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. Author manuscript; available in PMC: 2011 Feb 1.
Published in final edited form as: Nat Neurosci. 2010 Jul 4;13(8):979–986. doi: 10.1038/nn.2594

Figure 1.

Figure 1

Activity of LA neurons during acquisition of fear conditioning. (a) freezing behaviour during the 20 s CX (open white bars) and CS (shaded bars) periods is graphed on the Y-axis before (pre) and after (post) fear conditioning (*p =.004, **p=.0007 for Newman-Keuls posthoc tests). (b) Normalized stimulus-evoked responses (y-axis) averaged over the population of shock responsive LA neurons (n=27) for each of the four conditioning trial blocks (4 trials/block) and for the first four trials of the pre- and post-conditioning test sessions. (c) Pie chart showing the percentage of shock-responsive LA cells that significantly reduced (−), increased (+) or did not change (0) their US-evoked responses between the first (early) and last (late) conditioning trial block. (d) Pie chart showing the percentage of shock responsive LA cells that significantly changed their CS-evoked responses between the pre- and post-conditioning test sessions. (e) top graph, PSTH (bin size=100 ms) shows normalized activity during shock trains (individual shock pulses indicated by red hash marks) for early versus late conditioning trials, averaged over the subpopulation of LA neurons that significantly reduced their shock evoked response (n=12); bottom graphs, PSTHs and spike rasters show US-evoked responses for two example neurons from different rats, along with waveforms and cluster plots for spikes fired during the session (‘ppX v ppY’ above scatter plots denotes channel numbers for peak-to-peak spike voltages plotted on the X and Y axes, respectively). (f) top graph, PSTH (bin size = 2 ms) shows CS-evoked responses (onset of white noise pip indicated by vertical line) during the pre- versus post-conditioning test sessions for the subpopulation of LA cells shown in ‘E’; bottom graphs, CS-evoked responses for the same two example neurons shown in ‘E’. (g) Responses to the US (left y-axis) on each of the 16 conditioning trials (averaged over the subpopulation of LA cells that significantly reduced their US responsiveness during conditioning) is graphed alongside average freezing scores (right y-axis) during the CS period on each trial.