Category deficits and paradoxical dissociations in Alzheimer's disease and Herpes Simplex Hencephalitis

Most studies examining category specificity are single-case studies of patients with living or non living deficits. Nevertheless, no explicit or agreed criteria exist for establishing category-specific deficits in single-cases regarding the type of analyses, whether to compare with healthy controls, the number of tasks, or the type of tasks. We examined to groups of patients with neurological pathology frequently accompained with impaired semantic memory (19 patients with Alzheimer disease and 15 with Herpes Simplex Encephalitis). Category knowledge was examined using three tasks (picture naming, naming-to-description and features verification). Both patients groups were compared with aged- and education- matched healthy controls. The profile of each patients was examined for consistency across tasks and across different analyses; however both prove to be inconsistent. One striking findings was the presence of a paradoxical dissociation ( i.e., patients who were impaired on living things on one task and non living things on another task). The findings have significant implication for how we determine category effects and, more generall for the methods use to document double dissociation across individual cases in this literature

Effects of cue focality on the neural mechanisms of prospective memory: A meta-analysis of neuroimaging studies

Remembering to execute pre-defined intentions at the appropriate time in the future is typically referred to as Prospective Memory (PM). Studies of PM showed that distinct cognitive processes underlie the execution of delayed intentions depending on whether the cue associated with such intentions is focal to ongoing activity processing or not (i.e., cue focality). The present activation likelihood estimation (ALE) meta-analysis revealed several differences in brain activity as a function of focality of the PM cue. The retrieval of intention is supported mainly by left anterior prefrontal cortex (Brodmann Area, BA 10) in nonfocal tasks, and by cerebellum and ventral parietal regions in focal tasks. Furthermore, the precuneus showed increased activation during the maintenance phase of intentions compared to the retrieval phase in nonfocal tasks, whereas the inferior parietal lobule showed increased activation during the retrieval of intention compared to maintenance phase in the focal tasks. Finally, the retrieval of intention relies more on the activity in anterior cingulate cortex for nonfocal tasks, and on posterior cingulate cortex for focal tasks. Such focality-related pattern of activations suggests that prospective remembering is mediated mainly by top-down and stimulus-independent processes in nonfocal tasks, whereas by more automatic, bottom-up, processes in focal tasks

False Identity Detection Using Complex Sentences

The use of faked identities is a current issue for both physical and online security. In this paper, we test the differences between subjects who report their true identity and the ones who give fake identity responding to control, simple, and complex questions. Asking complex questions is a new procedure for increasing liars' cognitive load, which is presented in this paper for the first time. The experiment consisted in an identity verification task, during which response time and errors were collected. Twenty participants were instructed to lie about their identity, whereas the other 20 were asked to respond truthfully. Different machine learning (ML) models were trained, reaching an accuracy level around 90-95% in distinguishing liars from truth tellers based on error rate and response time. Then, to evaluate the generalization and replicability of these models, a new sample of 10 participants were tested and classified, obtaining an accuracy between 80 and 90%. In short, results indicate that liars may be efficiently distinguished from truth tellers on the basis of their response times and errors to complex questions, with an adequate generalization accuracy of the classification models

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

Post-Action Determinants of the Reported Time of Conscious Intentions

The question of whether our behavior is guided by our conscious intentions is gaining momentum within the field of cognitive neuroscience. It has been demonstrated that the subjective experience that conscious intentions are the driving force of our actions, is built partially on a post hoc reconstruction. Our hypothesis was that this reconstructive process is mediated by an action-monitoring system that compares the predicted and the actual sensory consequences of an action. We applied event-related potentials (ERP) to a variant of the Libet's task in which participants were asked to press a button and to report the time of decision – will judgment (W) – to press. We provided delayed auditory feedbacks after participants’ action to signify an action time later than the actual action. We found that auditory feedbacks evoked a negative component in the 250–300 time range, namely action-effect negativity (NAE), that is thought to reflect the activity of a system that detects violation from expectancies. We showed that the amplitude of the NAE was sensitive to the delay of the auditory feedback, with a larger amplitude for more delayed feedbacks. Furthermore, changes in the NAE were also associated with changes in the reported W. These results not only confirm that we infer the time we decided to act from events occurring after the response, but these results also indicate that the subjective experience of when an action is decided is influenced by the activity of an action-monitoring system that detects mismatches between predicted and actual sensory consequences of the actions

The guilty brain: the utility of neuroimaging and neurostimulation studies in forensic field

Several studies have aimed to address the natural inability of humankind to detect deception and accurately discriminate lying from truth in the legal context. To date, it has been well established that telling a lie is a complex mental activity. During deception, many functions of higher cognition are involved: the decision to lie, withholding the truth, fabricating the lie, monitoring whether the receiver believes the lie, and, if necessary, adjusting the fabricated story and maintaining a consistent lie. In the previous 15 years, increasing interest in the neuroscience of deception has resulted in new possibilities to investigate and interfere with the ability to lie directly from the brain. Cognitive psychology, as well as neuroimaging and neurostimulation studies, are increasing the possibility that neuroscience will be useful for lie detection. This paper discusses the scientific validity of the literature on neuroimaging and neurostimulation regarding lie detection to understand whether scientific findings in this field have a role in the forensic setting. We considered how lie detection technology may contribute to addressing the detection of deception in the courtroom and discussed the conditions and limits in which these techniques reliably distinguish whether an individual is lying

From an idea to a scalable working model: merging economic benefits with social values in Sardex

The remarkable growth of Sardex as a local currency throughout the island of Sardinia over the past 4 years motivated an in-depth look at its starting assumptions, its design and operational principles, and its socio- economic context. The paper looks at Sardex as a social innovation start-up, as a medium of exchange and unit of account, as an online and offline mutual credit system, and as a closed economic community or ‘circuit’. The analysis relies on interviews of circuit members conducted in the Summer of 2014 and benefits from the reflexive point of view of one of its founders. The main findings are that trust was and continues to be fundamentally important for the creation and operation of the local Sardex currency and of the circuit, and that Sardex mediates both economic and social value(s). These properties make it an ideal space for experimentation in socio-economic innovation that can be characterized as a ‘laboratory of institutional learning.

From an idea of a scalable working model: merging economic benefits with social values in Sardex

The remarkable growth of Sardex as a local currency throughout the island of Sardinia over the past 5 years motivated an in-depth look at its starting assumptions, design and operational principles, and socioeconomic context. The paper looks at Sardex as a social innovation start-up, a medium of exchange and unit of account, an online and offline mutual credit system, and a closed economic community or ‘circuit’. The analysis relies on semi-structured in-depth interviews of circuit members and benefits from the reflexive point of view of one of its founders. The main findings are that trust was and continues to be fundamentally important for the creation and operation of the mutual credit system, and that Sardex encompasses and mediates both economic and social value(s). Compared to other mutual credit systems, in addition to its unique design features Sardex is distinguished by its federated model of expansion and its strong commitment to keeping a balance between the economic and social aspects. In Sardex, money’s fungibility is defined by market utility and social values at the same time