Fig. 4. Blocking AMPA receptor endocytosis acutely alters place field formation dynamics.
A–D Linearized position and spike locations for one example cell from a Scrambled treated rat (A) and GluA23Y treated rat (C) and the lap-by-lap firing field (B, D) upon first exposure to a novel environment. Faster field formation was apparent in GluA23Y treated rats. E On the exposure day rats were administered GluA23Y or Scrambled peptide (2.25 μmol/kg IV) prior to a baseline exploration of the familiar configuration, followed by exploration of a novel configuration (gray shading). Place fields were highly correlated and similar between groups in the familiar configuration (n = 76 Scrambled in N = 6 rats, n = 60 GluA23Y in N = 6 rats), but were lower in the first several laps of a novel configuration (dark gray shading). Cells from GluA23Y treated rats were highly correlated by the second lap, relative to Scrambled peptide treated rats (Scrambled n = 76 baseline, n = 78 novel from N = 6 rats; GluA23Y n = 60 baseline, n = 72 novel from N = 6 rats). F The cumulative distribution of correlations on the first four laps developed progressively over four trials in Scrambled treated rats. G Highly correlated fields were established after a single lap in GluA23Y peptide treated rats. H Rats previously administered GluA23Y peptide (red) or Scrambled peptide (blue) were re-exposed to the novel environment (gray shading) after baseline exploration of the familiar environment. Lap by lap correlations were high in the familiar configuration in both groups, however only rats previously treated with Scrambled peptide showed highly correlated fields in the early laps on the previously novel environment (Scrambled n = 80 baseline, n = 91 novel from N = 6 rats; GluA23Y n = 67 baseline, n = 74 novel from N = 6 rats). I Cumulative distribution of correlations over the first four laps showed highly correlated field on re-exposure in Scrambled peptide treated rats. J Re-exposure in GluA23Y treated rats showed evidence of consolidation over early laps. In contrast, correlations developed over several laps in rats treated with GluA23Y peptide, reminiscent of the initial exposure to the environment in control rats. * indicates p < 0.05 follow-up t-test (two-way) comparison after significant lap by group ANOVA interaction, and p < 0.05 ks-test vs lap 4 distribution. Error bars represent ± SEM.