At baseline, there were no significant differences observed between the real and sham groups in any of the variables, which included age, sex, years of education, and handedness.
The mean age of the general sample was 28.31 years (standard deviation = 11.21), and the average number of completed years of education was 14.74 (standard deviation = 2.69). Among the general sample, 46.6% were male, and 53.4% were female.
Effects of Neuro Gamma on DT and CT Scores:
The total DT and CT scores at baseline and post-treatment are displayed in Table 2.
ANCOVA results (post-treatment comparisons controlling for baseline scores) are shown in Table 3.
Change score distributions in verbal DT (UU), visual DT (PC), and total DT are shown in Figure 3.
- The results revealed significant differences between both groups in verbal DT (total UU) with a medium effect size (n²p = 0.10), indicating higher performance after tPBM compared to sham.
- The visual DT (total PC) score was also significant, suggesting that tPBM produced higher performance than the sham group, demonstrating a large effect size (n²p = 0.14).
- Lastly, the total DT score was significantly higher after tPBM compared to sham, displaying a large effect size (n²p = 0.24).
Effects of tPBM on DT Subdomains:
- Regarding verbal DT subdomains, the results suggest that the originality dimension was significantly higher after tPBM compared to sham (see Table 4), indicating a large effect size (n²p = 0.15).
- The effects on PC showed significant differences in fluency, with a medium effect size (n²p = 0.13).
- In terms of the percentage of original responses, there was a significantly higher percentage of original responses in UU (F = 5.90, p = .018) after tPBM (Marginal mean = 75.23, Standard Error = 3.73).
The study aimed to examine the impact of transcranial photobiomodulation (tPBM) on the default mode network (DMN) in healthy individuals and its effect on creative thinking, specifically divergent thinking (DT), while also exploring the role of anxiety in this relationship. The results supported the hypothesis that tPBM of the DMN improves DT without influencing anxiety levels.
The tPBM treatment significantly enhanced verbal and visual DT, particularly in the dimensions of originality and fluency. These findings align with previous neuroimaging studies linking the DMN to DT. The DMN is associated with cognitive processes like mind wandering and episodic memory, which have been linked to creativity.
However, the relationship between mind wandering and DT is not consistently supported, as negative rumination and mind wandering during idea generation may hinder creativity. Although this study did not assess mind wandering, future research could explore whether tPBM’s effect on DT is partially mediated by mind wandering.
The role of episodic memory in creativity and its connection to the default mode network (DMN) is explored in this passage. The idea generation process in divergent thinking (DT) tasks is suggested to involve the flexible retrieval of specific episodic details. The DMN plays a potential role in this process by facilitating the generation of unique and novel ideas while inhibiting mundane ones.
The study presented in Table 4 compares the effects of transcranial photobiomodulation (tPBM) and sham stimulation on different subdomains of DT. Results indicate that tPBM over the DMN significantly enhances verbal and visual DT, particularly in the dimensions of originality and fluency. The DMN’s involvement in DT is consistent with previous research, although creativity also relies on the synchronization between the DMN and other brain networks such as the executive control network and salience network.
The study did not find a significant effect of tPBM on convergent thinking (CT), which further supports the specific role of the DMN in the idea generation phase of creativity. It is suggested that tPBM may facilitate the transition from mind-wandering (DMN) to focused attention (salience and executive control networks), potentially explaining the improvement in DT tasks. Previous studies on tES and tPBM have demonstrated changes in functional connectivity and power levels in specific brain regions associated with creativity.
The lack of adverse effects and the broader stimulation of the DMN are advantages of tPBM compared to tES. However, limitations of the study include the limited time for DT tasks, the inclusion of compound items in the RAT measure, and the immediate assessment after stimulation. Future research should address these limitations, explore the mediating effects of other cognitive functions, and incorporate neuroimaging techniques to examine the neurophysiological effects of tPBM.
The study’s findings contribute to the growing body of research on tPBM’s cognitive effects and its potential applications in various cognitive and behavioral domains.