Dual-tasking alleviated sleep deprivation disruption in visuomotor tracking: an fMRI study

Effects of dual-responding on tracking performance after 49-h of sleep deprivation (SD) were evaluated behaviorally and with functional magnetic resonance imaging (fMRI). Continuous visuomotor tracking was performed simultaneously with an intermittent color-matching visual detection task in which a pair of color-matched stimuli constituted a target and non-matches were non-targets. Tracking error means were binned time-locked to stimulus onset of the detection task in order to observe changes associated with dual-responding by comparing the error during targets and non-targets. Similar comparison was made with fMRI data. Our result showed that despite a significant increase in the overall tracking error post SD, from 20 pixels pre SD to 45 pixels post SD, error decreased to a minimum of about 25 pixels 0-6s after dual-response. Despite an overall reduced activation post SD, greater activation difference between targets and non-targets was found post SD in task-related regions, such as the left cerebellum, the left somatosensory cortex, the left extrastriate cortex, bilateral precuneus, the left middle frontal gyrus, and the left motor cortex. Our results suggest that dual-response helps to alleviate performance impairment usually associated with SD. The duration of the alleviation effect was on the order of seconds after dual-responding.     

Does anxiety sensitivity correlate with startle habituation? An examination in two independent samples

Individuals with anxiety disorders have previously demonstrated abnormal habituation to aversiveness over time. As anxiety sensitivity (AS), or an individuals' propensity to fear of anxiety-related sensations, has been shown to be a risk factor for anxiety disorders (particularly panic disorder), the present study examined whether AS was also associated with abnormal habituation. This association was examined in two independent samples of undergraduates (N_total=178). Habituation was operationalised as the reduction in startle response to multiple startle probes presented over 2.5 minutes and three definitions of this reduction were employed. Results indicated that individuals with higher levels of AS evidenced deficits in startle habituation, but the strength of this relationship was somewhat dependent on the definition of startle habituation, with the most robust definition being an analysis of participants' individual slopes across all nine blinks. The present findings suggest that startle habituation is a key mechanism underlying AS, and may help elucidate the role this risk factor plays in the pathogenesis of anxiety disorders.     

Are individual differences in appetitive and defensive motivation related? A psychophysiological examination in two samples

Appetitive and defensive motivation account for a good deal of variance in personality and mental health, but whether individual differences in these systems are correlated or orthogonal has not been conclusively established. Previous investigations have generally relied on self-report and have yielded conflicting results. We therefore assessed the relation between psychophysiological indices of appetitive and defensive motivation during elicitation of these motivational states: specifically, frontal electroencephalogram asymmetry during reward anticipation and startle response during anticipation of predictable or unpredictable threat of shock. Results in a sample of psychopathology-free community members (n=63), an independent sample of undergraduates with a range of internalising symptoms (n=64), and the combination of these samples (n=127) revealed that differences in responding to the two tasks were not significantly correlated. Average coefficients approached zero in all three samples (community: .04, undergraduate: ?.01, combined: .06). Implications of these findings for research on normal and abnormal personality are discussed.     

The Mother Teresa Effect: Counterproductive Effects of Touching an Altruist’s Possessions on Charitable Giving

Charities that recruit famous humanitarians, or obtain celebrity endorsements, may promote products associated with these altruistic superstars in an effort to increase donations. Previous research supports that “superstar” role models can promote desirable behavior. Charitable organizations may assume if people handle a product associated with a famous humanitarian, they will be inspired and more motivated to donate as a result. An opposite possibility is that physically handling reminders of an extreme altruist may result in contrast effects. Such positive exemplars may result in more negative perceptions of one’s own charitable behavior, and decrease the perceived efficacy of one’s own contributions. In two studies, participants did or did not touch items said to have belonged to a very altruistic person (Experiment 1) or to Mother Teresa (Experiment 2). Compared to participants in non-touch and other control conditions, those who physically touched items said to belong to an altruist subsequently donated fewer raffle tickets to charity. The results are related to theories of perceived efficacy, metacognitive processes, and the counterproductive influence of extremely positive role models.     

Adaptive Coping Reduces the Impact of Community Violence Exposure on Violent Behavior among African American and Latino Male Adolescents

This study examined whether coping moderated the impact of community violence exposure (CVE) on violent behavior among 285 urban African American and Latino adolescent males assessed annually across 5 years. Composites indicating overall CVE (having knowledge of others’ victimization, witnessing violence, direct victimization) and approach to coping with CVE were created by averaging across years 1–3 (Time 1; mean ages 14–16). Adolescents classified as coping effectively tended to respond to CVE in beneficial ways (e.g., developing long-term solutions, engaging in positive reappraisal). Violent behavior was examined across years 1–3 (Time 1) and years 4–5 (Time 2; mean ages 18–19). CVE was longitudinally associated with greater violent behavior, adjusting for Time 1 levels of violent behavior. This association was significant only among adolescents with less effective coping strategies. Interventions targeting the enhancement of coping skills may be an effective method of reducing the impact of CVE on adolescent violent behavior. Sonya S. Brady is now an Assistant Professor in the Division of Epidemiology and Community Health, School of Public Health at the University of Minnesota (1300 South Second Street, Suite 300, Minneapolis, MN 55454-1015, USA; Tel.: +1-612-6241818; Fax: +1-612-6240315.     

Neuropsychological profile following suicide attempt by hanging: two adolescent case reports.

Hippocampal damage and amnesia following hypoxia and ischemia are described in the few published adult cases of suicide attempt by hanging. However, a recent review (Caine & Watson, 2000) suggests a variable pattern of brain involvement and neuropsychological impairments following hypoxic-ischemic injury that may or may not involve amnesia. To help clarify the impact of hanging on the developing brain, we examined neuropsychological functioning in two adolescents who survived suicide attempt by hanging. Despite differences in Glasgow Coma Scale (GCS), coma duration, and structural imaging findings, both patients had similar IQ (VIQ>PIQ) and presented with various combinations of deficits in expressive/receptive language, visual-constructional and perceptual ability, processing speed, attention, working memory, and/or executive functioning shortly after injury. In spite of their similarities, only one of the patients presented with classic amnesia symptoms in his early recovery. This patient was evaluated 1 year postinjury, and persistent deficits in processing speed and memory encoding were noted. Several hanging-related variables, including longer estimated hanging duration, greater weight, and severe airway edema, were thought to place this patient at increased risk for cognitive deficits. Clinical MRI scans of this patient obtained 6 weeks postinjury revealed mild volume loss as well as abnormalities in bilateral superior cortex. However, CT and MRI scans obtained throughout early recovery did not reveal overt evidence of injury to specific memory-related structures. Comprehensive neuropsychological evaluation of all adolescent survivors of suicide attempt by hanging is recommended, as a variety of postacute cognitive deficits were observed in these patients despite relatively short (相似文献