Matthew W. Jerram

Cortical morphology of visual creativity

BACKGROUND AND OBJECTIVE The volume of cortical tissue devoted to a function often influences the quality of a persons ability to perform that function. Up to now only white matter correlates of creativity have been reported, and we wanted to learn if the creative visuospatial performance on the figural Torrance Test of Creative Thinking (TTCT) is associated with measurements of cerebral gray matter volume in the regions of the brain that are thought to be important in divergent reasoning and visuospatial processing. METHODS Eighteen healthy college educated men (mean age=40.78; 15 right-handers) were recruited (via advertisement) as participants. High-resolution MRI scans were acquired on a 1.5T MRI scanner. Voxel-based morphometry regression analyses of TTCT to cortical volume were restrained within the anatomic regions identified. RESULTS One significant positive focus of association with TTCT emerged within the right parietal lobe gray matter (MNI coordinates: 44, -24, 63; 276 voxels). CONCLUSIONS Based on theories of parietal lobe function and the requirements of the TTCT, the area observed may be related due to its dominant role in global aspects of attention and visuospatial processing including the capacity for manipulating spatial representations.

Prefrontal regional correlates of self-control in male psychiatric patients: Impulsivity facets and aggression

Investigating the organization of trait aggression and impulsivity in the prefrontal cortex (PFC) advances our understanding of the neuropsychobiology of self-control. While the orbital aspect of the PFC (OFC) has received attention, there is reason to believe the lateral aspect is also relevant. In the current study using magnetic resonance imaging, gray matter volumes in lateral PFC (LPFC) were derived in a heterogeneous male psychiatric sample (N=36) in which OFC volumes had previously been reported. In an analysis using self-report measures of trait impulsivity and aggression, the left LPFC accounted for significant variance in attentional aspects of impulsivity (13%) and aggression (10%) but not motor aspects of impulsivity, as hypothesized. The OFC was associated with motor impulsivity (left-20%; right-14%) and was also more robustly associated with aggression (left-36%; right-16%). A social/emotional information processing model was explored, based upon whether the LPFC or the OFC depended upon one another for their association to trait aggression and impulsivity. It was demonstrated that association of the LPFC to both aggression and attentional impulsivity depended upon the OFC, while the converse was not supported. The LPFC appears relevant to the higher-order aspects of a cortical self-control network, and that relevance is dependent upon the robust contribution of the OFC.

Comparing alternative metrics to assess performance on the Iowa Gambling Task

This study was conducted in response to calls to develop Iowa Gambling Task (IGT) metrics reflecting more homogeneous aspects of decision making, as well as to add to the literature on reliability and validity of the instrument. The conventional IGT metric, advantageous minus disadvantageous deck selections, was compared to alternatives in which Decks B and C or the first 40 selections were eliminated. We correlated these alternative metrics with performance on other neuropsychological tests in 214 healthy adults, and we compared participant subgroups stratified by health status (214 healthy and 43 unhealthy participants). Internal consistency of the IGT was low and could explain the modest levels of construct validity observed. Alternative metrics, especially Deck D minus Deck A selections (D–A), did improve construct and criterion validity of the IGT. They also showed different patterns of correlation with other neuropsychological measures and might enhance the clinical and scientific usefulness of this test. Future research with an eye to modifying the paradigm and/or administration procedures to increase intertrial consistency might also give a needed boost to construct and criterion validity.

Neural correlates of impulsivity factors in psychiatric patients and healthy volunteers: a voxel-based morphometry study

According to bottom-up/top-down models, impulsivity facets are represented across the cerebral cortex and subcortex. Hypothesized gray matter correlates of motor, attentional and non-planning impulsivity were examined in groups of 35 psychiatric patients characterized by self-control problems and 18 healthy volunteers. Among patients, a positive correlation was found between motor impulsivity and the right cerebellum, and a negative correlation emerged between attentional impulsivity and the left lateral orbitofrontal cortex (OFC). Among controls, attentional and motor impulsivity correlated negatively with the left superior temporal gyrus, while non-planning impulsivity correlated positively with the left OFC and lateral frontopolar cortex. Follow-up analyses revealed convergence in correlation patterns from patients to controls, but not vice versa. That pattern suggested broader neural representation of the trait in the healthy controls, who were less impulsive than the psychiatric patients.

Levels of Dissociation and Nonsuicidal Self-Injury: A Quartile Risk Model

Extant research indicates that dissociation may act as a risk factor for nonsuicidal self-injury (NSSI), but the data are mixed. In this study, 75 university and community females ages 18–35 were assessed for rates of normative, clinical, and severely clinical dissociation as well as for NSSI. Significant differences in normative dissociation were found between the control group and the group reporting a history of NSSI. In addition, normative dissociation—but not clinical or severely clinical dissociation—was found to be significantly associated with NSSI in this sample. Considering this finding in the context of the existing literature, we propose a quartile risk model of dissociation and NSSI as a new approach to the influences of levels of dissociation on NSSI risk.

The neural correlates of the dominance dimension of emotion

Emotion has been conceptualized as a dimensional construct, while the number of dimensions - two or three - has been debated. Research has consistently identified two dimensions - valence and arousal - though ample evidence exists that three dimensions are necessary to describe emotion. One proposed third dimension, identified as dominance, is relevant in clinical syndromes, personality and consumer psychology. Dominance refers to an individuals sense of having an ability to affect the environment. Neuroimaging studies have generally focused on the two dimensions of valence and arousal, leaving the neural correlates of dominance unexplored. The current study used functional magnetic resonance imaging to explore the neural basis of dominance in 17 healthy male controls. Participants viewed images from the International Affective Picture System that were selected to represent high and low dominance conditions. Results indicated activation in paralimbic regions, including the bilateral anterior insula for high dominance and the right precuneus for low. The findings of this exploratory study support the consideration of dominance in dimensional models of emotion and suggest that further research is needed to understand the neural representation of dominance in emotional experience.

Functional anatomic dissociation of description and picture naming in the left temporal lobe

Functional magnetic resonance imaging (fMRI) was used in a non-patient experimental sample to assess the neuroanatomical dissociation of picture and description naming (PN and DN) in temporal lobe (TL). The purpose was to determine the generalizability of findings in semantic organization in the epilepsy patient population to the broader population. It was hypothesized that, akin to patient derived findings, DN would uniquely activate left TL regions anterior to those associated with PN, while overlapping in middle and posterior left TL. Participants (n = 16) underwent fMRI while silently naming target words during a picture naming task (PNT; line drawings) and description naming task (DNT; orthographic phrases). Analysis was a priori restricted to the left TL. Group results of direct contrasts (DNT > PNT and PNT > DNT) confirmed the hypothesized dissociation with DNT > PNT activating anterior left TL. Within-condition contrasts (DNT and PNT alone) yielded additional support, revealing areas of shared and unique activation in each condition. This is the first imaging study to contrast DN and PN in the same sample. The results suggest DN and PN are meaningfully different constructs subserved by converging and diverging TL neuroanatomy and may be differentially affected by disease.

Hierarchical Organization of Cortical Morphology of Decision-Making when Deconstructing Iowa Gambling Task Performance in Healthy Adults

The Iowa Gambling Task (IGT) is a measure of decision-making, in which alternative metrics have greater construct validity than conventional metrics. No large scale study has examined the neural correlates in healthy adults. We administered the IGT and structural MRI to 124 healthy participants. We analyzed the conventional IGT metric of advantageous minus disadvantageous choices (i.e., decks C + D minus decks A + B), and three alternative metrics based on choices from decks D and A alone, and all selections from each deck. Using regression and voxel-based morphometry, we examined regional gray matter volumes as predictors of IGT performance. No neural correlates of the conventional metric emerged, and the neural correlates of individual deck selections were disparate from one another. Alternative metrics showed expected neural correlates of decision-making in prefrontal cortex, insula, thalamus, and other regions. IGT alternative metrics have neural correlates consistent with decision-making theory as those difference scores reduce heterogeneity in cognitive processes. The CD-AB metric construct failure may reflect an artificial amalgamation of processes. The D-A metric appears to more successfully combine multiple levels of representation (dorsolateral prefrontal cortex, sub-cortical, cerebellar).

A Comparison of Voxel-Based Morphometry and Volumetry Methods in the Context of the Neural Basis of Aggression

The assumption that voxel-based morphometry (VBM) offers an automated substitution for manually-traced volumetry was subjected to empirical evaluation. Data available from a previous volumetry study (Gansler et al. Psychiatry Research: Neuroimaging 171:145–154, 2009) provided the basis for the current study, which assessed for convergence between the methods. Optimized modulated VBM was used to preprocess images (N = 40). Gray matter volume and self-reported aggression associations were tested. Results indicate convergence, as both methods revealed significant negative associations of the left orbitofrontal cortex (OFC) and aggression. VBM detected an additional positive left OFC result not revealed with volumetry, suggesting that VBM may allow greater within-region localization than volumetry. However, the methods differentially deal with error rates and power demands and as such are better conceptualized as complementary than interchangeable.

Relationship of mindful awareness to neural processing of angry faces and impact of mindfulness training: A pilot investigation

Mindfulness is paying attention, non-judgmentally, to experience in the moment. Mindfulness training reduces depression and anxiety and influences neural processes in midline self-referential and lateralized somatosensory and executive networks. Although mindfulness benefits emotion regulation, less is known about its relationship to anger and the corresponding neural correlates. This study examined the relationship of mindful awareness and brain hemodynamics of angry face processing, and the impact of mindfulness training. Eighteen healthy volunteers completed an angry face processing fMRI paradigm and measurement of mindfulness and anger traits. Ten of these participants were recruited from a Mindfulness-Based Stress Reduction (MBSR) class and also completed imaging and other assessments post-training. Self-reported mindful awareness increased after MBSR, but trait anger did not change. Baseline mindful awareness was negatively related to left inferior parietal lobule activation to angry faces; trait anger was positively related to right middle frontal gyrus and bilateral angular gyrus. No significant pre-post changes in angry face processing were found, but changes in trait mindful awareness and anger were associated with sub-threshold differences in paralimbic activation. These preliminary and hypothesis-generating findings, suggest the analysis of possible impact of mindfulness training on anger may begin with individual differences in angry face processing.