Conjunctive Processing of Locomotor Signals by the Ventral Tegmental Area Neuronal Population
(A) Peri-event rasters and histograms of four simultaneously recorded VTA neurons in response to the conditioned tone that reliably predicted food delivery (units 1 & 2: putative DA neurons; units 3 & 4: non-DA neurons). (B) Smoothed cross-correlation histograms of the same four neurons (as shown in A) during voluntary wheel running. Unit 3 was used as the reference for cross-correlation calculations. (C) Smoothed cross-correlation histograms of shuffled units 1 and 2 (randomized spikes). The same unit 3 (as shown in B) was used as the reference for cross-correlation calculations. (D) Correlation coefficient analyses and comparisons between the recoded and shuffled spikes. A set of simulated sine oscillation curves y = sin (ax + b) were used as the reference for the correlation coefficient analysis (see Materials and Methods). n = 14 and 29 for DA and non-DA neurons, respectively; *P<0.001, Student's paired t-test. Error bars represent s.d.