Chiara Cobelli

Motivational mechanisms (BAS) and prefrontal cortical activation contribute to recognition memory for emotional words. rTMS effect on performance and EEG (alpha band) measures

The present research addressed the question of where memories for emotional words could be represented in the brain. A second main question was related to the effect of personality traits, in terms of the Behavior Activation System (BAS), in emotional word recognition. We tested the role of the left DLPFC (LDLPFC) by performing a memory task in which old (previously encoded targets) and new (previously not encoded distractors) positive or negative emotional words had to be recognized. High-BAS and low-BAS subjects were compared when a repetitive TMS (rTMS) was applied on the LDLPFC. We found significant differences between high-BAS vs. low-BAS subjects, with better performance for high-BAS in response to positive words. In parallel, an increased left cortical activity (alpha desynchronization) was observed for high-BAS in the case of positive words. Thus, we can conclude that the left approach-related hemisphere, underlying BAS, may support faster recognition of positive words.

Facial feedback and autonomic responsiveness reflect impaired emotional processing in Parkinson’s Disease

Emotional deficits are part of the non-motor features of Parkinson’s disease but few attention has been paid to specific aspects such as subjective emotional experience and autonomic responses. This study aimed to investigate the mechanisms of emotional recognition in Parkinson’s Disease (PD) using the following levels: explicit evaluation of emotions (Self-Assessment Manikin) and implicit reactivity (Skin Conductance Response; electromyographic measure of facial feedback of the zygomaticus and corrugator muscles). 20 PD Patients and 34 healthy controls were required to observe and evaluate affective pictures during physiological parameters recording. In PD, the appraisal process on both valence and arousal features of emotional cues were preserved, but we found significant impairment in autonomic responses. Specifically, in comparison to healthy controls, PD patients revealed lower Skin Conductance Response values to negative and high arousing emotional stimuli. In addition, the electromyographic measures showed defective responses exclusively limited to negative and high arousing emotional category: PD did not show increasing of corrugator activity in response to negative emotions as happened in heathy controls. PD subjects inadequately respond to the emotional categories which were considered more “salient”: they had preserved appraisal process, but impaired automatic ability to distinguish between different emotional contexts.

ID 42 – Empowering executive functions by neuromodulation (tDCS) in healthy elderly: Psychometric and EEG evidences

Objective While the contribution of non-invasive brain stimulation (NIBS) in preventing cognitive decline is looked with interest, NIBS empowerment of healthy elderly is understudied. The present research aims at investigating the effect of prefrontal transcranial direct current stimulation (tDCS) in empowering executive functions and electrophysiologic attention responses in healthy aging. Methods 22 participants have been assigned to the intervention or control group and underwent a complex assessment at T0 and at T1 – after three months. The anodal tDCS protocol lasted eight weeks (three sessions per week), with twice-weekly administration of tasks tapping on executive functions. A complete set of standardized cognitive tests and an electroencephalographic recording during a challenging computerized attention task have been integrated in the assessment protocol. Results T0–T1 comparisons highlighted a significant increase in post-intervention performances for the tDCS group. Specifically, tests tapping on executive functions and automatic electrophysiologic attention responses showed positive modulations. Conclusions The consistency of behavioral and electrophysiologic findings suggests that a moderately intensive NIBS protocol might mediate the empowerment of specific cognitive functions even in healthy aging people. Key message Physiological aging is a dynamic process, where non-invasive interventions may capitalize on resources of the cognitive reserve to help improving cognitive functioning.

NETWORK-BASED MODULATION OF CEREBRAL PERFUSION AND FUNCTIONAL CONNECTIVITY IN ALZHEIMER’S DISEASE

of dysfunctional networks: anodal stimulation of the DMN (right inferior parietal lobe), cathodal stimulation of the SN (right dorsolateral prefrontal cortex). Changes from preto post-treatment in clinical scales and functional connectivity were defined as outcome measures. Outcomes from clinical scales were compared by using the Wilcoxon signed-rank test, while changes in connectivity were assessed with the Functional Connectivity Toolbox. A seed-to-voxel approach was used to assess connectivity differences between the stimulated node and the other network areas. Results:To date, 16 patients have completed the treatment. 8 patients were allocated to the anodal and 8 to the cathodal arm. Analysis of clinical-neuropsychological scores revealed a beneficial effect of anodal stimulation over cognition (Immediate recall of Rey Word Recognition test, Token test, Clock test and Semantic Fluency test; p<0.05), whereas cathodal stimulation resulted in amelioration of behavioral symptoms (Neuropsychiatric inventory; p<0.05). In the anodal arm, rsfMRI analysis revealed decreased connectivity between the stimulated parietal node and the posterior cingulate (cluster size: 142 voxels; cluster-wise FDR corrected; p<0.05) after tDCS. In the cathodal arm, no change in connectivity was detected between the stimulated node and SN nodes. Conclusions:These data suggest a different effect of the two neuromodulator paradigms over clinical and cognitive outcomes. Our results suggest that anodal tDCS may be more effective than cathodal tDCS in modulating cognition and intra-network connectivity of aberrant networks in AD. Further studies might clarify whether different paradigms or target networks could also be effective interventions in AD.