Firing properties of chopper and delay neurons in the lateral superior olive of the rat.

摘要: Neurons in the lateral superior olivary nucleus (LSO) respond to acoustic stimuli with ”chopper response”, a regular repetitive firing pattern short and precise latency. In past, this has been attributed dendritic integration of synaptic inputs. We investigated possible contribution intrinsic membrane properties using intracellular recording techniques tissue slice preparation. found two electrophysiological classes neurons LSO. Chopper responded depolarizing current pulses single onset spike at short, latency close threshold repetitive, regular, but accommodating discharges greater intensities. An emphasis response subsequent rate accommodation resulted from activation voltage- time-dependent sustained outward rectification range depolarized rest. Responses hyperpolarizing were characterized by an inward rectification, which caused voltage sag negative –65 mV. Peristimulus time histograms multimodal, discharge regularity was evident narrow unimodal interspike interval low coefficients variation. The course usually fit best exponentials constants τ1=3–8 ms τ2=32–97 ms. Delay depolarization pulses. However, occurred prolonged, variable delay 25–180 High intensities evoked additional Activation transient conductance early repolarization, terminated as ramp, reaching after delay. Flat peristimulus spite Intracellular neurobiotin injections revealed morphological differences between these classes. large fusiform, bipolar distribution oriented perpendicular curvature small spherical, highly branched tortuous arbours origin orientation. are probably LSO principal cells olivocochlear efferent neurons, respectively. Our findings suggest that activity sound, vivo, is determined extent properties. Somato-dendritic inputs fundamental encoding interaural sound differences, non-linearities play important role determining postsynaptic patterns.