Non-invasive brain stimulation: current and future applications in neurology

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).