Figure 4: Maintenance of cue encoding in the PFC is disrupted in KO mice.
A. Schematic of multi-electrode drive targeting the prelimbic region of frontal cortex (PFC).
B. Example rasters and PSTHs of control (black, left) or a KO (red, right) PFC neurons during the cued noisy discrimination task. To discriminate the PFC encoding of the meaning of noise predictive cue from the sensory aspects of cue stimulus, we included noise unpredictive cues. Only correct trials are shown, separated according to the cueing condition. Zero time indicates cue presentation (100msec duration, predictive cue – purple bar, unpredictive cue – green bar; PSTH scale bar: z-score = 1).
C. Example PSTHs from 5 simultaneously recorded control (black, left) or KO (red, right) PFC neurons. KO neurons show predictive cue selective response peaks concentrated near the start of the delay.
D. Distribution of peak times for control (top, black) or KO (bottom, red) mice as a percentage of total neurons showing distinct temporal profiles of peak concentration (totals for each genotype shown as inset pie-charts yellow – peak cells; p < 0.01, Binomial test, N = 4 control, 4 KO mice, n = 863 control, 947 KO total neurons).
E. Poisson Naïve bayes decoding of predictive cue against unpredictive cue in control (grey) or KO (red) mice showing a significantly weaker and less stable encoding in the KO (p < 8.5x10−89, MANOVA, N = 4 control, 4 KO mice, n = 863 control, 947 KO neurons recorded). Decoding was limited to the 100 most strongly task modulated cells in each trial set. Shaded region indicates 95% confidence intervals.
F. Schematic of Poisson Generalized linear model (GLM) used to model PFC spiking activity.
G. Example of GLM estimated coupling filters for PFC neurons in control (top) and KO (bottom) mice showing qualitatively similar coupling profiles across genotypes.
H. Quantification of the positive coupling for regular spiking (RS) neurons in PFC of control (grey) and KO (red) mice during the delay period. Values shown include coupling for each neuron to all other simultaneously recorded neurons, averaged for each cell. Coupling was significantly reduced in the KO during both periods suggesting that KO PFC exhibited reduced functional connectivity (p < 1.3x10−23, MANOVA, N = 4 control, 4 KO mice, n = 863 control, 947 KO neurons recorded, *** p < 0.001, rank-sum test)
Boxplots: median (line), quartiles (box), 95% confidence interval (whiskers)