Personalized beta band HD-tACS over the left SMA improves speech and limb movement by modulating prefrontal delta oscillations in neurotypical young adults.

Objective: The supplementary motor area (SMA) demonstrates abnormal beta activity (13-30 Hz) during speech and limb movement tasks in neurological conditions such as Parkinson's disease (PD). Transcranial Alternating Current Stimulation (tACS) has demonstrated promising improvements in motor and non-motor functions by entraining endogenous neural oscillations. We conducted an exploratory study on the modulatory effects of personalized beta high-definition (HD)-tACS over the left SMA on speech production and limb movement.

HD-tACS over the left frontal aslant tract entrains theta activity associated with speech motor control.

Transient disruption or permanent damage to the left Frontal Aslant Tract (FAT) is associated with deficits in speech production. The present study examined the application of theta (4 Hz) high-definition transcranial alternating current stimulation (HD-tACS) over the left SMA and IFG -as a part of FAT- as a potential multisite protocol to modulate neural and behavioral correlates of speech motor control. Twenty-one young adults participated in three counterbalanced sessions in which they received in-phase, anti-phase, and sham theta HD-tACS.

Speech, voice, and language outcomes following deep brain stimulation: A systematic review.

Background: Deep brain stimulation (DBS) reliably ameliorates cardinal motor symptoms in Parkinson's disease (PD) and essential tremor (ET). However, the effects of DBS on speech, voice and language have been inconsistent and have not been examined comprehensively in a single study.

Objective: We conducted a systematic analysis of literature by reviewing studies that examined the effects of DBS on speech, voice and language in PD and ET.

HD-tDCS over left supplementary motor area differentially modulated neural correlates of motor planning for speech vs. limb movement.

The supplementary motor area (SMA) is implicated in planning, execution, and control of speech production and limb movement. The SMA is among putative generators of pre-movement EEG activity which is thought to be neural markers of motor planning. In neurological conditions such as Parkinson's disease, abnormal pre-movement neural activity within the SMA has been reported during speech production and limb movement.

Right frontal HD-tDCS reveals causal involvement of time perception networks in temporal processing of concepts.

Evidence suggests that perceptual and action related features of concepts are grounded in the corresponding sensory-motor networks in the human brain. However, less is known about temporal features of event concepts (e.g.