Biomedical subjects

Diane Dubreuil

Publications and source records attributed to Diane Dubreuil.

4 recordsLinked to original sources

PubMed2006

Are capuchin monkeys (Cebus apella) inequity averse?

It has been reported that capuchin monkeys reject a less preferred food (LPF) when they see a partner capuchin receive a more preferred food (PF) for performing the same task. This behaviour was taken as evidence of 'inequity aversion', but an alternative hypothesis is that capuchins reject the LPF because of the mere presence of the PF. We tested this hypothesis in a paradigm, which consisted of presenting two different foods (one PF and one LPF) on a tray and allowing the capuchin to take only the LPF. Refusals to initiate the trial and refusals to take and eat the LPF were higher when the PF was hidden (hiding condition) and when the PF was accumulated in sight but out of reach of the subject (accumulation condition) compared to when two pieces of LPF were placed on the tray (control condition). Interestingly, the subject behaved as in the control condition when its partner was given and ate the PF (partner condition). We argue that capuchins' refusals were due to the frustration of seeing and not obtaining the PF, and that seeing the partner eating increases the LPF acceptance.

Animals↗

PubMed2003

Head-only exposure to GSM 900-MHz electromagnetic fields does not alter rat's memory in spatial and non-spatial tasks.

Over the last decade, exposure to high frequency (2450 MHz) electromagnetic fields (EMFs) has been found to induce performance deficit in rodents in spatial memory tasks. As concern was expressed about potential biological effects of mobile communication microwaves, studies testing the effects of signals such as GSM were required. In a previous study, using head-only exposure to 900 MHz GSM EMF, we could not demonstrate any behavioural deficit in two simple learning tasks. The present study aimed at extending these results with more complex spatial learning tasks and a non-spatial task. In a first experiment, rats were trained in a radial-arm maze with a 10-s confinement between each visited arm. In a second experiment, a 15-min intra-trial delay was introduced after four visited arms. In a third experiment, non-spatial memory was tested in an object recognition task. In all experiments, performance of the head-only exposed rats (1 and 3.5 W/kg) was compared with that of sham and control rats. In the first experiment, a slightly improved performance was found after 3.5 W/kg exposure, a result that was not observed in the delay-task. In the third experiment, although some effects on exploratory activity were found, recognition memory was unaffected in exposed rats. Altogether, this set of experiments provides no evidence indicating that spatial and non-spatial memory can be affected by a 45-min head-only exposure to 900 MHz GSM EMF.

Animals↗

PubMed2003

Does the radial arm maze necessarily test spatial memory?

Since its design 25 years ago (Olton & Samuelson, 1976), the eight-arm radial maze has become very popular and is now widely used to assess spatial memory in rodents. Two versions of the full-baited maze protocol are present in the literature: with or without confinement between the visit of each arm. The confinement was introduced by Olton himself as early as 1977 (Olton, Collison, & Werz, 1977) to eliminate stereotypic behaviors that he had previously observed. It is widely regarded that the confinement prevents rodents from developing these response patterns, and as such it is considered an improved procedure to test spatial memory. Surprisingly, to the best of our knowledge, no study has been especially designed to demonstrate the efficacy of the confinement in blocking the stereotypic behaviors of the animals. The present study compares the strategies of rats trained with or without a confinement procedure. The results show that, after nine days of training, rats submitted to a 5- or a 10-s confinement reach the same level of performance as rats without confinement. The confinement totally prevents stereotypic behaviors like clockwise serial searching strategies which are often observed without confinement. Even a 0-s confinement is sufficient to prevent clockwise strategies, but rats seem to develop other stratagems which do not imply spatial memory. Furthermore, rats previously trained without confinement are unable to perform the task when confinement is introduced on a test day. In contrast, rats previously trained with confinement perform the task correctly when the confinement is no longer present. Thus, without confinement, good levels of performance can be achieved without precise spatial representations.

Animals↗

PubMed2002

Does head-only exposure to GSM-900 electromagnetic fields affect the performance of rats in spatial learning tasks?

The rapid expansion of mobile communication has generated intense interest, but has also fuelled ongoing concerns. In both humans and animals, radiofrequency radiations are suspected to affect cognitive functions. More specifically, several studies performed in rodents have suggested that spatial learning can be impaired by electromagnetic field exposure. However, none of these previous studies have simulated the common conditions of GSM mobile phones use. This study is the first using a head-only exposure system emitting a 900-MHz GSM electromagnetic field (pulsed at 217 Hz). The two behavioural tasks that were evaluated here have been used previously to demonstrate performance deficits in spatial learning after electromagnetic field exposure: a classical radial maze elimination task and a spatial navigation task in an open-field arena (dry-land version of the Morris water maze). The performances of rats exposed for 45 min to a 900-MHz electromagnetic field (1 and 3.5 W/kg) were compared to those of sham-exposed and cage-control rats. There were no differences among exposed, sham, and cage-control rats in the two spatial learning tasks. The discussion focuses on the potential reasons that led previous studies to conclude that learning deficits do occur after electromagnetic field exposure.

Animals↗