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 choices than expected by chance, cons...

Nucleus accumbens (NAcc) are a collection of neurons that form the main part of the ventral striatum, which is a significant dopaminergic structure. Also, NAcc is thought to play an important role in reward, pleasure, laughter, addiction, aggression, fear, and the placebo effect. In the present work we were interested in studying the effects of a 6-OHDA induced lesion in the nucleus accumbens (...

The present study was designed to evaluate the learning and memory, in an altered physiological state associated with increased blood pressure and activated renin angiotensin system in Wistar rats. The role of angiotensin in cognitive function was assessed by treatment with angiotensin converting enzyme (ACE) inhibitor enalapril (2 mg/kg), angiotensin 1 receptor (AT(1)) antagonist losartan (5 m...

We previously demonstrated that degus (Octodon degus), which are a species of small caviomorph rodents, could be trained to use a T-shaped rake as a hand tool to expand accessible spaces. To elucidate the neurobiological underpinnings of this higher brain function, we compared this tool use learning task with a simple spatial (radial maze) memory task and investigated the changes that were indu...

several studies point to an important function of cyclooxygenase (cox) and prostaglandin signaling in models of synaptic plasticity which is associated with n-methyl-d-aspartate receptors (nmdars). cyclooxygenase gene is suggested to be an immediate early gene that is tightly regulated in neurons by nmda dependent synaptic activity. nonsteroid antiinflammatory drugs (nsaids) exert their antiinf...

It has been proposed that there are paradoxical sleep windows (PSW) during which REM sleep is required for effective learning. Thus, rats deprived of REM sleep during 0-4 (but not 5-8) h after training show impaired learning of a radial maze task. As cholinergic (ACh) systems are active during REM sleep and may be involved in learning, this experiment investigated the effects on learning of pha...

The present study examined the effects of electrolytic lesions of the Medial SeptumrVertiŽ . Ž . cal Diagonal Band of Broca MSrVDBB , the Globus Pallidus GP and the SubstantiaŽ . InnominatarVentral Pallidum SIrVP on the performance of rats in object-recognition memory and radial-maze learning tests. In the latter test, subgroups of sham-operated, MSrVDBB, SIrVP and GP rats were treated with sal...

Pfiesteria piscicida Steidinger & Burkholder, an estuarine dinoflagellate known to kill fish, has also been associated with neurocognitive deficits in humans. We have developed a rat model to determine the cause-and-effect relationship between exposure to Pfiesteria-containing water and cognitive impairment and to determine the neurobehavioral mechanisms underlying the Pfiesteria effect. The ra...

Anxiolytic benzodiazepines, at low doses, reportedly impair the radial arm maze with nonspatial visual/tactile but not spatial cues. We replicated the former result controlling for changes in drug state and cue effectiveness. Rats learned an eight-arm radial maze with reward in only four arms. The reward varied in spatial position from trial to trial but was always cued by a piece of sandpaper ...

The present study tested the effects of electrolytic lesions in two mPFC subregions, the dorsal anterior cingulate area (dACA) and prelimbic cortex, as well as the effects of a larger medial prefrontal cortex (mPFC) lesion which included both subregions, on 4-arm baited, 4-arm unbaited, 8-arm radial maze task and its reversal (Experiments 1 and 4), two-way active avoidance (Experiments 2 and 5)...