Comparing transcranial direct current stimulation and transcranial random noise stimulation over left dorsolateral prefrontal cortex and left inferior frontal gyrus: Effects on divergent and convergent thinking

The impact of internet pornography addiction on brain function: a functional near-infrared spectroscopy study

Introduction

There is extensive awareness of internet pornography addiction. It not only affects the mental health of adolescents but also promotes criminal activity. However, the impact of internet pornography addiction on functional in the brain remains unclear.

Methods

16 healthy college students and five college students with severe internet pornography addiction were invited to participate in the experiment and watch a pornographic video. Functional near-infrared spectroscopy (fNIRS) was used to measure the dynamic changes in hemoglobin in the brain during a 10 min session of viewing internet pornography. Participants completed the Stroop Color and Word Task (SCWT) before and after they had watched the video. Facial expressions and life signs were measured continuously during the experiment.

Results

Compared with the group that frequently viewed pornographic videos, the group with low-frequency pornography viewing exhibited enhanced functional connectivity in the inferior prefrontal cortex and pars triangularis of Broca's area in the frontal lobe, the primary somatosensory cortex in the parietal lobe, and the pre-motor and supplementary motor cortices. Moreover, the high-frequency pornography-viewing group exhibited hyperactive parasympathetic activity, more pronounced sexual arousal, and stronger functional connectivity in the dorsolateral prefrontal cortex and frontopolar area. After viewing the pornography, the high-frequency group demonstrated longer reaction times and significantly reduced accuracy while completing the Stroop Color and Word Test (SCWT) compared to the low-frequency group and also their own performance before and after viewing the pornography.

Discussion

This study demonstrated the hyperactive and inhibited brain areas under the impact of pornography video addiction. The results may strengthen our understanding of neurobiology and facilitate the development of prevention policies for adolescents.

The effect of transcranial random noise stimulation (tRNS) over bilateral parietal cortex in visual cross-modal conflicts

In complex sensory environments, visual cross-modal conflicts often affect auditory performance. The inferior parietal cortex (IPC) is involved in processing visual conflicts, namely when cognitive control processes such as inhibitory control and working memory are required. This study investigated the effect of bilateral IPC tRNS on reducing visual cross-modal conflicts and explored whether its efficacy is dependent on the conflict type. Forty-four young adults were randomly allocated to receive either active tRNS (100-640 Hz, 2-mA for 20 min) or sham stimulation. Participants repeatedly performed tasks in three phases: before, during, and after stimulation. Results showed that tRNS significantly enhanced task accuracy across both semantic and non-semantic conflicts compared to sham, as well as a greater benefit in semantic conflict after stimulation. Correlation analyses indicated that individuals with lower baseline performance benefited more from active tRNS during stimulation in the non-semantic conflict task. There were no significant differences between groups in reaction time for each conflict type task. These findings provide important evidence for the use of tRNS in reducing visual cross-modal conflicts, particularly in suppressing semantic distractors, and highlight the critical role of bilateral IPC in modulating visual cross-modal conflicts.

Examining tolerability, safety, and blinding in 1032 transcranial electrical stimulation sessions for children and adolescents with neuropsychiatric and neurodevelopmental disorders

The present study first extensively evaluated the tolerability, safety, and blinding of transcranial direct current stimulation (tDCS) and transcranial random noise stimulation (tRNS) in paediatric clinical populations, composed of 92 children and adolescents (54 females, age range: 8-17 years), involving 1032 sessions across neuropsychiatric (i.e., anorexia nervosa) and neurodevelopmental (i.e., attention deficit and hyperactivity disorder, developmental dyscalculia) conditions. It compared adverse events (AEs) occurrence between active and sham transcranial electrical stimulation (tES) conditions (i.e., 528 active vs. 504 sham sessions) as well as tDCS and tRNS (i.e., 772 tDCS sessions vs. 260 tRNS sessions), while considering demographic and emotional-behavioural factors. Results showed tES safety with no "moderate" or "severe" AEs reported; about 77% of sessions were AE-free, supporting tES use in these populations. Itching was the most common symptom, and active sessions were found to be more likely to induce AEs compared to sham sessions. Notably, tRNS had a higher AE likelihood than tDCS, possibly due to experimental differences. In the current study, demographic and emotional-behavioural variables did not significantly affect AEs. Blinding procedures were moderately effective, with about half of participants correctly identifying their condition. As indicated in prior studies, tRNS seems to better preserve blinding integrity. In conclusion, this study provides comprehensive insights into tES tolerability and safety in paediatric clinical populations, emphasizing the need for further AEs exploration in tES and blinding procedure refinement in future research.

Transcranial direct current stimulation combined with swimming exercise improves the learning and memory abilities of vascular dementia rats by regulating microglia through miR-223-3p/PRMT8

BACKGROUND

Vascular dementia (VD) is the second most common type of dementia worldwide. Previous studies have proven that transcranial direct current stimulation (tDCS) has potential applications in relieving cognitive impairment in VD animal models. The purpose of this study was to probe the mechanism by which tDCS combined with swimming exercise improves the learning and memory abilities of VD model rats.

METHOD

The VD rat model was induced using the permanent bilateral common carotid artery occlusion (2-VO) method; tDCS was applied to the rats and then they took part in swimming exercises. Rat memory, platform crossing time, and platform crossing frequency were analyzed via a water maze experiment. Nerve damage in the cortex and hippocampal CA1 area of the rats was observed using Nissl staining. Western blotting, immunohistochemistry, immunofluorescence staining and reverse transcription quantitative polymerase chain reaction (RT - qPCR) were used to determine the expression of related proteins and genes. The levels of oxidative stress were detected by kits.

RESULTS

We demonstrated that VD model rats treated with tDCS combined with swimming exercise exhibited significant improvement in memory, and VD model rats exhibited significantly reduced neuronal loss in the hippocampus, and reduced microglial activation and M1 polarization. tDCS combined with swimming exercise protects VD model rats from oxidative stress through the miR-223-3p/protein arginine methyltransferase 8 (PRMT8) axis and inhibits the activation of the TLR4/NF-κB signaling pathway.

CONCLUSION

Our results suggest that tDCS combined with swimming exercise improved the learning and memory ability of VD model rats by regulating the expression of PRMT8 through miR-223-3p to affect microglial activation and M1 polarization.

Effects of online tDCS and hf-tRNS on reading performance in children and adolescents with developmental dyslexia: a study protocol for a cross sectional, within-subject, randomized, double-blind, and sham-controlled trial

Background

Developmental Dyslexia (DD) is a brain-based developmental disorder causing severe reading difficulties. The extensive data on the neurobiology of DD have increased interest in brain-directed approaches, such as transcranial direct current stimulation (tDCS), which have been proposed for DD. While positive outcomes have been observed, results remain heterogeneous. Various methodological approaches have been employed to address this issue. However, no studies have compared the effects of different transcranial electrical stimulation techniques (e.g., tDCS and transcranial random noise stimulation, tRNS), on reading in children and adolescents with DD.

Methods

The present within-subject, double-blind, and sham-controlled trial aims to investigate the effects of tDCS and hf-tRNS on reading in children and adolescents with DD. Participants will undergo three conditions with a one-week interval session: (A) single active tDCS session; (B) single active hf-tRNS session; and (C) single sham session (tDCS/hf-tRNS). Left anodal/right cathodal tDCS and bilateral tRNS will be applied over the temporo-parietal regions for 20 min each. Reading measures will be collected before and during each session. Safety and blinding parameters will be recordered.

Discussion

We hypothesize that tRNS will demonstrate comparable effectiveness to tDCS in improving reading compared to sham conditions. Additionally, we anticipate that hf-tRNS will exhibit a similar safety profile to tDCS. This study will contribute novel insights into the effectiveness of hf-tRNS, expediting the validation of brain-based treatments for DD.