15 research outputs found

    Establishing links between abnormal eating behaviours and semantic deficits in dementia

    No full text
    The hypothesis that semantic deficits in dementia may contribute in producing changes in eating preferences has never been experimentally investigated despite this association has been clinically observed. We administered tasks assessing semantic memory and the Appetite and Eating Habits Questionnaire (APEHQ) to 23 patients with dementia (behavioural frontotemporal dementia, primary progressive aphasia, and Alzheimer\u2019s disease) and to 21 healthy controls. We used voxel-based morphometry and diffusion tensor imaging to identify regions and white matter tracts of significant atrophy associated with the performance at the semantic tasks and the pathological scores at the APEHQ. We observed that the lower the patients\u2019 scores at semantic tasks, the higher their changes in eating habits and preferences. Both semantic disorders and eating alterations correlated with atrophy in the temporal lobes and white matter tracts connecting the temporal lobe with frontal regions such as the arcuate fasciculus, the cingulum, and the inferior longitudinal fasciculus. These results confirm that semantic deficits underlie specific eating alterations in dementia patients

    The smell of terroir! Olfactory discrimination between wines of different grape variety and different terroir

    No full text
    The French term 'terroir' refers to the relationship between a particular wine and the specific place where it is produced. To date, no investigation has directly tested in an experimentally-controlled setting whether participants can detect different terroirs in wines, and if their level of expertise can modulate such performance. We investigated wine olfactory discrimination ability by using a computer-controlled olfactometer. Participants' ability to discriminate two wines only based on the olfactory features of their terroir (zone and vineyard), their variety (e.g., cabernet vs. merlot) or both was tested. Olfactory discrimination performance of both novices and wine-professionals reflected whether two wines differed by terroir, variety or both. Performance peaked when wines differed in both terroir and variety, with terroir being more easily discriminated than variety. These results, obtained by controlling for the first time the precision of the olfactory stimulation, provide insightful clues in understanding the wine appreciation process, specifically with respect to the perceptual aspects of terroir

    Distinct brain representations of processed and unprocessed foods

    No full text
    Among all of the stimuli surrounding us, food is arguably the most rewarding for the essential role it plays in our survival. In previous visual recognition research, it has already been demonstrated that the brain not only differentiates edible stimuli from non-edible stimuli but also is endowed with the ability to detect foods\u2019 idiosyncratic properties such as energy content. Given the contribution of the cooked diet to human evolution, in the present study we investigated whether the brain is sensitive to the level of processing food underwent, based solely on its visual appearance. We thus recorded visual evoked potentials (VEPs) from normal-weight healthy volunteers who viewed color images of unprocessed and processed foods equated in caloric content. Results showed that VEPs and underlying neural sources differed as early as 130 ms post-image onset when participants viewed unprocessed versus processed foods, suggesting a within-category early discrimination of food stimuli. Responses to unprocessed foods engaged the inferior frontal and temporal regions and the premotor cortices. In contrast, viewing processed foods led to the recruitment of occipito-temporal cortices bilaterally, consistently with other motivationally relevant stimuli. This is the first evidence of diverging brain responses to food as a function of the transformation undergone during its preparation that provides insights on the spatiotemporal dynamics of food recognition

    Optimizing the ITER NBI ion source by dedicated RF driver test stand

    No full text
    The experimental fusion reactor ITER will feature two (or three) heating neutral beam injectors (NBI) capable of delivering 33(or 50) MW of power into the plasma. A NBI consists of a plasma source for production of negative ions (extracted negative ion current up to 329 A/m2 in H and 285 A/m2 in D) then accelerated up to 1 MeV for one hour. The negative ion beam is neutralized, and the residual ions are electrostatically removed before injection. The beamline was designed for a beam divergence between 3 and 7 mrad. The ion source in ITER NBIs relies on RF-driven, Inductively-Coupled Plasmas (ICP), based on the prototypes developed at IPP Garching; RF-driven negative-ion beam sources have never been employed in fusion devices up to now. The recent results of SPIDER, the full size ITER NBI ion source operating at NBTF in Consorzio RFX, Padova, measure a beamlet divergence minimum of 12mrad and highlighted beam spatial non-uniformity. SPIDER results confirmed the experimental divergence found in smaller prototype sources, which is larger compared to filament-arc ion sources. Although prototype experiments have shown that the extracted current requirement can be achieved with minor design improvements, the beamlet divergence is expected to marginally achieve the design value of 7 mrad, which in multi-grid long accelerators results in unexpected heat loads over the accelerator grids. A contributor to the beam divergence is the energy/temperature of the extracted negative ions, so it is believed that plasma differences between the two source types play a role. Research is focused on the plasma parameters in the ion source. One RF driver, identical to the ones used in SPIDER, installed in a relatively small-scale experimental set-up, inherently more flexible than large devices, is starting operations devoted to the investigation of the properties of RF-generated plasmas, so as to contribute to the assessment of negative ion precursors, and of their relationship with the plasma parameters, particularly when enhancing plasma confinement. The scientific questions, that have arisen from the preliminary results of SPIDER, guided the design of the test stand, which are described in this contribution, together with the diagnostic systems and related simulation tools. The test stand, which shares with the larger experiment all the geometrical features and constraints, will allow technological developments and optimized engineering solutions related to the ICP design for the ITER NBIs.SPC-I
    corecore