Fig. 2: Predictive firing in place cell ensembles developed with learning.
From: Hippocampal place cell sequences differ during correct and error trials in a spatial memory task
A Bayesian decoder (see Methods) was applied to ensemble spiking activity to estimate posterior probability distributions across sample-test trials. a–c The sum of posterior probability (P(x | n)) extending ahead of rats to the stop location (i.e., the sum of the maximum 5 posterior probabilities from 2 bins ahead of the rat’s current location to the stop location) as rats ran toward the stop location is shown for each trial (Multiple linear regression: n = 224 trials, no significant interaction effect between trial type and trial number: t(436) = −0.5, p = 0.6; no significant effect of trial type: t(436) = 0.5, p = 0.6; significant effect of trial number: t(436) = 2.1, p = 0.04). Regression lines are shown for sample and test trials separately (correlation coefficient: r = 0.26, p = 6.4 × 10−5 for sample and r = 0.19, p = 0.005 for test). Each dot indicates the sum for a lap of the indicated trial type. The sum is shown for all trials (a), correct trials (b), and error trials (c). d–f The maximum posterior probability (P(x | n)) estimates behind rats’ current positions (i.e., the maximum 5 posterior probabilities from the beginning of the track to a rat’s current position) was summed for each lap. In contrast to the results reported in (a–c), the sum of posterior probability behind a rat’s current position did not increase across trials for all trials (d; multiple linear regression model, n = 224 trials, F(3,439) = 2.2, p = 0.08; no significant trial type by trial number interaction effect: t(436) = −0.2, p = 0.8; no significant effect of trial type: t(436) = −0.8, p = 0.4; no significant effect of trial number: t(436) = −0.3, p = 0.8), correct trials (e), and error trials (f). g–i The sum of the posterior probability (P(x | n)) estimates from the beginning of the trajectory to the stop location is also shown for each lap for all trials (g; repeated measures ANOVA: n = 224 trials, no significant main effect of trial number: F(7,378) = 1.6, p = 0.2), correct trials (h) and errors trials (i).
