Facilitation of acquisition and performance of operant and spatial learning tasks in self-stimulation experienced rats.

Abstract

Adult male Wistar rats were implanted bilateraly with bipolar electrodes in substantia nigra-ventral tegmental area (SN-VTA) to experience intracranial self-stimulation (ICSS) for 15 min per day over a period of 10 days. These rats were then assessed for the acquisition and performance of the operant and the spatial learning tasks. ICSS experienced rats showed rapid acquisition of both the operant and the spatial learning tasks. Both the lever press performance for 7 sessions in the operant learning task and mean number of alternations per session in the spatial learning task were significantly higher (p < .001) in ICSS experienced rats compared with controls. The results suggest that prior ICSS experience facilitates the acquisition and performance in both the operant and the spatial learning tasks, which may be due to the structural and neurochemical alterations in the hippocampus induced by ICSS experience.

Reversal of stress-induced dendritic atrophy in the prefrontal cortex by intracranial self-stimulation

“…When the current results are examined in conjunction with our earlier reports that ICSS facilitates learning in operant and spatial learning tasks (Yoganarasimha et al 1998;Ramkumar et al 2008), it is plausible that the enhanced learning could be at least in part due to the increased dendritic arborization of the PFC neurons.…”

“…When the effects of stress and ICSS on the T-maze task in our earlier study and the effects on the morphology of PFC neurons in the current study are examined together, it is reasonable to speculate that the plasticity of PFC neurons are responsible at least in part for the behavioral effects considering that the T-maze task is thought to recruit the PFC (de Brabander et al 1991). In addition to reversal of stress-induced deficits, earlier studies show that ICSS ameliorates fornix lesion-or parafascicular nucleus lesion-induced learning impairments (Yoganarasimha et al 1998;Redolar-Ripoll et al 2003).…”

“…The electrode implantation, behavioral testing and training for ICSS were done as described earlier (Shankaranarayana Rao et al 1993, 1998a, b, 1998c, 1999bYoganarasimha et al 1998). ICSS and ST ?…”

Self-Stimulation Rewarding Experience Restores Stress-Induced CA3 Dendritic Atrophy, Spatial Memory Deficits and Alterations in the Levels of Neurotransmitters in the Hippocampus

“…In contrast to the effects of stress, ICSS increases the dendritic arborization [20][21][22], spine and synaptic density in CA3 pyramidal neurons [23][24][25] and enhances the levels of noradrenaline (NA), dopamine (DA), glutamate, and acetylcholinesterase (AChE) activity in the hippocampus [26]. In addition, ICSS experience facilitates the acquisition and performance in operant and spatial learning tasks and ameliorates the fornix lesion induced spatial learning deficits [27,28].…”

Conditioned drug reward enhances subsequent spatial learning and memory in rats

“…Previous studies have shown that when drug reinforcement has been repeatedly paired with drug-associated cues, these conditioned cues can elicit Pavlovian approach responses and preference for the drug-paired environment (Bardo and Bevins 2000). In preclinical studies, stimuli that are associated with reinforcement and increased dopamine release in the mesolimbic system, such as intracranial selfstimulation (ICSS), have been shown to enhance the performance of a variety of learned responses including operant and spatial learning (Aldavert-Vera et al 1996;Segura-Torres et al 1988, 1991Yoganarasimha et al 1998). Stimulant drugs such as amphetamine and cocaine (as well as others), but not aversive stimuli such as those associated with opiate withdrawal, exaggerate the incentive salience of conditioned stimuli that are closely associated in space and time with self-administered drugs (Robinson and Berridge 1993).…”