Increased resting functional connectivity of the medial prefrontal cortex in creativity by means of cognitive stimulation

Abstract

Creativity is imperative to the progression of civilization and is central to cultural life. Many neuroimaging studies have investigated the patterns of functional activity in the brain during different creative tasks, and the structural and functional characteristics of the highly creative individuals. However, few studies have investigated resting-state functional connectivity (RSFC) in the brain related to individual differences in creativity, and it is still unclear whether the RSFC underlying creativity can be changed by training. The present study therefore used resting-state functional magnetic resonance imaging (Rs-fMRI) to investigate the relationship between RSFC and creativity (divergent thinking, measured by the Torrance Tests of Creative Thinking) to explore whether RSFC can be influenced by cognitive stimulation. The results of 269 adults showed that creativity was positively correlated with the strength of RSFC between the medial prefrontal cortex (mPFC) and the middle temporal gyrus (mTG). In addition, behavioral data showed that cognitive stimulation was successful in enhancing originality in a subset of the original participants (n = 34). Most interesting, we found that there was also a significantly increased RSFC between the mPFC and the mTG by analyzing the data of Rs-fMRI after creativity training. Taken together, these results suggest that increased RSFC between mPFC and mTG, which belong to the default mode network might be crucial to creativity, and that RSFC between the mPFC and mTG can be improved by means of cognitive stimulation (reflecting creativity training-induced changes in functional connectivity, especially in the lower creativity individuals who had lower scores of Torrance Tests of Creative Thinking).

Introduction

Creativity is imperative to the progression of civilization and is central to cultural life. There has been increasing interest in the gray and white matter structural magnetic resonance imaging characteristics associated with inter-individual differences in human creativity, particularly divergent thinking (creative ability to consciously generate new ideas that branch out and allow for many possible solutions to a given problem) (Kase et al., 2011, Silvia et al., 2008). However, the functions of implicated brain regions remain unclear, as does the functional connectivity associated with individual differences in creativity.

Communication between brain regions may be crucial in complex cognitive processes (e.g., creativity) (den Heuvel et al., 2010). Examination of resting-state functional connectivity (RSFC), which reflects temporal correlations between blood oxygen level-dependent signals in different brain regions during rest, can indicate direct or indirect functional relations between brain regions (Fox and Raichle, 2007, Friston et al., 1993). Previous studies have demonstrated that RSFC of default mode network (DMN) is highly test–retest reliable (Shehzad et al., 2009, Zuo et al., 2010). Specifically, a recent resting-state functional magnetic resonance imaging (Rs-fMRI) study showed that higher creativity was associated with RSFC between the medial prefrontal cortex (mPFC) and the posterior cingulate cortex (PCC), which are key nodes of the DMN (Takeuchi et al., 2012). Thus, higher levels of creativity might be attained through increased interaction in the DMN. In other words, higher creativity may be associated with the strength of RSFC among specific brain regions, and the interactions between these brain regions might be crucial.

Few studies have investigated RSFC associated with individual differences in creativity, and although previous studies indicated that RSFC can be changed after task (Calhoun et al., 2008, Fransson, 2006), the robustness of RSFC altered by creativity training is uncertain. In a series of studies, Fink et al. (2010) and Fink, Graif, and Neubauer (2009) used cognitive stimulation to enhance creative cognition, wherein participants performed the alternative uses task after exposure to other people's ideas (participants are required to come up with unusual use of those common and everyday life objects after being showed the example answers from others). In fact, cognitive stimulation is a person's creative cognition, which can be influenced by other's cognition (confronting with ideas produced by other people) (Fink et al., 2010, Osborn, 1957). The authors found that originality (the statistical rarity of the unusual uses of common, everyday objects) performance improvement was associated with activation increases in the temporal–parietal junction, mPFC and PCC (Fink et al., 2010). Therefore, the present study used Rs-fMRI to examine the relationship between RSFC and creativity measured by the Torrance Tests of Creative Thinking (TTCT) which is a questionnaire included seven tasks to measure individual's verbal creativity ability, and explore whether RSFC in a post-task (creativity training task) resting state can be influenced by cognitive stimulation.

As the anterior core of the DMN backbone, mPFC has been associated with individual differences in creativity with its structure and function (Ellamil et al., 2012, Moore et al., 2009, Takeuchi et al., 2012). Thus, the current study explored correlations between the TTCT scores and the strength of RSFC between the mPFC and other brain regions. Based on previous studies (Gansler et al., 2011, Jung et al., 2009, Qiu et al., 2010, Takeuchi et al., 2010), we hypothesized that higher creativity might be associated with RSFC between the mPFC, and other brain regions including the PCC (Takeuchi et al., 2012), temporal gyrus (implicated in novel association and conceptual expansion) (Ellamil et al., 2012); and inferior parietal lobe (associated with spatial representations and processing) (Gansler et al., 2011). We also predicted that RSFC between the mPFC and other brain regions would be altered after creativity training (cognitive stimulation), which can improve participants' originality of creative response (Fink et al., 2010, Fink et al., 2009). Specifically, we presumed that RSFC between the mPFC and other specific brain regions would be increased during the post-task resting state. The applications of creativity-related neural plasticity evoked by training are considerable, particularly regarding educational practice.