Reversible effects of ambient housing stimulation upon stimulation-seeking in rats

Two types of housing condition, low and high ambient stimulation, were alternated. The effects of this treatment upon rats' subsequent stimulation-seeking behaviour were assessed in a multiple-choice head-input apparatus. The aim of the experiment was to determine whether adult animals would adapt and re-adapt to varying periods of upward and downward shifts in the levels of housing stimulation. A given housing-stimulation had a lawfully cumulative effect which could be completely reversed when housing conditions altered. The most sensitive measures were latency and response rate in the first 5 min of the test. One measure, relative preference for illuminated stimuli over a dark stimulus, gave an indication of the time-lag involved in adaptation to a new housing condition.