Frontal Lobe Activation Mediates the Relation Between Sensation Seeking and Cortisol Increases

Risk Factors Associated With Driving After Cannabis Use Among Canadian Young Adults

This study identifid the most prominent risk factors associated with driving after cannabis use (DACU). 1,126 Canadian drivers (17–35 years old) who have used cannabis in the past 12 months completed an online questionnaire about sociodemographic information, substance use habits, cannabis effect expectancies, driving behaviours and peers’ behaviours and attitudes concerning DACU. A hierarchical logistic regression allowed identifying variables that were associated with DACU. Income (CA$30,000–CA$69,000), weekly-to-daily cannabis use, higher level of cannabis-related problems, expectation that cannabis facilitates social interactions, drunk driving, belief that DACU is safe, general risky driving behaviours, having a few friends who had DACU and injunctive norms predicted past 12-month DACU. Older age, holding negative expectations concerning cannabis, driving aggressively and perceived accessibility of public transportation decreased the probability of DACU. With restricted resources, programmes will be more efficient by targeting Canadian young adults most inclined to DACU by focussing on these risk factors.

Shared Neural Mechanisms for the Evaluation of Intense Sensory Stimulation and Economic Reward, Dependent on Stimulation-Seeking Behavior

Why are some people strongly motivated by intense sensory experiences? Here we investigated how people encode the value of an intense sensory experience compared with economic reward, and how this varies according to stimulation-seeking preference. Specifically, we used a novel behavioral task in combination with computational modeling to derive the value individuals assigned to the opportunity to experience an intense tactile stimulus (mild electric shock). We then examined functional imaging data recorded during task performance to see how the opportunity to experience the sensory stimulus was encoded in stimulation-seekers versus stimulation-avoiders. We found that for individuals who positively sought out this kind of sensory stimulation, there was common encoding of anticipated economic and sensory rewards in the ventromedial prefrontal cortex. Conversely, there was robust encoding of the modeled probability of receiving such stimulation in the insula only in stimulation-avoidant individuals. Finally, we found preliminary evidence that sensory prediction error signals may be positively signed for stimulation-seekers, but negatively signed for stimulation-avoiders, in the posterior cingulate cortex. These findings may help explain why high intensity sensory experiences are appetitive for some individuals, but not for others, and may have relevance for the increased vulnerability for some psychopathologies, but perhaps increased resilience for others, in high sensation-seeking individuals.

SIGNIFICANCE STATEMENT

People vary in their preference for intense sensory experiences. Here, we investigated how different individuals evaluate the prospect of an unusual sensory experience (electric shock), compared with the opportunity to gain a more traditional reward (money). We found that in a subset of individuals who sought out such unusual sensory stimulation, anticipation of the sensory outcome was encoded in the same way as that of monetary gain, in the ventromedial prefrontal cortex. Further understanding of stimulation-seeking behavior may shed light on the etiology of psychopathologies such as addiction, for which high or low sensation-seeking personality has been identified as a risk factor.

Testosterone and cortisol jointly modulate risk-taking

Recent theories propose that testosterone should be positively related to risk-taking, but empirical support is mixed. Building on the dual-hormone hypothesis, the present research tested whether testosterone's role in risk-taking depends on cortisol. Study 1 (N=115) tested this hypothesis in a mixed-sex sample with self and informant reports of risk-taking. Study 2 (N=165) tested this hypothesis in a male-only sample with the Balloon Analog Risk Task, a behavioral measure of risk-taking. Across both studies, there was a positive association between basal testosterone and risk-taking among individuals low in basal cortisol but not individuals high in basal cortisol. This pattern emerged in both males and females and across multiple measures of risk-taking (self reports, informant reports, behavior). These studies provide novel empirical support for the claim that testosterone and cortisol jointly regulate risk-taking. Discussion focuses on putative mechanisms as well as implications for real-world risk-taking behaviors.

The Evolutionary Logic of the Obsessive Trait Complex: Obsessive Compulsive Personality Disorder as a Complementary Behavioral Syndrome

Freud noted that the obsessive traits of orderliness, parsimony, and obstinacy incontestably belonged together. This observation has been unfailingly justified, but unsatisfactorily explained. Being a highly heritable pattern essentially unaffected by parental influence, it is counterfactual to continue to explain the obsessive trait constellation as a pathological signature of harsh, authoritarian parenting. Alternatively, the present paper, building upon a previously promulgated evolutionary etiological model, describes how obsessive traits work in unison to enable survival within harsh northerly climates. What appears to be a loosely federated inventory of pathology, after the application of evolutionary reasoning, becomes a coherent behavioral package, adaptive suite, or behavioral syndrome. All three of these terms, taken from behavioral biology, suggest that traits strategically covary, such that the adaptive value of each trait is enhanced by the presence of the others. In this vein, the union of anxious tension and conscientiousness drives the obsessive personality to labor incessantly. The fruits of obsessive labor are then conserved through parsimoniousness, hoarding, vigilance, and niggardliness. And so, obsessive personality is a coherent behavioral package in that the drive to work towards the acquisition of necessities is paired with the drive to conserve and defend them.

Lower Cortisol Activity is Associated with First-Time Driving while Impaired

Driving while impaired (DWI) is a grave and persistent high-risk behavior. Previous work demonstrated that DWI recidivists had attenuated cortisol reactivity compared to non-DWI drivers. This suggests that cortisol is a neurobiological marker of high-risk driving. The present study tested the hypothesis that this initial finding would extend to first-time DWI (fDWI) offenders compared to non-DWI drivers. Male fDWI offenders (n = 139) and non-DWI drivers (n = 31) were exposed to a stress task, and their salivary cortisol activity (total output and reactivity) was measured. Participants also completed questionnaires on sensation seeking, impulsivity, substance use, and engagement in risky and criminal behaviors. As hypothesized, fDWI offenders, compared to non-DWI drivers, had lower cortisol reactivity; fDWI offenders also showed lower total output. In addition, cortisol activity was the most important predictor of group membership, after accounting for alcohol misuse patterns and consequences and other personality and problem behavior characteristics. The findings indicate that attenuated cortisol activity is an independent factor associated with DWI offending risk at an earlier stage in the DWI trajectory than previously detected.

"Frontal systems" behaviors in comorbid human immunodeficiency virus infection and methamphetamine dependency

Human immunodeficiency virus (HIV) infection and methamphetamine (MA) dependence are associated with neural injury preferentially involving frontostriatal circuits. Little is known, however, about how these commonly comorbid conditions impact behavioral presentations typically associated with frontal systems dysfunction. Our sample comprised 47 HIV-uninfected/MA-nondependent; 25 HIV-uninfected/MA-dependent; 36 HIV-infected/MA-nondependent; and 28 HIV-infected/MA-dependent subjects. Participants completed self-report measures of "frontal systems" behaviors, including impulsivity/disinhibition, sensation-seeking, and apathy. They also underwent comprehensive neurocognitive and neuropsychiatric assessments that allowed for detailed characterization of neurocognitive deficits and comorbid/premorbid conditions, including lifetime Mood and Substance Use Disorders, Attention-Deficit/Hyperactivity Disorder, and Antisocial Personality Disorder. Multivariable regression models adjusting for potential confounds (i.e., demographics and comorbid/premorbid conditions) showed that MA dependence was independently associated with increased impulsivity/disinhibition, sensation-seeking and apathy, and HIV infection with greater apathy. However, we did not see synergistic/additive effects of HIV and MA on frontal systems behaviors. Global neurocognitive impairment was relatively independent of the frontal systems behaviors, which is consistent with the view that these constructs may have relatively separable biopsychosocial underpinnings. Future research should explore whether both neurocognitive impairment and frontal systems behaviors may independently contribute to everyday functioning outcomes relevant to HIV and MA.

Superior temporal sulcus and social cognition in dangerous drivers

Understanding the neural systems underpinning social cognition is a primary focus of contemporary social neuroscience. Using functional magnetic resonance imaging (fMRI), the present study asked if brain activity reflecting socio-cognitive processes differs between individuals according to their social behavior; namely, between a group of drivers with frequent traffic offenses and a group with none. Socio-cognitive processing was elicited by employing videos from a traffic awareness campaign, consisting of reckless and anti-social driving behavior ending in tragic consequences, and control videos with analogous driving themes but without such catastrophic endings. We investigated whether relative increases in brain function during the observation of these campaign stimuli compared with control videos differed between these two groups. To develop the results of our previous study we focused our analyses on superior temporal sulcus/gyrus (STS/STG). This revealed a bigger increase in brain activity within this region during the campaign stimuli in safe compared with dangerous drivers. Furthermore, by thematically coding drivers' verbal descriptions of the stimuli, we also demonstrate differences in STS reactivity according to drivers' scores on two indices of socio-cognitive processing: subjects' perceived consequences of actors' actions, and their affective evaluation of the clips. Our results demonstrate the influence of social behavior and socio-cognitive processing on STS reactivity to social stimuli, developing considerably our understanding of the role of this region in social cognition.

Sensation seeking in major depressive patients: relationship to sub-threshold bipolarity and cyclothymic temperament

BACKGROUND

High levels of sensation seeking (SS) have been traditionally reported for lifetime bipolar disorder (BD) and/or substance use disorder (SUD) rather than major depressive disorder (MDD). Nonetheless, a renewed clinical attention toward the burden of sub-threshold bipolarity in MDD, solicits for a better assessment of "unipolar" major depressive episodes (MDEs) via characterization of putative differential psychopathological patterns, including SS and predominant affective temperament.

METHODS

Two hundred and eighty currently depressed cases of MDD and 87 healthy controls were screened using the Zuckerman's sensation seeking scale-Form-V, the Hypomania Check List-32-item (HCL-32), the Temperament Evaluation of Memphis, Pisa, Paris and San Diego Auto-questionnaire-110-item, the Barratt Impulsivity Scale-11-item, the State-Trait Anxiety Inventory modules and the Structured Clinical Interview for DSM-IV axis-I disorders. Cases were divided into HCL-32(+)(sub-threshold bipolar)/HCL-32(-)("true" unipolar depressed) depending on the HCL-32 total score.

RESULTS

Upon correlation and multivariate regression analyses, the HCL-32(+) patients showed the highest levels of SS, higher prevalence of cyclothymic temperament, and higher rates of multiple lifetime axis-I co-morbidities, including SUD.

LIMITS

Recall bias on some diagnoses, including BD, grossly matched healthy control group, lack of ad-hoc validated measures for ADHD, SUD, or axis-II disorders.

CONCLUSIONS

In our sample, the occurrence of higher levels of SS in "sub-threshold" bipolar cases outlined a differential psychopathological profile compared to DSM-defined "true unipolar" cases of MDE. If confirmed by replication studies, these findings may aid clinicians in delivering a more accurate diagnosis and a safer use of antidepressants in some MDD cases.

Neural correlates of personality: an integrative review

This review examines the neural correlates of Gray's model (Gray and McNaughton, 2000; McNaughton and Corr, 2004), supplemented by a fourth dimension: constraint (Carver, 2005). The purpose of this review is to summarize findings from fMRI studies that tap on neural correlates of personality aspects in healthy subjects, in order to provide insight into the neural activity underlying human temperament. BAS-related personality traits were consistently reported to correlate positively to activity of the ventral and dorsal striatum and ventral PFC in response to positive stimuli. FFFS and BIS-related personality traits are positively correlated to activity in the amygdala in response to negative stimuli. There is limited evidence that constraint is associated with PFC and ACC activity. In conclusion, functional MRI research sheds some light on the specific neural networks underlying personality. It is clear that more sophisticated task paradigms are required, as well as personality questionnaires that effectively differentiate between BAS, FFFS, BIS, and constraint. Further research is proposed to potentially reveal new insight in the neural subsystems governing basic human behavior.

Too little, too late or too much, too early? Differential hemodynamics of response inhibition in high and low sensation seekers

High sensation seeking is associated with strong approach behaviors and weak avoidance responses. The present study used functional magnetic resonance imaging (fMRI) to further characterize the neurobiological underpinnings of this behavioral profile using a Go/No-go task. Analysis of brain activation associated with response inhibition (No-go) versus response initiation and execution (Go) revealed the commonly reported right lateral prefrontal, insula, cingulate, and supplementary motor area network. However, right lateral activation was associated with greater No-go than Go responses only in low sensation seekers. High sensation seekers showed no differential activation in these regions but a more pronounced Go compared to No-go response in several other regions that are involved in salience detection (insula), motor initiation (anterior cingulate) and attention (inferior parietal cortex). Temporal analysis of the hemodynamic response for Go and No-go conditions revealed that the stronger response to Go than No-go trials in high sensation seekers occurred in in the earliest time window in the right middle frontal gyrus, right mid-cingulate and right precuneus. In contrast, the greater No-go than Go response in low sensation seekers occurred in the later time window in these same regions. These findings indicate that high sensation seekers more strongly attend to or process Go trials and show delayed or minimal inhibitory responses on No-go trials in regions that low sensation seekers use for response inhibition. Failure to engage such regions for response inhibition may underlie some of the risky and impulsive behaviors observed in high sensation seekers.