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The hippocampus has been suggested to be involved in spatial (or configural) memory and also in the inhibition of certain response or goal alternatives. An increasing number of anatomical, physiological, and behavioral studies indicate that the hippocampus is functionally heterogeneous along the dorsal-ventral axis. Identification of distinct behavioral(More)
The effects of amygdala lesions on passive avoidance of drinking (dPA) and social interactions in a resident-intruder test were examined in two experiments that utilized different lines of Long-Evans hooded rats. The lesions were fairly well restricted to the rostral half of the central nucleus (rACe), or the cholinergically richly innervated basolateral(More)
Rats received small bilateral electrolytic or ibotenate lesions of the rostral part of the amygdaloid central (rACE) or lateral (rAL) nuclei, or caudal part of the basolateral nuclei (cBL), or electrolytic lesions of the dorsal hippocampus (HIPP). All groups were tested in a drinking passive avoidance (PA) task that appears less sensitive to deficits in(More)
Previous studies have suggested that the hippocampus may play an important role in some forms of inhibitory learning. The goal of the present study was to assess whether the hippocampus is also important for inhibition of fear acquired after serial feature-negative discrimination training. Rats were given aspiration lesions of the hippocampus either before(More)
The plasma corticosterone levels of rats were examined prior to their morning meal on Days 1, 7 and 20 of a regimen of 1 hr access daily to food mash and water. The relationship between external cues and meal provision was varied by feeding some groups immediately upon room entry each morning, and others with a variable interval 90-min delay. On Day 1,(More)
Pavlovian delay conditioning, in which a conditioned stimulus (CS) and unconditioned stimulus (US) co-terminate, is thought to reflect non-declarative memory. In contrast, trace conditioning, in which the CS and US are temporally separate, is thought to reflect declarative memory. Hippocampal lesions impair acquisition and expression of trace conditioning(More)
This study examined the nature of a stimulus-induced decrease in the plasma corticosterone levels of rats. Rats maintained on a 23-hr food and water deprivation regimen were fed each morning immediately upon entrance of the experimenter into the otherwise isolated animal quarters. After only 14 feeding trials, the rats showed a marked decrease in(More)
Sprague-Dawley male rats were deprived of food for 40 hr and subjected to sleep deprivation by the "flower pot" or handling intervention procedures during the final 24 hr. Five of six rats in the flower pot group exhibited stomach erosions. Only one rat in the handling group, and no rats in a food deprived control group showed such erosions. The flower pot(More)
The results of three experiments indicated that male hooded rats exhibit marked corticosterone elevations when they freely consume .740 mol/l (23.2% w/w) sucrose in tap water while nondeprived or .298 mol/l (9.8% w/w) sucrose when deprived of water for 36 hr. The magnitude of the corticosterone elevation was increased by lengthening the duration of prior(More)