaptic integration using immunohistochemistry and slice electrophysiology techniques. Results will uncover how the membrane properties of MSO neurons help to surmount the unique computational challenges associated with encoding brief sound localization cues embedded in high frequency signals. [unreadable] [unreadable] [unreadable]