Modulating Inhibitory Control Processes Using Individualized High Definition Theta Transcranial Alternating Current Stimulation (HD θ-tACS) of the Anterior Cingulate and Medial Prefrontal Cortex

Abstract

Increased frontal midline theta activity generated by the anterior cingulate cortex (ACC) is induced by conflict processing in the medial frontal cortex (MFC). There is evidence that theta band transcranial alternating current stimulation (θ-tACS) modulates ACC function and alters inhibitory control performance during neuromodulation. Multi-electric (256 electrodes) high definition θ-tACS (HD θ-tACS) using computational modeling based on individual MRI allows precise neuromodulation targeting of the ACC via the medial prefrontal cortex (mPFC), and optimizes the required current density with a minimum impact on the rest of the brain. We therefore tested whether the individualized electrode montage of HD θ-tACS with the current flow targeted to the mPFC-ACC compared with a fixed montage (non-individualized) induces a higher post-modulatory effect on inhibitory control. Twenty healthy subjects were randomly assigned to a sequence of three HD θ-tACS conditions (individualized mPFC-ACC targeting; non-individualized MFC targeting; and a sham) in a double-blind cross-over study. Changes in the Visual Simon Task, Stop Signal Task, CPT III, and Stroop test were assessed before and after each session. Compared with non-individualized θ-tACS, the individualized HD θ-tACS significantly increased the number of interference words and the interference score in the Stroop test. The changes in the non-verbal cognitive tests did not induce a parallel effect. This is the first study to examine the influence of individualized HD θ-tACS targeted to the ACC on inhibitory control performance. The proposed algorithm represents a well-tolerated method that helps to improve the specificity of neuromodulation targeting of the ACC.

Structural and functional network mechanisms of rescuing cognitive control in aging

“…In younger adults, PFC theta tACS also shows promise for improving sustained attention, related to strengthened alpha (8–12 Hz) connectivity in the dorsal attention network ( Rostami et al, 2021 ). Improved inhibitory control has also been observed following PFC theta tACS, however, only when the theta frequency matches an individual’s peak frequency ( Klírová et al, 2021 ), similar to results from working memory studies ( Reinhart and Nguyen, 2019 ). The recent successes of tACS, when optimized to affect brain networks, set the groundwork for developing therapeutics for individuals with clinical diagnoses that implicate cognitive control.…”

Modulation of Sustained Attention by Theta-tACS over the Lateral and Medial Frontal Cortices

“…The third limitation is the lack of a control frequency. Similar to previous tACS studies [ 43 – 46 ], we compared stimulation effects between a frequency of interest and sham condition, without involving any control frequencies to rule out confounding effects brought by the frequency factor [ 47 – 48 ]. Future study could provide more convincing evidence of frequency-specific effects by introducing a control frequency condition.…”

Theta oscillations within right dorsolateral prefrontal cortex contribute differently to speech versus limb inhibition

“…Brain stimulation studies also support the role of pre/frontal theta activity in response inhibition (Klírová et al, 2021). Obeso et al (2017) showed that continuous theta burst magnetic stimulation over pre-supplementary motor cortex facilitated motor inhibition in healthy participants.…”