Abdelkader Ennaceur

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 The first experiment assessed the effects of neurotoxic lesions in either the anterior cingulate cortex (ACc) or the retrosplenial cortex (RSc) on a test of object recognition. Neither lesion affected performance on this task, which takes advantage of the rat’s normal preference to spend more time investigating novel rather than familiar stimuli. In(More)
The effects of perirhinal (Prh) and fornix (Fx) lesions were compared on a series of spatial and nonspatial memory tests. These tests included delayed nonmatching-to-position in an operant chamber, a spatial (lever) discrimination and its subsequent reversals, delayed spatial alternation in a T-maze, and an object recognition memory test using both normal(More)
The effects of fornix lesions were examined in an object recognition memory test based on spontaneous exploration. In the standard condition an object (A) was presented in the sample phase and then presented again in the test phase alongside a new object (B). Both fornix-transected (Fx) and control (Co) rats spent more time exploring the new object than the(More)
The effects of lesions centred in the perirhinal cortex region (Prh) or in both the perirhinal cortex region and the fornix (Prh + Fx) were assessed in two different working memory tasks, one spatial the other nonspatial. For the spatial task the rats were tested in an eight arm radial maze, using a standard procedure in which they were rewarded for(More)
The effects of physostigmine and scopolamine were evaluated on working memory of rats in object recognition and radial-maze tests. Three doses of physostigmine hemi-sulfate (Phys: 0.05, 0.10 and 0.20 mg/kg), five doses of scopolamine hydrobromide (Scop: 0.125, 0.25, 0.5, 1.0 and 2.0 mg/kg), and one dose of scopolamine methylbromide (Mscop: 2.0 mg/kg) were(More)
The one-trial object recognition task involves memory of a familiar object in parallel with the detection and encoding of a novel object. It provides the basis for the study of a wide range of cognitive and neuropsychological functions and processes in rats and mice. However, unlike in humans, primate and pigeon studies, object recognition in rats and mice(More)
Traveling across time zones causes disruption to the normal circadian rhythms and social schedules because of travelers' shift in time. As the endogenous circadian timing system adapts slowly to new time cues, the phase relationship between biological rhythms and external time cues are out of synchronization for a period of time. This disturbance of(More)
Exposure to novelty has been shown to induce anxiety responses in a variety of behavioural paradigms. The purpose of the present study was to investigate whether exposition of naïve rats to novelty would result in a comparable or a different pattern of responses in an open space versus enclosed space with or without the presence of an object in the centre(More)
The present report describes the emotional responses of different strains of mice to exposure to a novel open space model of anxiety using a 3D spatial navigation task. The 3D maze is modification of the radial maze with flexible arms that can be raised above or lowered below the horizontal level of a central platform. To access the arms animals need to(More)
The present study, examines some issues in the measure and analysis of behavior in animals. Two strains of rats of both genders were used to illustrate and discuss these issues. We examined to what extent various behavioral measures reflect different or identical emotional or cognitive factors and, how sensitive are the various parameters of a task to(More)