Wesley A. White

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The present study examined the assumption that immediate food reward is the critical determinant of efficient performance on the radial maze. Food-deprived and nondeprived rats were run on a large-platformed, S-arm radial maze that was either baited or unbaited. Food-deprived rats that were rewarded entered significantly more novel arms in their first eight(More)
Although lesion studies suggest that the rat medial prefrontal cortex (mPFc) is involved in the process necessary for reversal of a particular set of contingencies, the nature of lesion-induced deficits is unclear. The involvement of rat mPFc in reversal of a simple spatial discrimination was examined in the present study. Our hypothesis was that(More)
Exposure to methamphetamine (METH) and phencyclidine (PCP) during early development is thought to produce later behavioral deficits. We postulated that exposure to METH and PCP during later development would produce similar behavioral deficits, particularly learning deficits in adulthood. Wistar rats were treated with METH (9 mg/kg), PCP (9 mg/kg), or(More)
Nicotine produces interoceptive stimulus effects in humans, which may be critical in understanding tobacco use. It has not yet clearly been demonstrated that discrimination of nicotine, or any drug, in humans is due to its central effects. We compared effects of mecamylamine (10 mg p.o.), a central and peripheral nicotine antagonist, on nicotine(More)
Ten female rats were fed early and late in the dark period of a 12-12 h light-dark cycle and then were fed at the same times in constant darkness. In both conditions rats were active prior to mealtimes and manifested no free-running components of activity. When the rats were placed in constant darkness and either were fed early and late in the inactive(More)
Large meals scheduled at greater-than-circadian periods (such as T = 31 h) tend to elicit enhanced activity approximately 24 h subsequent to receipt. These studies characterized the process responsible for this meal-engendered "circadian ensuing activity" (meal CEA). Female Sprague-Dawley rats were housed in stations containing a running wheel, pellet(More)
We examined the effect of presenting two meals at fixed times on the activity of six intact female rats. Rats maintained on a 12-12 h light-dark cycle were fed: ad lib, at two randomly chosen times during the active period, and at 3 and 9 h, 1 and 7 h, and 5 and 11 h after light offset. During ad lib and random feeding conditions, wheel turning primarily(More)
The effects of different schedules of cocaine administration on circadian activity patterns and locomotor sensitization were studied. Rats received intraperitoneal injections of either saline or 20 mg/kg cocaine at either 24- or 33-hr intervals for 8 cycles (development). After a 2-day withdrawal, they were given a cocaine challenge in a novel environment.(More)
RATIONALE Discrimination of a drug's interoceptive stimulus effects often depends substantially on training and testing conditions. OBJECTIVES We examined changes in nicotine discrimination behavior in humans as a function of lowering the training dose and of varying the discrimination testing procedure. METHODS Smokers and never-smokers (n=10 each)(More)
Using lesions and infusions, the present study investigated the way in which and the extent to which the ventral hippocampus (vHIP) modulates amphetamine-induced hyperactivity in rats. Rats were lesioned (excitotoxic or sham) in the vHIP or were implanted with cannulae for subsequent infusions. A high dose (12.5 microg/microl) of N-methyl-D-aspartate (NMDA)(More)