Extended Data Fig. 2: Noise correlation between pairs of neurons is negative at reactivation, as predicted by the attractor model. | Nature Neuroscience

Extended Data Fig. 2: Noise correlation between pairs of neurons is negative at reactivation, as predicted by the attractor model.

From: Interplay between persistent activity and activity-silent dynamics in the prefrontal cortex underlies serial biases in working memory

Extended Data Fig. 2

Bump-attractor dynamics are characterized by negative pairwise noise correlations for cues presented between the preferred locations (within pref) of the two neurons, but not for other cues (outside pref) 6. a, Periods used in noise correlation analyses: early (activity-silent), and late fixation (reactivation; n=94 ensembles, zoom-in of Fig. 1c). Error shading, bootstrapped 95% C.I. b, In the computational model (n=1,000 independent simulations), bump reactivations from subthreshold traces are characterized by negative noise correlations only during reactivation for within-pref trials, following the nonspecific input drive (Fig. 4). c, Noise correlations of PFC pairs with dissimilar preferred angles (60° < Δθ < 120°, n=34 pairs) were lower in late than in early fixation for within-pref trials (bootstrap test, p=0.0001, n=34, Cohen’s d=0.61). d, On average, lower noise correlations occurred only during reactivation and in within-pref trials (ANOVA trial condition x time point, F(4)=2.5, p=0.06, n=34). For within-pref trials, noise correlations differed between early and late fixation (bootstrap test, p=0.0001, Cohen’s d=0.61, n=34), being negative in late (bootstrap test, p=0.035, Cohen’s d=-0.32, n=34), but positive in early fixation (bootstrap test, p=0.018, Cohen’s d=0.37, n=34). Correlations were positive in outside-pref trials both during late and early fixation (bootstrap test, p=0.024 and p=0.06, respectively), with no significant difference (two-sided bootstrap test, p=0.93, n=34). In addition, negative noise correlations diminished when using the previous saccade location rather than the previous stimulus as reference (paired bootstrap test, p=0.005, Cohen’s d=-0.47, n=34), suggesting that the bump diffused only during the delay period, but not after the saccade 6. Unless stated otherwise, all bootstrap tests were one-tailed in the direction of the model predictions in b. All error bars indicate ±s.e.m.

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