Biomedical subjects

V Monfort

Publications and source records attributed to V Monfort.

4 recordsLinked to original sources

PubMed2006

Trait-anxiety dependence of movement time performance in a bimodal choice task in subjects exposed to moderate anxiogenic conditions.

Recent studies have provided insight into the interdependence between state-anxiety, trait-anxiety and motor performances. In the present study, we investigated in very low trait-anxiety (VLTA) and normal trait-anxiety (NTA) subjects, the effects of moderate state-anxiety induced by the video-recorded Stroop color word interference test, on reaction time and movement time in bimodal choice response time task providing either visual or auditory modality. We found that in anxiogenic condition, movement time performances were improved in visual modality in NTA subjects, and in auditory modality in VLTA subjects. Our results show that depending on their trait-anxiety level, individuals exposed to anxiogenic condition would allocate attentional resources towards a specific relevant modality. Such attentional resources would influence movement time, but not reaction time.

Adaptation, Physiological↗

PubMed2002

Detection of polychlorinated biphenyls and dioxins in Belgian cattle and estimation of the maximal potential exposure in humans through diets of bovine origin.

The methodology used to detect a polychlorinated biphenyl (PCB)/dioxin contamination in a Belgian cattle population that was not exposed to the PCB/dioxin incident in 1999 is presented. This population is directly or indirectly destined for human consumption. The methodology consisted in the systematic sampling of all calf-fattening stations and groups of cattle destined for export, and in the random sampling of slaughter cattle. This approach is compared to the method described in directive 96/23/CE from the European Council. When PCB concentrations exceeded the tolerance level of 0.2 micro g/g body fat (seven congeners with numbers 28, 52, 101, 118, 138, 153, and 180), dioxins (seventeen 2,3,7,8-substituted congeners of PCDD and PCDF) were also determined. The prevalence of Belgian slaughter cattle with PCB concentrations above this cutoff was 0.3% (95% confidence interval: 0.01-1.50%). Results indicate that the incidence of contamination was minimal, with environmental origin and common in all industrial countries. The maximal potential exposure of an adult human consumer to dioxins through diet of bovine origin is estimated in two worst-case scenarios. The first one corresponds to the consumption of contaminated food products by a small number of consumers during a long period (local consumption) and the second simulates the consumption of contaminated products by a large number of consumers during a short period (supermarket purchase). The theoretical maximum daily intake of dioxins in adults was respectively 374 and 123 pg TEQ/d. The estimated maximum increase of dioxin body burden corresponds to 7 pg TEQ/g fat in the local consumption scheme and 0.07 pg TEQ/g fat in the supermarket consumption scheme.

Adult↗

PubMed2000

Role of frontal cortex in memory for duration: an event-related potential study in humans.

Event-related potentials were recorded in order to determine how brain activity is lateralized during the encoding and the recognition of visual durations (700 and 2500 ms ranges). It is assumed in the Hemispheric Encoding Retrieval Asymmetry model that the encoding of words, faces and odours involves left frontal areas whereas their recognition involves right frontal areas. The present results indicate that, for temporal information, the hemispheric bias is different: a negativity developed over right frontal electrodes for both encoding and recognition, and for both duration ranges. Thus, the involvement of right frontal areas appears critical for time perception. Conversely to what was expected, contingent negative variation during recognition was large over both left and right frontal electrodes. These results suggest that the involvement of both hemispheres is necessary for recognition of temporal information.

Adult↗

PubMed1998

Timed active avoidance learning in lurcher mutant mice.

Lurcher mutant mice (+/Lc) which exhibit a massive loss of neurons in the cerebellar cortex and in the inferior olivary nuclei were subjected to an active avoidance learning task; the animals' avoidance response must occur within a small time window after a short or a long delay. The control mice needed a mean of 8.3 sessions of 10 trials (short delay group) and of 11.8 sessions (long delay group) and showed good retention after a 24 h interval. When subjected to the same number of sessions, the +/Lc mice were unable to learn the timing task. However, a subgroup of lurcher mutants was able to learn after a high number of sessions (25.4 sessions as a mean). There was no intergroup difference in the standard version of one-way active avoidance. These results indicate that the cerebellar cortex is involved in time processing during active avoidance. The cerebellum may be part of a loop including the cerebral cortex known to be involved in time perception. An alternative explanation is that the cerebellar mutant animals had persevering tendencies acquired during performance of the one-way avoidance task.

Animals↗