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PubMed1994

A panoramic code for sound location by cortical neurons.

By conventional spike count measures, auditory neurons in the cat's anterior ectosylvian sulcus cortical area are broadly tuned for the location of a sound source. Nevertheless, an artificial neural network was trained to classify the temporal spike patterns of single neurons according to sound location. The spike patterns of 73 percent of single neurons coded sound location with more than twice the chance level of accuracy, and spike patterns consistently carried more information than spike counts alone. In contrast to neurons that are sharply tuned for location, these neurons appear to encode sound locations throughout 360 degrees of azimuth.

Acoustic Stimulation↗

PubMed1993

Neural correlates of temporal integration in the cochlear nucleus of the chinchilla.

Single unit thresholds were measured as a function of stimulus duration for Primary-like and Chopper units in the anteroventral cochlear nucleus (AVCN) of the chinchilla to examine the neural correlates of temporal integration. Thresholds were measured with a two-alternative, forced-choice (2AFC) adaptive tracking procedure. The time constants and the slopes of the threshold-duration functions were estimated by fitting the threshold data with an exponential function and a power law function. The results showed that Primary-like units exhibited greater threshold improvement and a longer time constant than Chopper units. Units with low characteristic frequencies (CF) showed a larger decrease in threshold with increasing duration and a longer time constant than mid-CF or high-CF units. Units with low spontaneous rates (SR) showed a smaller threshold decrease with increasing duration and a shorter time constant than mid-SR or high-SR units. The single unit time constants and the rate of threshold improvement are similar to those measured psychophysically in the chinchilla.

Acoustic Stimulation↗