Figure 1. Video tracking and baseline firing rate calculation.
A Each rat's head position was tracked and used to isolate 1s periods of non-movement. B Operant head movements were measured accurately in the corner by a custom photocell device in order to reward vertical head movement responses with cocaine. A criterion head movement (PC2-PC5; <1s) produced an infusion. C Photographs of the actual photocell device mounted outside the corner of the operant chamber (top) and from the animal's perspective (bottom). D An animal's position tracked continuously over 10 trials of a self-administration session, plotted in alternating colors for clarity. E Positional data from an entire session overlaid with FR data, used to determine FRs during non-movement only.