5% ± 2.1%; UT: 37.4% ± 2.1%; p = 0.97). A similar classification was performed after a swapping procedure to determine the contribution

of single taste-responsive neurons. Selleckchem Dasatinib Responses for neurons that were taste specific in the first bin of the ExpT condition were swapped with those evoked by UT. The performance for UT significantly increased (32.4% ± 2.1%; p < 0.01), whereas ExpT classification significantly decreased (30.5% ± 1.8%; p < 0.05), making the difference in classification for the two conditions no longer statistically significant (p = 0.41). The contribution of taste-specific neurons was determinant in mediating the faster onset of stimulus coding. To further understand the factors determining the improvement in early taste coding, response tuning and trial-to-trial variability were computed. Breadth of tuning was quantified by analyzing the entropy of response profiles (H; see Smith and Travers, 1979, for its standard application to taste coding) for the neurons mediating the increase in taste coding. Trial-to-trial variability was determined by measuring the average Euclidean distance between single-trial population Pfizer Licensed Compound Library ic50 responses for each session (in Figure 1E referred to as dissimilarity index). In the first 125 ms bin,

the average H value for responses to ExpT showed a small, but significant, decrease relative to that for UT (0.89 ± 0.01 for ExpT and 0.95 ± 0.01 for UT, p < 0.01 n = 32; Figure 1D, black trace), indicating that responses to ExpT are more narrowly tuned. In the same bin, population responses for ExpT had a significantly lower trial-to-trial Histone demethylase variability (average Euclidean distance: 0.59 ± 0.02 for ExpT and 0.76 ± 0.02 for UT, p < 0.01 n = 152 Figure 1E, black trace). Thus, narrowing of tuning and reduction of trial-to-trial variability co-occurred in the first bin. Responses to ExpT in the second 125 ms bin, on the other hand, showed a very small decrease in H (0.87 ± 0.02 for ExpT and 0.90 ± 0.02 for UT,

p < 0.01 n = 32; Figure 1D, gray trace) and a trending, but no significant increase in the trial-to-trial variability (0.63 ± 0.02 for ExpT and 0.69 ± 0.02 for UT, p = 0.06 n = 152; Figure 1E, gray trace). Figure 1F displays a representative example of a neuron changing its breadth of tuning in response to ExpT. The histograms on the right in Figure 1F detail response profiles in the first 125 ms bin and show a slight sharpening of the tuning in favor of expected sucrose. Figure 1G shows dissimilarity matrices and the corresponding trial-by-trial ensemble responses in the first bin for a representative session, further confirming the differences in trial-to-trial variability in response to UT and ExpT. Visual inspection of the representative responses to ExpT in Figure 1F highlights an additional feature of responses to ExpT: the presence of a prestimulus ramp in firing rates at the time in which auditory cues are presented (see vertical black lines).