Does my brain want what my eyes like? - How food liking and choice influence spatio-temporal brain dynamics of food viewing.

How food valuation and decision-making influence the perception of food is of major interest to better understand food intake behavior and, by extension, body weight management. Our study investigated behavioral responses and spatio-temporal brain dynamics by means of visual evoked potentials (VEPs) in twenty-two normal-weight participants when viewing pairs of food photographs. Participants rated how much they liked each food item (valuation) and subsequently chose between the two alternative food images. Unsurprisingly, strongly liked foods were also chosen most often. Foods were rated faster as strongly liked than as mildly liked or disliked irrespective of whether they were subsequently chosen over an alternative. Moreover, strongly liked foods were subsequently also chosen faster than the less liked alternatives. Response times during valuation and choice were positively correlated, but only when foods were liked; the faster participants rated foods as strongly liked, the faster they were in choosing the food item over an alternative. VEP modulations by the level of liking attributed as well as the subsequent choice were found as early as 135-180ms after food image onset. Analyses of neural source activity patterns over this time interval revealed an interaction between liking and the subsequent choice within the insula, dorsal frontal and superior parietal regions. The neural responses to food viewing were found to be modulated by the attributed level of liking only when foods were chosen, not when they were dismissed for an alternative. Therein, the responses to disliked foods were generally greater than those to foods that were liked more. Moreover, the responses to disliked but chosen foods were greater than responses to disliked foods which were subsequently dismissed for an alternative offer. Our findings show that the spatio-temporal brain dynamics to food viewing are immediately influenced both by how much foods are liked and by choices taken on them. These valuation and choice processes are subserved by brain regions involved in salience and reward attribution as well as in decision-making processes, which are likely to influence prospective dietary choices in everyday life

Brain dynamics of meal size selection in humans.

Although neuroimaging research has evidenced specific responses to visual food stimuli based on their nutritional quality (e.g., energy density, fat content), brain processes underlying portion size selection remain largely unexplored. We identified spatio-temporal brain dynamics in response to meal images varying in portion size during a task of ideal portion selection for prospective lunch intake and expected satiety. Brain responses to meal portions judged by the participants as 'too small', 'ideal' and 'too big' were measured by means of electro-encephalographic (EEG) recordings in 21 normal-weight women. During an early stage of meal viewing (105-145ms), data showed an incremental increase of the head-surface global electric field strength (quantified via global field power; GFP) as portion judgments ranged from 'too small' to 'too big'. Estimations of neural source activity revealed that brain regions underlying this effect were located in the insula, middle frontal gyrus and middle temporal gyrus, and are similar to those reported in previous studies investigating responses to changes in food nutritional content. In contrast, during a later stage (230-270ms), GFP was maximal for the 'ideal' relative to the 'non-ideal' portion sizes. Greater neural source activity to 'ideal' vs. 'non-ideal' portion sizes was observed in the inferior parietal lobule, superior temporal gyrus and mid-posterior cingulate gyrus. Collectively, our results provide evidence that several brain regions involved in attention and adaptive behavior track 'ideal' meal portion sizes as early as 230ms during visual encounter. That is, responses do not show an increase paralleling the amount of food viewed (and, in extension, the amount of reward), but are shaped by regulatory mechanisms

The impact of replacing sugar- by artificially-sweetened beverages on brain and behavioral responses to food viewing - An exploratory study.

Several studies indicate that the outcome of nutritional and lifestyle interventions can be linked to brain 'signatures' in terms of neural reactivity to food cues. However, 'dieting' is often considered in a rather broad sense, and no study so far investigated modulations in brain responses to food cues occurring over an intervention specifically aiming to reduce sugar intake. We studied neural activity and liking in response to visual food cues in 14 intensive consumers of sugar-sweetened beverages before and after a 3-month replacement period by artificially-sweetened equivalents. Each time, participants were presented with images of solid foods differing in fat content and taste quality while high-density electroencephalography was recorded. Contrary to our hypotheses, there was no significant weight loss over the intervention period and no changes were observed in food liking or in neural activity in regions subserving salience and reward attribution. However, neural activity in response to high-fat, sweet foods was significantly reduced from pre-to post-intervention in prefrontal regions often linked to impulse control. This decrease in activity was associated with weight loss failure, suggesting an impairment in individuals' ability to exert control and adjust their solid food intake over the intervention period. Our findings highlight the need to implement multidisciplinary approaches when aiming to help individuals lose body weight

Troubles cognitifs et interventions non médicamenteuses : qualité de vie des patients et de leurs proches [Cognitive impairment and non-medical interventions: quality of life of patients and their caregivers]

In the absence of curative pharmaceutical treatment for evolving cognitive impairment, non-drug interventions are key components in patients' and caregivers' care. These interventions, when combined and adapted to the needs of the patient and the caregiver, allow for maintaining functional autonomy, decreasing caregiver burden and, possibly, slowing down cognitive decline. An on-going study in Suisse Romande (INDID-MCI-QOL) assesses the effect of the number and type of interventions conducted over a year on the evolution of physical, psychological and cognitive health in this population

How non-drug interventions affect the quality of life of patients suffering from progressive cognitive decline and their main caregiver.

In the absence of cure for age-related neurodegenerative diseases, non-drug interventions (NDIs) represent useful options. Quality of life (QOL) is a multidimensional concept progressively affected by cognitive decline. How single or multiple NDIs impact QOL is unknown. We found no significant effect of multiple over single NDI on QOL. Socio-demographic variables influenced patients' (age, gender, caregivers' occupational status, management of patients' financial affairs) and caregivers' (gender, occupational status, patients' severity of cognitive decline) QOL. When dyads interrupted interventions after 6 months, their QOL was lower and caregivers' anxiety, depression and physical symptoms were higher at the end of the study. While the type and number of interventions do not appear to be critical, the continuity of adapted interventions in the long-term might be important for maintaining QOL of patients and caregivers. This is a multicenter (7 Swiss Memory Clinics), quasi-experimental, one-year follow-up study including 148 subjects (mild cognitive impairment or mild dementia patients and their caregivers). Primary outcome was the effect of multiple vs single NDIs on QOL. Secondary outcome included NDIs effect on patients' cognitive impairment and functional autonomy, caregivers' burden, severity of patients' neuropsychiatric symptoms and dyads' anxiety and depression