Use of slope and feature cues in pigeon (Columba livia) goal-searching behavior

Terrain slope provides a directional frame of reference for reorientation and navigation, similar to cardinal directions. Previous studies have shown that, in a goal location task, slope is a very salient cue and that pigeons tend to rely on it even if it is not the most informative cue. Such a strong dependence on one type of information, when there are more effective predictors of reward, is a key premise for a modular view of information processing. Here we tested the provocative hypothesis of a "slope module" for reorientation in slanted environments. Pigeons had to solve a goal location task using slope or another, theoretically salient cue: a beacon feature. Overall, searching behavior was controlled almost equally by the two cues. The fact that, for the first time, slope failed to capture most of the associative strength allows us to reject a strong modularity view and suggests instead that there is competition between cues based on salience. As an interesting additional finding, the reliance on slope and the feature was affected by training location (uphill vs. downhill), suggesting the possibility of a modulatory role of effort on the cue-weighting mechanism of reorientation.     

Social support, positive states of mind, and HIV treatment adherence in men and women living with HIV/AIDS.

Numerous studies have linked social support to better medication adherence among illness groups, but few have examined potential mechanisms for this relationship. Relationships were examined between social support, depression, positive states of mind (PSOM), and medication adherence among HIV positive men who have sex with men (n = 61) and women (n = 29) on highly active antiretroviral therapy. Depression and PSOM were evaluated as potential mediators of the relationship between support and adherence. Cross-sectional data showed that greater social support and PSOM related to better adherence whereas higher depression scores related to nonadherence. PSOM partially mediated the relationship between social support and adherence. PSOM may be an important mechanism through which social support is related to better medication adherence in this population.     

Cognitive-behavioral stress management increases free testosterone and decreases psychological distress in HIV-seropositive men.

The effects of a 10-week group-based cognitive-behavioral stress management (CBSM) intervention on psychological distress and plasma free testosterone in symptomatic, HIV-seropositive men were examined. Participants were randomized to either CBSM (n = 42) or a wait-list control group (n = 23). Men in the CBSM intervention showed significant increases in testosterone, whereas control participants showed significant decreases. Those participating in CBSM had significant distress reductions, whereas controls showed no such change. Alterations in free testosterone were inversely related to changes in distress states over time, independent of any changes in cortisol. These findings demonstrate that a short-term CBSM intervention increases free testosterone levels among symptomatic, HIV-seropositive men, and alterations in free testosterone are associated with changes in psychological distress observed during CBSM.     

Social Support Mediates Loneliness and Human Herpesvirus Type 6 (HHV-6) Antibody Titers

The current study investigated the impact of a severe environmental stressor and the role that declining social integration played in mediating its effect on loneliness and immune status. Increased loneliness and decreased social support in the months following the stressor (storm) were significantly associated with increased HHV-6 antibody liters, reflecting poorer control over the virus. Poorer social integration mediated the relationship between loneliness and HHV-6, even after controlling for nonspecific polyclonal B-cell activation, disease status (CD3+CD4+ cell counts), living arrangements, acute social losses (bereavement), and potential disruptions in social-support resources. These findings suggest that specific elements of social support may explain the oft-noted negative effects of loneliness on the immune system, and generalized to a medically vulnerable population.