Recovery from prior stimulation. I: Relationship to spontaneous firing rates of primary auditory neurons.

Recovery of neural thresholds following a forward masker was measured for auditory neurons in anesthetized chinchillas. We find that recovery of forward-masked thresholds is slower for low spontaneous-rate neurons compared to high spontaneous-rate neurons. In addition, we studied the dependence of the shape of PST histograms on the time between repetitions of a tone-burst. We find that for low spontaneous-rate neurons, peak onset responses increase in magnitude over a longer range of interstimulus intervals compared to high spontaneous-rate neurons. Both results are consistent with the conclusion that low spontaneous-rate neurons take longer to recover from prior stimulation compared to high spontaneous-rate neurons. We suggest applications of this finding in psychophysical experiments to investigate the role of low spontaneous-rate neurons in intensity coding.