Right temporal alpha oscillations as a neural mechanism for inhibiting obvious associations

Operating in a second language lowers cognitive interference during creative idea generation: Evidence from brain oscillations in bilinguals

Tasks measuring human creativity overwhelmingly rely on both language comprehension and production. Although most of the world's population is bilingual, few studies have investigated the effects of language of operation on creative output. This is surprising given that fluent bilinguals master inhibitory control, a mechanism also at play in creative idea evaluation. Here, we compared creative output in the two languages of Polish(L1)-English(L2) bilinguals engaged in a cyclic adaptation of the Alternative Uses Task increasing the contribution of idea evaluation (convergent thinking). We show that Polish-English bilinguals suffer less cognitive interference when generating unusual uses for common objects in the L2 than the L1, without incurring a significant drop in idea originality. Right posterior alpha oscillation power, known to reflect creative thinking, increased over cycles. This effect paralleled the increase in originality ratings over cycles, and lower alpha power (8-10 Hz) was significantly greater in the L1 than the L2. Unexpectedly, we found greater beta (16.5-28 Hz) desynchronization in the L2 than the L1, suggesting that bilingual participants suffered less interference from competing mental representations when performing the task in the L2. Whereas creative output seems unaffected by language of operation overall, the drop in beta power in the L2 suggests that bilinguals are not subjected to the same level of semantic flooding in the second language as they naturally experience in their native language.

Alpha and Beta Oscillations Differentially Support Word Production in a Rule-Switching Task

Research into the role of brain oscillations in basic perceptual and cognitive functions has suggested that the alpha rhythm reflects functional inhibition while the beta rhythm reflects neural ensemble (re)activation. However, little is known regarding the generalization of these proposed fundamental operations to linguistic processes, such as speech comprehension and production. Here, we recorded magnetoencephalography in participants performing a novel rule-switching paradigm. Specifically, Dutch native speakers had to produce an alternative exemplar from the same category or a feature of a given target word embedded in spoken sentences (e.g., for the word "tuna", an exemplar from the same category-"seafood"-would be "shrimp", and a feature would be "pink"). A cue indicated the task rule-exemplar or feature-either before (pre-cue) or after (retro-cue) listening to the sentence. Alpha power during the working memory delay was lower for retro-cue compared with that for pre-cue in the left hemispheric language-related regions. Critically, alpha power negatively correlated with reaction times, suggestive of alpha facilitating task performance by regulating inhibition in regions linked to lexical retrieval. Furthermore, we observed a different spatiotemporal pattern of beta activity for exemplars versus features in the right temporoparietal regions, in line with the proposed role of beta in recruiting neural networks for the encoding of distinct categories. Overall, our study provides evidence for the generalizability of the role of alpha and beta oscillations from perceptual to more "complex, linguistic processes" and offers a novel task to investigate links between rule-switching, working memory, and word production.

Penalized canonical correlation analysis reveals a relationship between temperament traits and brain oscillations during mind wandering

INTRODUCTION

There has been a growing interest in studying brain activity under naturalistic conditions. However, the relationship between individual differences in ongoing brain activity and psychological characteristics is not well understood. We investigated this connection, focusing on the association between oscillatory activity in the brain and individually characteristic dispositional traits. Given the variability of unconstrained resting states among individuals, we devised a paradigm that could harmonize the state of mind across all participants.

METHODS

We constructed task contrasts that included focused attention (FA), self-centered future planning, and rumination on anxious thoughts triggered by visual imagery. Magnetoencephalography was recorded from 28 participants under these 3 conditions for a duration of 16 min. The oscillatory power in the alpha and beta bands was converted into spatial contrast maps, representing the difference in brain oscillation power between the two conditions. We performed permutation cluster tests on these spatial contrast maps. Additionally, we applied penalized canonical correlation analysis (CCA) to study the relationship between brain oscillation patterns and behavioral traits.

RESULTS

The data revealed that the FA condition, as compared to the other conditions, was associated with higher alpha and beta power in the temporal areas of the left hemisphere and lower alpha and beta power in the parietal areas of the right hemisphere. Interestingly, the penalized CCA indicated that behavioral inhibition was positively correlated, whereas anxiety was negatively correlated, with a pattern of high oscillatory power in the bilateral precuneus and low power in the bilateral temporal regions. This unique association was found in the anxious-thoughts condition when contrasted with the focused-attention condition.

CONCLUSION

Our findings suggest individual temperament traits significantly affect brain engagement in naturalistic conditions. This research underscores the importance of considering individual traits in neuroscience and offers an effective method for analyzing brain activity and psychological differences.

Alpha oscillations encode Bayesian belief updating underlying attentional allocation in dynamic environments

In a dynamic environment, expectations of the future constantly change based on updated evidence and affect the dynamic allocation of attention. To further investigate the neural mechanisms underlying attentional expectancies, we employed a modified Central Cue Posner Paradigm in which the probability of cues being valid (that is, accurately indicated the upcoming target location) was manipulated. Attentional deployment to the cued location (α), which was governed by precision of predictions on previous trials, was estimated using a hierarchical Bayesian model and was included as a regressor in the analyses of electrophysiological (EEG) data. Our results revealed that before the target appeared, alpha oscillations (8∼13 Hz) for high-predictability cues (88 % valid) were significantly predicted by precision-dependent attention (α). This relationship was not observed under low-predictability conditions (69 % and 50 % valid cues). After the target appeared, precision-dependent attention (α) correlated with alpha band oscillations only in the valid cue condition and not in the invalid condition. Further analysis under conditions of significant attentional modulation by precision suggested a separate effect of cue orientation. These results provide new insights on how trial-by-trial Bayesian belief updating relates to alpha band encoding of environmentally-sensitive allocation of visual spatial attention.

The influence of perceptual and semantic chunking on the neural mechanism of remote association

Studies on remote association tests (RATs) have mainly focused on cognitive processes involved in searching for remote associations. However, factors affecting these search processes and remote associations remain unclear. In order to address this issue, this study compared non-chunking condition (e.g., "//") with perceptual chunking (two red color characters in the three-character item "//") and semantic chunking (high-frequency word-pair in the item; e.g., "//", "," literally "philosophy") conditions in the Chinese Remote Association Test (CRAT). The behavioral results on the CRAT found that the semantic ones resulted in significantly lower successful solving rates and longer response times than the other two conditions. The event-related potential (ERP) results showed that in contrast to the perceptual-chunking and the non-chunking condition, the semantic-chunking elicited enhanced P200, which might be related to the intuitive awareness of the mental fixation. However, relative to the non-chunking condition, the two chunking conditions evoked increased N400 and late positive component (LPC), indexing the late reflection and implementation of cognitive control. Our results suggest that it is the early awareness of the semantic chunk, rather than the general cognitive control process involved in representing and solving the semantically and perceptually chunk-induced interferences, that critically determines the final solving of RATs.

Behavioral and oscillatory signatures of switch costs in highly proficient bilinguals

Bilinguals with a high proficiency in their first (L1) and second language (L2) often show comparable reaction times when switching from their L1 to L2 and vice-versa ("symmetrical switch costs"). However, the neurophysiological signatures supporting this effect are not well understood. Here, we ran two separate experiments and assessed behavioral and MEG responses in highly proficient Spanish-Basque bilinguals while they overtly name pictures in a mixed-language context. In the behavioral experiment, bilinguals were slower when naming items in switch relative to non-switch trials, and this switch cost was comparable for both languages (symmetrical). The MEG experiment mimicked the behavioral one, with switch trials showing more desynchronization than non-switch trials across languages (symmetric neural cost) in the alpha band (8-13 Hz). Source-localization revealed the engagement of right parietal and premotor areas, which have been linked to language selection and inhibitory control; and of the left anterior temporal lobe (ATL), a cross-linguistic region housing conceptual knowledge that generalizes across languages. Our results suggest that highly proficient bilinguals implement a language-independent mechanism, supported by alpha oscillations, which is involved in cue-based language selection and facilitates conceptually-driven lexical access in the ATL, possibly by inhibiting non-target lexical items or disinhibiting target ones.

Functional EEG Alpha Activation Patterns During Malevolent Creativity

On the dark side of creativity, creative ideation is intentionally used to damage others. This first EEG study on malevolent creativity investigated task-related power (TRP) changes in the alpha band while n = 89 participants (52 women, 37 men) generated original ideas for revenge in the psychometric Malevolent Creativity Test. TRP changes were assessed for different stages of the idea generation process and linked to performance indicators of malevolent creativity. This study revealed three crucial findings: 1) Malevolent creativity yielded topographically distinct alpha power increases similar to conventional creative ideation. 2) Time-related activity changes during malevolent creative ideation were reflected in early prefrontal and mid-stage temporal alpha power increases in individuals with higher malevolent creativity performance. This performance-related, time-sensitive pattern of TRP changes during malevolent creativity may reflect early conceptual expansion from prosocial to antisocial perspectives, and subsequent inhibition of dominant semantic associations in favor of novel revenge ideas. 3) The observed, right-lateralized alpha power increases over the entire ideation phase may denote an additional emotional load of creative ideation. Our study highlights the seminal role of EEG alpha oscillations as a biomarker for creativity, also when creative processes operate in a malevolent context.

Learning at your brain's rhythm: individualized entrainment boosts learning for perceptual decisions

Training is known to improve our ability to make decisions when interacting in complex environments. However, individuals vary in their ability to learn new tasks and acquire new skills in different settings. Here, we test whether this variability in learning ability relates to individual brain oscillatory states. We use a visual flicker paradigm to entrain individuals at their own brain rhythm (i.e. peak alpha frequency) as measured by resting-state electroencephalography (EEG). We demonstrate that this individual frequency-matched brain entrainment results in faster learning in a visual identification task (i.e. detecting targets embedded in background clutter) compared to entrainment that does not match an individual's alpha frequency. Further, we show that learning is specific to the phase relationship between the entraining flicker and the visual target stimulus. EEG during entrainment showed that individualized alpha entrainment boosts alpha power, induces phase alignment in the pre-stimulus period, and results in shorter latency of early visual evoked potentials, suggesting that brain entrainment facilitates early visual processing to support improved perceptual decisions. These findings suggest that individualized brain entrainment may boost perceptual learning by altering gain control mechanisms in the visual cortex, indicating a key role for individual neural oscillatory states in learning and brain plasticity.

Uncovering the Interplay of Oscillatory Processes During Creative Problem Solving: A Dynamic Modeling Approach

To solve a new problem, people spontaneously engage multiple cognitive processes. Previous work has identified a diverse set of oscillatory components critical at different stages of creative problem solving. In this project, we use hidden state modeling to untangle the roles of oscillation processes over time as people solve puzzles. Building on earlier work, we further developed analytical methods, such as incorporating source separating techniques and identifying the optimal number of states using cross-validation. We extracted brain states characterized by spatio-spectral topographies from time-resolved EEG spectral powers. The data driven approach allowed us to infer the dynamic, trial-by-trial, state sequences, and provided a comprehensive depiction of how various oscillation components interact recurrently throughout the trial. The properties of the states suggest their dissociable cognitive functions. For example, we identified three states with dominant activation in alpha bands but having distinct spatial distributions. People were differentially engaged in these states depending on the stages (e.g., onset or response) and outcomes of the trials (solved with insight or analysis). The current approach, applicable to many tasks requiring extended trial duration, can potentially reconcile findings from previous EEG studies and drive new hypotheses to further our understanding of the complex creative process.

Women and men have a similar potential for malevolent creativity - But their underlying brain mechanisms are different

Research interest in gender differences in aggression and creative ideation cumulates in the phenomenon of malevolent creativity. Taking another critical step in understanding malevolent creativity, we investigated gender differences in brain activation and functional coupling of cortical sites in the EEG alpha band while n = 88 women and men purposefully generated malevolent creative ideas for taking revenge on others. Results showed that malevolent creativity performance between the genders was similar; however, their underlying EEG patterns were markedly different. While women exhibited a steep decrease of task-related alpha power from frontal to left central-temporal, men's malevolent creative ideation was characterized by a more diffuse pattern of task-related alpha power changes, along with decreased frontal-central coupling. Per interpretation, women's malevolent creative thinking may more strongly rely on controlled semantic memory retrieval and novel re-combination of social/relationship information, while men may utilize more automatic motor-related imagery that may predominantly facilitate physical revenge ideation. Our findings add novel evidence to the idea that women and men engage different neurocognitive strategies to achieve similar creative performance and may help to further illuminate the darker side of creative ideation.

A meta-analysis showing improved cognitive performance in healthy young adults with transcranial alternating current stimulation

Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation used for improving cognitive functions via delivering weak electrical stimulation with a certain frequency. This systematic review and meta-analysis investigated the effects of tACS protocols on cognitive functions in healthy young adults. We identified 56 qualified studies that compared cognitive functions between tACS and sham control groups, as indicated by cognitive performances and cognition-related reaction time. Moderator variable analyses specified effect size according to (a) timing of tACS, (b) frequency band of simulation, (c) targeted brain region, and (b) cognitive domain, respectively. Random-effects model meta-analysis revealed small positive effects of tACS protocols on cognitive performances. The moderator variable analyses found significant effects for online-tACS with theta frequency band, online-tACS with gamma frequency band, and offline-tACS with theta frequency band. Moreover, cognitive performances were improved in online- and offline-tACS with theta frequency band on either prefrontal and posterior parietal cortical regions, and further both online- and offline-tACS with theta frequency band enhanced executive function. Online-tACS with gamma frequency band on posterior parietal cortex was effective for improving cognitive performances, and the cognitive improvements appeared in executive function and perceptual-motor function. These findings suggested that tACS protocols with specific timing and frequency band may effectively improve cognitive performances.

Assessing creativity independently of language: A language-independent remote associate task (LI-RAT)

Most creativity measures are either complex or language-dependent, hindering cross-cultural creativity assessment. We have therefore developed and tested a simple, language-independent insight task based on pictures in the style of the widely used verbal remote associate task (RAT). We demonstrate that the language-independent RAT (LI-RAT) allows assessment of different aspects of insight across large samples with different languages. It also correlates with other creativity and general problem-solving tasks. The entire stimulus set, including its preliminary normative data, is made freely available. This information can be used to select items based on accuracy, mean solution time, likelihood to produce an insight, or conceptual and perceptual similarity between the pictures per item.

Functional brain activation patterns of creative metacognitive monitoring

Creative metacognitive monitoring represents the ability to accurately evaluate the quality of own ideas during idea generation. To the best of our knowledge, this study presents the first EEG investigation of creative metacognitive monitoring in the brain, using data, of 100 participants, who generated single, original uses of common objects (alternate uses task). After each response, participants subjectively rated the creative quality of their idea. Additionally, five independent external judges rated the creative quality of all ideas. The correspondence between the subjective and the external performance ratings served as a measure of monitoring accuracy. We applied a generalized linear mixed effects model to investigate effects of creative metacognitive monitoring and creative potential on EEG activity in the alpha band at idea and person level. Participants with both higher monitoring skills and higher creative potential showed stronger alpha power decreases at parietal/occipital sites during creative idea generation and evaluation. Interestingly, only more creative people with lower metacognitive monitoring skills showed the expected alpha power increases at parietal/occipital sites during both phases. Furthermore, metacognitive monitoring skills were associated with lower frontal and temporal/central alpha power during idea evaluation (compared to generation) at the person level. This pattern of findings seems to suggest that less internal attention, less memory load, and increased sensory processing are associated with more effective and accurate monitoring of the creative process. This study sheds first light on the brain mechanisms underlying the interplay of creative metacognitive monitoring skills and creative potential.

Understanding creativity process through electroencephalography measurement on creativity-related cognitive factors

Introduction

Neurotechnology approaches, such as electroencephalography (EEG), can aid understanding of the cognitive processes behind creativity.

Methods

To identify and compare the EEG characteristics of creativity-related cognitive factors (remote association, common association, combination, recall, and retrieval), 30 participants were recruited to conduct an EEG induction study.

Results

From the event-related potential (ERP) results and spectral analysis, the study supports that creativity is related to the frontal lobe areas of the brain and common association is an unconscious process.

Discussion

The results help explain why some creativity-related cognitive factors are involved either more or less readily than others in the creative design process from workload aspects. This study identifies the part of the brain that is involved in the combination cognitive factor and detects the ERP results on cognitive factors. This study can be used by designers and researchers to further understand the cognitive processes of creativity.

Everyday Creativity is Associated with Increased Frontal Electroencephalography Alpha Activity During Creative Ideation

Everyday creativity is the basic ability of human survival and penetrates every aspect of life. Nevertheless, the neural mechanisms underlying everyday creativity was largely unexplored. In this study, seventy-five participants completed the creative behaviour inventory, a tool for assessing creative behaviour in daily life. The participants also completed the alternate uses task (AUT) during an electroencephalography (EEG) assessment to evaluate creative thinking. Alpha power was used to quantify neural oscillations during the creative process, while alpha coherence was used to quantify information communication between frontal regions and other sites during creative ideation. Moreover, these two task-related quantitative measures were combined to investigate the relationship between individual differences in everyday creativity and EEG alpha activity during creative idea generation. Compared with the reference period, increased alpha power was observed in the frontal cortex of the right hemisphere and increased functional coupling was observed between frontal and parietal/temporal regions during the activation period. Interestingly, individual differences in everyday creativity were associated with distinct patterns of EEG alpha activity. Specifically, individuals with higher everyday creativity had increased alpha power in the frontal cortex, and increased changes in coherence in frontal-temporal regions of the right hemisphere while performing the AUT. It might indicate that individuals with higher everyday creativity had an enhanced ability to focus on internal information processing and control bottom-up stimuli, as well as better selection of novel semantic information when performing creative ideation tasks.

More creative ideas are associated with increased right posterior power and frontal-parietal/occipital coupling in the upper alpha band: A within-subjects study

The neurophysiological investigation of creative idea generation is a growing research area. EEG studies congruently reported the sensitivity of upper alpha power (10-12 Hz) for the creative ideation process and its outcome. However, the majority of studies were between-subject design studies and research directly comparing the neurophysiological activation pattern when generating more and less creative ideas within a person are rare. Therefore, the present study was specifically focused on investigating brain activation patterns associated with the generation of more vs. less creative ideas. We applied an alternate uses task (AU-task; i.e., finding original uses for everyday objects such as a brick) in a sample of 74 participants and recorded the brain activation during the AU-task and reference period. A portable EEG system with 21 dry electrodes arranged in the international 10-20 system and linked ear as reference was used. We found a higher increase of upper alpha power during creative ideation (relative to reference period, i.e., task-related power, TRP) over right posterior sites when people generated more compared to less creative ideas. This was accompanied by an increase of functional coupling (i.e., task-related coherence increase) between frontal and parietal/occipital sites, which suggests higher internal attention and more control over sensory processes. Taken together, these findings complement the existing creativity research literature and indicate the importance of alpha power for the creative ideation process also within people.

Ecological Momentary Assessment of Creative Ideation

Abstract. Creative ideas in daily life show substantial variation in quality. Yet, most studies investigate the creative ideation process in highly controlled laboratory contexts, which challenges the ecological validity of creativity research findings. In this article, we advocate the use of ambulatory assessments of creative ideation to gain deeper insight into the variability of ideation processes (between- and within-subjects) in everyday life. We demonstrate this approach by the example of the ambulatory battery of creativity (ABC), which constitutes a reliable and valid approach to assess divergent thinking ability in the verbal and figural domain in everyday life context. Furthermore, it differentiates between-person and within-person variation of creative ideation performance. The first part of this paper will shortly describe the general approach using ABC as an example. In the second part, we use the 7 C’s heuristic to explore applications and implications of this novel method for creativity research. We focus on four C’s with special relevance for ambulatory assessment: Creator, Creating, Context, and Curricula. To this end, we review the findings of strongly controlled laboratory studies and discuss and illustrate applications of the ambulatory assessment. We conclude that the assessment of creative ideation performance in the field might help move the spotlight of creative ideation research from the laboratory to more naturalistic settings. This would increase the ecological validity of creative ideation research and facilitate fresh or unprecedented perspectives on past and future questions on a person’s creative potential and its moment-to-moment fluctuation.

Cognitive control of invalid predominant ideas in insight-like problem solving

Predominant ordinary ideas are insufficient for solving insight-like problems; they interfere with subordinate original ideas and can produce a mental impasse. However, how people monitor and control invalid predominant ideas remains largely unknown. In the current study, participants were asked to solve a sequence of several similar practice problems that had the same solution to strengthen a predominant idea; the participants were then presented with an insight-like test problem that could not be solved by the predominant idea. The results showed that if the test problem was similar to the practice problems in which the predominant idea could typically be applied, it elicited greater late sustained potential (LSP) over the whole brain but no conflict-related N2 or N400 components, which suggests that the participants did not experience cognitive conflict and continued to verify the predominant but currently invalid idea. When the test problem differed from the practice problems, the items that participants reported trying to solve elicited greater N2-N400 and LSP over the whole brain, which suggests that the participants experienced cognitive conflict and exerted more reactive control over the invalid predominant idea; in contrast, the items that participants reported thinking about how to solve did not evoke greater conflict-related N2-N400 components and evoked even lower LSP, which likely indicates an ineffective state. These findings demonstrate three kinds of cognitive control toward invalid predominant ideas in situations where they are typically and not typically applied and provide empirical evidence of a mental impasse in insight-like problem-solving behaviors.

Acute and Chronic Physical Activity Increases Creative Ideation Performance: A Systematic Review and Multilevel Meta-analysis

BACKGROUND

Physical activity is a health-relevant lifestyle factor associated with various benefits on physical and mental health. Several meta-analyses indicated effects of acute and chronic physical activities on elementary cognitive functions such as executive control processes, memory, and attention. Meta-analytic evidence on the effects of physical activity on creative idea generation, which involves a conglomerate of these elementary cognitive functions, is largely missing.

OBJECTIVE

A twofold approach was used to evaluate (1) if there is an association between habitual physical activity and creative ideation and (2) if physical activity interventions (acute and chronic) enhance creative ideation performance.

METHODS

Multilevel meta-analytic methods were applied to (1) evaluate the cross-sectional association between creative ideation performance and measures of habitual physical activity and (2) the effect of physical activity on creative ideation performance. Indicators of creative ideation (fluency, flexibility, originality, elaboration, or composite score), creativity domain (verbal, figural), population (adults, children), gender, study quality, and publication year served as moderator variables for both meta-analyses. Analyses of intervention studies additionally examined the moderator variables study design (between, within), time of measurement (during, after), and implementation of intervention (acute, chronic).

RESULTS

The applied meta-analytic multilevel analysis indicated a medium effect for cross-sectional studies (r = 0.22, SE = 0.06, p = 0.002, 95% CI [0.10-0.34]) based on 17 effects sizes from seven studies. The pooled effects of 28 intervention studies, providing 115 effect sizes, indicated a medium effect size of Hedges' g = 0.47 (SE = 0.09, p < 0.001, 95% CI [0.30-0.65]). Furthermore, a stronger effect was observed for chronic interventions of several days or weeks in comparison with acute interventions of one single bout.

CONCLUSION

This study adds important new meta-analytic evidence on the beneficial role of physical activity beyond mental and physical health outcomes: Physical activity has a positive impact on creative ideation, which expands the literature on the role of physical activity in more elementary cognitive functions such as executive control, memory, and attention. Moderator analyses suggested that chronic interventions showed stronger effects than single bouts of physical activity. Rigorously conducted randomized controlled intervention studies and more cross-sectional studies are needed to broaden the evidence in this nascent field of research.

An Empirical Approach to Analyzing the Effects of Stress on Individual Creativity in Business Problem-Solving: Emphasis on the Electrocardiogram, Electroencephalogram Methodology

In this study, experiments were conducted on 30 subjects by means of electrocardiogram (ECG) and electroencephalogram (EEG) methodologies as well as a money game to examine the effects of stress on creativity in business problem-solving. The study explained the relationship between creativity and human physiological response using the biopsychosocial model of challenge and threat. The subjects were asked to perform a cognitive mapping task. Based on the brain wave theory, we identified the types of brain waves and locations of brain activities that occurred during the creative problem-solving process in a business environment and studied the effects of stress on creativity. The results of the experiments showed significant differences in creativity in business problem-solving depending on whether or not stress was triggered. Differences were found in the time domain (SDNN, RMSSD) and frequency domain (HF, LF/HF ratio) of heart rates, a physiological stress indicator, between the stress group and the no-stress group. A brain wave analysis confirmed that alpha waves increased in the frontal lobe of the brain during creative business problem-solving but decreased when the subjects were under stress, during which beta waves in the brain increased. This study seeks to examine creativity in business problem-solving by studying the effects of stress on human physiological response and cognitive functions in the hope of providing a new and objective interpretation of existing research results.

Functional lateralization of the medial temporal lobe in novel associative processing during creativity evaluation

Although hemispheric lateralization of creativity has been a longstanding topic of debate, the underlying neurocognitive mechanism remains poorly understood. Here we designed 2 types of novel stimuli-"novel useful and novel useless," adapted from "familiar useful" designs taken from daily life-to demonstrate how the left and right medial temporal lobe (MTL) respond to novel designs of different usefulness. Taking the "familiar useful" design as a baseline, we found that the right MTL showed increased activation in response to "novel useful" designs, followed by "novel useless" ones, while the left MTL only showed increased activation in response to "novel useful" designs. Calculating an asymmetry index suggests that usefulness processing is predominant in the left MTL, whereas the right MTL is predominantly involved in novelty processing. Moreover, the left parahippocampal gyrus (PHG) showed stronger functional connectivity with the anterior cingulate cortex when responding to "novel useless" designs. In contrast, the right PHG showed stronger connectivity with the amygdala, midbrain, and hippocampus. Critically, multivoxel representational similarity analyses revealed that the left MTL was more effective than the right MTL at distinguishing the usefulness differences in novel stimuli, while representational patterns in the left PHG positively predicted the post-behavior evaluation of "truly creative" products. These findings suggest an apparent dissociation of the left and right MTL in integrating the novelty and usefulness information and novel associative processing during creativity evaluation, respectively. Our results provide novel insights into a longstanding and controversial question in creativity research by demonstrating functional lateralization of the MTL in processing novel associations.

Creativity in an Affective Context

Abstract. Everyday life often requires considerable creativity in dealing with challenging circumstances. This implies that creativity regularly operates in an affective context, however, this “C” of creativity is rarely addressed in contemporary research. In this brief review article, we address some important milestones in this nascent field of research. Starting with early accounts on emotional creativity, we discuss seminal research intertwining creativity and mood states, and finally introduce two recent developments in this field: reappraisal inventiveness as the capacity to generate manifold cognitive reappraisals for aversive situations, and malevolent creativity as creative ideation intentionally used to damage others. We discuss the conceptual origins of reappraisal inventiveness and malevolent creativity and provide an extensive review of past behavioral and neuroscientific findings regarding these differently motivated instances of affective creativity. Additionally, novel pilot findings and prospects on both lines of research will be provided, which may help to advance investigations into more real-world applications of creative cognition.

Neural Rhythmic Underpinnings of Intergroup Bias: Implications for Peace-Building Attitudes and Dialogue

Intergroup bias is a ubiquitous socio-cognitive phenomenon that, while sustaining human dependence on group living, often leads to prejudice, inequity, and violence; yet, its neural underpinnings remain unclear. Framed within the Israeli-Palestinian conflict and targeting youth, this study utilized magnetoencephalography to describe intrinsic neural oscillatory processes that represent the intergroup bias and may link with engagement in peacemaking in order to shed further light on the neural mechanisms underpinning intergroup conflict. Across the oscillatory spectrum, from very low to very high frequency bands, the only rhythm found to underlie the intergroup bias was the alpha rhythm. Alpha was continuously activated across the task and integrated a rapid perceptual component in occipital cortex with a top-down cognitive-control component in medial cingulate cortex. These components were distinctly associated with real-life intergroup dialog style and expressed attitudes that promote active engagement in peacemaking. Our findings suggest that the cortical alpha rhythm plays a crucial role in sustaining intergroup bias and address its impact on concrete intergroup experiences. Results highlight the need to provide opportunities for active peace-building dialog to youth reared amidst intractable conflicts.

Effects of Transcranial Alternating Current Stimulation and Neurofeedback on Alpha (EEG) Dynamics: A Review

Transcranial alternating current stimulation (tACS) and neurofeedback (NFB) are two different types of non-invasive neuromodulation techniques, which can modulate brain activity and improve brain functioning. In this review, we compared the current state of knowledge related to the mechanisms of tACS and NFB and their effects on electroencephalogram (EEG) activity (online period/stimulation period) and on aftereffects (offline period/post/stimulation period), including the duration of their persistence and potential behavioral benefits. Since alpha bandwidth has been broadly studied in NFB and in tACS research, the studies of NFB and tACS in modulating alpha bandwidth were selected for comparing the online and offline effects of these two neuromodulation techniques. The factors responsible for variability in the responsiveness of the modulated EEG activity by tACS and NFB were analyzed and compared too. Based on the current literature related to tACS and NFB, it can be concluded that tACS and NFB differ a lot in the mechanisms responsible for their effects on an online EEG activity but they possibly share the common universal mechanisms responsible for the induction of aftereffects in the targeted stimulated EEG band, namely Hebbian and homeostatic plasticity. Many studies of both neuromodulation techniques report the aftereffects connected to the behavioral benefits. The duration of persistence of aftereffects for NFB and tACS is comparable. In relation to the factors influencing responsiveness to tACS and NFB, significantly more types of factors were analyzed in the NFB studies compared to the tACS studies. Several common factors for both tACS and NFB have been already investigated. Based on these outcomes, we propose several new research directions regarding tACS and NFB.

Beta and Theta Oscillations Correlate With Subjective Time During Musical Improvisation in Ecological and Controlled Settings: A Single Subject Study

In this paper, we describe the results of a single subject study attempting at a better understanding of the subjective mental state during musical improvisation. In a first experiment, we setup an ecological paradigm measuring EEG on a musician in free improvised concerts with an audience, followed by retrospective rating of the mental state of the improviser. We introduce Subjective Temporal Resolution (STR), a retrospective rating assessing the instantaneous quantization of subjective timing of the improviser. We identified high and low STR states using Hidden Markov Models in two performances, and were able to decode those states using supervised learning on instantaneous EEG power spectrum, showing increases in theta and alpha power with high STR values. In a second experiment, we found an increase of theta and beta power when experimentally manipulating STR in a musical improvisation imagery experiment. These results are interpreted with respect to previous research on flow state in creativity, as well as with the temporal processing literature. We suggest that a component of the subjective state of musical improvisation may be reflected in an underlying mechanism related to the subjective quantization of time. We also demonstrate the feasibility of single case studies of musical improvisation using brain activity measurements and retrospective reports, by obtaining consistent results across multiple sessions.

Clustering and switching in divergent thinking: Neurophysiological correlates underlying flexibility during idea generation

EEG alpha synchronization, especially in posterior parietal cortical regions of the right hemisphere, is indicative of high internal processing demands that are typically involved in divergent thinking (DT). During the course of DT, as ideation proceeds, ideas tend to become more creative, being more likely to be drawn from new conceptual categories through the use of the cognitive mechanism of flexibility. The present study investigated whether EEG alpha synchronization can be modulated by flexibility in DT by comparing cortical activation patterns during the switch of category (switching) and the stay in the same category (clustering). Twenty participants were required to generate alternative uses of everyday objects during EEG recording. Differential results were specifically found in the lower alpha band (8-10 Hz): whereas clustering showed synchronization typically lateralized in the right posterior parietal areas, switching induced posterior parietal synchronization over both right and left hemispheres. These findings indicate that the two distinct cognitive mechanisms subsuming flexibility (switching and clustering) are associated with a different hemispheric modulation of lower alpha activity, as switching, in comparison to clustering, is related to higher power in the lower alpha band over the left hemisphere. Switching in comparison to clustering may thus require a larger investment of cognitive resources due to the exploratory process of moving from one semantic conceptual category to another in the course of creative ideation.

Augmenting ideational fluency in a creativity task across multiple transcranial direct current stimulation montages

Neuroimaging and transcranial direct current stimulation (tDCS) research has revealed that generating novel ideas is associated with both reductions and increases in prefrontal cortex (PFC) activity, and engagement of posterior occipital cortex, among other regions. However, there is substantial variability in the robustness of these tDCS‐induced effects due to heterogeneous sample sizes, different creativity measures, and methodological diversity in the application of tDCS across laboratories. To address these shortcomings, we used twelve different montages within a standardized tDCS protocol to investigate how altering activity in frontotemporal and occipital cortex impacts creative thinking. Across four experiments, 246 participants generated either the common or an uncommon use for 60 object pictures while undergoing tDCS. Participants also completed a control short-term memory task. We applied active tDCS for 20 min at 1.5 mA through two 5 cm × 5 cm electrodes over left or right ventrolateral prefrontal (areas F7, F8) or occipital (areas O1, O2) cortex, concurrent bilateral stimulation of these regions across polarities, or sham stimulation. Cathodal stimulation of the left, but not right, ventrolateral PFC improved fluency in creative idea generation, but had no effects on originality, as approximated by measures of semantic distance. No effects were obtained for the control tasks. Concurrent bilateral stimulation of the ventrolateral PFC regardless of polarity direction, and excitatory stimulation of occipital cortex did not alter task performance. Highlighting the importance of cross-experimental methodological consistency, these results extend our past findings and contribute to our understanding of the role of left PFC in creative thinking.

Enhancement of semantic integration reasoning by tRNS

The right hemisphere is involved with the integrative processes necessary to achieve global coherence during reasoning and discourse processing. Specifically, the right temporal lobe has been proven to facilitate the processing of distant associate relationships, such as generating novel ideas. Previous studies showed a specific swing of alpha and gamma oscillatory activity over the right parieto-occipital lobe and the right anterior temporal lobe respectively, when people solve semantic problems with a specific strategy, i.e., insight problem-solving. In this study, we investigated the specificity of the right parietal and temporal lobes for semantic integration using transcranial Random Noise Stimulation (tRNS). We administered a set of pure semantics (i.e., Compound Remote Associates [CRA]) and visuo-semantic problems (i.e., Rebus Puzzles) to a sample of 31 healthy volunteers. Behavioral results showed that tRNS stimulation over the right temporal lobe enhances CRA accuracy (+12%), while stimulation on the right parietal lobe causes a decrease of response time on the same task (-2,100 ms). No effects were detected for Rebus Puzzles. Our findings corroborate the involvement of the right temporal and parietal lobes when solving purely semantic problems but not when they involve visuo-semantic material, also providing causal evidence for their postulated different roles in the semantic integration process and promoting tRNS as a candidate tool to boost verbal reasoning in humans.

Evaluating Human-Computer Co-creative Processes in Music: A Case Study on the CHAMELEON Melodic Harmonizer

CHAMELEON is a computational melodic harmonization assistant. It can harmonize a given melody according to a number of independent harmonic idioms or blends between idioms based on principles of conceptual blending theory. Thus, the system is capable of offering a wealth of possible solutions and viewpoints for melodic harmonization. This study investigates how human creativity may be influenced by the use of CHAMELEON in a melodic harmonization task. Professional and novice music composers participated in an experiment where they were asked to harmonize two similar melodies under two different conditions: one with and one without computational support. A control group harmonized both melodies without computational assistance. The influence of the system was examined both behaviorally, by comparing metrics of user-experience, and in terms of the properties of the artifacts (i.e., pitch class distribution and number of chord types characterizing each harmonization) that were created between the two experimental conditions. Results suggest that appreciation of the system was expertise-dependent (i.e., novices appreciated the computational support more than professionals). At the same time, users seemed to adopt more explorative strategies as a result of interaction with CHAMELEON based on the fact that the harmonizations created this way were more complex, diverse, and unexpected in comparison to the ones of the control group.

The neurobiology of prefrontal transcranial direct current stimulation (tDCS) in promoting brain plasticity: A systematic review and meta-analyses of human and rodent studies

The neurobiological mechanisms underlying prefrontal transcranial direct current stimulation (tDCS) remain elusive. Randomized, sham-controlled trials in humans and rodents applying in vivo prefrontal tDCS were included to explore whether prefrontal tDCS modulates resting-state and event-related functional connectivity, neural oscillation and synaptic plasticity. Fifty studies were included in the systematic review and 32 in the meta-analyses. Neuroimaging meta-analysis indicated anodal prefrontal tDCS significantly enhanced bilateral median cingulate activity [familywise error (FWE)-corrected p < .005]; meta-regression revealed a positive relationship between changes in median cingulate activity after tDCS and current density (FWE-corrected p < .005) as well as electric current strength (FWE-corrected p < .05). Meta-analyses of electroencephalography and magnetoencephalography data revealed nonsignificant changes (ps > .1) in both resting-state and event-related oscillatory power across all frequency bands. Applying anodal tDCS over the rodent hippocampus/prefrontal cortex enhanced long-term potentiation and brain-derived neurotrophic factor expression in the stimulated brain regions (ps <.005). Evidence supporting prefrontal tDCS administration is preliminary; more methodologically consistent studies evaluating its effects on cognitive function that include brain activity measurements are needed.

Creative Connections: Computational Semantic Distance Captures Individual Creativity and Resting-State Functional Connectivity

Recent studies of creative cognition have revealed interactions between functional brain networks involved in the generation of novel ideas; however, the neural basis of creativity is highly complex and presents a great challenge in the field of cognitive neuroscience, partly because of ambiguity around how to assess creativity. We applied a novel computational method of verbal creativity assessment-semantic distance-and performed weighted degree functional connectivity analyses to explore how individual differences in assembly of resting-state networks are associated with this objective creativity assessment. To measure creative performance, a sample of healthy adults (n = 175) completed a battery of divergent thinking (DT) tasks, in which they were asked to think of unusual uses for everyday objects. Computational semantic models were applied to calculate the semantic distance between objects and responses to obtain an objective measure of DT performance. All participants underwent resting-state imaging, from which we computed voxel-wise connectivity matrices between all gray matter voxels. A linear regression analysis was applied between DT and weighted degree of the connectivity matrices. Our analysis revealed a significant connectivity decrease in the visual-temporal and parietal regions, in relation to increased levels of DT. Link-level analyses showed higher local connectivity within visual regions was associated with lower DT, whereas projections from the precuneus to the right inferior occipital and temporal cortex were positively associated with DT. Our results demonstrate differential patterns of resting-state connectivity associated with individual creative thinking ability, extending past work using a new application to automatically assess creativity via semantic distance.

Dimensions of Musical Creativity

Current literature on creative cognition has developed rich conceptual landscapes dedicated to the analysis of both individual and collective forms of creativity. This work has favored the emergence of unifying theories on domain-general creative abilities in which the main experiential, behavioral, computational, and neural aspects involved in everyday creativity are examined and discussed. But while such accounts have gained important analytical leverage for describing the overall conditions and mechanisms through which creativity emerges and operates, they necessarily leave contextual forms of creativity less explored. Among the latter, musical practices have recently drawn the attention of scholars interested in its creative properties as well as in the creative potential of those who engage with them. In the present article, we compare previously posed theories of creativity in musical and non-musical domains to lay the basis of a conceptual framework that mitigates the tension between (i) individual and collective and (ii) domain-general and domain-specific perspectives on creativity. In doing so, we draw from a range of scholarship in music and enactive cognitive science, and propose that creative cognition may be best understood as a process of skillful organism-environment adaptation that one cultivates endlessly. With its focus on embodiment, plurality, and adaptiveness, our account points to a structured unity between living systems and their world, disclosing a variety of novel analytical resources for research and theory across different dimensions of (musical) creativity.

The left prefrontal cortex supports inhibitory processing during semantic memory retrieval

Semantic control refers to a set of neural and cognitive mechanisms that govern semantic processing and retrieval. Neuroimaging studies have indicated that controlled semantic processing engages the left prefrontal cortex (PFC), yet the functional role of the prefrontal activity in semantic control is poorly understood and was therefore addressed in the present study. We used a double-blind randomized controlled experiment, in which participants from three distinct groups received anodal transcranial direct current stimulation (tDCS) over left lateral PFC (n = 40), a control tDCS over temporoparietal cortex (n = 40), or sham stimulation (n = 41), while executing automatic and controlled semantic retrieval tasks as well as additional control tasks assessing working memory and semantic judgement. We demonstrate that anodal tDCS of the left lateral PFC improved inhibition of prepotent semantic associations but had no significant effect on retrieval of habitual associates or switching between retrieval rules. The prefrontal tDCS also enhanced working memory capacity, but this effect did not account for the improved semantic inhibition. The control temporoparietal tDCS did not affect semantic retrieval. Our findings show that semantic inhibition and switching represent distinct components of the semantic control system and indicate that the left lateral PFC is involved in a filtering process that constrains the accessible semantic representations (i.e., a proactive pre-retrieval inhibition) or suppresses already retrieved responses (i.e., a retroactive post-retrieval inhibition). The recognition of such an inhibitory process could inspire novel treatments targeting altered semantic processing.

A Systematic Review of Creativity-Related Studies Applying the Remote Associates Test From 2000 to 2019

The study examines how the remote associates test (RAT) has been used to examine theories of creativity through a review of recent studies on creativity. Creativity-related studies published between 2000 and 2019 were retrieved from the SCOPUS database. A total of 172 papers were chosen for further analysis. Content analysis shows that research on creativity using RAT mainly concerns remote association, insight problem-solving, general creative process, test development, individual difference, effect of treatment, clinical case, social interaction effect, and predictor or criterion. The study constructs a theoretical framework based on the 4P (Product–Person–Process–Place) model and demonstrates how empirical studies using the RAT explore the individual differences, internal processes, and external influences of creative thinking. In addition, the most commonly used version of the RAT is the Compound Remote Associates Problems (Bowden and Jung-Beeman, 2003a). Current research shows a trend whereby the creative thinking process has been receiving greater attention. In particular, a growing number of studies in this field have been carried out using cognitive neuroscience technologies. These findings suggest that the RAT provides researchers with a way to deepen their understanding of different levels of creativity.

The effect of transcranial random noise stimulation (tRNS) over bilateral posterior parietal cortex on divergent and convergent thinking

Creativity pervades many areas of everyday life and is considered highly relevant in several human living domains. Previous literature suggests that the posterior parietal cortex (PPC) is related to creativity. However, none of previous studies have compared the effect of transcranial random noise stimulation (tRNS) over bilateral PPC on both verbal and visual divergent thinking (DT) and Remote Associates Test (RAT) in the same experimental design. Forty healthy participants were randomly assigned to tRNS (100–500 Hz) over bilateral PPC or sham group, for 15 min and current was set at 1.5 mA. Participants’ creativity skills were assessed before and after brain stimulation with the Unusual Uses and the Picture Completion subtests from the Torrance Test of Creative Thinking and the RAT. ANCOVA (baseline scores as covariate) results indicated that tRNS group had significantly higher scores at post-test in RAT and visual originality compared to sham group. Unusual Uses, on the other hand, was not significant. Improvement in RAT suggests the involvement of PPC during via insight solution which may reflect internally directed attention that helps the recombination of remotely associated information. The improvement in visual originality dimension from DT may be due to a higher internally directed attention while reducing externally oriented attention.

Are All Remote Associates Tests Equal? An Overview of the Remote Associates Test in Different Languages

The Remote Associates Test (RAT, CRA) is a classic creativity test used to measure creativity as a function of associative ability. The RAT has been administered in various different languages. Nonetheless, because of how embedded in language the test is, only a few items are directly translatable, and most of the time, the RAT is created a new in each language. This process of manual (and in two cases, computational) creation of RAT items is guided by the researchers' understanding of the task. This paper focuses on the question of whether RAT datasets administered in different languages within the literature are comparable. To answer this question, datasets acquired using different RAT stimuli are analyzed qualitatively and quantitatively. Kruskal-Wallis tests are conducted to find out whether there is a significant difference between any of the datasets for a given time frame. Pairwise Mann-Whitney post-hoc tests are then used to find out which pairs are different. Significant differences are observed between 18 dataset pairings regarding Accuracy and between 16 in terms of Response Time. The potential sources of these differences are discussed, together with what this means for creativity psychometrics and computational vs. manual creation of stimuli.

Motivational Factors in the Typical Display of Humor and Creative Potential: The Case of Malevolent Creativity

Research is still disputing if an individual's use of humor in everyday life is also indicative of his or her creative potential. To date, the focus has been mainly restricted to shared cognitive factors, while motivational aspects that may link the production of humor and of creative ideas have been largely neglected. Humor motivation implicates latent social goals the creator pursues through the use of humor. These goals can be benign or more malicious and manifest in an individual's typical display of comic styles. While often overlooked, creativity often serves social functions as well, especially in common everyday situations. Similar to humor, creativity is typically regarded as beneficial for individuals and society. Yet, creative ideas may also originate from less prosocial goals. This is reflected in the concept of malevolent creativity, where novel ideas are generated to deliberately harm others. The present study investigated individuals' typical display of humor, differentiated in eight distinct comic styles in relation to their productivity in a behavioral test for malevolent creativity and general creative potential (n = 106). Individuals with higher scores on comic styles that are affiliated with malicious interpersonal goals - such as hurting or upsetting others or demonstrating superiority over others - were more fluent in producing malevolent creative ideas in the malevolent creativity test. This finding shows that individual differences in humor motivation relate to the capacity of coming up with relevant creative ideas also outside the domain of humor. The pattern of relationships between humor motivation and general creative potential differed from that of malicious creativity and implied the comic style "wit" only, primarily adding to the notion of shared cognitive processes in the production of humor and creative ideas. The study offers a novel perspective for how the inclusion of motivational factors that are inherent to conceptualizations of humor may also benefit creativity research.

Humor comprehension and creative cognition: Shared and distinct neurocognitive mechanisms as indicated by EEG alpha activity

Humor comprehension is increasingly recognized as showing parallels to more conventional creative cognition; yet our understanding of brain mechanisms underlying creative cognition in a humorous context is still limited. The present study addressed this issue by investigating functional patterns of EEG alpha activity while 93 participants viewed nonverbal humorous cartoons until they indicated having recognized the punch line, and subsequently vocalized their idea as to what constituted it. In a similar fashion, EEG was also assessed during performance of the Alternate Uses Task (AUT), in order to identify similarities and differences in EEG alpha activity implicated in conventional creative cognition vs. humor comprehension. Analyses revealed a pattern of robust task-related alpha power increases in both tasks, which were markedly more right-lateralized at ventral fronto-temporal sites in the humor task as compared to the AUT. Findings are interpreted in line with recent literature on the functional role of alpha activity in the creativity domain. Altogether, this study adds further evidence to the particular role of EEG alpha oscillations in creative cognition and supports the idea that conventional creative ideation and the comprehension of humor share neural mechanisms affiliated to creative cognition.

The dynamics of resting-state alpha oscillations predict individual differences in creativity

The neuronal mechanisms underlying creativity are poorly understood. Arguably, the brain's ability to switch states would contribute to achieving novel ideas, and thus to creativity. Faster brain-state switching is reflected in the temporal dynamics of functional brain activity. Stronger autocorrelations in brain activity measures can make a brain stay in a certain state for longer periods, whereas low temporal autocorrelations reflect faster state switching. We established the brain's inherent tendency to switch or stay in a resting, no-task condition using 128 channel electroencephalography (EEG). We assessed temporal autocorrelations of the amplitude modulation of the dominant alpha oscillations (8-13 Hz). Creativity was measured by a self-rating, an examiner-rating and the alternative uses task in 40 healthy young adults, which was scored on dimensions of verbal fluency, originality, elaboration, usefulness, and flexibility. For each dimension, the total number of subject-reported alternative uses that matched the criterion was noted (the quantity measure), as well as the proportion of uses that matched the dimensional criterion. A principal components analysis confirmed the two-component structure of quantity and quality. Partial correlation analysis was used controlling for gender and age, and a cluster permutation test was performed to correct for multiple testing. A significant cluster over right central/temporal brain areas was found with a negative correlation between creativity and temporal autocorrelations were observed (p = 0.028). To our knowledge, this is the first demonstration that individual variation in the dynamically changing activity in the brain may offer a neuronal explanation for individual variation in creative ideation.

The function of the hippocampus and middle temporal gyrus in forming new associations and concepts during the processing of novelty and usefulness features in creative designs

Creative thought relies on the reorganization of existing knowledge to generate novel and useful concepts. However, how these new concepts are formed, especially through the processing of novelty and usefulness (which are usually regarded as the key properties of creativity), is not clear. Taking familiar and useful (FU) objects/designs as the starting point or fundamental baseline, we modified them into novel and useless (NS) objects/designs or novel and useful (NU) ones (i.e., truly creative ones) to investigate how the features of novelty and usefulness are processed (processing of novelty: NU minus FU; processing of usefulness: NU minus NS). Specifically, we predicted that the creative integration of novelty and usefulness entails not only the formation of new associations, which could be critically mediated by the hippocampus and adjacent medial temporal lobe (MTL) areas, but also the formation of new concepts or categories, which is supported by the middle temporal gyrus (MTG). We found that both the MTL and the MTG were involved in the processing of novelty and usefulness. The MTG showed distinctive patterns of information processing, reflected by strengthened functional connectivity with the hippocampus to construct new concepts and strengthened functional connectivity with the executive control system to break the boundaries of old concepts. Additionally, participants' subjective evaluations of concept distance showed that the distance between the familiar concept (FU) and the successfully constructed concept (NU) was larger than that between the FU and the unsuccessfully constructed concept (NS), and this pattern was found to correspond to the patterns of their neural representations in the MTG. These findings demonstrate the critical mechanism by which new associations and concepts are formed during novelty and usefulness processing in creative design; this mechanism may be critically mediated by the hippocampus-MTG connection.

Neural theta oscillations support semantic memory retrieval

Lexical-semantic retrieval emerges through the interactions of distributed prefrontal and perisylvian brain networks. Growing evidence suggests that synchronous theta band neural oscillations might play a role in this process, yet, their functional significance remains elusive. Here, we used transcranial alternating current stimulation to induce exogenous theta oscillations at 6 Hz (θ-tACS) over left prefrontal and posterior perisylvian cortex with a 180° (anti-phase) and 0° (in-phase) relative phase difference while participants performed automatic and controlled retrieval tasks. We demonstrate that θ-tACS significantly modulated the retrieval performance and its effects were both task- and phase-specific: the in-phase tACS impaired controlled retrieval, whereas the anti-phase tACS improved controlled but impaired automatic retrieval. These findings indicate that theta band oscillatory brain activity supports binding of semantically related representations via a phase-dependent modulation of semantic activation or maintenance.

Functional coupling of brain networks during creative idea generation and elaboration in the figural domain

The neuroscientific investigation of creative cognition has advanced by considering the functional connectivity between brain regions and its dynamic changes over time, which are consistent with stages in the ideation process. Surprisingly, although the communication between neuronal networks takes place in a time-scale of milliseconds, EEG studies investigating a time-course in cortico-cortical communication during creative ideation are rare and findings are typically restricted to the verbal domain. Therefore, this study examined functional coupling using EEG (task-related phase-locking in the upper-alpha range) during creative thinking in the figural domain. Using an innovative computerized experimental paradigm, we specifically investigated the stage of idea generation and the stage of idea elaboration in an adapted picture completion task. The findings confirmed a hypothesized increase of functional coupling from idea generation to elaboration, which was most pronounced in frontal-central as well as frontal-temporal networks. The connectivity in the frontal-parietal/occipital network already increased during idea generation and remained constant during elaboration. Importantly, more original participants generally showed higher functional connectivity in all brain networks. This elevated functional coupling with frontal brain regions might reflect increased executive processes related to internal attention, motor planning, and semantic selection processes supporting highly original thought in the figural domain.

Predicting response originality through brain activity: An analysis of changes in EEG alpha power during the generation of alternative ideas

Growing neurophysiological evidence points to a role of alpha oscillations in divergent thinking (DT). In particular, studies have shown a consistent EEG alpha synchronization during performance on the Alternative Uses Task (AUT), a well-established DT task. However, there is a need for investigating the brain dynamics underlying the production of a sequence of multiple, alternative ideas at the AUT and their relationship with idea originality. In twenty young adults, we investigated changes in alpha power during performance on a structured version of the AUT, requiring to ideate four alternative uses for conventional objects in distinct and sequentially balanced time periods. Data analysis followed a three-step approach, including behaviour aspects, physiology aspects, and their mutual relationship. At the behavioural level, we observed a typical serial order effect during DT production, with an increase of originality associated with an increase in ideational time and a decrease in response percentage over the four responses. This pattern was paralleled by a shift from alpha desynchronization to alpha synchronization across production of the four alternative ideas. Remarkably, alpha power changes were able to explain response originality, with a differential role of alpha power over different sensor sites. In particular, alpha synchronization over frontal, central, and temporal sites was able to predict the generation of original ideas in the first phases of the DT process, whereas alpha synchronization over centro-parietal sites persistently predicted response originality during the entire DT production. Moreover, a bilateral hemispheric effect in frontal sites and a left-lateralized effect in central, temporal, and parietal sensor sites emerged as predictors of the increase in response originality. These findings highlight the temporal dynamics of DT production across the generation of alternative ideas and support a partially distinct functional role of specific cortical areas during DT.