Temporal coding of sensation: mimicking taste quality with electrical stimulation of the brain.

Two experiments suggested that the temporal pattern of a taste response in the brain can convey meaningful information. In Experiment 1, rats avoided lick-contingent electrical stimulation of the nucleus of the solitary tract (NTS; the first synaptic relay for taste) when the temporal pattern of pulses mimicked the electrophysiological response to quinine, but not when the temporal pattern was randomized. In Experiment 2, rats avoided lick-contingent electrical stimulation of the NTS that mimicked the temporal pattern of a sucrose response following stimulation-illness pairings. This aversion generalized to sucrose but not to the other tastants; extinction of the aversion to electrical stimulation also extinguished the aversion to sucrose. Results replicate and extend previous findings (P. M. Di Lorenzo & G. S. Hecht, 1993).