Media Violence Effects on Brain Development: What Neuroimaging Has Revealed and What Lies Ahead

Substantial research has indicated that media violence induces both short- and long-term increases in aggressive thoughts, feelings, and behaviors. Recently, neuroimaging techniques have begun to identify the mechanisms driving these changes. An important avenue that these neuroimaging tools can address is how exposure to media violence in childhood affects brain development, which can have lifelong behavioral consequences. This review highlights neuroimaging research examining how media violence exposure affects the pediatric brain. While such research is limited, evidence suggests that prefrontal mechanisms for controlling emotion and behavior are altered by exposure to violent media. Therefore, long-term increases in aggression and decreases in inhibitory control due to excessive media violence exposure may result from impaired development of prefrontal regions. However, additional neuroimaging research is necessary to establish whether and how exposure to media violence specifically shapes subsequent neural maturation. To optimize the use of neuroimaging in this inquiry, imaging studies should not stand on their own, but instead must be integrated with more traditional research paradigms to establish a more complete picture of effects. Future research must employ more longitudinal approaches to better characterize long-term effects that high exposure to violent screen media may have on brain development, particularly prefrontal and limbic brain regions

Relationship of Negative Urgency to Cingulo-Insular and Cortico-Striatal Resting State Functional Connectivity in Tobacco Use

Negative urgency, defined as a tendency to act rashly under extreme negative emotion, is strongly associated with tobacco use. Despite the robust evidence linking negative urgency and tobacco use and accumulating evidence suggesting that localized, segregated brain regions such as the nucleus accumbens (NAcc), insula, and amygdala are related to negative urgency, resting state functional connectivity (rsFC) of negative urgency in tobacco use has not yet been examined. This study included 34 daily tobacco users and 62 non-users matched on age, gender, race/ethnicity, and lifetime psychiatric diagnosis from a publicly available neuroimaging dataset collected by the Nathan Kline Institute-Rockland Project. Using the bilateral NAcc, insula, and amygdala as seed regions, seed-based rsFC analyses were conducted on the whole brain. In the whole sample, negative urgency was positively correlated with rsFC between the left insula and right dorsal anterior cingulate cortex (dACC). Compared to non-users, tobacco users had a stronger rsFC strength between the right amygdala and right middle temporal gyrus. In tobacco users, negative urgency was negatively associated with rsFC between the left NAcc and right dACC and between the left NAcc and right dorsolateral prefrontal cortex; these relationships were positive in non-users. Identifying functional connectivity implicated in negative urgency and tobacco use is the crucial first step to design and test pharmacological and physiological interventions to reduce negative urgency related tobacco use

Emotional response inhibition in bipolar disorder: a functional magnetic resonance imaging study of trait- and state-related abnormalities

BACKGROUND: Impaired response inhibition and poor impulse control are hallmarks of the manic phase of bipolar disorder but are also present during depressive and, to a lesser degree, euthymic periods. The neural mechanisms underlying these impairments are poorly understood, including how mechanisms are related to bipolar trait or state effects. METHODS: One-hundred four unmedicated participants with bipolar mania (BM) (n = 30), bipolar depression (BD) (n = 30), bipolar euthymia (BE) (n = 14), and healthy control subjects (n = 30) underwent functional magnetic resonance imaging during emotional and nonemotional go/no-go tasks. The go/no-go task requires participants to press a button for go stimuli, while inhibiting the response to no-go trials. In separate blocks, participants inhibited the response to happy faces, sad faces, or letters. RESULTS: The BE group had higher insula activity during happy face inhibition and greater activity in left inferior frontal gyrus during sad face inhibition, demonstrating bipolar trait effects. Relative to the BE group, BD and BM groups demonstrated lower insula activity during inhibition of happy faces, though the depressed sample had lower activity than manic patients. The BD and BM groups had a greater response to inhibiting sad faces in emotion processing and regulation regions, including putamen, insula, and lateral prefrontal cortex. The manic group also had higher activity in insula and putamen during neutral letter inhibition. CONCLUSIONS: These results suggest distinct trait- and state-related neural abnormalities during response inhibition in bipolar disorder, with implications for future research and treatment

Feasibility of Functional Neuroimaging to Understand Adolescent Women’s Sexual Decision Making

Purpose For young women, new sexual experiences normatively increase after puberty and coincide with extensive changes to brain regions governing self-regulation of risk behavior. These neurodevelopmental changes could leave some young women vulnerable for negative sexual outcomes, including sexually transmitted infection and unintended pregnancy. We evaluated the feasibility of using functional neuroimaging to understand the sexual decision making of adolescent women. Methods Adolescent women (N = 14; 14–15 years) completed enrollment interviews, a neuroimaging task gauging neural activation to appetitive stimuli, and 30 days of prospective diaries following the scan characterizing daily affect and sexual behaviors. Descriptive and inferential statistics assessed the association between imaging and behavioral data. Results Young women were highly compliant with neuroimaging and diary protocol. Neural activity in a cognitive-affective network, including prefrontal and anterior cingulate regions, was significantly greater during low-risk decisions. Compared with other decisions, high-risk sexual decisions elicited greater activity in the anterior cingulate, and low-risk sexual decision elicited greater activity in regions of the visual cortex. Young women's sexual decision ratings were linked to their sexual history characteristics and daily self-reports of sexual emotions and behaviors. Conclusions It is feasible to recruit and retain a cohort of female participants to perform a functional magnetic resonance imaging task focused on making decisions about sex, on the basis of varying levels of hypothetical sexual risk, and to complete longitudinal prospective diaries following this task. Preliminary evidence suggests that risk level differentially impacts brain activity related to sexual decision making in these women, which may be related to past and future sexual behaviors

Metacognition in Early Phase Psychosis: Toward Understanding Neural Substrates

Individuals in the early phases of psychotic illness have disturbed metacognitive capacity, which has been linked to a number of poor outcomes. Little is known, however, about the neural systems associated with metacognition in this population. The purpose of this study was to elucidate the neuroanatomical correlates of metacognition. We anticipated that higher levels of metacognition may be dependent upon gray matter density (GMD) of regions within the prefrontal cortex. Examining whole-brain structure in 25 individuals with early phase psychosis, we found positive correlations between increased medial prefrontal cortex and ventral striatum GMD and higher metacognition. These findings represent an important step in understanding the path through which the biological correlates of psychotic illness may culminate into poor metacognition and, ultimately, disrupted functioning. Such a path will serve to validate and promote metacognition as a viable treatment target in early phase psychosis

Neural activation during risky decision-making in youth at high risk for substance use disorders

Risky decision-making, particularly in the context of reward-seeking behavior, is strongly associated with the presence of substance use disorders (SUDs). However, there has been little research on the neural substrates underlying reward-related decision-making in drug-naïve youth who are at elevated risk for SUDs. Participants comprised 23 high-risk (HR) youth with a well-established SUD risk phenotype and 27 low-risk healthy comparison (HC) youth, aged 10-14. Participants completed the balloon analog risk task (BART), a task designed to examine risky decision-making, during functional magnetic resonance imaging. The HR group had faster reaction times, but otherwise showed no behavioral differences from the HC group. HR youth experienced greater activation when processing outcome, as the chances of balloon explosion increased, relative to HC youth, in ventromedial prefrontal cortex (vmPFC). As explosion probability increased, group-by-condition interactions in the ventral striatum/anterior cingulate and the anterior insula showed increasing activation in HR youth, specifically on trials when explosions occurred. Thus, atypical activation increased with increasing risk of negative outcome (i.e., balloon explosion) in a cortico-striatal network in the HR group. These findings identify candidate neurobiological markers of addiction risk in youth at high familial and phenotypic risk for SUDs

Decreased Prefrontal Activity During a Cognitive Inhibition Task Following Violent Video Game Play: A Multi-Week Randomized Trial

There is substantial evidence that exposure to violent media increases aggressive thoughts and behaviors, potentially due in part to alterations to inhibitory mechanisms mediated by prefrontal cortex. Past research has demonstrated that playing a violent video game for short periods decreases subsequent prefrontal activity during inhibition, yet the impact of long-term game play is unclear. To assess how extensive video game play impacts brain activity, young adult males (n = 49; ages 18–29) with limited video game experience performed a go/no-go task during fMRI for 3 consecutive weeks. Following a baseline scan, these men were randomly assigned to extensively play a violent video game (VG) or avoid all video game play (control) during the subsequent week. After 1 week, inhibition-related activity decreased in right inferior frontal gyrus and right cerebellum in the VG group, compared to the control sample, and self-reported executive functioning problems were higher. VG participants assigned to a second week of game play had similarly reduced bilateral prefrontal activity during inhibition, relative to the control group. However, VG participants assigned to avoid game play or play a cognitive training game during the second week demonstrated similar overall changes from baseline as the control group. This research provides preliminary evidence indicating how long-term video game play may impact brain function during inhibition, which may impair control of aggressive behavior

Functional neuroanatomical correlates of episodic memory impairment in early phase psychosis

Studies have demonstrated that episodic memory (EM) is often preferentially disrupted in schizophrenia. The neural substrates that mediate EM impairment in this illness are not fully understood. Several functional magnetic resonance imaging (fMRI) studies have employed EM probe tasks to elucidate the neural underpinnings of impairment, though results have been inconsistent. The majority of EM imaging studies have been conducted in chronic forms of schizophrenia with relatively few studies in early phase patients. Early phase schizophrenia studies are important because they may provide information regarding when EM deficits occur and address potential confounds more frequently observed in chronic populations. In this study, we assessed brain activation during the performance of visual scene encoding and recognition fMRI tasks in patients with earlyphase psychosis (n = 35) and age, sex, and race matched healthy control subjects (n = 20). Patients demonstrated significantly lower activation than controls in the right hippocampus and left fusiform gyrus during scene encoding and lower activation in the posterior cingulate, precuneus, and left middle temporal cortex during recognition of target scenes. Symptom levels were not related to the imaging findings, though better cognitive performance in patients was associated with greater right hippocampal activation during encoding. These results provide evidence of altered function in neuroanatomical circuitry subserving EM early in the course of psychotic illness, which may have implications for pathophysiological models of this illness

Robust estimation of fractal measures for characterizing the structural complexity of the human brain: optimization and reproducibility

High-resolution isotropic three-dimensional reconstructions of human brain gray and white matter structures can be characterized to quantify aspects of their shape, volume and topological complexity. In particular, methods based on fractal analysis have been applied in neuroimaging studies to quantify the structural complexity of the brain in both healthy and impaired conditions. The usefulness of such measures for characterizing individual differences in brain structure critically depends on their within-subject reproducibility in order to allow the robust detection of between-subject differences. This study analyzes key analytic parameters of three fractal-based methods that rely on the box-counting algorithm with the aim to maximize within-subject reproducibility of the fractal characterizations of different brain objects, including the pial surface, the cortical ribbon volume, the white matter volume and the grey matter/white matter boundary. Two separate datasets originating from different imaging centers were analyzed, comprising, 50 subjects with three and 24 subjects with four successive scanning sessions per subject, respectively. The reproducibility of fractal measures was statistically assessed by computing their intra-class correlations. Results reveal differences between different fractal estimators and allow the identification of several parameters that are critical for high reproducibility. Highest reproducibility with intra-class correlations in the range of 0.9–0.95 is achieved with the correlation dimension. Further analyses of the fractal dimensions of parcellated cortical and subcortical gray matter regions suggest robustly estimated and region-specific patterns of individual variability. These results are valuable for defining appropriate parameter configurations when studying changes in fractal descriptors of human brain structure, for instance in studies of neurological diseases that do not allow repeated measurements or for disease-course longitudinal studies

Functional network connectivity in early-stage schizophrenia

Schizophrenia is a disorder of altered neural connections resulting in impaired information integration. Whole brain assessment of within- and between-network connections may determine how information processing is disrupted in schizophrenia. Patients with early-stage schizophrenia (n = 56) and a matched control sample (n = 32) underwent resting-state fMRI scans. Gray matter regions were organized into nine distinct functional networks. Functional connectivity was calculated between 278 gray matter regions for each subject. Network connectivity properties were defined by the mean and variance of correlations of all regions. Whole-brain network measures of global efficiency (reflecting overall interconnectedness) and locations of hubs (key regions for communication) were also determined. The control sample had greater connectivity between the following network pairs: somatomotor-limbic, somatomotor-default mode, dorsal attention-default mode, ventral attention-limbic, and ventral attention-default mode. The patient sample had greater variance in interactions between ventral attention network and other functional networks. Illness duration was associated with overall increases in the variability of network connections. The control group had higher global efficiency and more hubs in the cerebellum network, while patient group hubs were more common in visual, frontoparietal, or subcortical networks. Thus, reduced functional connectivity in patients was largely present between distinct networks, rather than within-networks. The implications of these findings for the pathophysiology of schizophrenia are discussed