Overt attempts to change hand preference: a study of group and individual characteristics

Previous work by Porac, Coren, and Searleman (1986) looked at overt attempts to change hand preference from the left to the right side. We extended this research by studying individuals who shifted their handedness from the left to the right side as well as a group who attempted a shift in the opposite direction (right to left). Comparisons of the two shift attempts revealed that the timing, method, and agent of change differed significantly for right versus left shifts. More right than left shifts were successful. Overall, most shift attempts were rated as unsuccessful because they did not result in a handedness classification consistent with the direction of the shift. Individuals classified as successful shifters, whether in the right or left direction, displayed a more ambihanded behavioural pattern than either unsuccessful shifters or the no shift control group. Evidence suggested that left-shift attempts were promoted by original ambihanded tendencies but that ambihandedness in successful right shifts stemmed from the partial success of the switch attempt.     

Patterns of neuronal activation in the rat brain and spinal cord in response to increasing durations of restraint stress

By most accounts the psychological stressor restraint produces a distinct pattern of neuronal activation in the brain. However, some evidence is incongruous with this pattern, leading us to propose that the restraint-induced pattern in the central nervous system might depend on the duration of restraint used. We therefore determined the pattern of neuronal activation (as indicated by the presence of Fos protein) seen in the paraventricular nucleus (PVN), bed nucleus of the stria terminalis, amygdala, locus coeruleus, nucleus tractus solitarius (NTS), ventrolateral medulla (VLM) and thoracic spinal cord of the rat in response to 0, 15, 30 or 60 min periods of restraint. We found that although a number of cell groups displayed a linear increase in activity with increasing durations of restraint (e.g. hypothalamic corticotrophin-releasing factor (CRF) cells, medial amygdala neurons and sympathetic preganglionic neurons of the thoracic spinal cord), a number of cell groups did not. For example, in the central amygdala restraint produced both a decrease in CRF cell activity and an increase in non-CRF cell activity. In the locus coeruleus, noradrenergic neurons did not display Fos in response to 15 min of restraint, but were significantly activated by 30 or 60 min restraint. After 30 or 60 min restraint a greater degree of activation of more rostral A1 noradrenergic neurons was observed compared with the pattern of A1 noradrenergic neurons in response to 15 min restraint. The results of this study demonstrate that restraint stress duration determines the amount and the pattern of neuronal activation seen in response to this psychological stressor.     

The central nucleus of the amygdala; a conduit for modulation of HPA axis responses to an immune challenge?

Physical stressors such as infection, inflammation and tissue injury elicit activation of the hypothalamic-pituitary-adrenal (HPA) axis. This response has significant implications for both immune and central nervous system function. Investigations in rats into the neural substrates responsible for HPA axis activation to an immune challenge have predominantly utilized an experimental paradigm involving the acute administration of the pro-inflammatory cytokine interleukin- 1β (IL-1β). It is well recognized that medial parvocellular corticotrophin-releasing factor cells of the paraventricular nucleus (mPVN CRF) are critical in generating HPA axis responses to an immune challenge but little is known about how peripheral immune signals can activate and/or modulate the mPVN CRF cells. Studies that have examined the afferent control of the mPVN CRF cell response to systemic IL-1β have centred largely on the inputs from brainstem catecholamine cells. However, other regulatory neuronal populations also merit attention and one such region is a component of the limbic system, the central nucleus of the amygdala (CeA). A large number of CeA cells are recruited following systemic IL-lβ administration and there is a significant body of work indicating that the CeA can influence HPA axis function. However, the contribution of the CeA to HPA axis responses to an immune challenge is only just beginning to be addressed. This review examines three aspects of HPA axis control by systemic IL-1β: (i) whether the CeA has a role in generating HPA axis responses to systemic IL-1β, (ii) the identity of the neural connections between the CeA and mPVN CRF cells that might be important to HPA axis responses and(iii) the mechanisms by which systemic IL-Iβ triggers the recruitment of CeA cells.     

Does Participation Affect Deception Success?

Communication episodes may range from highly interactive to noninteractive. The principle of interactivity refers to the constellation of structural and experiential features associated with interactivity that systematically affect communication processes and outcomes. One such feature is degree of participation. In deceptive interchanges, senders may engage in dialogic (high participation, two‐way) or monologic (low participation, one‐way) communication. According to the principle of interactivity, dialogue should advantage deceivers relative to monologue due to increased mutuality between sender and receiver and greater opportunities for deceivers to improve their performance over time. An experiment in which friends or strangers alternated between deceiving and telling the truth to a partner under dialogue or monologue conditions tested this principle. All hypotheses received some support. Relative to monologue, dialogue created more mutuality among strangers. Dialogue also enabled deceivers to better manage their informational content, speech fluency, nonverbal demeanor, and image, resulting in less accurate deception detection by partners. These results support the interactivity principle and interpersonal deception theory, from which the principle emanated.     

Mediation of a middle school skin cancer prevention program.

This study tested potential mediators of a school-based skin cancer prevention intervention for middle school children (6th-8th grades; N = 1,788). Ten variables were tested on 4 criteria to establish mediation, including (a) intervention related to outcome, (b) intervention related to mediators, (c) mediators related to outcome, and (d) mediated effect statistically significant. Sun-safe behaviors (e.g., sunscreen use) and potential mediators were measured with a self-report questionnaire. All criteria were met for Barriers--Sunscreen, Perceived Self-Efficacy, and Knowledge when the mediators were tested separately. In multiple mediator analyses, barriers to sunscreen use and self-efficacy satisfied Criteria 1-3 but were not statistically significant (Criterion 4). Barriers to sunscreen use, perceived self-efficacy for sun-safe behavior, and knowledge may serve as mediators.     

Neuroimmune stress responses: reciprocal connections between the hypothalamus and the brainstem

Hypothalamic nuclei, particularly the paraventricular nuclei (PVN), are important brain sites responsible for eliciting stress responses following a systemic immune challenge. The activation of PVN cells by a systemic immune challenge is critically dependent on the integrity of inputs from brainstem cells situated in the nucleus tractus solitarius (NTS) and ventrolateral medulla (VLM). Interestingly, a descending pathway from the PVN to the brainstem, recruited by systemic immune challenge, might also exist. It is well documented that PVN neurons innervate the NTS and VLM and recent evidence from our laboratory shows that lesions of the PVN reduce brainstem cell responses elicited by a systemic bolus of the proinflammatory cytokine interleukin-1beta (IL-1beta). Although a number of different PVN divisions are candidates for the source of inputs to the brainstem, we have demonstrated that the majority of descending PVN projections recruited by systemic IL-1beta arise from cell bodies localized in the medial and lateral parvocellular PVN. These findings suggest that central nervous system responses to an immune challenge are likely to involve complex reciprocal connections between the PVN and the brainstem, whereby brainstem cell populations could essentially act as integratory sites for descending and ascending immune signals. For instance, these brainstem pathways may have significant implications not only for the regulation of central hypothalamic and extra-hypothalamic targets but also the autonomic nervous system.     

The mediation of mothers' self-fulfilling effects on their children's alcohol use: self-verification, informational conformity, and modeling processes

This research examined whether self-fulfilling prophecy effects are mediated by self-verification, informational conformity, and modeling processes. The authors examined these mediational processes across multiple time frames with longitudinal data obtained from two samples of mother-child dyads (N-sub-1 = 486; N-sub-2 = 287), with children's alcohol use as the outcome variable. The results provided consistent support for the mediational process of self-verification. In both samples and across several years of adolescence, there was a significant indirect effect of mothers' beliefs on children's alcohol use through children's self-assessed likelihood of drinking alcohol in the future. Comparatively less support was found for informational conformity and modeling processes as mediators of mothers' self-fulfilling effects. The potential for self-fulfilling prophecies to produce long-lasting changes in targets' behavior via self-verification processes are discussed.