Simultaneous behavioral and neural (cochlear nucleus) measurement during signal detection in the rabbit

Classical conditioning of the rabbit nictitating membrane (NM) response was adapted as a model system for simultaneous measurement of behavioral and neural responses in auditory signal detection. Animals were trained to a 36-dB spectral-level white-noise CS paired with a corneal airpuff US. The CS intensity was then reduced to threshold, using a modified staircase procedure, and responses on detect and nondetect trials were compared for the same stimulus intensities. At threshold, the behavioral NM response was dichotomous, being present on detect trials and completely absent on nondetect trials. In marked contrast, evoked neural unit activity to the CS recorded from the anteroventral cochlear nucleus was clearly present and identical on both detect and nondetect trials, suggesting that the detection “decision” is made more centrally than the cochlear nucleus.