The framework of graph theory provides useful tools for investigating the neural substrates of neuropsychiatric disorders. Graph description measures may be useful as predictor variables in classification procedures. Here, we consider several centrality measures as predictor features in a classification algorithm to identify nodes of resting-state networks containing predictive information that can discriminate between typical developing children and patients with attention-deficit/hyperactivity disorder (ADHD). The prediction was based on a support vector machines classifier. The analyses were performed in a multisite and publicly available resting-state fMRI dataset of healthy children and ADHD patients: the ADHD-200 database. Network centrality measures contained little predictive information for the discrimination between ADHD patients and healthy subjects. However, the classification between inattentive and combined ADHD subtypes was more promising, achieving accuracies higher than 65% (balance between sensitivity and specificity) in some sites. Finally, brain regions were ranked according to the amount of discriminant information and the most relevant were mapped. As hypothesized, we found that brain regions in motor, frontoparietal, and default mode networks contained the most predictive information. We concluded that the functional connectivity estimations are strongly dependent on the sample characteristics. Thus different acquisition protocols and clinical heterogeneity decrease the predictive values of the graph descriptors.

The study of addiction and impulsion control disorders has shown that behaviors of seeking and consumption of addictive substances are subserved by neurobiological alterations specifically related to brain networks for reward, stress, and executive control, representing the brain's adaptation to the continued use of an addictive substance. In parallel, studies using neuromodulation techniques such as transcranial direct current stimulation (tDCS) have demonstrated promising effects in modulating cognitive and motor functions. This review aims to describe the neurobiology of addiction and some of the most relevant cognitive models of addictive behavior and to clarify how tDCS application modulates the intake and craving for several addictive substances, such as food, alcohol, nicotine, cocaine, crack, methamphetamine, and cannabis. We also discuss the positive and null outcomes of the use of this neuromodulatory technique in the treatment of addiction disorders resulting from the use of these substances. The reviewed findings lead us to conclude that tDCS interventions hold several promising clinical avenues in addiction and impulsive control. However, methodological investigations are necessary for undercover optimal parameters before implementing its clinical application.

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Face recognition is characterized by the interaction between discrete brain regions and consecutive stages of detection and individuation, that is, categorizing an object as a face and categorizing a face at the individual level. We address recent divergences in the literature and integrate theoretical and empirical evidence into a novel neurofunctional model. The main features of the model are 2 separate, but interdependent, neural networks for the tasks of face detection and face individuation, distinguished by distinct patterns of neural activation and temporal signatures. Specifically, we take into account differences in the degree to which view-dependent or -independent processing is integrated, the differential contributions of coarse-template and fine-detail processing to each task, the suggestion that accurate face detection may depend on both face-specific and category-general processing and the role of the lateral occipital complex in the central network for face detection.

The superior temporal gyrus (STG) has been found to play a crucial role in the recognition of actions and facial expressions and may, therefore, be critical for the processing of humorous information. Here we investigated whether tDCS application to the STG would modulate the ability to recognize and appreciate the comic element in serious and comedic situations of misfortune. To this aim, the effects of different types of tDCS stimulation on the STG were analyzed during a task in which the participants were instructed to categorize various misfortunate situations as "comic" or "not comic". Participants underwent three different tDCS conditions: Anodal-right/Cathodal-left; Cathodal-right/Anodal-left; Sham. Images depicting people involved in accidents were grouped into three categories based on the facial expression of the victim: angry or painful (Affective); bewildered and funny (Comic); and images that did not contain the victim's face (No Face). An improvement in mean reaction times in response to both the Comic and No Face stimuli was observed following Anodal-left/Cathodal-right stimulation when compared to sham stimulation. This suggests that this stimulation type reduced the reaction times to socio-emotional complex scenes, regardless of facial expression. The Anodal-right/Cathodal-left stimulation reduced the mean reaction times for Comic stimuli only, suggesting that specifically the right STG may be involved in facial expression recognition and in the appreciation of the comic element in misfortunate situations. These results suggest a functional hemispheric asymmetry in STG response to social stimuli: the left STG might have a role in a general comprehension of social complex situations, while the right STG may be involved in the ability to recognize and integrate specific emotional aspects in a complex scene.

Objective:In schizophrenia, scores reflecting deficits in different cognitive processes are strongly correlated, making it difficult to establish a solid relationship between different cognitive mechanisms and other features of this disorder. The objective of this study was to explore whether three frequently postulated executive functions (updating, shifting, and inhibition) could be compared between groups and considered independently in terms of their respective roles in functional outcome.Methods:This study relied on confirmatory factor analysis of schizophrenia patients (n=141) and healthy controls (n=119). The main analyses examined the degree to which three executive functions (updating, set-shifting, and inhibition) could be separated in schizophrenia and compared this model among groups. Structural equation modeling analysis was also performed to examine the extent to which executive function components contribute to functional outcome in schizophrenia.Results:Multiple-group confirmatory factor analysis with unconstrained model parameters indicated that the full three-factor model may fit the data in both groups (χ2 = 61.48, degrees of freedom = 34, p < 0.001, comparative fit index = 0.95; standardized root mean square residual = 0.037; root mean square error of approximation = 0.04; Akaike’s information criteria = 169.49; normed fit index = 0.90), although there was also a good data fit for the patient group with a two-factor model. In the patient group, structural equation modeling suggested that shifting and (principally) updating were associated with the general measure of functional outcome (regression path coefficients: 0.34, p < 0.005; 0.39, p < 0.005, respectively), although when combined the mechanisms fail to contribute.Conclusion:This data suggests that the factor structure may be similar but not identical between groups, and both updating and shifting may play an important role in functional outcome in schizophrenia.

Makeup is a form of body art which has been used for more than 7,000 years and is present in the great majority of human cultures, often used to enhance facial attractiveness and to accentuate features that represent femininity. This study examines how cumulative levels of facial makeup influenced approach and avoidance tendencies and on facial muscle responses associated with emotional response obtained through facial electromyography (EMG) in a passive viewing task. Experiment 1 used the joystick variant of the approach-avoidance task, where 30 subjects categorized female faces by visual orientation (portrait/landscape) in seven cumulatively added makeup levels. In Experiment 2, facial EMG was recorded from 40 subjects in the passive viewing of the same images. The present study shows that makeup application modulates implicit responses and reveals two distinct implicit preferences, behavioral and affective, with a male behavioral preference for heavy eye cosmetics, a female behavioral preference for light makeup, and an overall affective preference in both men and women for makeup accentuating visual contrast in the eye and mouth regions. These results are consistent with the conception that perceptual cues underlying cosmetic enhancement are key determinants in aesthetic facial preferences.

The aim of the present study was to investigate the ways in which tobacco addiction affects a person’s ability to recognize facial patterns. Facial detection was assessed in 16 individuals with tobacco use disorder and 16 healthy nonsmokers. Facial stimuli were taken from the Ignatian Educational Foundation (FEI) database, from which 12 male and 12 female faces were randomly selected. In the facial detection task, the subjects’ task was to detect the location of a face when it was presented with a face/nonface pair on the screen. The order of stimulus presentation was randomized within sessions. Bayesian adaptive estimation was used for stimulus presentation. Presentation times varied between 16.7 and 3,006 ms. Lower response accuracy was associated with worse discrimination. No predictive effects of the cognitive tests on facial detection were found. A person’s ability of facial detection can be applied to provide initial descriptions of impairments in the visual processing system. Early stage visual processing is impaired by chronic smoking, and subjects are able to recognize this. Therefore, there is a possibility of reversing this effect and promoting a better prognosis. The present task has biopsychosocial applications and may improve smokers’ health by detecting subtle initial changes in visual processing.