3% ± 5.4% of amplitude ExpT). A small, significant difference was observed in their latency: ExpT evoked mouth movements at 66 ± 4 ms, whereas UT at 96 ± 6 ms. Palatability-related

behaviors (i.e., tongue protrusions and gapes) also showed differences in the two conditions. In general Y-27632 clinical trial ExpT evoked more tongue protrusions and less gapes than UT, indicating an expectation-dependent increase of perceived palatability and reduction of aversiveness (Table S1). These types of behaviors occurred at a latency longer than 125 ms (Figures 2A, 2B, and S1; Table S1). The results presented here demonstrate the effects of cue-triggered expectation on temporal processing of gustatory stimuli in alert animals and describe cortical and amygdalar anticipatory signals responsible for this modulation. Analysis of temporal dynamics of spiking

responses in GC revealed that expectation effects were maximal in the early portion of the response. Early changes in firing rates evoked by ExpT resulted in more rapid coding of gustatory information. This effect was mediated by an increase in the number of neurons that were selective for expected tastants, by a sharpening of their tuning, and by a reduction of trial-to-trial variability selleck screening library in ensemble responses. These changes were related to anticipatory modifications of the cortical state triggered by the associative cue prior to gustatory stimulation. Cues predicting the availability of gustatory stimuli dramatically altered the activity of GC neurons. Multiple lines of evidence confirmed that cue responses in GC were not secondary to mouth movements. Instead, they appeared to emerge with learning and were the result of top-down inputs from BLA, a hub of anticipatory signals known to project to GC. Further analysis of responses

from putative pyramidal neurons unveiled a strong correlation between cue-evoked Phosphatidylinositol diacylglycerol-lyase responses and activity triggered by UT. Similarly to early activity evoked by UT, which is not specific to the chemical identity of the stimulus, cue-evoked responses acted by priming cortical circuits. The presence of the anticipatory priming before delivery of ExpT allowed GC to “save” time and more readily encode expected tastants. Although no analysis of the correlation patterns was performed on interneurons (due to the small sample size), the same analyses applied to the entire population of cue-responsive neurons yielded similar results. Gustatory cortical neurons process taste-related information via dynamic modulations of firing activity (Gutierrez et al., 2010, Jones et al., 2006, Katz et al., 2002 and Stapleton et al., 2006). Three temporal windows, each coding different aspects of gustatory experience, have been classically described in the time course of responses to UT delivered via IOC (Fontanini and Katz, 2006, Grossman et al., 2008 and Katz et al., 2002).