Functional correlates of musical and visual ability in frontotemporal dementia

Speech-language within and between network disruptions in primary progressive aphasia variants

Primary progressive aphasia (PPA) variants present with distinct disruptions in speech-language functions with little known about the interplay between affected and spared regions within the speech-language network and their interaction with other functional networks. The Neurodegenerative Research Group, Mayo Clinic, recruited 123 patients with PPA (55 logopenic (lvPPA), 44 non-fluent (nfvPPA) and 24 semantic (svPPA)) who were matched to 60 healthy controls. We investigated functional connectivity disruptions between regions within the left-speech-language network (Broca, Wernicke, anterior middle temporal gyrus (aMTG), supplementary motor area (SMA), planum temporale (PT) and parietal operculum (PO)), and disruptions to other networks (visual association, dorsal-attention, frontoparietal and default mode networks (DMN)). Within the speech-language network, multivariate linear regression models showed reduced aMTG-Broca connectivity in all variants, with lvPPA and nfvPPA findings remaining significant after Bonferroni correction. Additional loss in Wernicke-Broca connectivity in nfvPPA, Wernicke-PT connectivity in lvPPA and greater aMTG-PT connectivity in svPPA were also noted. Between-network connectivity findings in all variants showed reduced aMTG-DMN and increased aMTG-dorsal-attention connectivity, with additional disruptions between aMTG-visual association in both lvPPA and svPPA, aMTG-frontoparietal in lvPPA, and Wernicke-DMN breakdown in svPPA. These findings suggest that aMTG connectivity breakdown is a shared feature in all PPA variants, with lvPPA showing more extensive connectivity disruptions with other networks.

Creative therapy in health and disease: Inner vision

Can we better understand the unique mechanisms of de novo abilities in light of our current knowledge of the psychological and neuroscientific literature on creativity? This review outlines the state-of-the-art in the neuroscience of creativity and points out crucial aspects that still demand further exploration, such as brain plasticity. The progressive development of current neuroscience research on creativity presents a multitude of prospects and potentials for furnishing efficacious therapy in the context of health and illness. Therefore, we discuss directions for future studies, identifying a focus on pinpointing the neglected beneficial practices for creative therapy. We emphasize the neglected neuroscience perspective of creativity on health and disease and how creative therapy could offer limitless possibilities to improve our well-being and give hope to patients with neurodegenerative diseases to compensate for their brain injuries and cognitive impairments by expressing their hidden creativity.

Serial reversal learning in an olfactory discrimination task in 3xTg-AD mice

Male and female 3xTg-AD mice between 5 and 24 mo of age and their B6129F2/J wild-type controls were tested on a series of 18 olfactory discrimination and reversal tasks in an operant olfactometer. All mice learned the odor discriminations and reversals to a criterion of 85% correct, but the 3xTg-AD mice made fewer errors than the B6129F2/J mice in the odor discriminations and in the first six reversal learning tasks. Many mice showed evidence of near errorless learning, and on the reversal tasks the 3xTg-AD mice showed more instances of near errorless learning than the B6129F2/J mice. There was no evidence of an age effect on odor discrimination, but there was a decrease in errorless reversal learning in aged B6129F2/J mice. In long-term memory tests, there was an increase in the number of errors made but no genotype difference. The high level of performance indicates that the mice were able to develop a "learning to learn" strategy. The finding that the 3xTg-AD mice outperformed their littermate controls provides an example of paradoxical functional facilitation in these mice.

The unity and diversity of verbal and visuospatial creativity: Dynamic changes in hemispheric lateralisation

The investigation of similarities and differences in the mechanisms of verbal and visuospatial creative thinking has long been a controversial topic. Prior studies found that visuospatial creativity was primarily supported by the right hemisphere, whereas verbal creativity relied on the interaction between both hemispheres. However, creative thinking also involves abundant dynamic features that may have been ignored in the previous static view. Recently, a new method has been developed that measures hemispheric laterality from a dynamic perspective, providing new insight into the exploration of creative thinking. In the present study, dynamic lateralisation index was calculated with resting-state fMRI data. We combined the dynamic lateralisation index with sparse canonical correlation analysis to examine similarities and differences in the mechanisms of verbal and visuospatial creativity. Our results showed that the laterality reversal of the default mode network, fronto-parietal network, cingulo-opercular network and visual network contributed significantly to both verbal and visuospatial creativity and consequently could be considered the common neural mechanisms shared by these creative modes. In addition, we found that verbal creativity relied more on the language network, while visuospatial creativity relied more on the somatomotor network, which can be considered a difference in their mechanism. Collectively, these findings indicated that verbal and visuospatial creativity may have similar mechanisms to support the basic creative thinking process and different mechanisms to adapt to the specific task conditions. These findings may have significant implications for our understanding of the neural mechanisms of different types of creative thinking.

One hundred years of neurosciences in the arts and humanities, a bibliometric review

BACKGROUND

Neuroscientific approaches have historically triggered changes in the conception of creativity and artistic experience, which can be revealed by noting the intersection of these fields of study in terms of variables such as global trends, methodologies, objects of study, or application of new technologies; however, these neuroscientific approaches are still often considered as disciplines detached from the arts and humanities. In this light, the question arises as to what evidence the history of neurotechnologies provides at the intersection of creativity and aesthetic experience.

METHODS

We conducted a century-long bibliometric analysis of key parameters in multidisciplinary studies published in the Scopus database. Screening techniques based on the PRISMA method and advanced data analysis techniques were applied to 3612 documents metadata from the years 1922 to 2022. We made graphical representations of the results applying algorithmic and clusterization processes to keywords and authors relationships.

RESULTS

From the analyses, we found a) a shift from a personality-focus quantitative analysis to a field-focus qualitative approach, considering topics such as art, perception, aesthetics and beauty; b) The locus of interest in fMRI-supported neuroanatomy has been shifting toward EEG technologies and models based on machine learning and deep learning in recent years; c) four main clusters were identified in the study approaches: humanistic, creative, neuroaesthetic and medical; d) the neuroaesthetics cluster is the most central and relevant, mediating between creativity and neuroscience; e) neuroaesthetics and neuroethics are two of the neologism that better characterizes the challenges that this convergence of studies will have in the next years.

CONCLUSIONS

Through a longitudinal analysis, we evidenced the great influence that neuroscience is having on the thematic direction of the arts and humanities. The perspective presented shows how this field is being consolidated and helps to define it as a new opportunity of great potential for future researchers.

A shared novelty-seeking basis for creativity and curiosity

Curiosity and creativity are central pillars of human growth and invention. Although they have been studied extensively in isolation, the relationship between them has not yet been established. We propose that both curiosity and creativity emanate from the same mechanism of novelty seeking. We first present a synthesis showing that curiosity and creativity are affected similarly by a number of key cognitive faculties such as memory, cognitive control, attention, and reward. We then review empirical evidence from neuroscience research, indicating that the same brain regions are involved in both curiosity and creativity, focusing on the interplay between three major brain networks: the default mode network, the salience network, and the executive control network. After substantiating the link between curiosity and creativity, we propose a novelty-seeking model (NSM) that underlies them and suggests that the manifestation of the NSM is governed by one's state of mind.

Can we really 'read' art to see the changing brain? A review and empirical assessment of clinical case reports and published artworks for systematic evidence of quality and style changes linked to damage or neurodegenerative disease

The past three decades have seen multiple reports of people with neurodegenerative disorders, or other forms of changes in their brains, who also show putative changes in how they approach and produce visual art. Authors argue that these cases may provide a unique body of evidence, so-called 'artistic signatures' of neurodegenerative diseases, that might be used to understand disorders, provide diagnoses, be employed in treatment, create patterns of testable hypotheses for causative study, and also provide unique insight into the neurobiological linkages between the mind, brain, body, and the human penchant for art-making itself. However-before we can begin to meaningfully build from such emerging findings, much less formulate applications-not only is such evidence currently quite disparate and in need of systematic review, almost all case reports and artwork ratings are entirely subjective, based on authors' personal observations or a sparse collection of methods that may not best fit underlying research aims. This leads to the very real question of whether we might actually find patterns of systematic change if fit to a rigorous review-Can we really 'read' art to illuminate possible changes in the brain? How might we best approach this topic in future neuroscientific, clinical, and art-related research? This paper presents a review of this field and answer to these questions. We consider the current case reports for seven main disorders-Alzheimer's and Parkinson's disease, frontotemporal and Lewy body dementia, corticobasal degeneration, aphasia, as well as stroke-consolidating arguments for factors and changes related to art-making and critiquing past methods. Taking the published artworks from these papers, we then conduct our own assessment, employing computerized and human-rater-based approaches, which we argue represent best practice to identify stylistic or creativity/quality changes. We suggest, indeed, some evidence for systematic patterns in art-making for specific disorders and also find that case authors showed rather high agreement with our own assessments. More important, through opening this topic and past evidence to a systematic review, we hope to open a discussion and provide a theoretical and empirical foundation for future application and research on the intersection of art-making and the neurotypical, the changed, and the artistic brain.

Free Your Mind: Creative Thinking Contributes to Overcoming Conflict-Related Biases

Conflicts between groups are difficult to resolve, partly because humans tend to be biased in judging outgroup members. The aim of the current article is to review findings on the link between creativity and conflict-related biases and to offer a model that views creative cognition as an ability that may contribute to overcoming conflict-related biases. Our proposed model conforms to the twofold model of creativity. According to this model, creativity involves a generation phase and an evaluation phase, and these phases correspond to the neural mechanisms that underlie conflict-related biases. Specifically, we contend that the generation phase of creativity affects conflict-related biases by exerting an influence on stereotypes and prejudice, outgroup-targeted emotions, and ingroup empathy biases, all of which rely on the default mode network. Conversely, the evaluation phase of creativity, which is usually associated with activation in the executive control network and action-observation system, may be related to herding behaviors. Building on the shared mechanisms of creativity and conflicts, we propose that studies examining creativity-based interventions may be effective in promoting reconciliation.

Case Report: Accessible Digital Musical Instrument Can Be Used for Active Music Therapy in a Person With Severe Dementia and Worsening Behavioral and Psychological Symptoms: A Case Study Over a Year and a Half

Despite the fact that accessible digital musical instruments can take into account the level of cognitive demands, previous studies have been conducted with patients with mild cognitive impairment (MCI), and it is not known whether they can be used by people with moderate to severe dementia or dementia with worsening behavioral and psychological symptoms of dementia (BPSD). The participant was an 88-year-old woman with vascular dementia (VaD) (Mini-Mental State Examination [MMSE] and Neuropsychiatric Inventory [NPI] scores: 8 and 20, respectively). Music therapy (MT) was provided twice a week for 15 min, and MT sessions spanned over 18 months. For the MT, we used the cyber musical instrument with score (Cymis), an accessible digital musical instrument; it could be played using a touch panel and switches. The cognitive function of the participant declined further, with MMSE scores of 4 after 1 year and 0 after 1.5 years. BPSD peaked with the NPI score of 54 at 1 year and declined thereafter, although only apathy remained. Despite these changes, during MT, she was able to play the accessible digital musical instrument and focus on the performance. These results suggest that even patients with severe VaD can play an accessible digital instrument and continue active music therapy even if their BPSD progress with cognitive decline.

A pilot study of cognition and creativity among persons with HIV disease referred for neuropsychological evaluation

Creativity can help people to innovate, overcome obstacles, and successfully navigate challenges in daily life. Some aspects of creativity rely on the prefrontostriatal loops and executive functions, which can be compromised in persons with HIV (PWH). This pilot study examined whether neuropsychological functioning plays a role in creativity in PWH. A consecutive series of 41 PWH who were referred to an urban neuropsychology clinic in southeastern Texas were enrolled. Participants completed the Abbreviated Torrance Test for Adults (ATTA) to measure creativity, from which standardized creativity scores of fluency, originality, elaboration, and flexibility were derived. Participants also completed several measures of everyday functioning and a brief clinical neuropsychological battery measuring executive functions, motor skills, memory, and visuoconstruction. Global neuropsychological functioning showed a large, positive association with ATTA creativity performance that did not vary meaningfully by creativity domain and was independent of premorbid IQ. ATTA creativity scores were not associated with any measure of everyday functioning. Findings from this pilot study suggest that higher levels of neuropsychological functioning may support multiple dimensions of creativity in adults with HIV disease. Future studies might examine whether creativity moderates the association between HIV-associated neurocognitive impairment and various health behaviors (e.g., adherence, appointment attendance).

Paradoxical Enhancement of Spatial Learning Induced by Right Hippocampal Lesion in Rats

The left–right hemispheric differences in some brain functions are well known in humans. Among them, savant syndrome has unique features, such as exceptional abilities in vision, memory, computation, and music, despite brain abnormalities. In cases of acquired savant and transient savant, brain damage or inhibition is often seen in the left hemisphere, suggesting a link between left hemispheric dysfunction and these talents. On the other hand, some functional left–right differences have been reported in rodent brains, and therefore, unilateral damage in rodents may also result in savant-like enhancements. In the present study, we examined the effects of hippocampal damage on spatial learning in rats with left, right, or bilateral hippocampal lesion. The results showed that learning performance was impaired in the bilateral lesion group, and there was no significant difference in the left lesion group, while performance was enhanced in the right lesion group. These results suggest that damage to the right hippocampus in rats may lead to savant-like enhancement in learning and memory. The construction of the savant model through these results will contribute to the neuroscientific elucidation of the paradoxical phenomenon observed in savants, that some abilities are enhanced despite their brain dysfunction.

Premorbid de novo artistic creativity in frontotemporal dementia (FTD) syndromes

The emergence of new artistic activities or shifts in artistic style in patients with frontotemporal dementia (FTD) syndromes is well documented at or after disease onset. However, a closer look in the literature reveals emerging artistic creativity also before FTD onset, although the significance and underlying pathology of such creative endeavors remain elusive. Here, we systematically review relevant studies and report an additional FTD case to elaborate on artistic activities that developed years before disease manifestation by paying particular attention to the sequence of events in individual patients' biography and clinical history. We further discuss the FTD patient's creative activities in the context of their life events, other initial or "premorbid" dementia symptoms or risk factors described in the literature such as mental illness and mild behavioral impairment (MBI), as well as changes in neuronal systems (i.e., neuroimaging and neuropathology). In addition to our FTD patient, we identified five published cases with an FTD syndrome, including three with FTD, one with primary progressive aphasia (PPA), and one with the behavioral variant of PPA (bvPPA). Premorbid novel creativity emerged across different domains (visual, musical, writing), with the FTD diagnosis ensuing artistic productivity by a median of 8 years. Data on late-life and pre-dementia life events were available in four cases. The late creative phase in our case was accompanied by personality changes, accentuation of personality traits, and cessation of painting activities occurred with the onset of memory complaints. Thus, premorbid personality changes in FTD patients can be associated with de novo creative activity. Stressful life events may also contribute to the burgeoning of creativity. Moreover, primary neocortical areas that are largely spared by pathology at early FTD stages may facilitate the engagement in artistic activities, offering a window of opportunity for art therapy and other therapeutic interventions during the MBI stage or even earlier.

Emergent creativity in frontotemporal dementia

Numerous papers report on connections between creative work and dementing illness, particularly in frontotemporal dementia (FTD), which may combine with motor neuron disease (FTD-MND). However, the emergence of FTD(-MND) patients' de novo artistic activities is rarely reported and underappreciated. Therefore, the present review summarizes relevant case studies' outcomes, capturing creativity's multifaceted nature. Here, we systematically searched for case reports by paying particular attention to the chronological development of individual patients' clinical symptoms, signs, and life events. We synoptically compared the various art domains to the pattern of brain atrophy, the clinical and pathological FTD subtypes. 22 FTD(-MND) patients were identified with creativity occurring either at the same time (41%) or starting after the disease onset (59%); the median lag between the first manifestation of disease and the beginning of creativity was two years. In another five patients, novel artistic activity was developed by a median of 8 years before the start of dementia symptoms. Artistic activity usually evolved over time with a peak in performance, followed by a decline that was further hampered by physical impairment during disease progression. Early on, the themes and objects depicted were often concrete and realistic, but they could become more abstract or symbolic at later stages. Emergent artistic processes may occur early on in the disease process. They appear to be a communication of inner life and may also reflect an attempt of compensation or "self-healing". The relative preservation of primary neocortical areas such as the visual, auditory, or motor cortex may enable the development of artistic activity in the face of degeneration of association cortical areas and subcortical, deeper central nervous system structures. It is crucial to understand the differential loss of function and an individual's creative abilities to implement caregiver-guided, personalized therapeutic strategies such as art therapy.

Enhancing creativity by altering the frontoparietal control network functioning using transcranial direct current stimulation

The left angular gyrus (AG), part of the frontotemporal network, is implicated in creative thinking, including verbal creativity tasks such as novel metaphor generation. The current study tested the effects of tDCS over the left AG on two metaphor generation tasks. The study was a randomized, double-blind, sham-controlled, crossover study of anodal vs. cathodal stimulation by tDCS. Compared to sham, cathodal stimulation resulted in significantly increased novel metaphor generation, while anodal stimulation increased conventional metaphor generation. Higher motivation (behavioral approach system's "fun-seeking") was associated with greater metaphor creativity in the sham condition, and lower fun seeking was associated with producing a greater quantity of conventional metaphors. Following active stimulation, motivation traits no longer contributed to creative metaphor generation. Thus, the beneficial effect of cathodal tDCS over the left AG in generation of novel metaphors is through restraining the control network. The current study gives a glimpse into the neural basis for creative thinking.

Altered functional connectivity of cortical networks in semantic variant Primary Progressive Aphasia

As their illness progresses, patients with the semantic variant of Primary Progressive Aphasia (svPPA) frequently exhibit peculiar behaviors indicative of altered visual attention or an increased interest in artistic endeavors. In the present study, we examined changes within and between large-scale functional brain networks that may explain this altered visual behavior. We first examined the connectivity of the visual association network, the dorsal attention network, and the default mode network in healthy young adults (n = 89) to understand the typical architecture of these networks in the healthy brain. We then compared the large-scale functional connectivity of these networks in a group of svPPA patients (n = 12) to a group of age-matched cognitively normal controls (n = 30). Our results showed that the between-network connectivity of the dorsal attention and visual association networks was elevated in svPPA patients relative to controls. We further showed that this heightened between-network connectivity was associated with a decrease in the within-network connectivity of the default mode network, possibly due to progressive degeneration of the anterior temporal lobes in svPPA. These results suggest that focal neurodegeneration can lead to the reorganization of large-scale cognitive networks beyond the primarily affected network(s), possibly contributing to cognitive or behavioral changes that are commonly present as part of the clinical phenotype of svPPA.

Effects of transcranial direct current stimulation of left and right inferior frontal gyrus on creative divergent thinking are moderated by changes in inhibition control

Divergent thinking (DT) as one component of creativity is the ability to search for multiple solutions to a single problem and is reliably tested with the Alternative Uses Task (AUT). DT depends on activity in the inferior frontal gyrus (IFG), a prefrontal region that has also been associated with inhibitory control (IC). Experimentally manipulating IC through transcranial direct current stimulation (tDCS) led to alterations in DT. Here, we aimed at further examining such potential mediating effects of IC on DT (measured as flexibility, fluency, and originality in the AUT) by modulating IC tDCS. Participants received either cathodal tDCS (c-tDCS) of the left IFG coupled with anodal tDCS (a-tDCS) of the right IFG (L−R + ; N = 19), or the opposite treatment (L + R−; N = 21). We hypothesized that L + R− stimulation would enhance IC assessed with the Go NoGo task (GNGT), and that facilitated IC would result in lower creativity scores. The reversed stimulation arrangement (i.e., L− R +) should result in higher creativity scores. We found that tDCS only affected the originality component of the AUT but not flexibility or fluency. We also found no effects on IC, and thus, the mediation effect of IC could not be confirmed. However, we observed a moderation effect: inhibition of left and facilitation of right IFG (L−R +) resulted in enhanced flexibility and originality scores, only when IC performance was also improved. We conclude that inducing a right-to-left gradient in IFG activity by tDCS is efficient in enhancing DT, but only under conditions where tDCS is sufficient to alter IC performance as well.

Do painters need their whole brain to excel?

Skilled professional artists are sometimes able to maintain their talents while other cognitive functions deteriorate due to brain diseases. The objective of this study is to asses the preserved artistry of a professional painter in spite of the presence of strokes affecting brain areas implicated in art expression. She had a neurologic evaluation and brain imaging after the stroke; painter-curators analyzed and compared the painter's pictorial artwork created before and after the stroke. In spite of cerebellar, visuospatial, motor, cognitive, and functional deficits likely related to strokes affecting bilateral cerebellar, left occipital, and right temporal-occipital areas, the patient was able to maintain most of their artistic painting skills.. After a short period of functional recovery, our patient showed discrepancy among their impaired cerebellar cerebral functions in day activities and their preserved painting abilities.

Neuropsychiatric Aspects of Frontotemporal Dementia

Frontotemporal dementia (FTD) encompasses a group of clinical syndromes, including behavioral-variant FTD, nonfluent variant primary progressive aphasia, semantic variant primary progressive aphasia, FTD motor neuron disease, progressive supranuclear palsy syndrome, and corticobasal syndrome. Early on in its course, FTD is commonly seen in psychiatric clinics. We review the clinical features and diagnostic criteria in FTD spectrum disorders.

Music evoked autobiographical memories in people with behavioural variant frontotemporal dementia

Music is highly efficient at evoking autobiographical memories in both healthy and neurological populations. Music evoked autobiographical memories (MEAMs) are preserved in people with Alzheimer's Dementia (AD), and occur at the same frequency as in healthy people. To date there has been no investigation of the integrity of MEAMs in people with non-AD dementia. This study provides the first characterisation of the frequency and specificity of MEAMs and photo evoked autobiographical memories (PEAMs) in 6 people with Behavioural variant frontotemporal dementia (Bv-FTD). We found significantly reduced frequency and specificity of MEAMs and PEAMs in people with Bv-FTD compared with healthy elderly. This supports the known decline in autobiographical memory function in this population, and the integral role of medial frontal regions in the retrieval of MEAMs. Our findings highlight that the mnemonic effects of music vary between people with different types of dementia, which has implications for dementia care.

Emergence of artistic talent in progressive nonfluent aphasia: a case report

Some patients with frontotemporal lobar degeneration have developed artistic skills after the onset mainly in painting and music. Most of these cases have semantic dementia (SD), one of the frontotemporal lobar degeneration subtypes. In previously reported cases, the paintings made by patients with SD were usually hyper realistic, without a significant symbolic or abstract component. Here, we report on a patient with progressive nonfluent aphasia (PNFA), another frontotemporal lobar degeneration subtype, who started making creative bamboo crafts after PNFA onset. His techniques were completely his original; he devised the shapes of the crafts and made them without samples. His work did not become an obsessive preoccupation. The artistic style expressed by patients with PNFA differs from that expressed by patients with SD. Therefore, the underlying mechanisms for the emergence of artistic talent might differ between SD and PNFA.

Brain hemispheric involvement in visuospatial and verbal divergent thinking

Hemispheric lateralization for creative thinking remains a controversial topic. Early behavioral and neuroimaging research supported right hemisphere dominance in creative thinking, but more recent evidence suggests the left hemisphere plays an equally important role. In addition, the extent to which hemispheric lateralization in specific brain regions relates to individual creative ability, and whether hemispheric dominance relates to distinct task performance, remain poorly understood. Here, using multivariate predictive modeling of resting-state functional MRI data in a large sample of adults (N = 502), we estimated hemispheric segregation and integration for each brain region and investigated these lateralization indices with respect to individual differences in visuospatial and verbal divergent thinking. Our analyses revealed that individual visuospatial divergent thinking performance could be predicted by right-hemispheric segregation within the visual network, sensorimotor network, and some regions within the default mode network. High visuospatial divergent thinking was related to stronger functional connectivity between the visual network, fronto-parietal network, and default mode network within the right hemisphere. In contrast, high verbal divergent thinking performance could be predicted by inter-hemispheric balance within regions mainly involved in complex semantic processing (e.g., lateral temporal cortex and inferior frontal gyrus) and cognitive control processing (e.g., inferior frontal gyrus, middle frontal cortex, and superior parietal lobule). The current study suggests that two distinct forms of functional lateralization support individual differences in visuospatial and verbal divergent thinking. These findings have important implications for our understanding of hemispheric interaction mechanisms of creative thinking.

Links Between Painting and Neurology: The Example of Dementia

Art is a system of human communication arising from symbolic cognition, conveying ideas, experiences, and feelings. The goal of this review is to describe the link between painting and dementia. Individuals with neurodegenerative diseases inevitably experience cognitive dysfunction that has the potential to limit and impair the artist's ability to realize their creative and expressive intentions through painting. The strategy to advance our understanding of the neural bases for art is to map locations and nature of neural damage to changes onto artistic production.

Neurodegenerative disorders of the human frontal lobes

The frontal lobes play an integral role in human socioemotional and cognitive function. Sense of self, moral decisions, empathy, and behavioral monitoring of goal-states all depend on key nodes within frontal cortex. While several neurodegenerative diseases can affect frontal function, frontotemporal dementia (FTD) has particularly serious and specific effects, which thus provide insights into the role of frontal circuits in homeostasis and adaptive behavior. FTD represents a collection of disorders with specific clinical-pathologic correlates, imaging, and genetics. Patients with FTD and initial prefrontal degeneration often present with neuropsychiatric symptoms such as loss of social decorum, new obsessions, or lack of empathy. In those patients with early anterior temporal degeneration, language (particularly in patients with left-predominant disease) and socioemotional changes (particularly in patients with right-predominant disease) precede eventual frontal dysregulation. Herein, we review a brief history of FTD, initial clinical descriptions, and the evolution of nomenclature. Next, we consider clinical features, neuropathology, imaging, and genetics in FTD-spectrum disorders in relation to the integrity of frontal circuits. In particular, we focus our discussion on behavioral variant FTD given its profound impact on cortical and subcortical frontal structures. This review highlights the clinical heterogeneity of behavioral phenotypes as well as the clinical-anatomic convergence of varying proteinopathies at the neuronal, regional, and network level. Recent neuroimaging and modeling approaches in FTD reveal varying network dysfunction centered on frontal-insular cortices, which underscores the role of the human frontal lobes in complex behaviors. We conclude the chapter reviewing the cognitive and behavioral neuroscience findings furnished from studies in FTD related to executive and socioemotional function, reward-processing, decision-making, and sense of self.

Amygdala Represents Diverse Forms of Intangible Knowledge, That Illuminate Social Processing and Major Clinical Disorders

Amygdala is an intensively researched brain structure involved in social processing and multiple major clinical disorders, but its functions are not well understood. The functions of a brain structure are best hypothesized on the basis of neuroanatomical connectivity findings, and of behavioral, neuroimaging, neuropsychological and physiological findings. Among the heaviest neuroanatomical interconnections of amygdala are those with perirhinal cortex (PRC), but these are little considered in the theoretical literature. PRC integrates complex, multimodal, meaningful and fine-grained distributed representations of objects and conspecifics. Consistent with this connectivity, amygdala is hypothesized to contribute meaningful and fine-grained representations of intangible knowledge for integration by PRC. Behavioral, neuroimaging, neuropsychological and physiological findings further support amygdala mediation of a diversity of such representations. These representations include subjective valence, impact, economic value, noxiousness, importance, ingroup membership, social status, popularity, trustworthiness and moral features. Further, the formation of amygdala representations is little understood, and is proposed to be often implemented through embodied cognition mechanisms. The hypothesis builds on earlier work, and makes multiple novel contributions to the literature. It highlights intangible knowledge, which is an influential but insufficiently researched factor in social and other behaviors. It contributes to understanding the heavy but neglected amygdala-PRC interconnections, and the diversity of amygdala-mediated intangible knowledge representations. Amygdala is a social brain region, but it does not represent species-typical social behaviors. A novel proposal to clarify its role is postulated. The hypothesis is also suggested to illuminate amygdala's involvement in several core symptoms of autism spectrum disorder (ASD). Specifically, novel and testable explanations are proposed for the ASD symptoms of disorganized visual scanpaths, apparent social disinterest, preference for concrete cognition, aspects of the disorder's heterogeneity, and impairment in some activities of daily living. Together, the presented hypothesis demonstrates substantial explanatory potential in the neuroscience, social and clinical domains.

The neural underpinnings of cross-cultural differences in creativity

Whereas Western individualistic cultures emphasize uniqueness, collectivistic East-Asian cultures discourage it. Here we examined whether cross-cultural differences in creativity as measured by a task of divergent thinking (DT) are explained by enhanced activity in brain regions that mediate inhibitory control (e.g., the left inferior frontal gyrus [L-IFG]). We therefore predicted that the L-IFG would be "hyperactive" among individuals from East-Asian cultures compared to Western ones. In Study 1, Israeli and South Korean participants were compared on a classic DT task (AUT; "Alternate uses: Manual of instructions and interpretation"). Israelis generated more original ideas compared to South Koreans. In Study 2, Israeli participants and South Korean participants currently living in Israel were scanned while performing the AUT. In line with previous studies, the results indicate that generation of original ideas across cultures is associated with activation of the posterior cingulate cortex (PCC), which is part of the default mode network (DMN). As hypothesized, South Koreans showed enhanced activation of the L-IFG compared to Israelis. This enhanced activation was associated with lower originality scores. The cultural dimension of traditionalism, being higher in the South Korean sample than in the Israeli Sample, was related to enhance L-IFG activity, further supporting our hypothesis regarding cultural influences on inhibitory control. Furthermore, functional connectivity analysis indicated that activation of the L-IFG was positively coupled with PCC activity among Israelis and with preSMA activity among South Koreans. The results suggest that cross-cultural differences in creativity might be explained by variations in inhibitory control.

Transcranial direct current stimulation (tDCS) targeting the left inferior frontal gyrus: Effects on creativity across cultures

Although evidence points to the existence of cultural differences in creativity, the mechanisms that underlie these differences are largely unknown. The twofold model of creativity posits two recursive stages: a generation phase and an evaluation phase. Considering that recent studies suggest that the left inferior frontal gyrus) L-IFG(may inhibit creativity during the evaluation phase, we hypothesized that manipulating IFG activity would affect participants' level of creativity. We further predicted that the IFG may be "hyperactive" in a culture that typically discourages uniqueness (e.g., Japan) as compared to a Western culture (e.g., Israel); therefore the effect of inhibiting the L-IFG was expected to be higher in Japanese. To support this hypothesis we altered L-IFG activation using tDCS (transcranial direct current stimulation) in 30 Japanese and 30 Israeli participants and examined the effect of anodal and cathodal stimulation on divergent thinking (DT). Regardless of culture, cathodal stimulation increased creativity compared to sham, while anodal stimulation diminished creativity. Although cultural differences were found in DT scores, stimulation had no differential effect between the cultures. Taken together, the results confirm that the L-IFG plays a key role in creativity across cultures. The null findings regarding the expected interaction between stimulation and culture are discussed.

Participation of the left inferior frontal gyrus in human originality

Human creative cognition is commonly described as a twofold cyclic process that involves an idea generation phase and an idea evaluation phase. Although the evaluation phase makes a crucial contribution to originality, its underlying mechanisms have not received sufficient research attention. Here, we suggest that the left inferior frontal gyrus (lIFG) plays a major role in the interplay between the evaluation and generation networks and that inhibiting this region's activity may have an effect on "releasing" the generation neural network, resulting in greater originality. To examine the neural networks that mediate the generation and evaluation of ideas, we conducted an fMRI experiment on a group of healthy human participants (Study 1), in which we compared an idea generation task to an idea evaluation task. We found that evaluating the originality of ideas is indeed associated with a relative increase in lIFG activation, as opposed to generating original ideas. We further showed that temporarily inhibiting the lIFG using continuous theta-burst stimulation (Study 2) results in less strict evaluation on the one hand and increased originality scores on the other. Our findings provide converging evidence from multiple methods to show that the lIFG participates in evaluating the originality of ideas.

Frontotemporal Dementia

Frontotemporal dementia (FTD) is a heterogeneous disorder with distinct clinical phenotypes associated with multiple neuropathologic entities. Presently, the term FTD encompasses clinical disorders that include changes in behavior, language, executive control, and often motor symptoms. The core FTD spectrum disorders include behavioral variant FTD, nonfluent/agrammatic variant primary progressive aphasia, and semantic variant PPA. Related FTD disorders include frontotemporal dementia with motor neuron disease, progressive supranuclear palsy syndrome, and corticobasal syndrome. In this article, the authors discuss the clinical presentation, diagnostic criteria, neuropathology, genetics, and treatments of these disorders.

Drawing Disorders in Alzheimer's Disease and Other Forms of Dementia

Drawing is a multicomponential process that can be impaired by many kinds of brain lesions. Drawing disorders are very common in Alzheimer's disease and other forms of dementia, and can provide clinical information for the distinction of the different dementing diseases. In our review we started from an overview of the neural and cognitive bases of drawing, and from a recollection of the drawing tasks more frequently used for assessing individuals with dementia. Then, we analyzed drawing disorders in dementia, paying special attention to those observed in Alzheimer's disease, from the prodromal stages of the amnesic mild cognitive impairment to the stages of full-blown dementia, both in the sporadic forms with late onset in the entorhino-hippocampal structures and in those with early onset in the posterior neocortical structures. We reviewed the drawing features that could differentiate Alzheimer's disease from vascular dementia and from the most frequent forms of degenerative dementia, namely frontotemporal dementia and Lewy body disease. Finally, we examined some peculiar aspects of drawing disorders in dementia, such as perseverations, rotations, and closing-in. We argue that a careful analysis of drawing errors helps to differentiate the different forms of dementia more than overall accuracy in drawing.

Functional neuroimaging of visual creativity: a systematic review and meta-analysis

INTRODUCTION

The generation of creative visual imagery contributes to technological and scientific innovation and production of visual art. The underlying cognitive and neural processes are, however, poorly understood.

METHODS

This review synthesizes functional neuroimaging studies of visual creativity. Seven functional magnetic resonance imaging (fMRI) and 19 electroencephalography (EEG) studies were included, comprising 27 experiments and around 800 participants.

RESULTS

Activation likelihood estimation meta-analysis of the fMRI studies comparing visual creativity to non-rest control tasks yielded significant clusters in thalamus, left fusiform gyrus, and right middle and inferior frontal gyri. The EEG studies revealed a tendency for decreased alpha power during visual creativity compared to baseline, but comparisons of visual creativity to non-rest control tasks revealed inconsistent findings.

CONCLUSIONS

The findings are consistent with suggested contributions to visual creativity of prefrontally mediated inhibition, evaluation, and working memory, as well as visual imagery processes. Findings are discussed in relation to prominent theories of the neural basis of creativity.

Anatomical Correlates of Non-Verbal Perception in Dementia Patients

Purpose: Patients with dementia who have dissociations in verbal and non-verbal sound processing may offer insights into the anatomic basis for highly related auditory modes.

Methods: To determine the neuronal networks on non-verbal perception, 16 patients with Alzheimer’s dementia (AD), 15 with behavior variant fronto-temporal dementia (bv-FTD), 14 with semantic dementia (SD) were evaluated and compared with 15 age-matched controls. Neuropsychological and auditory perceptive tasks were included to test the ability to compare pitch changes, scale-violated melody and for naming and associating with environmental sound. The brain 3D T1 images were acquired and voxel-based morphometry (VBM) was used to compare and correlated the volumetric measures with task scores.

Results: The SD group scored the lowest among 3 groups in pitch or scale-violated melody tasks. In the environmental sound test, the SD group also showed impairment in naming and also in associating sound with pictures. The AD and bv-FTD groups, compared with the controls, showed no differences in all tests. VBM with task score correlation showed that atrophy in the right supra-marginal and superior temporal gyri was strongly related to deficits in detecting violated scales, while atrophy in the bilateral anterior temporal poles and left medial temporal structures was related to deficits in environmental sound recognition.

Conclusions: Auditory perception of pitch, scale-violated melody or environmental sound reflects anatomical degeneration in dementia patients and the processing of non-verbal sounds are mediated by distinct neural circuits.

Savant-like Numerosity Skills Revealed in Normal People by Magnetic Pulses

Oliver Sacks observed autistic twins who instantly guessed the exact number of match-sticks that had just fallen on the floor, saying in unison “111”. To test the suggestion that normal individuals have the capacity for savant numerosity, we temporarily simulated the savant condition in normal people by inhibiting the left anterior temporal lobe of twelve participants with repetitive transcranial magnetic stimulation (rTMS). This site has been implicated in the savant condition. Ten participants improved their ability to accurately guess the number of discrete items immediately following rTMS and, of these, eight became worse at guessing as the effects of the pulses receded. The probability of as many as eight out of twelve people doing best just after rTMS and not after sham stimulation by chance alone is less than one in one thousand.

Ugly aesthetic perception associated with emotional changes in experience of art by behavioural variant of frontotemporal dementia patients

The aesthetic experience through art is a window into the study of emotions. Patients with behavioural variant of frontotemporal dementia (bvFTD) have early alteration of emotional processing. A new appreciation of art has been reported in some of these patients. We designed a computerized task using 32 abstract paintings that allowed us to investigate the integrity of patients' emotions when viewing the artwork. We evaluated both conscious and explicit appraisal of emotions [aesthetic judgment (beautiful/ugly), emotional relevance (affected or not by the painting), emotional valence (pleasant/unpleasant), emotional reaction (adjective choice) and arousal] and unconscious processing. Fifteen bvFTD patients and 15 healthy controls were included. BvFTD patients reported that they were "little touched" by the paintings. Aesthetic judgment was very different between the two groups: the paintings were considered ugly (negative aesthetic bias) and unpleasant (negative emotional bias) more often by the patients than by controls. Valence and aesthetic judgments correlated in both groups. In addition, there was a positive bias in the implicit task and for explicit emotional responses. Patients frequently chose the word "sad" and rarely expressed themselves with such adjectives as "happy". Our results suggest that bvFTD patients can give an aesthetic judgment, but present abstraction difficulties, as spectators, resulting from impairments in the cognitive processes involved. They also have difficulties in terms of emotional processes with the loss of the ability to feel the emotion per se (i.e., to feel an emotion faced with art) linked to behaviour assessment. This cognitive approach allows us to better understand which spectators are bvFTD patients and to show interactions between emotions and behavioural disorders.

Stroke, music, and creative output: Alfred Schnittke and other composers

Alfred Schnittke (1934-1998), a celebrated Russian composer of the twentieth century, suffered from several strokes which affected his left cerebral hemisphere. The disease, however, did not diminish his musical talent. Moreover, he stated that his illness in a way facilitated his work. The composer showed amazingly high productivity after his first and second injuries of the central nervous system. The main topic of this chapter is the effect of strokes on Schnittke's output, creativity, and style of music. A brief biography of the composer with the chronology of his brain hemorrhages is included. In addition, the influence of cerebrovascular lesions on creative potential of other prominent composers such as Benjamin Britten, Jean Langlais, Vissarion Shebalin, Igor Stravinsky, and Ira Randall Thompson is discussed.

The emergence of artistic ability following traumatic brain injury

In this study, the case of a patient who developed artistic ability following a traumatic brain injury is reported. The subject was a 49-year-old male who suffered brain injury at the age of 44 due to an accidental fall. At age 48, he began drawing with great enthusiasm and quickly developed a personal style with his own biomorphic iconography. At first, his drawing was restricted to realistic reproductions of photographs of buildings, but his style of drawing changed and became more personal and expressionistic over the following 6 months.

Verbal creativity in semantic variant primary progressive aphasia

Emergence of visual and musical creativity in the setting of neurologic disease has been reported in patients with semantic variant primary progressive aphasia (svPPA), also called semantic dementia (SD). It is hypothesized that loss of left anterior frontotemporal function facilitates activity of the right posterior hemispheric structures, leading to de novo creativity observed in visual artistic representation. We describe creativity in the verbal domain, for the first time, in three patients with svPPA. Clinical presentations are carefully described in three svPPA patients exhibiting verbal creativity, including neuropsychology, neurologic exam, and structural magnetic resonance imaging (MRI). Voxel-based morphometry (VBM) was performed to quantify brain atrophy patterns in these patients against age-matched healthy controls. All three patients displayed new-onset creative writing behavior and produced extensive original work during the course of disease. Patient A developed interest in wordplay and generated a large volume of poetry. Patient B became fascinated with rhyming and punning. Patient C wrote and published a lifestyle guidebook. An overlap of their structural MR scans showed uniform sparing in the lateral portions of the language-dominant temporal lobe (superior and middle gyri) and atrophy in the medial temporal cortex (amygdala, limbic cortex). New-onset creativity in svPPA may represent a paradoxical functional facilitation. A similar drive for production is found in visually artistic and verbally creative patients. Mirroring the imaging findings in visually artistic patients, verbal preoccupation and creativity may be associated with medial atrophy in the language-dominant temporal lobe, but sparing of lateral dominant temporal and non-dominant posterior cortices.

Music and dementia

There is an increasing incidence of dementia in our aging population, and consequently an urgent need to develop treatments and activities that may alleviate the symptoms of dementia. Accumulating evidence shows that persons with dementia enjoy music, and their ability to respond to music is potentially preserved even in the late or severe stages of dementia when verbal communication may have ceased. Media interest in this topic has contributed to the public perception that music abilities are an "island of preservation" in an otherwise cognitively impaired person with dementia. In this chapter, we review the current literature on music cognition in dementia and show that there has been very scarce rigorous scientific investigation of this issue, and that various types of music memory exist and are differentially impaired in the different types of dementia. Furthermore, we discuss the recent development of music activities as a nonpharmacological treatment for dementia and highlight the methodological limitations of the current literature on this topic. While it has been reported that music activities can improve behavior, (particularly agitation), mood, and cognition in persons with dementia, recent large-scale randomized control studies have questioned the specificity of the effect of music and found that it is no more beneficial than other pleasant activities. Nevertheless, music is unique in its powerful ability to elicit both memories and emotions. This can provide an important link to individual's past and a means of nonverbal communication with carers, which make it an ideal stimulus for persons with dementia.

Postmorbid learning of saxophone playing in a patient with frontotemporal dementia

Some patients with frontotemporal dementia (FTD) show an artistic enhancement of musical abilities. However, no patients with FTD, to date, have been reported to be able to learn how to play a musical instrument after disease onset. Herein we describe a patient (J. K.) who had never played any musical instruments premorbidly, but who learned to play the saxophone after being diagnosed with a behavioral variant of FTD. He mastered a repertoire that consisted of 10 pieces of Korean folk songs over a period of three years. Furthermore, his saxophone skills were high enough to outperform other students in his class.

Hearing and music in dementia

Music is a complex acoustic signal that relies on a number of different brain and cognitive processes to create the sensation of hearing. Changes in hearing function are generally not a major focus of concern for persons with a majority of neurodegenerative diseases associated with dementia, such as Alzheimer disease (AD). However, changes in the processing of sounds may be an early, and possibly preclinical, feature of AD and other neurodegenerative diseases. The aim of this chapter is to review the current state of knowledge concerning hearing and music perception in persons who have a dementia as a result of a neurodegenerative disease. The review focuses on both peripheral and central auditory processing in common neurodegenerative diseases, with a particular focus on the processing of music and other non-verbal sounds. The chapter also reviews music interventions used for persons with neurodegenerative diseases.

Savant syndrome: realities, myths and misconceptions

It was 126 years ago that Down first described savant syndrome as a specific condition and 70 years ago that Kanner first described Early Infantile Autism. While as many as one in ten autistic persons have savant abilities, such special skills occur in other CNS conditions as well such that approximately 50 % of cases of savant syndrome have autism as the underlying developmental disability and 50 % are associated with other disabilities. This paper sorts out realities from myths and misconceptions about both savant syndrome and autism spectrum disorders (ASD) that have developed through the years. The reality is that low IQ is not necessarily an accompaniment of savant syndrome; in some cases IQ can be superior. Also, savants can be creative, rather than just duplicative, and the skills increase over time on a continuum from duplication, to improvisation to creation, rather than diminishing or suddenly disappearing. Genius and prodigy exist separate from savant syndrome and not all such highly gifted persons have Asperger's Disorder. This paper also emphasizes the critical importance of separating 'autistic-like' symptoms from ASD especially in children when the savant ability presents as hyperlexia (children who read early) or as Einstein syndrome (children who speak late), or have impaired vision (Blindisms) because prognosis and outcome are very different when that careful distinction is made. In those cases the term 'outgrowing autism' might be mistakenly applied when in fact the child did not have ASD in the first place.

Frontal lobe neurology and the creative mind

Concepts from cognitive neuroscience strongly suggest that the prefrontal cortex (PFC) plays a crucial role in the cognitive functions necessary for creative thinking. Functional imaging studies have repeatedly demonstrated the involvement of PFC in creativity tasks. Patient studies have demonstrated that frontal damage due to focal lesions or neurodegenerative diseases are associated with impairments in various creativity tasks. However, against all odds, a series of clinical observations has reported the facilitation of artistic production in patients with neurodegenerative diseases affecting PFC, such as frontotemporal dementia (FTD). An exacerbation of creativity in frontal diseases would challenge neuroimaging findings in controls and patients, as well as the theoretical role of prefrontal functions in creativity processes. To explore this paradox, we reported the history of a FTD patient who exhibited the emergence of visual artistic productions during the course of the disease. The patient produced a large amount of drawings, which have been evaluated by a group of professional artists who were blind to the diagnosis. We also reviewed the published clinical cases reporting a change in the artistic abilities in patients with neurological diseases. We attempted to reconcile these clinical observations to previous experimental findings by addressing several questions raised by our review. For instance, to what extent can the cognitive, conative, and affective changes following frontal damage explain changes in artistic abilities? Does artistic exacerbation truly reflect increased creative capacities? These considerations could help to clarify the place of creativity—as it has been defined and explored by cognitive neuroscience—in artistic creation and may provide leads for future lesion studies.

Expertise in musical improvisation and creativity: the mediation of idea evaluation

The current study explored the influence of musical expertise, and specifically training in improvisation on creativity, using the framework of the twofold model, according to which creativity involves a process of idea generation and idea evaluation. Based on the hypothesis that a strict evaluation phase may have an inhibiting effect over the generation phase, we predicted that training in improvisation may have a “releasing effect” on the evaluation system, leading to greater creativity. To examine this hypothesis, we compared performance among three groups - musicians trained in improvisation, musicians not trained in improvisation, and non-musicians - on divergent thinking tasks and on their evaluation of creativity. The improvisation group scored higher on fluency and originality compared to the other two groups. Among the musicians, evaluation of creativity mediated how experience in improvisation was related to originality and fluency scores. It is concluded that deliberate practice of improvisation may have a “releasing effect” on creativity.

Neurophysiological basis of creativity in healthy elderly people: a multiscale entropy approach

OBJECTIVES

Creativity, which presumably involves various connections within and across different neural networks, reportedly underpins the mental well-being of older adults. Multiscale entropy (MSE) can characterize the complexity inherent in EEG dynamics with multiple temporal scales. It can therefore provide useful insight into neural networks. Given that background, we sought to clarify the neurophysiological bases of creativity in healthy elderly subjects by assessing EEG complexity with MSE, with emphasis on assessment of neural networks.

METHODS

We recorded resting state EEG of 20 healthy elderly subjects. MSE was calculated for each subject for continuous 20-s epochs. Their relevance to individual creativity was examined concurrently with intellectual function.

RESULTS

Higher individual creativity was linked closely to increased EEG complexity across higher temporal scales, but no significant relation was found with intellectual function (IQ score).

CONCLUSIONS

Considering the general "loss of complexity" theory of aging, our finding of increased EEG complexity in elderly people with heightened creativity supports the idea that creativity is associated with activated neural networks.

SIGNIFICANCE

Results reported here underscore the potential usefulness of MSE analysis for characterizing the neurophysiological bases of elderly people with heightened creativity.

Enhanced creative thinking under dopaminergic therapy in Parkinson disease

OBJECTIVE

Creative thinking requires a combination of originality, flexibility, and usefulness. Several reports described enhanced artistic creativity in Parkinson disease (PD) patients treated with dopaminergic agents. We aimed to examine PD patients' ability to perform creativity tasks compared to healthy controls and to verify whether creativity is related to an impulse control disorder (ICD) as a complication of dopaminergic therapy.

METHODS

Right-handed PD patients treated with dopamine agonists and/or levodopa, and age- and education- matched neurologically healthy controls were assessed using the Montreal Cognitive Assessment, semantic verbal fluency, Beck Depression Inventory, and Questionnaire for Impulsive-Compulsive Disorders in Parkinson Disease Rating Scale (QUIP-RS). Creativity assessment included Comprehension of Novel Metaphors (CNM), Remote Association Test, and Tel Aviv Creativity Test (TACT). Groups were compared using analyses of variance, t tests, and correlation analyses.

RESULTS

Twenty-seven PD patients (age, mean ± standard deviation = 62 ± 7 years; education = 16 ± 3 years; disease duration = 5.8 ± 3.9 years) and 27 controls (age = 59 ± 9 years; education 17 ± 3 years) participated. PD patients performed significantly better than controls in divergent thinking tasks; specifically, the TACT-Visual for both fluency (33.48 ± 11.83 vs 25.59 ± 10.27, p = 0.034) and quality (15.78 ± 7.6 vs 11.19 ± 6.22, p = 0.025). Comprehension of Novel Metaphors was better in PD patients vs controls (0.71 ± 0.23 vs 0.55 ± 0.29, p = 0.04). QUIP-RS scores did not correlate with creativity measures.

INTERPRETATION

PD patients treated with dopaminergic drugs demonstrated enhanced verbal and visual creativity as compared to neurologically healthy controls. This feature was unrelated to ICD. Dopaminergic agents might act through the reduction of latent inhibition, resulting in widening of the associative network and enriched divergent thinking.