Food Palatability Directs Our Eyes Across Contexts

It is often believed that attentional bias (AB) for food is a stable trait of certain groups, like restrained eaters. However, empirical evidence from this domain is inconsistent. High-calorie foods are double-faceted, as they are both a source of reward and of weight/health concern. Their meaning might depend on the food-related context (i.e., focus on health or on enjoyment), which in turn could affect AB for food. This study primed 85 females with hedonic, healthy, and neutral contexts successively and examined whether food-related context affected AB for food and if effects were moderated by dietary restraint. Both the mean tendencies of AB for food and variability of AB for food were assessed in a food dot-probe task with a recording of both reaction times and eye movements. Contrary to our hypotheses, AB for food was not significantly affected by either context or the interaction between context and dietary restraint. Instead, liking of the presented food stimuli was related to longer initial fixations and longer dwell time on the food stimuli. In addition, in line with prior research, body mass index (BMI) was correlated with variability of AB for food instead of mean AB for food. In conclusion, this study did not find any support that AB for food is dependent on food-related context, but interestingly, reaction time-based variability of AB for food seems to relate to BMI, and eye movement-based mean AB seems to relate to appetitive motivation.

Pheromone components affect motivation and induce persistent modulation of associative learning and memory in honey bees

Since their discovery in insects, pheromones are considered as ubiquitous and stereotyped chemical messengers acting in intraspecific animal communication. Here we studied the effect of pheromones in a different context as we investigated their capacity to induce persistent modulations of associative learning and memory. We used honey bees, Apis mellifera, and combined olfactory conditioning and pheromone preexposure with disruption of neural activity and two-photon imaging of olfactory brain circuits, to characterize the effect of pheromones on olfactory learning and memory. Geraniol, an attractive pheromone component, and 2-heptanone, an aversive pheromone, improved and impaired, respectively, olfactory learning and memory via a durable modulation of appetitive motivation, which left odor processing unaffected. Consistently, interfering with aminergic circuits mediating appetitive motivation rescued or diminished the cognitive effects induced by pheromone components. We thus show that these chemical messengers act as important modulators of motivational processes and influence thereby animal cognition.

Selective memory and behavioral alterations after ambient ultrafine particulate matter exposure in aged 3xTgAD Alzheimer’s disease mice

Background A growing body of epidemiological literature indicates that particulate matter (PM) air pollution exposure is associated with elevated Alzheimer’s disease (AD) risk and may exacerbate AD-related cognitive decline. Of concern is exposure to the ultrafine PM (UFP) fraction (≤100 nm), which deposits efficiently throughout the respiratory tract, has higher rates of translocation to secondary organs, like brain, and may induce inflammatory changes. We, therefore, hypothesize that exposure to UFPs will exacerbate cognitive deficits in a mouse model of AD. The present study assessed alterations in learning and memory behaviors in aged (12.5 months) male 3xTgAD and non-transgenic mice following a 2-week exposure (4-h/day, 4 days/week) to concentrated ambient UFPs using the Harvard ultrafine concentrated ambient particle system (HUCAPS) or filtered air. Beginning one month following exposure, locomotor activity, spatial learning and memory, short-term recognition memory, appetitive motivation, and olfactory discrimination were assessed. Results No effects on locomotor activity were found following HUCAPS exposure (number concentration, 1 × 104–4.7 × 105 particles/cm3; mass concentration, 29–132 μg/m3). HUCAPS-exposed mice, independent of AD background, showed a significantly decreased spatial learning, mediated through reference memory deficits, as well as short-term memory deficits in novel object recognition testing. AD mice displayed diminished spatial working memory, potentially a result of olfactory deficits, and short-term memory. AD background modulated HUCAPS-induced changes on appetitive motivation and olfactory discrimination, specifically enhancing olfactory discrimination in NTg mice. Modeling variation in appetitive motivation as a covariate in spatial learning and memory, however, did not support the conclusion that differences in motivation significantly underlie changes in spatial learning and memory. Conclusions A short-term inhalation exposure of aged mice to ambient UFPs at human-relevant concentrations resulted in protracted (testing spanning 1–6.5 months post-exposure) adverse effects on multiple memory domains (reference and short-term memory) independent of AD background. Impairments in learning and memory were present when accounting for potential covariates like motivational changes and locomotor activity. These results highlight the need for further research into the potential mechanisms underlying the cognitive effects of UFP exposure in adulthood.

Tackling Fearful Avoidance using Counterconditioning: A Causal Test for the Role of Appetitive Motivation in Fearful Avoidance Behaviour

Anxiety disorders are prevalent in the population and costly for society, while current treatment is not effective in all individuals. A central symptom of anxiety is avoidance behaviour, with excessive avoidance being predictive of poor clinical outcomes. Appetitive motivation could play a role in decreasing avoidance behaviour by increasing the positive valuation of the feared object. The current study used an approach-avoidance conflict paradigm to measure costly avoidance behaviour in a healthy group of 22 participants. During counterconditioning training one stimulus was followed by eating a tasty snack (CS+), while another was never followed by an outcome (CS-). Results indicated that the CC-training was effective in reducing negative valuation and decreasing avoidance behaviour for the CS+. This study showed the importance of appetitive motivation for avoidance behaviour, suggesting that treatment may benefit from focussing on increasing appetitive motivation to overcome avoidance.

Threat, its impacts over survival systems, and related behavioral disorders

Defensive and appetitive motivation systems have evolved to propitiate more sophisticated interactions with environment threats and needs, such as nutrients, water, reproduction, and temperature regulation. In contact with survival-relevant environmental stimuli, organisms change as a whole to maximize fitness to that occasion. In this paper, an overview on defensive systems is described, as well as some relevant aspects of defensive states, including their impacts over appetitive functions. A parallel between these characteristics and what is called threat-related disorders in the present paper is drawn and, finally, these similarities are used as basis for a theoretical proposition that at least part of these disorders can be seen as persistent states of defense.