In the field of brain-machine interface (BMI) research, the development of cognitive BMI is a hot topic because it may lead to more intuitive and goal-directed findings than existing BMI technology. In this study, we devised a “visual-imagery method,” which enables visual imaging of the operation of a target. We also investigated an “inner-speech method,” which comprised internal pronunciation of words without emitting sounds, and an “inner-speech + visual-imagery method,” which combined the two methods. When only the high γ band (60-120 Hz) power in the prefrontal cortex was used, the average accuracy of the 15 participants, with 20-fold crossvalidation, was 81.3% in inner speech, 84.6% in visual imagery, and 83.2% in inner speech + visual imagery. This study also found that the frontal pole was the most useful region in the prefrontal cortex.

Human creative thinking is unique and capable of generating novel and valuable ideas. Recent research has clarified the contribution of different brain networks (default mode network, DN; executive control network; salience network) to creative thinking. However, the effects of brain stimulation on brain networks during creative thinking and on creative performance have not been clarified. The present study was designed to examine the changes in functional connectivity (FC) and effective connectivity (EC) of the large-scale brain network, and the ensuing changes in creative performance, induced by transcranial direct current stimulation (tDCS). Fourteen healthy male students underwent two tDCS sessions, one with actual stimulation and one with sham stimulation, on two separate days. Participants underwent tDCS (anode over the left dorsolateral prefrontal cortex, DLPFC; cathode over the right inferior parietal lobule, IPL) for 20 min. Before and after the tDCS session, electroencephalography signals were acquired from 32 electrodes over the whole head during the creative thinking task. On FC analysis, the delta band FC between the posterior cingulate cortex and IPL significantly increased only after real stimulation. We also found that the change of flexibility score was significantly correlated with the change in: (i) delta band FC between mPFC and left lateral temporal cortex (LTC) and (ii) alpha band FC between IPL and right LTC. On EC analysis, decreased flow within the DN (from left LTC to right IPL) was observed. Our results reveal that tDCS could affect brain networks, particularly the DN, during creative thinking and modulate key FC in the generation of flexible creative ideas.

Removal of the mesial temporal lobe (MTL) is an established surgical procedure that leads to seizure freedom in patients with intractable MTL epilepsy; however, it carries the potential risk of memory damage. Neurofeedback (NF), which regulates brain function by converting brain activity into perceptible information and providing feedback, has attracted considerable attention in recent years for its potential as a novel complementary treatment for many neurological disorders. However, no research has attempted to artificially reorganize memory functions by applying NF before resective surgery to preserve memory functions. Thus, this study aimed (1) to construct a memory NF system that used intracranial electrodes to feedback neural activity on the language-dominant side of the MTL during memory encoding and (2) to verify whether neural activity and memory function in the MTL change with NF training. Two intractable epilepsy patients with implanted intracranial electrodes underwent at least five sessions of memory NF training to increase the theta power in the MTL. There was an increase in theta power and a decrease in fast beta and gamma powers in one of the patients in the late stage of memory NF sessions. NF signals were not correlated with memory function. Despite its limitations as a pilot study, to our best knowledge, this study is the first to report that intracranial NF may modulate neural activity in the MTL, which is involved in memory encoding. The findings provide important insights into the future development of NF systems for the artificial reorganization of memory functions.

Neurofeedback (NF) shows promise in enhancing memory, but its application to the medial temporal lobe (MTL) still needs to be studied. Therefore, we aimed to develop an NF system for the memory function of the MTL and examine neural activity changes and memory task score changes through NF training. We created a memory NF system using intracranial electrodes to acquire and visualise the neural activity of the MTL during memory encoding. Twenty trials of a tug-of-war game per session were employed for NF and designed to control neural activity bidirectionally (Up/Down condition). NF training was conducted with three patients with drug-resistant epilepsy, and we observed an increasing difference in NF signal between conditions (Up–Down) as NF training progressed. Similarities and negative correlation tendencies between the transition of neural activity and the transition of memory function were also observed. Our findings demonstrate NF’s potential to modulate MTL activity and memory encoding. Future research needs further improvements to the NF system to validate its effects on memory functions. Nonetheless, this study represents a crucial step in understanding NF’s application to memory and provides valuable insights into developing more efficient memory enhancement strategies.

Creative design is an inquiry process that transforms unknowns into knowns while strategically accepting uncertainty to generate novelty. To understand this computationally, we applied the Inquiry Cycle Model (ICM), which extends the Free Energy Principle by positing that temporary increases in predictive uncertainty maximize long-term information gain. We investigated how modulating this uncertainty influences design ideation by conducting a double-blind, randomized controlled experiment using transcranial alternating current stimulation (tACS). By targeting right temporal alpha oscillations—a neural mechanism for inhibiting obvious semantic associations—we artificially lowered top-down predictive precision during divergent thinking. Results demonstrated that this intervention effectively enhanced self-reported originality in both problem-solving and problem-finding tasks. Crucially, the nature of this creative enhancement was fundamentally modulated by the baseline uncertainty of the task context. In more structured problem-solving scenarios, reducing predictive precision significantly increased objective, corpus-based Bayesian surprise (specifically, maximum information gain and optimal arousal). Conversely, in highly ambiguous problem-finding contexts where prior precision is inherently low, the intervention primarily amplified subjective, internal experiences of insight (aha strength) and confidence. These findings provide causal neurophysiological evidence linking right temporal alpha oscillations to predictive precision. Ultimately, they partially support the ICM and highlight the context-dependent role of predictive precision in fostering novelty during idea generation. This offers a mechanistic account of creative cognition based on the brain’s information-processing principles, laying the groundwork for evidence-based methodologies that deliberately regulate these cognitive states in design practice.