MRI-guided focused ultrasound for essential tremor.

This video depicts a left-sided MRI-guided focused ultrasound (MRgFUS) thalamotomy for a right-arm tremor in a 76-year-old, right-handed man with bilateral upper-extremity tremors. The patient tolerated the procedure well, with immediate tremor reduction that persisted at the 1-month follow-up, and there were no adverse events noted during intraoperative testing, postoperative testing, or follow-up. This case highlights MRgFUS as an effective, safe, incision-free treatment option for medically refractory essential tremor.

Aberrant fast spiking interneuronal activity precedes seizure transitions in humans.

There is active debate regarding how GABAergic function changes during seizure initiation and propagation, and whether interneuronal activity drives or impedes the pathophysiology. Here, we track cell-type specific firing during spontaneous human seizures to identify neocortical mechanisms of inhibitory failure. Fast-spiking interneuron activity was maximal over 1 second before equivalent excitatory increases, and showed transitions to out-of-phase firing prior to local tissue becoming incorporated into the seizure-driving territory.

Cell-type specific and multiscale dynamics of human focal seizures in limbic structures.

The relationship between clinically accessible epileptic biomarkers and neuronal activity underlying the transition to seizure is complex, potentially leading to imprecise delineation of epileptogenic brain areas. In particular, the pattern of interneuronal firing at seizure onset remains under debate, with some studies demonstrating increased firing and others suggesting reductions. Previous study of neocortical sites suggests that seizure recruitment occurs upon failure of inhibition, with intact feedforward inhibition in non-recruited territories.