An ERP study of low and high relevance semantic features

It is believed that the N400 elicited by concepts belonging to Living is larger than N400 to Non-living. This is considered as evidence that concepts are organized, in the brain, on the basis of categories. We conducted a feature-verification experiment where Living and Non-living concepts were matched for relevance of semantic features. Relevance is a measure of the contribution of semantic features to the “core” meaning of a concept. We found that when relevance is low the N400 is large. In addition, we found that when the two categories of Living and Non-living are equated for relevance the seemingly category effect at behavioral and neural level disappeared. In sum, N400 is sensitive, rather than to categories, to semantic features, thus showing that previously reported effects of semantic categories may arise as a consequence of the differing relevance of concepts belonging to Living and Non-living categories

FEATURE TYPE EFFECTS IN SEMANTIC MEMORY: AN EVENT RELATED POTENTIALS STUDY

It is believed that the N400 elicited by concepts belonging to Living is larger than N400 to Objects. This is considered as evidence that concepts are organized, in the brain, on the basis of categories. Similarly, differential N400 to sensory and non-sensory semantic features was taken as evidence for a neural organisation of conceptual memory based on semantic features. We conducted a feature-verification experiment where Living and Non-Living concepts are described by sensory and non-sensory features were matched for age-of-acquisition, typicality and familiarity and for relevance of semantic features. Relevance is a measure of the contribution of semantic features to the “core” meaning of a concept. We found that when Relevance is low then N400 is larger. In addition, we found that when the two categories of Living and Non-Living concepts are matched for relevance the seemingly category effect at the neural level disappeared. Also no difference between sensory and non-sensory descriptions was detected when relevance was matched. In sum, N400 does not differ between categories or feature types. Previously reported effects of semantic categories and feature type may have arisen as a consequence of the differing Relevance of concepts belonging to Living and Non-Living categories

Risk and Rationality: Decision-Making in the Brain

Taking decisions that are of advantage is an important survival skill. Classical economic models posit that people should try to maximize their gains and reduce losses, suggesting an idea of a perfectly rational man (Homo Economicus). Practically, people usually behave in manner that is very far from rationality. Employing neuroscience methods, the present thesis will describe a series of experiments that highlights as aspects not strictly related to payoffs affect decision-making. Experiment 1 studied brain activity (with ERPs) during gambling task, showing as decisions’ outcomes are assessed very early (within 250 ms) in terms of predictability and as this assessment is crucial for following decisions. Experiment 2 also employed ERPs, measuring risk-taking across different contexts. Results showed as P300 reflected changes in risk attitude as well as personal differences. Experiment 3 investigated decision making within social context in which people usually shows irrational behaviour. Brain activity show the involvement of theory of mind in this kind of decisions, suggesting that apparently irrational behaviour can be logic in the light of social interaction. Experiment 4 employed fMRI to study economic decision-making in social context, showing as monetary offers are perceived as social communications rather than mere economic divisions. Taken together these studies tried to narrow the gap between formal theory and real economic choice behaviour.Prendere decisioni vantaggiose è un’ importante abilità. I modelli economici classici sostengono che le persone dovrebbero provare a massimizzare i loro guadagni e a ridurre le perdite, suggerendo un’idea di uomo perfettamente razionale (Homo Economicus). In pratica, le persone si comportano in maniera molto distante dalla razionalità. Usando i metodi delle neuroscienze, la presente tesi descriverà una serie di esperimenti che mettono in luce come aspetti non strettamente legati alla ricompensa monetaria influenzano le decisioni. L’esperimento 1 ha studiato l’attività cerebrale (con gli ERPs) durante un gioco rischioso, mostrando come gli esiti delle decisioni vengano valutati molto presto ( entro 250 msec) in termini di predicibilità e come questa valutazione sia cruciale per le decisioni successive. L’esperimento 2 impiega ancora gli ERPs, misurando la propensione al rischio attraverso i diversi contesti. I risultati hanno mostrato come la P300 rifletta i cambiamenti di propensione al rischio e le differenze personali. L’esperimento 3 ha indagato la presa di decisione in contesti sociali in cui le persone si comportano di solito in maniera irrazionale. L’attività cerebrale mostra un coinvolgimento delle teorie della mente in questo tipo di decisioni, suggerendo che un comportamento apparentemente irrazionale può essere logico alla luce dell’interazione sociale. L’esperimento 4 usa la fMRI per studiare le decisioni economiche in contesti sociali, mostrando come le offerte monetarie siano percepite come comunicazioni sociali piuttosto che come mere suddivisioni economiche. In generale, questi studi cercano di ridurre la distanza fra teorie formali e comportamento di scelta reale

I bambini Gifted e la Scuola: quando le potenzialit\ue0 ostacolano l\u2019integrazione.

Children showing early abilities and uncommon interests according to the age may attract attention of scholastic, social, psychological and familiar environments. These children are defined as \u201cgifted\u201d and they belong to that limited part of population, approximately 2,28%, that have markedly cognitive abilities superior to general mean. They typically show early reading, very large vocabulary for the age as well as surprising curiosity for several matters, including abstract concepts that are hardly understood by the peers. Despite this amazing cognitive abilities, gifted children may show impairments at school, from both an educational and a social point of view. General development frequently shows asynchronies: early and advanced cognitive development, but typical or even later emotional and/or social/psychomotor development. These asynchronies are frequently the ground of criticalities that may become diseases, particularly during adolescent age. The incidence of mood diseases in the population is higher if compared to general population. According to recommendation n\ub0 1248 of European Council, Regione Veneto extensively informed teachers about giftedness and provided support to parents in order to facilitate scholastic and social adaptation, to promote wellness of gifted children

Inhibition and pleasure: economical risk-taking in the brain.

When making decisions, people show different attitudes in risk-taking. Classically, individual differences have been investigated using personality tests but, recently, neuroscience methods are providing a novel point of view through which this aspect can be better understood. Here, we present a study in which participants play a gambling task by choosing between a first option that constantly yielded a small gain and a second option that provided either a larger gain or a loss. While participants performed the task, event-related potentials (ERPs) were recorded in order to investigate brain activity during the gambling task. Two groups were analysed post hoc: The first group was more risk-prone, while the second group was more risk-averse. The Feedback Related Negativity (FRN) occurring between 250 and 450 millisecond after decision outcomes, was differentially affected in the two groups. In addition, source analyses indicated that distinct brain areas are responsible for such a difference: Anterior Cingulate Cortex (ACC) is more activated in risk-prone group, while Dorso-Lateral Prefrontal Cortex (DLPFC) is more activated in risk-averse group. Our results show that risk-taking behaviour is related to differential activations in the brain. How the brain works may be used to predict the participants risk-attitude

Predicting outcomes of decisions in the brain

When making decisions, the outcomes of different choices play an important role. Feedback is mainly processed in terms of gains and losses. It is as yet unclear whether this distinction holds for predictable as well as unpredictable outcomes. Using ERPs, the present study aimed to determine whether predictable and unpredictable outcomes are coded differently in the brain. Participants had to choose between one of two options: the certain option was always associated with a gain of 10(sic), while the uncertain option entailed a gain of 30(sic) or a loss of 10(sic), with a probability of 50% each. Overall, subjects showed a clear preference for the certain option, a tendency which became more pronounced during the course of the experiment. An early ERP component, the P200, reflected the predictability of outcomes, which was critical for the subsequent decisions. The later feedback related negativity (FRN) reflected the known distinction between gains and losses, while the N500 again reflected differential processing of predictable and unpredictable outcomes. Neither FRN nor the N500 were significantly related to behaviour. Predictability appears to play a central role in outcome evaluation

When people matter more than money: An ERPs study

In the present study, we showed that, in a social gambling task, individuals are influenced more by the type of social interaction than by the pattern of gains and losses. More precisely, the neural responses, as well as the level of pleasantness/unpleasantness following gains and losses, are modulated by social interaction factors. Here we present an Event-Related Potentials (ERPs) study in which three groups of participants were compared. Subjects were engaged in gambling tasks differing with regard to social factors: in a first condition, there was no social context; in a second condition, participants compared their outcomes with those of another individual; in a third condition, participants competed for a limited amount of money with another contender. In all conditions, all participants were revealed the outcome of an unselected alternative (non-obtained outcome) prior to the payoff associated with their selected option (obtained outcome). In addition, affective ratings were measured after the outcomes were presented. In the group without social context, ERPs results replicated previous findings. Interestingly, the P200 was modulated by varying social contexts, suggesting that attentive resources allocated to payoffs in comparison and competitive situations are decreased presumably in favor of social cues. Furthermore, Feedback Related Negativity (FRN) was predictive of the subjective feeling of pleasantness/unpleasantness following monetary outcomes. The present data provide information about neural and cognitive processing underlying economic decision-making when other individuals are involved