Long-term executive function deficits in children with traumatic brain injuries: assessment using the Behavior Rating Inventory of Executive Function (BRIEF).

Long-term deficits in executive functions following childhood traumatic brain injuries (TBI) were examined using the Behavior Rating Inventory of Executive Function (BRIEF). Parents completed the BRIEF approximately 5 years postinjury as part of a prospective study of children injured between the ages of 6 and 12. The children were between 10 and 19 years of age at the time of the assessment, and included 33 with severe TBI, 31 with moderate TBI, and 34 with orthopedic injuries. Parents also rated children's adaptive functioning and completed several other measures of parent and family functioning. Children were administered a neuropsychological test battery that included several measures of executive functions. The groups displayed a significant linear trend in BRIEF scores, with the largest deficits in executive functions reported in children with severe TBI. BRIEF scores were related consistently across groups to a test of working memory, but not to other neuropsychological measures. BRIEF scores also predicted children's adaptive functioning and behavioral adjustment, as well as parent psychological distress, perceived family burden, and general family functioning. The findings indicate that TBI results in long-term deficits in executive functions that are related to children's psychosocial outcomes, as well as to parent and family functioning.     

Prevalence of suicidal ideation among boys and men assessed annually from ages 9 to 29 years

In a sample of 206 boys (90% Caucasian), self-reported suicidal ideation (SI; ages 12 to 29) and parent-reported youth suicidal talk (ages 9 to 20) were assessed annually by questionnaire. One-week point prevalence of self-reported SI ranged from 2.6% to 16.3%. New cases emerged across adolescence; by age 29, 57.3% self-reported SI at least once. SI was associated with clinically significant elevations on concurrent depressive symptoms. Nearly one quarter (24.8%) of parents reported suicidal talk by their son by age 20. Parent- and self-reports showed low correspondence. SI was more common than retrospective studies suggest. Parent-reports and one-time self-reports are likely to miss large numbers of adolescent boys who may be at risk.     

The influence of perceptual and semantic categorization on inhibitory processing as measured by the N2–P3 response

In daily activities, humans must attend and respond to a range of important items and inhibit and not respond to unimportant distractions. Our current understanding of these processes is largely based on perceptually simple stimuli. This study investigates the interaction of conceptual-semantic categorization and inhibitory processing using Event Related Potentials (ERPs). Participants completed three Go–NoGo tasks that increased systematically in the degree of conceptual-semantic information necessary to respond correctly (from single items to categories of objects and animals). Findings indicate that the N2 response reflects inhibitory processing but does not change significantly with task difficulty. The P3 NoGo amplitude, on the other hand, is attenuated by task difficulty. Further, the latency of the peak of the P3 NoGo response elicited by the most difficult task is significantly later than are the peaks detected during performance of the other two tasks. Thus, the level of complexity of conceptual-semantic representations influences inhibitory processing in a systematic way. This inhibition paradigm may be a key for investigating inhibitory dysfunction in patient populations.     

Causal perception of action-and-reaction sequences in 8- to 10-month-olds

Four experiments with 202 8- to 10-month-old infants studied their sensitivity to causation-at-a-distance in schematic events seen as goal-directed action and reaction by adults and whether this depends on attributes associated with animate agents. In Experiment 1, a red square moved toward a blue square without making contact; in “reaction” events blue moved away while red was approaching, whereas in “delay” events blue started after red stopped. Infants were habituated to one event and then tested on its reversal. Spatiotemporal features reversed for both events, but causal roles changed only in reversed reactions. Infants dishabituated more to reversed reaction events than to reversed delay events. Squares moved rigidly or in a nonrigid animal-like fashion. Infants discriminated these, but motion pattern did not affect responses to reversal. Infants also discriminated reactions from launching and dishabituated to reversed reactions lacking self-initiated motion. These results suggest that sensitivity to causation-at-a-distance depends on the event structure but not pattern or onset typical of animal motion.     

ONE ENCHANTED BEING: NEUROEXISTENTIALISM AND MEANING

The Really Hard Problem: Meaning in a Material World is my attempt to explain whether and how existential meaning is possible in a material world, and how such meaning is best conceived naturalistically. Neuroexistentialism conceives of our predicament in accordance with Darwin plus neuroscience. The prospects for our kind of being-in-the-world are limited by our natures as smart but fully embodied short-lived animals. Many find this picture disenchanting, even depressing. I respond to four criticisms of my relentless upbeat naturalism: that naturalism can make no room for norms, for values; that I overvalue truth at the expense of happiness; that I underestimate the extent to which supernaturalism has made peace with naturalism; and that I can give no account for why humans as finite animals should want to overcome our given natures and seek impersonal, self-transcendent value.     

Are animal models predictive for humans?

It is one of the central aims of the philosophy of science to elucidate the meanings of scientific terms and also to think critically about their application. The focus of this essay is the scientific term predict and whether there is credible evidence that animal models, especially in toxicology and pathophysiology, can be used to predict human outcomes. Whether animals can be used to predict human response to drugs and other chemicals is apparently a contentious issue. However, when one empirically analyzes animal models using scientific tools they fall far short of being able to predict human responses. This is not surprising considering what we have learned from fields such evolutionary and developmental biology, gene regulation and expression, epigenetics, complexity theory, and comparative genomics.