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. Author manuscript; available in PMC: 2017 Nov 3.
Published in final edited form as: Nat Neurosci. 2017 May 3;20(7):987–996. doi: 10.1038/nn.4568

Figure 3. MD-mPFC functional directionality dynamically shifts across task phases.

Figure 3

(a) Schema of simultaneous recording of MD LFP and mPFC single-units. (b) Representative mPFC single-unit phase-locked to MD LFP filtered in the beta frequency range (13–30Hz). Left: Red line depicts filtered beta oscillation overlaid on raw MD LFP (black line). Vertical black lines below indicate simultaneous mPFC spike times with grey shading displaying the trough of the simultaneously recorded MD beta oscillation. Right: Polar plot of the distribution of mPFC spikes relative to a single cycle of the MD beta oscillation for the same unit. (ci) Normalized phase-locking values (pairwise phase comparison (PPC)) for each mPFC neuron during the sample phase of the DNMS T-maze after shifting mPFC spikes in 10ms steps +/−100ms. Only mPFC units with peak PPC values meeting Bonferonni-corrected p values are included (Rayleigh’s circular test, p<0.05/21) (165/547). (cii) Histogram displaying the lag at which the peak PPC value for each neuron in (cii) occurred. Black triangle indicates mean lag value across the population (mean=3.5ms; 2-tailed Signrank, ns: p=0.38; z(164)=0.88). (di–ii) as in ci–ii but for significantly phase-locked units in the delay phase (246/547; mean=−14.8; 2-tailed Signrank, ***p=0.000005; z(245)= −4.58). (ei–ii) as in ci–ii but for significantly phase-locked units in the choice phase (153/547; mean=13.3; 2-tailed Signrank, ***p=0.0002; z(152)=3.68). (f) Cumulative distribution of significantly phase-locked units during the sample phase across lag times. Solid green curve indicates light off trials and dotted green curve indicates light on sample trials (2-sample Kolmogorov-Smirnov; ns, p=0.98; k=0.049). Horizontal black line indicates 50% proportion, while vertical black line indicates lag time of 0. (g) As in f but for significantly phase-locked units during the delay phase on light off trials (solid red curve) and light on delay trials (dotted red curve) (2-sample Kolmogorov-Smirnov; *p=0.01; k=0.14). (h) As in f but for significantly phase-locked units during the choice phase on light off trials (solid blue curve) and light on delay trials (dotted blue curve) (2-sample Kolmogorov-Smirnov; ns, p=0.28; k=0.11).