22 Sep

Resilience mechanisms in Parkinson's disease: a domain-specific conceptual framework

While nigrostriatal dopaminergic cell loss is the pathological hallmark of Parkinson's disease, it is well-known that dopamine deficiency cannot fully explain the clinical severity or disease progression. Emerging data suggest that resilience, i.e. the brain's capacity to maintain function despite pathology, plays a key role in shaping clinical variability of both motor and non-motor symptoms. However, different contributing terms have been proposed, including brain compensation and reserve, and it remains unclear how these terms can be delineated both conceptually and mechanistically. Therefore, here we provide a synthesis of recent neuroimaging evidence on resilience mechanisms in Parkinson's disease, with the following aims: (1) clarify the terminology, (2) define the mechanisms and (3) relate resilience mechanisms to treatments, including dopamine replacement therapy and deep brain stimulation. We distinguish between compensation and reserve. We define compensation as adaptive neural activity that stabilises task performance in the presence of pathology, particularly under increased demands, and is inversely related to clinical deficits. By contrast, reserve (cognitive or motor) refers to capacity of neural resources that is built up across the lifetime, shaped by factors of an individual's exposome. 

22 Sep

A dual-fMRI investigation of interpersonal emotion regulation: Predicting strategy selection and implementation success from effective brain connectivity

Inter-personal emotion regulation (ER) is the social process whereby one individual (a "Regulator") assists another (the "Target") in regulating their emotional state. Despite the importance of inter-personal ER for maintaining well-being, very little is known about the neurocognitive mechanisms that support this process. In the present study, we performed functional magnetic resonance imaging on 23 pairs of Regulators and Targets whilst they engaged in a novel task designed to capture the two stages of inter-personal ER: the Regulator's selection of an ER strategy to recommend and its subsequent implementation by an affiliate Target. This paradigm allowed us to investigate the brain systems supporting both stages of the inter-personal process and identify personality characteristics that might influence the inter-personal dynamic through these neurocognitive mechanisms. Results revealed largely overlapping patterns of brain response during Regulators' selections and Targets' implementation of ER strategies, encompassing medial and lateral prefrontal and temporo-parietal cortices. 

8 Sep

Intracranial mapping identifies high-frequency cortical dynamics underlying visual discomfort

High-contrast striped patterns near 3 cycles per degree are well established as a cause of visual discomfort and perceptual distortions, which in clinical populations can manifest as symptoms such as migraines or seizures. This sensitivity has been linked to cortical hyperexcitability, characterized by abnormally increased neural responses to visual input. Although gamma-band oscillations in visual cortex are known to reflect excitatory-inhibitory dynamics associated with pattern sensitivity, the contribution of higher-frequency neural activity and large-scale network interactions has received limited direct investigation. Using intracranial EEG recordings from patients with non-photosensitive epilepsy, we examined how aversive gratings modulate local field potential activity across frequencies ranging from 55 to 1000 Hz. Analyses focused on visual cortex as well as higher-order parietal, temporal, insular, and limbic regions, assessing frequency-specific power changes and their relationship to self-reported visual discomfort. At the group level, aversive patterns elicited significantly greater high-gamma power than control patterns in extrastriate regions (BA 18 and, at later latencies, BA 19), while primary visual cortex (BA 17) showed no consistent condition-dependent modulation. 

8 Sep

Colchicine for Secondary Prevention After Stroke According to the Presence of Atherosclerosis

Background: Anti-inflammatory therapies reduce the risk of major adverse cardiovascular events (MACEs) in coronary disease, but efficacy has not been shown after stroke. It is uncertain if patients with atherosclerosis are more likely to benefit from anti-inflammatory prevention.

Methods: We performed a post hoc analysis of the CONVINCE trial (randomized, open-label, blinded-end point assessed; Colchicine for Prevention of Vascular Inflammation in Non-Cardioembolic Stroke), comparing colchicine 0.5 mg plus usual care versus usual care. We performed a subgroup analysis in patients stratified according to the presence/absence of atherosclerosis (defined as cervico-cranial/aortic artery plaque, coronary disease, peripheral arterial disease, and carotid revascularization). The primary outcome was MACE. Analyses were adjusted for age, qualifying event, time from event to randomization, and coronary disease.

Results: Three thousand one hundred forty-four participants were included. There were 338 MACE events during follow-up (median, 33.6 months). 

8 Sep

Right DLPFC repetitive transcranial magnetic stimulation in women with borderline personality disorder: A double-blind randomized sham-controlled trial

Background: Borderline personality disorder (BPD) is characterized by emotional dysregulation and high rates of suicidal and self-harming behavior, while effective treatments remain limited. This study evaluated short- and long-term effects of right dorsolateral prefrontal cortex (DLPFC) rTMS in a double-blind, sham-controlled design, accounting for concurrent treatment and trauma history.

Methods: Thirty women with BPD and recent nonsuicidal self-injury or suicidal behavior underwent 15 sessions of active or sham 10-Hz rTMS targeting the right DLPFC over three weeks. Outcomes were assessed at baseline, post-treatment, and three- and six-month follow-up. Primary analyses compared longitudinal trajectories between groups using linear mixed-effects models.

Results: No significant Group × Time interactions were observed for primary outcomes, indicating no evidence of differential longitudinal change between active and sham stimulation. 

14 Aug

An epigenetic view of anxiety disorders, one cell type at a time

Keywords: DNA methylation; aging; cell type-specific analysis; genetics; methylome-wide association analysis (MWAS); psychiatric disease.

14 Aug

Localizing value of verbal automatisms, vocal automatisms, singing, and humming: A systematic review

Objective: We performed a systematic review of the localizing and lateralizing value of verbal automatisms, vocal automatisms, ictal singing, and humming in focal epilepsy with the view to summarize the state-of-the-art clinico-anatomical correlations in the field and help guide interpretation of ictal semiology within the framework of presurgical evaluation.

Methods: A systematic review of the published evidence according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) statement was conducted. We performed a database search in PubMed and Embase with keywords vocalizations, vocal automatisms, verbal automatisms, singing, and humming combined with seizure or epilepsy. Obtained studies that met the eligibility criteria were evaluated for risk of bias in a QUADAS2-based approach and assessed for epileptogenic zone and lateralization confidence level. Relevant data from these studies were meta-analyzed using a random-effects model.

Results: A total of 44 studies consisting of video-EEG series, surgical series, case reports and case series were included in this review. 

14 Aug

Neural correlates of perceptual consciousness from within: A narrative review of human intracranial research

Keywords: awareness; consciousness; iEEG; intracranial recordings; neuroscience; perception.