Fig. 3.

An example of a PbN cell with short-latency responses to taste stimuli. This cell showed excitatory responses to NaCl, sucrose, and MSG that began during the stimulus presentation (5 consecutive licks). A significant response to citric acid was also present and increased gradually in magnitude over ∼2.5 s following the first stimulus lick. In each panel, a raster of the stimulus trials is shown at top; each black dot marks the occurrence of a spike, and each colored triangle indicates the occurrence of a reinforced (producing fluid) lick. Taste stimulus presentation consisted of 12 μl of taste stimulus delivered after each of 5 consecutive licks. Taste stimulus delivery was then followed by 5 licks that each produced 12 μl of water separated by 4–6 dry licks where licking was not followed by any fluid delivery. The peristimulus time histogram (PSTH) for each response is shown at bottom of each panel. Inset, top right: extracellular waveform of the recorded cell.