Transcranial alternating current stimulation ameliorates emotional attention through neural oscillations modulation

Abstract

Background Numerous clinical reports have suggested that psychopathy like schizophrenia, anxiety and depression is accompanied by early attentional abnormalities in emotional processing. Recently, the efficacy of transcranial alternating current stimulation (tACS) in changing emotional functioning has been repeatedly observed and demonstrated a causal relationship between endogenous oscillations and emotional processing. Aims Up to now, tACS effects on emotional attention have not yet been tested. To assess such ability, we delivered active-tACS at individual alpha frequency (IAF), 10 Hz or sham-tACS for 7 consecutive days in the bilaterally dorsolateral prefrontal cortex (dlPFC) to totally 79 healthy participants. Results IAF-tACS group showed significant alpha entrainment at-rest, especially in open state around stimulation area and showed an obvious advantage compared to 10 Hz-tACS. Event-related potential revealed a significant larger P200 amplitude after active-tACS and IAF group showed wider range of emotions than 10 Hz-tACS, indicating the attentional improvement in facial emotion processing. A notable positive correlation between alpha power and P200 amplitude provided an electrophysiological interpretation regarding the role of tACS in emotional attention modulation instead of somatosensory effects. Conclusion These results support a seminal outcome for the effect of IAF-tACS on emotional attention modulation, demonstrating a feasible and individual-specific therapy for neuropsychiatric disorders related to emotion processing, especially regarding oscillatory disturbances.

A Review on Biological Mechanisms of Negative Symptoms in Chronic Schizophrenia

“…According to various research reports, the abnormal or damaged brain areas with negative symptoms of schizophrenia is mainly focus on the area related to cognitive and memory function. Its pathological characteristics are mostly the reduction of gray matter volume and gray matter concentration, which will lead to certain neurodegeneration changes and progressive loss [11][12][13][14]. In a broad sense, the results support the following three models: schizophrenia is caused by frontal striaticular dysfunction, frontal temporal lobe dysfunction and frontal edge dysfunction [15].…”

Neurophysiological mechanisms of transcranial alternating current stimulation

“…According to studies, the induced electric field and inherent oscillation properties can account for between 54 and 65% of the variability in the tACS effect ( Zanto et al, 2021 ). According to our research, human participants with lower endogenous activity can benefit more from particular tACS, whereas subjects with beginning performance following stimulation showed mild or even negative alterations ( Liu et al, 2022 ).…”

Intensity- and frequency-specific effects of transcranial alternating current stimulation are explained by network dynamics

“…Currently no direct evidence, such as single unit recordings, of the Arnold tongue phenomenon in humans has been reported. However, some indirect evidence suggests that effects of tACS are more pronounced when using individual peak frequencies, compared to standard values [26] or control frequencies slightly above or below the peak frequency [27,28]. It should, however, be noted that such strong frequency dependency is not universally observed [29].…”

“…These observations are in line with the hypothesis that EEG frequency ranges are functionally distinct. Crucially, some human studies pointed toward frequency-specificity within a frequency range [26][27][28], although these findings are not demonstrated consistently [29].…”