Right-sided human prefrontal brain activation during acquisition of conditioned fear

This H2(15)O positron emission tomography (PET) study reports on relative regional cerebral blood flow (rCBF) alterations during fear conditioning in humans. In the PET scanner, subjects viewed a TV screen with either visual white noise or snake videotapes displayed alone, then with electric shocks, followed by final presentations of white noise and snakes. Autonomic nervous system responses confirmed fear conditioning only to snakes. To reveal neural activation during acquisition, while equating sensory stimulation, scans during snakes with shocks and white noise alone were contrasted against white noise with shocks and snakes alone. During acquisition, rCBF increased in the right medial frontal gyrus, supporting a role for the prefrontal cortex in fear conditioning to unmasked evolutionary fear-relevant stimuli.     

Increasing social initiations in children with autism: effects of a tactile prompt

An ABAB design was used to assess the effects of a tactile prompting device (i.e., a vibrating pager) as a prompt for the social initiations of 3 children with autism during free-play activities with typically developing peers. Results indicated that the tactile prompt was effective in increasing verbal initiations for all 3 children, and responses to peers' initiations were higher for 2 participants when the tactile prompt was used. Efforts to reduce the frequency of prompts while still maintaining rates of initiations were partially successful for 1 participant.     

Young adult follow-up of hyperactive children: self-reported psychiatric disorders,comorbidity, and the role of childhood conduct problems and teen CD

We report on the psychiatric disorders present at young adult follow-up (Mean age 20–21 years; 13 + year follow-up) and the comorbidity among them for a large sample of hyperactive (H; N = 147) and community control (CC; N = 71) children. The H group had a significantly higher risk for any nondrug psychiatric disorders than the CC group (59% vs. 36%). More of the H group met criteria for ADHD (5%); major depressive disorder (26%); and histrionic (12%), antisocial (21%), passive–aggressive (18%), and borderline personality disorders (14%) at follow-up than the CC group. Severity of childhood conduct problems contributed to the risk for passive–aggressive, borderline, and antisocial personality disorders. But it only affected risk for antisocial personality after controlling for severity of teen conduct disorder (CD), which also contributed to the risk for these same 3 disorders. Examination for comorbidity among these disorders indicated that presence of either borderline or antisocial personality disorder significantly increased the risk for major depression and the other significant personality disorders. More of the hyperactive group had received various forms of mental health treatment during and since leaving high school than the control group. Results suggest that hyperactive children are at significant risk for at least 1 nondrug disorder in young adulthood, principally major depression and several personality disorders, and that this risk is largely mediated by severity of CD at adolescence.     

Coauthorship in physics

In a large and detailed survey on the ethics of scientific coauthorship, members of the American Physical Society (APS) were asked to judge the number of appropriate coauthors on his or her last published paper. Results show that the first or second coauthor are more appropriate than later coauthors about whom there is equal and considerable doubt. The probability of any third and subsequent coathors being judged as inappropriate is 23% for the APS guideline, 67% for the tighter guideline of the International Committee of Medical Journal Editors, 59% if the guideline requires “direct contributions to scientific discovery or invention”. Only 3% of respondents report having personally rejected an undeserving scientist who expected to be an author on the last published paper. Respondents seem to be divided into two non-overlapping populations—those who report no inappropriate coauthorship and those who have a more graduated view.     

Selective reaching: evidence for multiple frames of reference

Students participated in 3 experiments investigating the use of environment- and action-centered reference frames in selective reaching. They pointed to a green target appearing either with or without a red distractor. Target-distractor distance was manipulated, and distractor interference (difference between distractor trials and no-distractor trials) was measured in reaction time, movement time, and movement endpoint. Target-distractor distance determined the dominant frame of reference. Small distances evoked an environment-centered framework that encoded targets within an external context. Large distances evoked an action-centered framework that encoded targets relative to the start position of the hand. Results support the hypothesis that the brain represents spatial information in multiple frames of reference, with the dominant frame of reference being dependent on the task demands.     

The same but different: an empirical investigation of the reducibility principle

According to classical utility theory the valuation of any lottery should depend only on its outcomes and their respective probabilities, and should not be affected by the nature, complexity and structure of the chance mechanism. Previous research has documented systematic violations of this principle. For example, most subjects prefer lotteries in which the payoffs are contingent on the joint occurrence of multiple (high probability) events to simple lotteries, and lotteries in which the earlier stages offer higher probabilities than the later stages. We review the various violations of this principle and suggest a classification into two major types associated with misunderstanding of chance mechanisms and attitude towards the chance mechanism and process. In the present study 40 subjects were presented with 30 pairs of binary gambles. In any given pair the lotteries had identical outcomes and equal ‘reduced’ probabilities (and thus equal expected values). However, the chance mechanisms varied along a variety of factors such as the size of the sample space, the number of stages, temporal ordering, order of probabilities, their transparency and time constraints. Half the subjects saw lotteries involving gains and the other half considered only losses. After choosing one lottery in each pair, the subjects were asked to explain and justify their choices. The findings revealed systematic violations of the reducibility principle: subjects displayed a preference for lotteries with larger sample spaces, and for lotteries that allow quicker resolutions in the earlier stages. A clear distinction between some patterns of preferences in the gains and loss domains was revealed. In gambles involving gains subjects preferred to have the highest probability on the first stage (and the lowest probability on the last stage), but displayed the opposite preferences for losses. A content analysis of the subjects' stated reasons for their choices identified eight major categories. The most frequently invoked were hope, fun, simplicity, stress and time. Copyright © 2001 John Wiley & Sons, Ltd.     

The Role of Network Support and Interference in Women's Perception of Romantic,Friend, and Parental Relationships

This study examined the association between support/interference from the best friend and closest parent to women's (a) satisfaction with the parent–daughter relationship, (b) satisfaction with the friendship, and (c) love for the romantic partner. The respondents (n = 162 females; 84% Caucasian, 1% Asian American, 10% Hispanic, 4% African American, and 1% Multiracial) completed a questionnaire packet to assess each of the factors. Results revealed that romantic love was unrelated to friend support, friend interference, or parental interference, but positively related to parental support. Parent support was a significant correlate of parent satisfaction, and a similar pattern emerged between friend support/friendship satisfaction. Further, best friend support moderated the relationship between friend interference and friendship satisfaction, such that interference was negatively related to satisfaction in low support conditions. Overall, the results suggested that network reactions to romance played a limited role in romantic affection, but were more strongly associated with network satisfaction.     

On the validity and utility of discriminating among impulsivity-like traits

The ability to make precise distinctions among related personality constructs helps clarify theory and increases the utility of clinical assessment. In three studies, the authors evaluated the validity of distinctions among four impulsivity-like traits: sensation seeking, lack of planning, lack of persistence, and urgency (acting rashly when distressed). Factor analyses indicated that lack of planning and lack of persistence are two distinct facets of one broader trait, whereas urgency and sensation seeking are both very modestly related to each other and to the planning/persistence measures. The authors developed interview assessments of each, and multitrait, multimethod matrix results indicated clear convergent and discriminant validity among the constructs. The distinctions among them were useful: The traits accounted for different aspects of risky behaviors. Sensation seeking appeared to relate to the frequency of engaging in risky behaviors, and urgency appeared to relate to problem levels of involvement in those behaviors.     

Brain activation while forming memories of fearful and neutral faces in women and men

Event-related functional MRI (fMRI) was used to assess brain activity during encoding of fearful and neutral faces in 12 women and 12 men. In a subsequent memory analysis, the authors separated successful from unsuccessful encoding of both types of faces, based on whether they were remembered or forgotten in a later recognition memory test. Overall, women and men recruited overlapping neural circuitries. Both sexes activated right-sided medial-temporal regions during successful encoding of fearful faces. Successful encoding of neutral faces was associated with left-sided lateral prefrontal and right-sided superior frontal activation in both sexes. In women, relatively greater encoding related activity for neutral faces was seen in the superior parietal and parahippocampal cortices. By contrast, men activated the left and right superior/middle frontal cortex more than women during successful encoding of the same neutral faces. These findings suggest that women and men use similar neural networks to encode facial information, with only subtle sex differences observed for neutral faces.