Figure 6. Use of existing ensemble code for CS-US relationship in a new context.
(A) After ~30 days of conditioning three rats underwent three recording sessions in a familiar (Epoch1/Box1) and novel (Epoch2/Box2) environment. (B) Conditioned responses (CRs) were absent during CS-alone trials (Box1 pink, Box2 beige) and high during CS-US trials (Box1 red; Box2 brown), with no apparent differences between familiar and novel environment. (C) Pseudocolor plots show normalized firing rate of 225 neurons (sampled across three rats) during four conditions (top left, ACS-US in Box1; top right, ACS-US in Box2; bottom left, ACS-alone in Box1; bottom right, ACS-alone in Box 2). Neurons were sorted based on ACS-evoked firing rate change during the Box1, ACS-US pairings (top: largest increase in neuron #1, bottom: largest decrease in neuron # 225). Ensemble activity during ACS-US pairings in Box 2 was similar to that during ACS-US in Box 1, but not to ACS alone trials. (D) The confusion matrix from an SVM classifier of trial type. Most errors were misclassifications of Box1 versus Box2 ACS-US trials. (E) Relative decoding accuracy (raw minus accuracy at chance ±SEM across 20 runs) between ACS-US versus ACS alone trials and Box1 versus Box2 trials. *** indicates p<0.001.