A right frontal network for analogical and deductive reasoning

Two of the most well-studied types of reasoning are analogical reasoning (AR) and deductive reasoning (DR). Yet, our understanding of the relationship between reasoning abilities and their neuroanatomical basis remains surprisingly limited. We aimed to conduct fine-grained anatomical mapping of performance on tests of AR, DR and fluid intelligence (Gf), in a large sample of patients with unilateral focal frontal or posterior lesions and healthy controls. We assessed 247 prospectively recruited patients using two new tests: the Analogical Reasoning Test (ART) and the Deductive Reasoning Test (DRT); and the best-established measure of Gf: Raven's Advanced Progressive Matrices (RAPM). Non-parametric Bayesian stochastic block modelling was used to reveal the community structure of lesion deficit networks, disentangling functional from confounding pathological distributed effects. ART and DRT performance was significantly impaired in patients with frontal lesions [ART: F(2,238) = 18.93; P < 0.001; Frontal group worse than Posterior group and healthy controls, both P < 0.001; DRT: F(2,387) = 18.491; P < 0.001; Frontal group worse than healthy controls, P < 0.01]. Right frontal effects were evident on both tests. Thus, on the ART, right frontal patients were more impaired than left (P < 0.05). On the DRT, right frontal patients were more impaired than left frontal patients on questions with indeterminate solutions (P < 0.05) but not on questions with determinate ones. Non-parametric Bayesian stochastic block modelling implicated a right frontal network in ART and DRT performance. Strikingly, we found that this network was also implicated in performance on RAPM. Our study represents the most robust investigation of AR and DR in the focally injured brain. Our findings imply that a right frontal network is critical. The ART and DRT appear to be promising new clinical tests, capable of evaluating reasoning abilities and identifying right frontal lobe dysfunction.

Non-literal language processing is jointly supported by the language and theory of mind networks: Evidence from a novel meta-analytic fMRI approach

Going beyond the literal meaning of language is key to communicative success. However, the mechanisms that support non-literal inferences remain debated. Using a novel meta-analytic approach, we evaluate the contribution of linguistic, social-cognitive, and executive mechanisms to non-literal interpretation. We identified 74 fMRI experiments (n = 1,430 participants) from 2001 to 2021 that contrasted non-literal language comprehension with a literal control condition, spanning ten phenomena (e.g., metaphor, irony, indirect speech). Applying the activation likelihood estimation approach to the 825 activation peaks yielded six left-lateralized clusters. We then evaluated the locations of both the individual-study peaks and the clusters against probabilistic functional atlases (cf. anatomical locations, as is typically done) for three candidate brain networks-the language-selective network (Fedorenko, Behr, & Kanwisher, 2011), which supports language processing, the Theory of Mind (ToM) network (Saxe & Kanwisher, 2003), which supports social inferences, and the domain-general Multiple-Demand (MD) network (Duncan, 2010), which supports executive control. These atlases were created by overlaying individual activation maps of participants who performed robust and extensively validated 'localizer' tasks that selectively target each network in question (n = 806 for language; n = 198 for ToM; n = 691 for MD). We found that both the individual-study peaks and the ALE clusters fell primarily within the language network and the ToM network. These results suggest that non-literal processing is supported by both i) mechanisms that process literal linguistic meaning, and ii) mechanisms that support general social inference. They thus undermine a strong divide between literal and non-literal aspects of language and challenge the claim that non-literal processing requires additional executive resources.

Common brain activation and connectivity patterns supporting the generation of creative uses and creative metaphors

Recent studies and reviews suggest that creative thinking is at least partly a domain-general cognitive ability, dependent on consistent patterns of brain activity including co-activation of the executive control and default mode networks. However, the degree to which the generation of ideas in different creative tasks relies on common brain activity remains unknown. In this fMRI study, participants were asked to generate creative ideas in both a uses generation task and a metaphor production task. Whole-brain analysis showed that generation of creative uses (relative to conventional uses) activated the bilateral inferior frontal gyrus (IFG), medial prefrontal cortex, left supplementary motor area, left angular gyrus (AG), left thalamus, and bilateral cerebellum posterior lobe. The generation of creative metaphors (relative to conventional metaphors) activated dorsal medial prefrontal cortex (dmPFC) and left AG. Importantly, regions active in both creative use and creative metaphor generation included the dmPFC and left AG. Psycho-physiological interactions analysis showed that the left AG was positively connected to the right precentral gyrus, and the dmPFC to the left IFG in both creative tasks. Our findings provide evidence that the generation of creative ideas relies on a core creative network related to remote semantic association-making and conceptual integration, offering new insight into the domain-general mechanisms underlying creative thinking.

The Neural Correlates of Analogy Component Processes

Analogical reasoning is a core facet of higher cognition in humans. Creating analogies as we navigate the environment helps us learn. Analogies involve reframing novel encounters using knowledge of familiar, relationally similar contexts stored in memory. When an analogy links a novel encounter with a familiar context, it can aid in problem solving. Reasoning by analogy is a complex process that is mediated by multiple brain regions and mechanisms. Several advanced computational architectures have been developed to simulate how these brain processes give rise to analogical reasoning, like the "learning with inferences and schema abstraction" architecture and the Companion architecture. To obtain this power to simulate human reasoning, theses architectures assume that various computational "subprocesses" comprise analogical reasoning, such as analogical access, mapping, inference, and schema induction, consistent with the structure-mapping framework proposed decades ago. However, little is known about how these subprocesses relate to actual brain processes. While some work in neuroscience has linked analogical reasoning to regions of brain prefrontal cortex, more research is needed to investigate the wide array of specific neural hypotheses generated by the computational architectures. In the current article, we review the association between historically important computational architectures of analogy and empirical studies in neuroscience. In particular, we focus on evidence for a frontoparietal brain network underlying analogical reasoning and the degree to which brain mechanisms mirror the computational subprocesses. We also offer a general vantage on the current- and future-states of neuroscience research in this domain and provide some recommendations for future neuroimaging studies.

The Elephant in the Room: A Systematic Review of Stimulus Control in Neuro-Measurement Studies on Figurative Language Processing

The processing of metaphors and idioms has been the subject of neuroscientific research for several decades. However, results are often contradictory, which can be traced back to inconsistent terminology and stimulus control. In this systematic review of research methods, we analyse linguistic aspects of 116 research papers which used EEG, fMRI, PET, MEG, or NIRS to investigate the neural processing of the two figurative subtypes metaphor and idiom. We critically examine the theoretical foundations as well as stimulus control by performing a systematic literature synthesis according to the PRISMA guidelines. We explicitly do not analyse the findings of the studies but instead focus on four primary aspects: definitions of figurative language and its subtypes, linguistic theory behind the studies, control for factors influencing figurative language processing, and the relationship between theoretical and operational definitions. We found both a lack and a broad variety in existing definitions and operationalisation, especially in regard to familiarity and conventionality. We identify severe obstacles in the comparability and validation potential of the results of the papers in our review corpus. We propose the development of a consensus in fundamental terminology and more transparency in the reporting of stimulus design in the research on figurative language processing.

Linking metaphor comprehension with analogical reasoning: Evidence from typical development and autism spectrum disorder

We examined the relationship between metaphor comprehension and verbal analogical reasoning in young adults who were either typically developing (TD) or diagnosed with Autism Spectrum Disorder (ASD). The ASD sample was highly educated and high in verbal ability, and closely matched to a subset of TD participants on age, gender, educational background, and verbal ability. Additional TD participants with a broader range of abilities were also tested. Each participant solved sets of verbal analogies and metaphors in verification formats, allowing measurement of both accuracy and reaction times. Measures of individual differences in vocabulary, verbal working memory, and autistic traits were also obtained. Accuracy for both the verbal analogy and the metaphor task was very similar across the ASD and matched TD groups. However, reaction times on both tasks were longer for the ASD group. Additionally, stronger correlations between verbal analogical reasoning and working memory capacity in the ASD group indicated that processing verbal analogies was more effortful for them. In the case of both groups, accuracy on the metaphor and analogy tasks was correlated. A mediation analysis revealed that after controlling for working memory capacity, the inter-task correlation could be accounted for by the mediating variable of vocabulary knowledge, suggesting that the primary common mechanisms linking the two tasks involve language skills.

Enhanced insightfulness and neural activation induced by metaphorical solutions to appropriate mental distress problems

Although the neural correlates of novelty and appropriateness of creative insight during cognitive tasks have been investigated in several studies, they have not been examined during mental distress in a psychotherapeutic setting. This study aimed to reveal the promoting effects of novelty and appropriateness processing on therapeutic insight in a micro-psychotherapeutic setting. We examined the effects of appropriateness (between-subject factor: appropriateness group, 20 participants; inappropriateness group, 21 participants) by manipulating the preceding negative scenarios that either fit or did not fit the subsequent solutions, and those of novelty (within-subject factor) by varying the linguistic expressions for describing solutions (metaphorical, literal, or problem-restatement). Event-related functional magnetic resonance images were collected. We found the following effects: an interactive effect of the two factors on insightfulness and activation in the bilateral hippocampus and amygdala, right superior frontal gyrus, and left superior/middle temporal gyrus; a simple effect of novelty on activation in the bilateral inferior frontal gyrus, fusiform gyrus, and inferior/middle occipital gyrus; and a simple effect of appropriateness on activation in the left inferior parietal lobule. Our findings indicate that solutions with high novelty and appropriateness generate the highest levels of therapeutic insightfulness as well as the strongest activation in the hippocampus and amygdala, which may be involved in episodic memory encoding.

The Creative Brain Under Stress: Considerations for Performance in Extreme Environments

Over the last 2 decades, we have begun to gain traction on the neural systems that support creative cognition. Specifically, a converging body of evidence from various domains has demonstrated that creativity arises from the interaction of two large-scale systems in the brain: Whereas the default network (DN) is involved in internally-oriented generation of novel concepts, the executive control network (ECN) exerts top-down control over that generative process to select task-appropriate output. In addition, the salience network (SN) regulates switching between those networks in the course of creative cognition. In contrast, we know much less about the workings of these large-scale systems in support of creativity under extreme conditions, although that is beginning to change. Specifically, there is growing evidence from systems neuroscience to demonstrate that the functioning and connectivity of DN, ECN, and SN are influenced by stress - findings that can be used to improve our understanding of the behavioral effects of stress on creativity. Toward that end, we review findings from the neuroscience of creativity, behavioral research on the impact of stress on creativity, and the systems-level view of the brain under stress to suggest ways in which creativity might be affected under extreme conditions. Although our focus is largely on acute stress, we also touch on the possible impact of chronic stress on creative cognition.

Relational Integration in the Human Brain: A Review and Synthesis

Relational integration is required when multiple explicit representations of relations between entities must be jointly considered to make inferences. We provide an overview of the neural substrate of relational integration in humans and the processes that support it, focusing on work on analogical and deductive reasoning. In addition to neural evidence, we consider behavioral and computational work that has informed neural investigations of the representations of individual relations and of relational integration. In very general terms, evidence from neuroimaging, neuropsychological, and neuromodulatory studies points to a small set of regions (generally left lateralized) that appear to constitute key substrates for component processes of relational integration. These include posterior parietal cortex, implicated in the representation of first-order relations (e.g., A:B); rostrolateral pFC, apparently central in integrating first-order relations so as to generate and/or evaluate higher-order relations (e.g., A:B::C:D); dorsolateral pFC, involved in maintaining relations in working memory; and ventrolateral pFC, implicated in interference control (e.g., inhibiting salient information that competes with relevant relations). Recent work has begun to link computational models of relational representation and reasoning with patterns of neural activity within these brain areas.

Context matters: Novel metaphors in supportive and non-supportive contexts

Creative language is defined as linguistic output that is both novel and appropriate. Metaphors are one such example of creative language in which one concept is used to express another by highlighting relevant semantic features. While novelty is an inherent property of unfamiliar metaphors, appropriateness depends on the context. The current study tests the hypothesis that the context in which metaphors are encountered affects their processing. We examined the neural effects of comprehending metaphors in context by comparing neural activations in response to novel metaphors and literal sentences that were either embedded in a meaningful narrative or in matched jabberwocky contexts. We found that the neural correlates of processing metaphoric sentences and their literal counterparts are indistinguishable when embedded in a narrative: both conditions activate bilateral areas along the anterior temporal poles, middle temporal gyri, superior temporal sulci, and the angular gyri. Metaphors embedded in a narrative as compared to their identical counterparts embedded in jabberwocky show increased responses in sensorimotor areas that correspond to the modality of the literal meaning of the target word, perhaps reflecting deeper semantic processing. Our results confirm that context affects neural mechanisms for understanding creative ideas.

The Fictive Brain: Neurocognitive Correlates of Engagement in Literature

Fiction is vital to our being. Many people enjoy engaging with fiction every day. Here we focus on literary reading as 1 instance of fiction consumption from a cognitive neuroscience perspective. The brain processes which play a role in the mental construction of fiction worlds and the related engagement with fictional characters, remain largely unknown. The authors discuss the neurocognitive poetics model ( Jacobs, 2015a ) of literary reading specifying the likely neuronal correlates of several key processes in literary reading, namely inference and situation model building, immersion, mental simulation and imagery, figurative language and style, and the issue of distinguishing fact from fiction. An overview of recent work on these key processes is followed by a discussion of methodological challenges in studying the brain bases of fiction processing.

Rostro-caudal Architecture of the Frontal Lobes in Humans

The nature of the inputs and outputs of a brain region defines its functional specialization. The frontal portion of the brain is essential for goal-directed behaviors, however, the biological basis for its functional organization is unknown. Here, exploring structural connectomic properties, we delineated 12 frontal areas, defined by the pattern of their white matter connections. This result was highly reproducible across neuroimaging centers, acquisition parameters, and participants. These areas corresponded to regions functionally engaged in specific tasks, organized along a rostro-caudal axis from the most complex high-order association areas to the simplest idiotopic areas. The rostro-caudal axis along which the 12 regions were organized also reflected a gradient of cortical thickness, myelination, and cell body density. Importantly, across the identified regions, this gradient of microstructural features was strongly associated with the varying degree of information processing complexity. These new anatomical signatures shed light onto the structural organization of the frontal lobes and could help strengthen the prediction or diagnosis of neurodevelopmental and neurodegenerative disorders.

One-way traffic: The inferior frontal gyrus controls brain activation in the middle temporal gyrus and inferior parietal lobule during divergent thinking

Contrary to earlier approaches that focused on the contributions of isolated brain regions to the emergence of creativity, there is now growing consensus that creative thought emerges from the interaction of multiple brain regions, often embedded within larger brain networks. Specifically, recent evidence from studies of divergent thinking suggests that kernel ideas emerge in posterior brain regions residing within the semantic system and/or the default mode network (DMN), and that the prefrontal cortex (PFC) regions within the executive control network (ECN) constrain those ideas for generating outputs that meet task demands. However, despite knowing that regions within these networks exhibit interaction, to date the direction of the relationship has not been tested directly. By applying Dynamic Causal Modeling (DCM) to fMRI data collected during a divergent thinking task, we tested the hypothesis that the PFC exerts unidirectional control over the middle temporal gyrus (MTG) and the inferior parietal lobule (IPL), vs. the hypothesis that these two sets of regions exert bidirectional control over each other (in the form of feedback loops). The data were consistent with the former model by demonstrating that the right inferior frontal gyrus (IFG) exerts unidirectional control over MTG and IPL, although the evidence was somewhat stronger in the case of the MTG than the IPL. Our findings highlight potential causal pathways that could underlie the neural bases of divergent thinking.

A critical analysis of cultural metaphors and static cultural frameworks with insight from cultural neuroscience and evolutionary biology

Purpose

The purpose of this paper is to conduct a critical analysis to address cultural metaphors – a much overlooked aspect of cross-cultural studies. Mainstream cultural metaphors (e.g. the iceberg, the software of the mind, the onion, and the distance) are not only limited in number, but are also overwhelmingly based on the static paradigm – as opposed to the dynamic paradigm that is often sidelined in academic discourse.

Design/methodology/approach

The paper introduces the Diagram of Diversity Pathways – an interdisciplinary framework that sheds some light on how the inherent meaning and heuristic orientation of static cultural metaphors may stand at odds with evidence from the newly emerged field of neurobiology.

Findings

The implications of these metaphors are called into question, namely, culture is all about differences; values are stable; values guide behaviors; and values are seen as binaries.

Research limitations/implications

The paper suggests that theorists and practitioners should pay more attention to the contribution and scholarly work of the dynamic paradigm since there appears to be substantial compatibility between them.

Originality/value

The matching of neurobiology and dynamic paradigm brings into focus alternative metaphors which not only offer insightful perspectives but also may open doors to perceive culture in a new way. Furthermore, cultural metaphors deserve more academic scrutiny because metaphors and theory development can have a symbiotic existence.

Neural Foundations of Creativity: A Systematic Review

When considering the importance of the human cognitive function of creativity, we often overlook the fact that it is due to human creativity and to the constant search for new sensory stimuli that our world has, throughout the years, been one of innovation in every aspect of our existence -in the sciences, the humanities, and the arts. Almost everything that surrounds us is the result of human creativity, therefore it is not difficult to understand that although neuroscientific research has led to valuable perceptions into the probable underpinnings of this multifaceted ability, the precise neurological substrates that underlie creativity are yet to be determined. Despite the establishment of a strong link between creativity and divergent thinking, other brain networks have been implicated in this mental process. The following review underlines recent studies on the neural foundations of creativity. A comprehensive analysis of the upmost important facts will be presented, with emphasis on concepts, tests, and methods that have been used to study creativity, and how they have outlined a pathway to the key understanding of this unique human ability.

Engagement of the left extrastriate body area during body-part metaphor comprehension

Grounded cognition explanations of metaphor comprehension predict activation of sensorimotor cortices relevant to the metaphor's source domain. We tested this prediction for body-part metaphors using functional magnetic resonance imaging while participants heard sentences containing metaphorical or literal references to body parts, and comparable control sentences. Localizer scans identified body-part-specific motor, somatosensory and visual cortical regions. Both subject- and item-wise analyses showed that, relative to control sentences, metaphorical but not literal sentences evoked limb metaphor-specific activity in the left extrastriate body area (EBA), paralleling the EBA's known visual limb-selectivity. The EBA focus exhibited resting-state functional connectivity with ipsilateral semantic processing regions. In some of these regions, the strength of resting-state connectivity correlated with individual preference for verbal processing. Effective connectivity analyses showed that, during metaphor comprehension, activity in some semantic regions drove that in the EBA. These results provide converging evidence for grounding of metaphor processing in domain-specific sensorimotor cortical activity.

General and specialized brain correlates for analogical reasoning: A meta-analysis of functional imaging studies

Reasoning by analogy allows us to link distinct domains of knowledge and to transfer solutions from one domain to another. Analogical reasoning has been studied using various tasks that have generally required the consideration of the relationships between objects and their integration to infer an analogy schema. However, these tasks varied in terms of the level and the nature of the relationships to consider (e.g., semantic, visuospatial). The aim of this study was to identify the cerebral network involved in analogical reasoning and its specialization based on the domains of information and task specificity. We conducted a coordinate-based meta-analysis of 27 experiments that used analogical reasoning tasks. The left rostrolateral prefrontal cortex was one of the regions most consistently activated across the studies. A comparison between semantic and visuospatial analogy tasks showed both domain-oriented regions in the inferior and middle frontal gyri and a domain-general region, the left rostrolateral prefrontal cortex, which was specialized for analogy tasks. A comparison of visuospatial analogy to matrix problem tasks revealed that these two relational reasoning tasks engage, at least in part, distinct right and left cerebral networks, particularly separate areas within the left rostrolateral prefrontal cortex. These findings highlight several cognitive and cerebral differences between relational reasoning tasks that can allow us to make predictions about the respective roles of distinct brain regions or networks. These results also provide new, testable anatomical hypotheses about reasoning disorders that are induced by brain damage. Hum Brain Mapp 37:1953-1969, 2016. © 2016 Wiley Periodicals, Inc.

The relationships between the amount of spared tissue, percent signal change, and accuracy in semantic processing in aphasia

Recovery from aphasia, loss of language following a cerebrovascular incident (stroke), is a complex process involving both left and right hemispheric regions. In our study, we analyzed the relationships between semantic processing behavioral data, lesion size and location, and percent signal change from functional magnetic resonance imaging (fMRI) data. This study included 14 persons with aphasia in the chronic stage of recovery (six or more months post stroke), along with normal controls, who performed semantic processing tasks of determining whether a written semantic feature matched a picture or whether two written words were related. Using region of interest (ROI) analysis, we found that left inferior frontal gyrus pars opercularis and pars triangularis, despite significant damage, were the only regions to correlate with behavioral accuracy. Additionally, bilateral frontal regions including superior frontal gyrus, middle frontal gyrus, and anterior cingulate appear to serve as an assistive network in the case of damage to traditional language regions that include inferior frontal gyrus, middle temporal gyrus, supramarginal gyrus, and angular gyrus. Right hemisphere posterior regions including right middle temporal gyrus, right supramarginal gyrus, and right angular gyrus are engaged in the case of extensive damage to left hemisphere language regions. Additionally, right inferior frontal gyrus pars orbitalis is presumed to serve a monitoring function. These results reinforce the importance of the left hemisphere in language processing in aphasia, and provide a framework for the relative importance of left and right language regions in the brain.

Neuroart: picturing the neuroscience of intentional actions in art and science

Intentional actions cover a broad spectrum of human behaviors involving consciousness, creativity, innovative thinking, problem-solving, critical thinking, and other related cognitive processes self-evident in the arts and sciences. The author discusses the brain activity associated with action intentions, connecting this activity with the creative process. Focusing on one seminal artwork created and exhibited over a period of three decades, Thought Assemblies (1979–82, 2014), he describes how this symbolic art interprets the neuropsychological processes of intuition and analytical reasoning. It explores numerous basic questions concerning observed interactions between artistic and scientific inquiries, conceptions, perceptions, and representations connecting mind and nature. Pointing to some key neural mechanisms responsible for forming and implementing intentions, he considers why and how we create, discover, invent, and innovate. He suggests ways of metaphorical thinking and symbolic modeling that can help integrate the neuroscience of intentional actions with the neuroscience of creativity, art and neuroaesthetics.

Neural correlates of creative thinking and schizotypy

Empirical studies indicate a link between creativity and schizotypal personality traits, where individuals who score highly on schizotypy measures also display greater levels of creative behaviour. However, the exact nature of this relationship is not yet clear, with only a few studies examining this association using neuroimaging methods. In the present study, the neural substrates of creative thinking were assessed with a drawing task paradigm in healthy individuals using fMRI. These regions were then statistically correlated with the participants' level of schizotypy as measured by the Oxford-Liverpool Inventory of Feelings and Experiences (O-LIFE), which is a questionnaire consisting of four dimensions. Neural activations associated with the creativity task were observed in bilateral inferior temporal gyri, left insula, left parietal lobule, right angular gyrus, as well as regions in the prefrontal cortex. This widespread pattern of activation suggests that creative thinking utilises multiple neurocognitive networks, with creative production being the result of collaboration between these regions. Furthermore, the correlational analyses found the Unusual Experiences factor of the O-LIFE to be the most common dimension associated with these areas, followed by the Impulsive Nonconformity dimension. These correlations were negative, indicating that individuals who scored the highest in these factors displayed the least amount of activation when performing the creative task. This is in line with the idea that 'less is more' for creativity, where the deactivation of specific cortical areas may facilitate creativity. Thus, these findings contribute to the evidence of a common neural basis between creativity and schizotypy.

Neurocognitive poetics: methods and models for investigating the neuronal and cognitive-affective bases of literature reception

A long tradition of research including classical rhetoric, esthetics and poetics theory, formalism and structuralism, as well as current perspectives in (neuro)cognitive poetics has investigated structural and functional aspects of literature reception. Despite a wealth of literature published in specialized journals like Poetics, however, still little is known about how the brain processes and creates literary and poetic texts. Still, such stimulus material might be suited better than other genres for demonstrating the complexities with which our brain constructs the world in and around us, because it unifies thought and language, music and imagery in a clear, manageable way, most often with play, pleasure, and emotion (Schrott and Jacobs, 2011). In this paper, I discuss methods and models for investigating the neuronal and cognitive-affective bases of literary reading together with pertinent results from studies on poetics, text processing, emotion, or neuroaesthetics, and outline current challenges and future perspectives.

Atlasing the frontal lobe connections and their variability due to age and education: a spherical deconvolution tractography study

In neuroscience, there is a growing consensus that higher cognitive functions may be supported by distributed networks involving different cerebral regions, rather than by single brain areas. Communication within these networks is mediated by white matter tracts and is particularly prominent in the frontal lobes for the control and integration of information. However, the detailed mapping of frontal connections remains incomplete, albeit crucial to an increased understanding of these cognitive functions. Based on 47 high-resolution diffusion-weighted imaging datasets (age range 22-71 years), we built a statistical normative atlas of the frontal lobe connections in stereotaxic space, using state-of-the-art spherical deconvolution tractography. We dissected 55 tracts including U-shaped fibers. We further characterized these tracts by measuring their correlation with age and education level. We reported age-related differences in the microstructural organization of several, specific frontal fiber tracts, but found no correlation with education level. Future voxel-based analyses, such as voxel-based morphometry or tract-based spatial statistics studies, may benefit from our atlas by identifying the tracts and networks involved in frontal functions. Our atlas will also build the capacity of clinicians to further understand the mechanisms involved in brain recovery and plasticity, as well as assist clinicians in the diagnosis of disconnection or abnormality within specific tracts of individual patients with various brain diseases.

Morphometry of Left Frontal and Temporal Poles Predicts Analogical Reasoning Abilities

Analogical reasoning is critical for making inferences and adapting to novelty. It can be studied experimentally using tasks that require creating similarities between situations or concepts, i.e., when their constituent elements share a similar organization or structure. Brain correlates of analogical reasoning have mostly been explored using functional imaging that has highlighted the involvement of the left rostrolateral prefrontal cortex (rlPFC) in healthy subjects. However, whether inter-individual variability in analogical reasoning ability in a healthy adult population is related to differences in brain architecture is unknown. We investigated this question by employing linear regression models of performance in analogy tasks and voxel-based morphometry in 54 healthy subjects. Our results revealed that the ability to reason by analogy was associated with structural variability in the left rlPFC and the anterior part of the inferolateral temporal cortex. Tractography of diffusion-weighted images suggested that these 2 regions have a different set of connections but may exchange information via the arcuate fasciculus. These results suggest that enhanced integrative and semantic abilities supported by structural variation in these areas (or their connectivity) may lead to more efficient analogical reasoning.

Creating metaphors: the neural basis of figurative language production

Neuroscience research has thoroughly studied how nonliteral language is processed during metaphor comprehension. However, it is not clear how the brain actually creates nonliteral language. Therefore, the present study for the first time investigates the neural correlates of metaphor production. Participants completed sentences by generating novel metaphors or literal synonyms during functional imaging. Responses were spoken aloud in the scanner, recorded, and subsequently rated for their creative quality. We found that metaphor production was associated with focal activity in predominantly left-hemispheric brain regions, specifically the left angular gyrus, the left middle and superior frontal gyri—corresponding to the left dorsomedial prefrontal (DMPFC) cortex—and the posterior cingulate cortex. Moreover, brain activation in the left anterior DMPFC and the right middle temporal gyrus was found to linearly increase with the creative quality of metaphor responses. These findings are related to neuroscientific evidence on metaphor comprehension, creative idea generation and episodic future thought, suggesting that creating metaphors involves the flexible adaptation of semantic memory to imagine and construct novel figures of speech. Furthermore, the left DMPFC may exert executive control to maintain strategic search and selection, thus facilitating creativity of thought.

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Figurative language production was studied for the first time with fMRI.

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Verbal responses were recorded and analyzed for quality.

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Generation of novel metaphors relies on activity in left AG and the PCC.

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Activity in left DMPFC increases linearly as a function of metaphor creativity.

Rostral and caudal prefrontal contribution to creativity: a meta-analysis of functional imaging data

Creativity is of central importance for human civilization, yet its neurocognitive bases are poorly understood. The aim of the present study was to integrate existing functional imaging data by using the meta-analysis approach. We reviewed 34 functional imaging studies that reported activation foci during tasks assumed to engage creative thinking in healthy adults. A coordinate-based meta-analysis using Activation Likelihood Estimation (ALE) first showed a set of predominantly left-hemispheric regions shared by the various creativity tasks examined. These regions included the caudal lateral prefrontal cortex (PFC), the medial and lateral rostral PFC, and the inferior parietal and posterior temporal cortices. Further analyses showed that tasks involving the combination of remote information (combination tasks) activated more anterior areas of the lateral PFC than tasks involving the free generation of unusual responses (unusual generation tasks), although both types of tasks shared caudal prefrontal areas. In addition, verbal and non-verbal tasks involved the same regions in the left caudal prefrontal, temporal, and parietal areas, but also distinct domain-oriented areas. Taken together, these findings suggest that several frontal and parieto-temporal regions may support cognitive processes shared by diverse creativity tasks, and that some regions may be specialized for distinct types of processes. In particular, the lateral PFC appeared to be organized along a rostro-caudal axis, with rostral regions involved in combining ideas creatively and more posterior regions involved in freely generating novel ideas.

The promises and perils of the neuroscience of creativity

Our ability to think creatively is one of the factors that generates excitement in our lives as it introduces novelty and opens up new possibilities to our awareness which in turn lead to developments in a variety of fields from science and technology to art and culture. While research on the influence of biologically-based variables on creativity has a long history, the advent of modern techniques for investigating brain structure and function in the past two decades have resulted in an exponential increase in the number of neuroscientific studies that have explored creativity. The field of creative neurocognition is a rapidly growing area of research that can appear chaotic and inaccessible because of the heterogeneity associated with the creativity construct and the many approaches through which it can be examined. There are also significant methodological and conceptual problems that are specific to the neuroscientific study of creativity that pose considerable limitations on our capacity to make true advances in understanding the brain basis of creativity. This article explores three key issues that need to be addressed so that barriers in the way of relevant progress being made within the field can be avoided. Are creativity neuroimaging paradigms optimal enough?What makes creative cognition different from normative cognition?Do we need to distinguish between types of creativity?

The pivotal role of semantic memory in remembering the past and imagining the future

Episodic memory refers to a complex and multifaceted process which enables the retrieval of richly detailed evocative memories from the past. In contrast, semantic memory is conceptualized as the retrieval of general conceptual knowledge divested of a specific spatiotemporal context. The neural substrates of the episodic and semantic memory systems have been dissociated in healthy individuals during functional imaging studies, and in clinical cohorts, leading to the prevailing view that episodic and semantic memory represent functionally distinct systems subtended by discrete neurobiological substrates. Importantly, however, converging evidence focusing on widespread neural networks now points to significant overlap between those regions essential for retrieval of autobiographical memories, episodic learning, and semantic processing. Here we review recent advances in episodic memory research focusing on neurodegenerative populations which has proved revelatory for our understanding of the complex interplay between episodic and semantic memory. Whereas episodic memory research has traditionally focused on retrieval of autobiographical events from the past, we also include evidence from the recent paradigm shift in which episodic memory is viewed as an adaptive and constructive process which facilitates the imagining of possible events in the future. We examine the available evidence which converges to highlight the pivotal role of semantic memory in providing schemas and meaning whether one is engaged in autobiographical retrieval for the past, or indeed, is endeavoring to construct a plausible scenario of an event in the future. It therefore seems plausible to contend that semantic processing may underlie most, if not all, forms of episodic memory, irrespective of temporal condition.