Chiara Gramegna

Increasing evidence suggests that the dorsolateral prefrontal cortex (dlPFC) plays a crucial role in aggression and that it may be possible to modulate this behavior using transcranial direct current stimulation (tDCS). Nevertheless, no previous study has specifically examined the differential effects of bilateral tDCS on reactive and proactive aggression, making the present research the first to explore this distinction using neuromodulation. With this aim, we examined the effect of bi-hemispheric prefrontal tDCS in 30 healthy adults using a double-blind, sham-controlled design. All participants received three types of stimulation over the dlPFC: right anodal/left cathodal, right cathodal/left anodal, and sham tDCS. During the stimulation, participants underwent a modified version of the Taylor Aggression Paradigm, which included two different tasks: one for measuring proactive aggression (i.e., pTAP) and one for reactive aggression (i.e., rTAP). They were also given self-report questionnaires measuring individual levels of aggression, impulsivity, and empathy to test whether these constructs were associated with aggressive responses at the pTAP and rTAP. Results showed increased proactive aggression in males with both active montages, while reactive aggression increased only with right cathodal/left anodal tDCS. Females exhibited increased proactive aggression during right cathodal/left anodal tDCS, but decreased reactive aggression during right anodal/left cathodal stimulation. These findings suggest sex-dependent modulation of aggression via dlPFC stimulation. The relevance of these results extends beyond healthy individuals, as dlPFC dysfunction is a common feature in several psychiatric disorders associated with aggressive behavior. Understanding how tDCS modulates these distinct forms of aggression in healthy populations can inform future research on its therapeutic potential within clinical settings.

A growing body of evidence has shown the key role of the dorsolateral prefrontal cortex (dlPFC) in aggressive behavior, along with the chance of modulating it by means of transcranial direct current stimulation (tDCS). However, the functional interplay between the two cerebral hemispheres in the regulation of aggressive behavior is still unclear. To address this issue, we assessed the effect of bi-hemispheric prefrontal tDCS in 76 healthy adults with a cross-over, double-blind, sham-controlled design. Half of the participants received the anodal stimulation over the right dlPFC and the cathodal stimulation over the left dlPFC (right anodal/left cathodal; Experiment 1), whereas the other half received the anodal stimulation over the left dlPFC and the cathodal stimulation over the right dlPFC (right cathodal/left anodal; Experiment 2). During tDCS, participants underwent the Point Subtraction Aggression Paradigm. All participants were also given self-report questionnaires measuring individual levels of aggression, impulsivity, and empathy to test whether these constructs were associated with the neuromodulation of aggressive responses at the Point Subtraction Aggression Paradigm. Results show a significant increase in aggressive reactions to provocation during right anodal/left cathodal prefrontal tDCS only within males, highlighting a sex-specific effect of the prefrontal neuromodulation that is also associated with individual levels of aggression. These findings provide a new insight into the brain mechanisms that regulate aggressiveness, their sex differences, and their association with dispositional aggressive tendencies.

Previous studies have shown an association between cigarette use and altered resting-state functional connectivity (rsFC) in many large-scale networks, sometimes complemented by measures of cortical atrophy. In this study, we aimed to further explore the neural differences between smokers and healthy non-smokers through the integration of functional and structural analyses. Imaging data of fifty-two smokers and forty-five non-smokers were analyzed through an independent component analysis for group differences in rsFC. Smokers showed lower rsFC within the dorsal attention network (DAN) in the left superior and middle frontal gyrus and left superior division of the lateral occipital cortex compared to non-smokers; moreover, cigarette use was found to be associated with reduced grey matter volume in the left superior and middle frontal gyrus and right orbitofrontal cortex, partly overlapping with functional findings. Within smokers, daily cigarette consumption was positively associated with increased rsFC within the cerebellar network and the default mode network and decreased rsFC within the visual network and the salience network, while carbon monoxide level showed a positive association with increased rsFC within the sensorimotor network. Our results suggest that smoking negatively impacts rsFC within the DAN and that changes within this network might serve as a circuit-based biomarker for structural deficits.

Background There is an increasing need for objective and standardized assessment of testamentary capacity (TC) in dementia. A new instrument, the Testamentary Capacity Assessment Tool (TCAT), has been recently developed; however, the lack of validation and normative data regarding this cognitive screening test has limited its adoption in forensic and clinical settings. The present study collects normative data for the TCAT and assesses its convergent validity with standardized cognitive tests and the capacity to define what a ‘testament’ is. Methods The study involved 323 neurologically healthy adults (123 males, 200 females) of different ages (31–93 years) and different educational levels (4–25 years). The TCAT was administered along with the Beck Depression Inventory-II (BDI-II), the Montreal Cognitive Assessment (MoCA), the Mini-Mental State Examination (MMSE), the Frontal Assessment Battery (FAB) and the Testament Definition Scale (TDS). Results Multiple regression analyses revealed a significant effect for gender, age and education on TCAT scores. Correlation analyses showed significant associations between the TCAT and the MMSE, MoCA, FAB and BDI-II. A positive correlation between the TCAT and TDS was also found, proving good convergent validity of the TCAT with respect to TC. Finally, cut-off scores and Equivalent Scores (ES) were computed. Discussion The present study provides normative data for using the TCAT as an adjuvant cognitive screening test in the neuropsychological evaluation of TC. Our findings shall be of interest for the adoption of the TCAT also in clinical practice, since it evaluates cognitive functions (e.g., autobiographic memory, Theory of Mind) not measured by traditional screening tests.

Background: Patients suffering from stroke in the acute/post-acute phases often present with depressive mood — which negatively impacts on patients’ prognosis. However, psychometric evaluation of mood in acute stroke patients may be challenging due to cognitive deficits. Tools investigating emotional states via a vertical analogue line may overcome language/visuo-spatial disorders. This study thus aimed at (a) investigating the clinical usability of a Visual Analogue Mood Scale (VAMS) in acute stroke patients and (b) investigating the interplay between mood and cognition in this population. Methods: Forty-one acute stroke patients were compared to 41 age-, education- and sex-matched healthy participants (HPs) on the VAMS and on cognitive measures (mental performance in acute stroke, MEPS). A control line bisection (LB) task was administered to control for potential visuo-spatial deficits in patients. Results: Patients reported higher depression levels than HPs (lower VAMS scores); this between-group difference stayed significant when covarying for LB scores. MEPS scores discriminated patients from HPs; among cognitive measures, only the Clock drawing test (CDT) was positively associated with VAMS scores. Lesion side did not affect patients’ mood state; however, disease duration was inversely related to VAMS scores. Discussion: The VAMS proved to be a suitable tool for assessing mood in acute stroke patients, as being independent from post-stroke cognitive sequelae. The CDT might represent an adequate measure of depression-induced, post-stroke cognitive efficiency decrease. Mood disorders might occur and thus should be adequately addressed also in post-acute phases — likely due to longer hospitalization times and regression of anosognosic features.

Background: Deficits of executive functioning (EF) are frequently found in neurological disorders. The Frontal Assessment Battery (FAB) is one of the most widespread and psychometrically robust EF screeners in clinical settings. However, in Italy, FAB norms date back to 15 years ago; moreover, its validity against “EF-loaded” global cognitive screeners (e.g., the Montreal Cognitive Assessment, MoCA) has yet to be tested. This study thus aimed at (a) providing updated normative data for the Italian FAB and (b) assessing its convergent validity with the MoCA. Methods: Four-hundred and seventy-five healthy Italian native speakers (306 females, 169 males; mean age: 61.08 ± 15.1; mean education: 11.67 ± 4.57) were administered by the MoCA and the FAB. FAB items were divided into three subscales: FAB-1 (linguistically mediated EF), FAB-2 (planning), and FAB-3 (inhibition). Regression-based norms were derived (equivalent scores) for all FAB measures. Results: Age and education were predictive of all FAB measures, whereas no gender differences were detected. The FAB and its sub-scales were related to MoCA measures—the strongest associations being found with MoCA total and MoCA-EF scores. FAB sub-scales were both internally related and associated with FAB total scores. Discussion: The FAB proved to have convergent validity with both global cognitive and EF measures in healthy individuals. The present study provides updated normative data for the FAB and its sub-scales in an Italian population sample, and thus supports an adaptive usage of this EF screener.

Background: Working memory (WM) abilities are frequently impaired in neurological disorders affecting fronto-parietal cortical/sub-cortical structures. WM deficits negatively influence interventional outcomes and everyday functioning. This study thus aimed at the following: (a) developing and standardizing an ecologically valid task for WM assessment ( Ice Cream Test, ICT); (b) validating and norming a novel WM test (Digit Ordering Test, DOT), as well as providing updated norms for digit span (DS) tasks, in an Italian population sample; (c) introducing a novel scoring procedure for measuring WM. Methods: One-hundred and sixty-eight Italian healthy participants—73 male, 95 females; age: 48.4 ± 19.1 (18–86); education: 12.1 ± 4.8 (4–21)—underwent a thorough WM assessment—DOT, ICT, and both forward and backward DS tasks (FDS, BDS). The ICT requires participants to act as waiters who have to keep track of customers’ orders. For each task, WM and total (T) outcomes were computed, i.e., the number of elements in the longest sequence and that of recalled sequences, respectively. Norms were derived via the equivalent score (ES) method. Results: DS ratios (DSRs) were computed for both WM/S and T outcomes on raw DS measures (BDS divided by FDS). Age and education significantly predicted all WM tasks; sex affected FDS and DSR-T scores (males > females). WM measures were highly internally related. Discussion: The present work provides Italian practitioners with a normatively updated, multi-component, adaptive battery for WM assessment (WoMAB) as well as with novel outcomes which capture different WM facets—WM capacity and attentive monitoring abilities.