Associations between cortical thickness and general intelligence in children,adolescents and young adults

Neuroimaging research indicates that human intellectual ability is related to brain structure including the thickness of the cerebral cortex. Most studies indicate that general intelligence is positively associated with cortical thickness in areas of association cortex distributed throughout both brain hemispheres. In this study, we performed a cortical thickness mapping analysis on data from 182 healthy typically developing males and females ages 9 to 24 years to identify correlates of general intelligence (g) scores. To determine if these correlates also mediate associations of specific cognitive abilities with cortical thickness, we regressed specific cognitive test scores on g scores and analyzed the residuals with respect to cortical thickness. The effect of age on the association between cortical thickness and intelligence was examined. We found a widely distributed pattern of positive associations between cortical thickness and g scores, as derived from the first unrotated principal factor of a factor analysis of Wechsler Abbreviated Scale of Intelligence (WASI) subtest scores. After WASI specific cognitive subtest scores were regressed on g factor scores, the residual score variances did not correlate significantly with cortical thickness in the full sample with age covaried. When participants were grouped at the age median, significant positive associations of cortical thickness were obtained in the older group for g-residualized scores on Block Design (a measure of visual-motor integrative processing) while significant negative associations of cortical thickness were observed in the younger group for g-residualized Vocabulary scores. These results regarding correlates of general intelligence are concordant with the existing literature, while the findings from younger versus older subgroups have implications for future research on brain structural correlates of specific cognitive abilities, as well as the cognitive domain specificity of behavioral performance correlates of normative gray matter thinning during adolescence.     

The Mechanisms of Space‐Time Association: Comparing Motor and Perceptual Contributions in Time Reproduction

The spatial‐temporal association indicates that time is represented spatially along a left‐to‐right line. It is unclear whether the spatial‐temporal association is mainly related to a perceptual or a motor component. In addition, the spatial‐temporal association is not consistently found using a time reproduction task. Our rationale for this finding is that, classically, a non‐lateralized button for performing the task has been used. Using two lateralized response buttons, the aim of the study was to find a spatial‐temporal association in a time reproduction task. To account for the perceptual component, reference and target stimuli were presented in different spaces through four experiments. In all experiments, a Spatial‐Temporal Association of Response Codes (STEARC) effect was found and this effect was not modulated by the spatial position of both reference and target stimuli. The results suggested that the spatial‐temporal association was mainly derived from the spatial information provided by response buttons, reflecting a motor but not visuospatial influence.     

Perceptual and motor congruency effects in time–space association

It is well established that temporal events are represented on a spatially oriented mental time line from left to right. Depending on the task characteristics, the spatial representation of time may be linked to different types of dimensions, including manual response codes and physical space codes. The aim of the present study was to analyze whether manual response and physical space codes are independent of each other or whether they interact when both types of information are involved in the task. The participants performed a temporal estimation task with two lateralized response buttons in four experiments. In the first experiment, the target stimuli were presented on the left side, at the center, or on the right side of the space, whereas the reference stimuli were always presented centrally. The reverse situation was presented in the second experiment. In the third experiment, both stimuli were presented in opposite spatial positions (e.g., left–right), whereas in the last experiment, both stimuli were presented in the same spatial position (e.g., left–left). In all experiments, perceptual and motor congruency effects were found, but no modulation of the congruency effects was found when both the perceptual and motor components were congruent. The results indicated that physical, spatial, and manual response codes are independent from each other for time–space associations, even when both codes are involved in the task. These results are discussed in terms of the “intermediate-coding” account.     

Psychiatric chrono‐epidemiology: its relevance for the study of aggression

Chrono‐epidemiology is the study of the distribution of health events according to time. The time intervals taken into account have cyclic patterns and include circadian, weekly, seasonal, and circannual rhythms. In the behavioural field, chrono‐epidemiology can be and has been applied to studies concerning the causes of death (suicide and homicide), clinical events such as admissions to and contacts with mental healthcare services, and the seasonal distribution of crime involving the use of violence. Frequently reported findings include clear circadian and seasonal rhythms present in the phenomenon of suicide (rhythms more evident in the case of violent suicide); seasonal rhythms in the expression of aggression by patients hospitalised for mental illness; and a circannual recurrence of crimes with a violent component. The intrinsic circadian and seasonal rhythms of some neuronal systems, particularly those of serotonin, involved in the control of mood and impulses, are thought to favour the behavioural rhythms observed, although the contribution of socio‐environmental factors, such as the fluctuation of supportive networks according to time, is also acknowledged. By demonstrating non‐casual recurrence of certain behaviour and by exploring the socio‐biological basis of the rhythms beneath these recurrences, chrono‐epidemiology may offer important etiologic and preventive clues to the understanding of the biological and environmental correlates of aggressive behaviour. Aggr. Behav. 28:477–490, 2002. © 2002 Wiley‐Liss, Inc.     

Crisis Support and Coping as Mediators of Well-Being in Persons with Spinal Cord Lesion

This study aims to investigate whether crisis support and coping mediate symptoms of posttraumatic stress disorder (PTSD) in individuals with spinal cord lesions (SCL). PTSD, crisis support, and coping were assessed an average of 83 days after the injury (T1), at discharge from the rehabilitation center (T2), and an average of 121 days following discharge (T3). Sixty-nine newly injured paraplegics and tetraplegics completed the questionnaire at T1, 40 (58%) at T2, and 38 (55%) at T3. Individuals with PTSD experienced significantly lower levels of social support, and used more emotional coping than did those without PTSD. On the basis of logistic regression analyses, emotional coping and the interaction between negative response and emotional coping predicted PTSD. Emotional coping is a strong predictor of PTSD in persons with new SCL.     

Expectancy priming of smoking cessation messages enhances the placebo effect of tailored interventions.

OBJECTIVE: Previous research (Webb, Simmons, & Brandon, 2005) suggested that smokers' reactions to self-help materials were more positive if they believed that the materials had been personally tailored to their individual characteristics and if they held expectancies that tailored interventions are superior to standard, or generic, interventions. The authors' objective in the current study was to replicate and extend this research by testing the efficacy expectancy priming before intervention delivery. DESIGN: In a 2 x 2 factorial experiment, 210 smokers (M = 23 cigarettes/day) recruited from the community (62% female; 92% Caucasian; mean age = 49) were randomly assigned to 1 of 4 conditions: placebo-tailored intervention/no priming, placebo-tailored intervention/priming, standard intervention/no priming, or standard intervention/priming. The tailoring-related expectancies of participants' in the priming conditions were primed before they were presented with the respective intervention booklets. MAIN OUTCOME MEASURES: Content evaluations, readiness to quit smoking, cessation self-efficacy, smoking-related knowledge, and progress toward quitting (behavior changes). Assessments occurred by mail at baseline and at 1-month postintervention. RESULTS: Similar to the earlier study, the placebo-tailored booklets produced superior evaluations and smoking-related cognitive and behavioral changes. Moreover, the pretreatment expectancy priming successfully altered participants' tailoring-related expectancies and also produced superior evaluations and outcomes. CONCLUSION: Findings support a causal role of tailoring-related expectancies on the efficacy of tailored interventions and suggest that interventions can be enhanced via expectancy priming.