We next analyzed in more detail how the similarity between spontaneous and evoked patterns changed in time, using the same analyses as illustrated in Figure 2G. We divided each spontaneous and evoked period into three subperiods, in which we analyzed latency correlations. Figures 6K–6N shows how the similarity

of spontaneous patterns to evoked patterns changed over time in different experimental conditions. Consistent with the above analyses and with S1 data, only in desynchronized state was there a significant increase in similarity between spontaneous and evoked patterns, and this effect was not observed after injection of MK801 (mean slope ± SD: sure = −0.01 ± 0.04; scarb+tail = 0.04 ± 0.05; samph = 0.05 ±

0.04; sMK = 0.01 ± selleck chemicals llc 0.06; pure = 0.6; pcarb+tail = 0.046; pamph = 0.016; pMK = 0.53; t test). Note that, in urethane and MK801 conditions, the higher baseline similarity may make it harder for the similarity to increase even further. To address this concern, we repeated analyses only on a subset of the data with intermediate values of prestimulation similarity, thus ensuring that values of similarity in all conditions are likewise (un)affected by any ceiling effects. Consistent with the previous results, the increase in similarity was significant only in amphetamine, carbachol, and awake conditions (p < 0.001; t test), thus showing that our results are not an artifact of ceiling effects (see Figures S4C and S4D for details). Altogether, these results show that, in the desynchronized brain state, repeated presentation of stimuli results http://www.selleckchem.com/products/BIBW2992.html in stimulus-specific reorganization of subsequent spontaneous activity and this process likely depends on NMDA-mediated plasticity. To investigate if the persistent patterned activity observed under anesthesia in the desynchronized brain state also occurs in awake animals, we reanalyzed previously published data from

head-restrained rats passively listening to tones before (Experimental Procedures; Luczak et al., 2009). During stimulation, 1 s long tones were interspersed with 1 s periods of silence, and activity occurring during silent periods was regarded as spontaneous. Because we did not have a sufficiently long period of spontaneous activity before or after stimulation, we calculated correlations between spontaneous and evoked latencies for 10 min periods at the beginning and at the end of stimulation. We found a significant stimulation-induced increase of latency correlations in all animals (Δccawake = 1.74 ± 0.01 SEM; pawake < 0.01; t test; Figures 6E and 6J). Consistent with these results, we observed a gradual increase in similarity when analyzing all consecutive periods during stimulation (mean slope: s = 0.009 ± 0.009 SD; p = 0.01; Figure 6O). We further validated those findings by reanalyzing our data using template matching and EV analysis, which revealed consistent results.