Effects of priming stimulation of catecholamine containing nuclei in rat brain on runway performance

Rats were implanted with bipolar fine wire stimulating electrodes in the region of the pontine nucleus locus coerulus (LC) and the pars compacta of the substantia nigra (SN). The reinforcing properties of stimulation of each electrode were determined. Subsequently, rats were run in a two alley runway and the effects of priming stimulation on performance in acquisition, discrimination and reversals were measured. It was found that LC priming caused an increased latency to exit from start box. Also, LC priming reduced running time in the rewarded alley in a reversal task whereas SN priming affected both performance in the rewarded and non-rewarded alley.