Representation of social content in dorsomedial prefrontal cortex underlies individual differences in agreeableness trait.

Personality traits reflect key aspects of individual variability in different psychological domains. Understanding the mechanisms that give rise to these differences requires an exhaustive investigation of the behaviors associated with such traits, and their underlying neural sources. Here we investigated the mechanisms underlying agreeableness, one of the five major dimensions of personality, which has been linked mainly to socio-cognitive functions. In particular, we examined whether individual differences in the neural representations of social information are related to differences in agreeableness of individuals. To this end, we adopted a multivariate representational similarity approach that captured within single individuals the activation pattern similarity of social and non-social content, and tested its relation to the agreeableness trait in a hypothesis-driven manner. The main result confirmed our prediction: processing social and non-social content led to similar patterns of activation in individuals with low agreeableness, while in more agreeable individuals these patterns were more dissimilar. Critically, this association between agreeableness and encoding similarity of social and random content was significant only in the dorsomedial prefrontal cortex, a brain region consistently involved during attributions of mental states. The present finding reveals the link between neural mechanisms underlying social information processing and agreeableness, a personality trait highly related to socio-cognitive abilities, thereby providing a step forward in characterizing its neural determinants. Furthermore, it emphasizes the advantage of multivariate pattern analysis approaches in capturing and understanding the neural sources of individual variations.

Bottom-up and top-down modulation of route selection in imitation.

The cognitive system selects the most appropriate action imitative process: a semantic process - relying on long-term memory representations for known actions, and low-level visuomotor transformations for unknown actions. These two processes work in parallel; however, how context regularities and cognitive control modulate them is unclear. In this study, process selection was triggered contextually by presenting mixed known and new actions in predictable or unpredictable lists, while a cue on the forthcoming action triggered top-down control. Known were imitated faster than the new actions in the predictable lists only. Accuracy was higher and reaction times faster in the uncued conditions, and the predictable faster than the unpredictable list in the uncued condition only. In the latter condition, contextual factors modulate process selection, as participants use statistical regularities to perform the task at best. With the cue, the cognitive system tries to control response selection, resulting in more errors and longer reaction times.

Distinct brain representations of processed and unprocessed foods.

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' 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.

Body weight and its association with impulsivity in middle and old age individuals.

Impulsivity, conceptualized as impulsive personality trait, poor inhibitory control and enhanced reward sensitivity, has been strongly linked to obesity. In particular, a disequilibrium between cognitive control and reward sensitivity has been observed in obese individuals in both behavioural and imaging studies. While this issue has been widely investigated in children and adults, it has received little attention in older adults. Here, obese and non-obese participants aged between 40 and 70 years completed the Barratt Impulsiveness scale (assessing motor, non-planning and attentional impulsiveness), a Go/no-go task with foods and non-foods (assessing inhibitory control) and a reward sensitivity battery with high and low caloric foods (assessing liking, wanting, tastiness and frequency of consumption). We observed that participants with higher BMI reported increased wanting for high calorie foods, but did not show poorer inhibitory control. Interestingly, participants who scored lower on the MMSE reported to consume high calorie more than low calorie foods. Finally, those who presented low scores on non-planning and motor impulsiveness subscales reported higher tastiness ratings for low calorie foods. These results show that increased reward sensitivity but not reduced inhibitory control may characterize higher BMI during aging. Importantly, they also highlight new findings concerning food preferences among older adults.

You stole my food! Eating alterations in frontotemporal dementia.

Patients with different types of dementia may exhibit pathological eating habits, including food fads, hyperphagia, or even ingestion of inanimate objects. Several findings reveal that such eating alterations are more common in patients with frontotemporal dementia (FTD) than other types of dementia. Moreover, eating alterations may differ between the two variants of the disease, namely the behavioral variant and semantic dementia (SD). In this review, we summarized evidences regarding four areas: eating and body weight alterations in FTD, the most common assessment methods, anatomical correlates of eating disorders, and finally, proposed underlying mechanisms. An increasing understanding of the factors that contribute to eating abnormalities may allow first, a better comprehension of the clinical features of the disease and second, shed light on the mechanism underlying eating behaviors in the normal population.

Thoughts for food in cognitive neuroscience: An introduction to the special issue.

Food is essential to our survival. It is also one of the greatest pleasures of life. Over the last decade, our understanding about how the brain responds to food cues and guides food search and intake has greatly increased. This special issue brings together various perspectives and research approaches on food cognitive neuroscience, encompassing a wide variety of techniques and methods. As these studies will add substantially to the ever-growing research on food cognitive neuroscience, we hope that they will also inspire new and useful ideas to fill the gaps that remain in this critical area of inquiry. By providing nutrients to generate energy and sustain life, food is an essential fuel for our survival and a pervasive element of our daily environment. Food also represents one of the greatest pleasures that we experience in life. More recently, numerous cognitive neuroscientific studies about how the brain responds to food cues and guides food search and consumption have been published. Evidence points to several and closely interrelated neural circuits underlying the homeostatic and hedonic mechanisms that regulate food intake.

A bait we cannot avoid: Food-induced motor distractibility.

Food is so central to humans' life that keeping our mind away from it is not an easy task. Because of its strong motivational value, food cues attract our attention. However, often food is truly not relevant to our on-going activities. In the present study we investigated the distracting role that task-irrelevant foods (natural and manufactured) and food-cues play in performing goal-directed reaching movements. We explored whether spatial and temporal parameters of reaching movement were influenced by the presence of task-irrelevant stimuli (i.e., distractor effect), and whether this effect was modulated by participants' implicit and explicit ratings of food items and participants' tendency to restrain their diet. First we found that the movement trajectory veered consistently toward food items and food-related distractors. Second, we found that participants' own evaluation of natural and manufactured food played a differential predicting role of the magnitude of temporal and spatial parameters of the distractor effect induced by these types of food. We conclude that perceptual and attentional systems provide preferential access to stimuli in the environment with high significance for organisms.

Lexical-semantic deficits in processing food and non-food items.

The study of category specific deficits in brain-damaged patients has been instrumental in explaining how knowledge about different types of objects is organized in the brain. Much of this research focused on testing putative semantic sensory/functional subsystems that could explain the observed dissociations in performance between living things (e.g., animals and fruits/vegetables) and non-living things (e.g., tools). As neuropsychological patterns that did not fit the original living/non-living distinction were observed, an alternative organization of semantic memory in domains constrained by evolutionary pressure was hypothesized. However, the category of food, that contains both living-natural items, such as an apple, and nonliving-manufactured items as in the case of a hamburger, has never been systematically investigated. As such, food category could turn out to be very useful to test whether the brain organizes the knowledge about food in sensory/functional subsystems, in a specific domain, or whether both approaches might need to be integrated. In the present study we tested the ability of patients with Alzheimer dementia (AD) and with Primary Progressive Aphasias (PPA) as well as healthy controls to perform a confrontation naming task, a categorization task, and a comprehension of edible (natural and manufactured food) and non edible items (tools and non-edible natural things) task (Tasks 1-3). The same photographs of natural and manufactured food were presented together with a description of food's sensory or functional property that could be either congruent or incongruent with that particular food (Task 4). Patients were overall less accurate than healthy individuals, and PPA patients were generally more impaired than AD patients, especially on the naming task. Food tended to be processed better than non-food in two out of three tasks (categorization and comprehension tasks). Patient groups showed no difference in naming food and non-food items, while controls were more accurate with non-food than food (controlling for the linguistic variables and calorie content). AD patients named manufactured food more accurately than natural food (with PPA and controls showing no difference). Recognition of food and, to some extent, of manufactured food seems to be more resilient to brain damage, possibly by virtue of its survival relevance. Furthermore, on Task 4 patients showed an advantage for the sensory-natural pairs over sensory-manufactured combination. Overall, findings do not fit an existing model of semantic memory and suggest that properties intrinsic to the food items (such as the level of transformation and the calorie content) or even to the participants like the Body Mass Index (as shown in another study reviewed here) should be considered.

The effect of goals and vision on movements: a case study of optic ataxia and limb apraxia.

Normally we can perform a variety of goal-directed movements effortlessly. However, damage to the parietal cortex may dramatically reduce this ability, giving rise to optic ataxia and limb apraxia. Patients with optic ataxia show clear misreaches towards targets when presented in the peripheral visual field, whereas limb apraxia refers to the inability to use common tools or to imitate simple gestures. In the present paper we describe the case of a left-brain damaged patient, who presented both symptoms. We systematically investigated both spatial and temporal parameters of his movements, when asked to reach and grasp common objects to move (Experiment 1) or to use them (Experiment 2), presented either in the central or peripheral visual field. Different movement parameters changed in relation to the goal of the task (grasp to move vs. grasp to use), reflecting a normal modulation of the movement to accomplish tasks with different goals. On the other hand, grip aperture appeared to be more affected from both task goal and viewing condition, with a specific decrement observed when CF was asked to use objects presented peripherally. On the contrary, a neat effect of the viewing condition was observed in the spatial distribution of the end-points of the movements, and of the horizontal end point in particular, which were shifted towards the fixation point when reaching towards peripheral targets. We hypothesized that optic ataxia and limb apraxia have a differential effect on the patient's performance. The specific presence of optic ataxia would have an effect on the movement trajectory, but both symptoms might interact and influence the grasping component of the movement. As a 'cognitive side of motor control impairment', the presence of limb apraxia may have increased the task demands in grasping to use the objects thus exacerbating optic ataxia.

On the Relationship Between Semantic Knowledge and Prejudice About Social Groups in Patients with Dementia.

OBJECTIVE AND BACKGROUND: Patterns of brain-damaged individuals' deficits in categorizing living versus non-living things indicate separation of semantic knowledge categories in the brain. Recent work in patients with dementia suggested that semantic knowledge about social groups differs from knowledge about living and non-living things. In this study we analyzed patients' social appraisal by testing whether their degree of impairment in social-group knowledge predicted their social-group evaluative reactions (prejudice). We hypothesized that impaired knowledge about social groups would correlate with either heightened or reduced prejudice. METHODS: In Rumiati et al, Cogn Neurosci (2014) http://dx.doi.org/10.1080/17588928.2013.876981, we had given a sorting task to 21 patients with frontotemporal dementia or dementia of the Alzheimer type and 23 healthy controls, to test their knowledge of social groups and living and non-living things. In this study we asked the same participants to evaluate social groups. We used controls' evaluations to rank 20 social groups from extremely negative to extremely positive. We used patients' severity of deficit in sorting social groups to predict the patients' evaluations of the groups, controlling for their levels of deficit in sorting living and non-living items. We also compared the evaluations by patients±deficits in social-group sorting to controls' evaluations. RESULTS: The patients with impaired social-group knowledge evaluated the less-admired groups more positively than did controls, and the more-admired groups less positively. CONCLUSIONS: Impaired social-group knowledge, not a general semantic loss, predicts reduced evaluative bias. Our findings are consistent with neuroimaging evidence for a relationship between semantic and evaluative social-group processes.

Selective imitation impairments differentially interact with language processing.

Whether motor and linguistic representations of actions share common neural structures has recently been the focus of an animated debate in cognitive neuroscience. Group studies with brain-damaged patients reported association patterns of praxic and linguistic deficits whereas single case studies documented double dissociations between the correct execution of gestures and their comprehension in verbal contexts. When the relationship between language and imitation was investigated, each ability was analysed as a unique process without distinguishing between possible subprocesses. However, recent cognitive models can be successfully used to account for these inconsistencies in the extant literature. In the present study, in 57 patients with left brain damage, we tested whether a deficit at imitating either meaningful or meaningless gestures differentially impinges on three distinct linguistic abilities (comprehension, naming and repetition). Based on the dual-pathway models, we predicted that praxic and linguistic performance would be associated when meaningful gestures are processed, and would dissociate for meaningless gestures. We used partial correlations to assess the association between patients' scores while accounting for potential confounding effects of aspecific factors such age, education and lesion size. We found that imitation of meaningful gestures significantly correlated with patients' performance on naming and repetition (but not on comprehension). This was not the case for the imitation of meaningless gestures. Moreover, voxel-based lesion-symptom mapping analysis revealed that damage to the angular gyrus specifically affected imitation of meaningless gestures, independent of patients' performance on linguistic tests. Instead, damage to the supramarginal gyrus affected not only imitation of meaningful gestures, but also patients' performance on naming and repetition. Our findings clarify the apparent conflict between associations and dissociations patterns previously observed in neuropsychological studies, and suggest that motor experience and language can interact when the two domains conceptually overlap.

The impact of subclinical psychotic symptoms on delay and effort discounting: Insights from behavioral, computational, and electrophysiological methods.

BACKGROUND: The ability to value rewards is crucial for adaptive behavior and is influenced by the time and effort required to obtain them. Impairments in these computations have been observed in patients with schizophrenia and may be present in individuals with subclinical psychotic symptoms (PS). METHODS: In this study, we employed delay and effort-discounting tasks with food rewards in thirty-nine participants divided into high and low levels of PS. We investigated the underlying mechanisms of effort-discounting through computational modelling of dopamine prefrontal and subcortical circuits and the electrophysiological biomarker of both delay and effort-discounting alterations through resting-state frontal alpha asymmetry (FAA). RESULTS: Results revealed greater delay discounting in the High PS group compared to the Low PS group but no differences in the effort discounting task. However, in this task, the same levels of estimated dopamine release were associated with a lower willingness to exert effort for high-calorie food rewards in High PS participants compared to Low PS participants. Although there were no significant differences in FAA between the High PS and Low PS groups, FAA was significantly associated with the severity of participants' negative symptoms. CONCLUSIONS: Our study suggests that the dysfunction in temporal and effort cost computations, seen in patients with schizophrenia, may be present in individuals with subclinical PS. These findings provide valuable insight into the early vulnerability markers (behavioral, computational, and electrophysiological) for psychosis, which may aid in the development of preventive interventions. These findings are preliminary and warrant further investigation.

Imitating others' actions: transcranial magnetic stimulation of the parietal opercula reveals the processes underlying automatic imitation.

The human tendency to imitate gestures performed by conspecifics is automatic in nature. However, whether this automatic imitation can be considered as a true imitative phenomenon or only as a special instance of spatial compatibility is still being debated. New evidence suggests that automatic imitation, otherwise known as 'imitative compatibility', shall be considered as a phenomenon that operates independently from spatial compatibility. So far there are only a few investigations directly aimed at identifying the neural structures dedicated to this process. In the present study, we applied double-pulse transcranial magnetic stimulation (TMS) over the parietal opercula to further investigate the role of these regions in coding imitative compatibility. We found that a temporary disruption of parietal opercula caused the reduction of the imitative compatibility relative to the sham condition. In particular, the TMS interference with the parietal opercula's activity modulated the imitative compatibility but not the spatial compatibility, suggesting that these two processes are likely to be independent.

The role of the basal ganglia in action imitation: neuropsychological evidence from Parkinson's disease patients.

Though previous studies have suggested that the basal ganglia are necessarily involved in action imitation, their precise role is unclear. An important source of evidence concerns patients with Parkinson's disease (PD) who suffer basal ganglia impairments. Some studies report poor execution of observed meaningful (MF) transitive (tool-related) actions but normal performance with intransitive (non-tool-related) MF and meaningless (ML) actions (Leiguarda et al. in Brain 120:75-90, 1997; Leiguarda 2001 in Neuroimage 14:137-141). In other cases, though, patients with lesions involving the basal ganglia appear impaired in imitating ML as compared to meaningful MF transitive pantomimes. Here, we tested a group of PD patients in a full 2 × 2 design with MF transitive and intransitive pantomimes and matched ML movements. PD patients generated higher scores when imitating MF transitive actions than ML-matched actions. On the other hand, ML than MF intransitive actions did not differ significantly. The performance of the patients on imitating ML transitive actions also correlated with their performance on the Corsi block test of visuospatial memory and their scores at the test of verbal fluency for phonemic categories (FAS) while MF intransitive actions correlated with FAS and the neurological evaluation (UPDRS) The results are discussed in terms of the factors that load on visual memory for action reproduction, as well as the possible role of the basal ganglia in communicative actions (for MF intransitive actions).

Tomato and tuna: a test for language-free assessment of action understanding.

OBJECTIVE: We introduce a novel test that allows pictorial, nonverbal assessment of action understanding. BACKGROUND: Focusing on action goals and the sequential nature of actions, the "Tomato and Tuna Test" tests whether exposure to the accomplished goal of an action is sufficient to infer the preceding action. This aspect has rarely been addressed in conventional paradigms. METHODS: We used the Tomato and Tuna Test in conjunction with another task, the Kissing and Dancing Test, to detect action understanding deficits in 11 patients (mean age 72 ± 6 years) with chronic brain lesions ± aphasia. We compared their performance to an age- and education-matched control group and to 15 young controls (mean age 24 ± 3 years). To investigate the influence of language deficits on test performance, we compared the scores of our patients with and without aphasia. RESULTS: Our patients were less accurate than the matched controls on the Tomato and Tuna Test, though not slower. The Kissing and Dancing Test did not differentiate between patients and matched controls. Young controls performed better than patients on both tests. CONCLUSIONS: We found no performance differences between our aphasic and nonaphasic patients, confirming our assumption that both tests measure action understanding without requiring intact language abilities. We recommend the "Tomato and Tuna Test" as a new nonverbal measure of action understanding that can reveal subtle deficits.

Attention to the other's body sensations modulates the ventromedial prefrontal cortex.

Theory of Mind (ToM) is involved in experiencing the mental states and/or emotions of others. A further distinction can be drawn between emotion and perception/sensation. We investigated the mechanisms engaged when participants' attention is driven toward specific states. Accordingly, 21 right-handed healthy individuals performed a modified ToM task in which they reflected about someone's emotion or someone's body sensation, while they were in a functional magnetic resonance imaging scanner. The analysis of brain activity evoked by this task suggests that the two conditions engage a widespread common network previously found involved in affective ToM (temporo-parietal junction (TPJ), parietal cortex, dorso-lateral prefrontal cortex (DLPFC), medial- prefrontal cortex (MPFC), Insula). Critically, the key brain result is that body sensation implicates selectively ventromedial prefrontal cortex (VMPFC). The current findings suggest that only paying attention to the other's body sensations modulates a self-related representation (VMPFC).

Numeracy Gender Gap in STEM Higher Education: The Role of Neuroticism and Math Anxiety.

The under-representation of women in Science, Technology, Engineering, and Mathematics (STEM) is ubiquitous and understanding the roots of this phenomenon is mandatory to guarantee social equality and economic growth. In the present study, we investigated the contribution of non-cognitive factors that usually show higher levels in females, such as math anxiety (MA) and neuroticism personality trait, to numeracy competence, a core component in STEM studies. A sample of STEM undergraduate students, balanced for gender (N F = N M = 70) and Intelligent Quotient (IQ), completed online self-report questionnaires and a numeracy cognitive assessment test. Results show that females scored lower in the numeracy test, and higher in the non-cognitive measures. Moreover, compared to males', females' numeracy scores were more strongly influenced by MA and neuroticism. We also tested whether MA association to numeracy is mediated by neuroticism, and whether this mediation is characterized by gender differences. While we failed to detect a significant mediation of neuroticism in the association between MA and numeracy overall, when gender was added as a moderator in this association, neuroticism turned out to be significant for females only. Our findings revealed that non-cognitive factors differently supported numeracy in females and males in STEM programs.

Psychological Impact in Healthcare Workers During Emergencies: The Italian Experience With COVID-19 First Wave.

Background: The COVID-19 outbreak imposed an overwhelming workload as well as emotional burdens on Healthcare workers (HCWs). In May 2020, an online survey was administered to HCWs in Italy to assess the pandemic's psychological impact and to investigate possible predictive factors that led to individual differences. Methods: The psychological experience was measured based on the prevalence of self-reported feelings during the pandemic, including negative and positive emotional states. We analyzed the relationship between factors of gender, age, geographic region, professional role, and operational unit, and the four-point scale used to rate the frequency of each emotional state experienced by performing several multinomial logistic regressions, one for each emotion. Results: Our findings suggest that more than half of HCWs experienced psychological distress during the first COVID-19 outbreak in Italy. Female and younger respondents, especially those operating in northern Italy experienced more frequently negative emotional states such as irritability, anxiety, loneliness, and insecurity. However, positive feelings, first of all solidarity, were also reported especially by female and older workers. The majority of the negative as well as positive emotional states were experienced almost equally by both doctors and nurses, and independently of the operational unit in which they operated. Conclusions: This study can be very useful as a contribution to the current literature on the psychological effects of this pandemic on health workers. Moreover, our findings can provide useful information in planning more tailored psychological interventions to support this category of workers in the ongoing and future emergencies.

Effects of tDCS on reward responsiveness and valuation in Parkinson's patients with impulse control disorders.

Parkinson's disease (PD) patients with impulse control disorders (ICD) frequently report hypersensitivity to rewards. However, a few studies have explored the effectiveness of modulation techniques on symptoms experienced by these patients. In this study, we assessed the effect of anodal tDCS over the DLPFC on reward responsiveness and valuation in PD patients with ICD. 43 participants (15 PD patients with ICD, 13 PD without ICD, and 15 healthy matched controls) were asked to perform a reward-craving test employing both explicit (self-ratings of liking and wanting) and implicit (heart rate and skin conductance response) measures, as well as two temporal discounting tasks with food and money rewards. Each participant performed the experimental tasks during active anodal tDCS of the left dorsolateral prefrontal cortex (DLPFC), anodal tDCS of the primary motor cortex (M1), and sham tDCS. Results showed increased wanting and a steeper temporal discounting of rewards in PD with ICD compared to the other groups. Moreover, we found that PD without ICD exhibit reduced liking for rewards. tDCS results capable to modulate the altered intensity of PD patients' liking, but not wanting and temporal discounting of rewards in PD patients with ICD. These findings confirm that alterations in reward responsiveness and valuation are characteristics of impulse control disorders in patients with PD but suggest that anodal tDCS over the left DLPFC is not capable to influence these processes. At the same time, they provide new insight into affective experience of rewards in PD.