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.     

Blockade of nucleus basalis magnocellularis or activation of insular cortex histamine receptors disrupts formation but not retrieval of aversive taste memory

Recent research, using several experimental models, demonstrated that the histaminergic system is clearly involved in memory formation. This evidence suggested that during different associative learning tasks, histamine receptor subtypes have opposite functions, related to the regulation of cortical cholinergic activity. Given that cortical cholinergic activity and nucleus basalis magnocellularis (NBM) integrity are needed during taste memory formation, the aim of this study was to determine the role of histamine receptors during conditioned taste aversion (CTA). We evaluated the effects of bilateral infusions of 0.5 μl of pyrilamine (100 mM), an H₁ receptor antagonist, into the NBM, or of R-α-methylhistamine (RAMH) (10 mM), an H₃ receptor agonist, into the insular cortex of male Sprague-Dawley rats 20 min before acquisition and/or retrieval of conditioned taste aversion. The results showed that blockade of H₁ receptors in NBM or activation of H₃ receptors in the insular cortex impairs formation but not retrieval of aversive taste memory. These results demonstrated differential roles for histamine receptors in two important areas for taste memory formation and suggest that these effects could be related with the cortical cholinergic activity modulation during CTA acquisition.     

Examining the relationship between use of sexually explicit media and sexual risk behavior in a sample of men who have sex with men in Norway

The purpose of this study was to investigate consumption patterns of gay‐oriented sexually explicit media (SEM) among men who have sex with men (MSM) in Norway, with a particular emphasis on a possible relationship between gay SEM consumption and HIV risk behavior. Participants included 529 MSM living in Norway recruited online to complete a SEM consumption and sexual risk survey. Of the 507 participants who responded to the all items measuring exposure to SEM, 19% reported unprotected anal intercourse with a casual partner (UAI) in last 90 days, and 14% reported having had sero‐discordant UAI. Among those with UAI experience, 23% reported receptive anal intercourse (R‐UAI) and 37% reported insertive anal intercourse (I‐UAI). SEM consumption was found to be significantly associated with sexual risk behaviors. Participants with increased consumption of bareback SEM reported higher odds of UAI and I‐UAI after adjusting for other factors using multivariable statistics. MSM who started using SEM at a later age reported lower odds of UAI and I‐UAI than MSM who started earlier. Future research should aim at understanding how MSM develop and maintain SEM preferences and the relationship between developmental and maintenance factors and HIV sexual risk behavior.     

Online response-selection and the attentional blink: Multiple-processing channels

Robust interference often arises when multiple targets (T1 and T2) are discriminated in rapid succession (the attentional blink or AB). The AB has been observed for a wide range of stimuli, and is often thought to reflect a central capacity limitation in working memory consolidation, attentional engagement, and/or online response selection. However, recent evidence challenges the existence of unitary bottleneck during postperceptual processing. Awh et al. (2004 Awh, E., Serences, J., Laurey, P., Dhaliwal, H., van der Jagt, T. and Dassonville, P. 2004. Evidence against a central bottleneck during the attentional blink: Multiple channels for configural and featural processing. Cognitive Psychology, 48(1): 95–126.  [Google Scholar]) found no AB interference when a digit target preceded a face target, presumably because these stimuli could be processed by means of separable processing channels. Using a modified AB procedure, recent studies have also demonstrated that speeded response selection of T1 leads to an AB effect for T2 identification, supporting the conclusion that response selection induces the same processing limitations that typically gives rise to an AB. The present research tests this hypothesis by examining the effects of response selection on the identification of faces. Although we replicated previous demonstrations that online response selection of a digit disrupts the identification of T2 letters, we found no interference in the identification of T2 faces. However, robust AB interference was once again observed when a speeded response to a T1 face was required, confirming that faces are not simply immune to central interference. These results dispute the existence of a unitary postperceptual capacity limitation that gives rise to the AB.     

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.     

Cognitive content-specificity in future expectancies: role of hopelessness and intolerance of uncertainty in depression and GAD symptoms

The present study examined cognitive content-specificity in future-event predictions associated with symptoms of depression and generalized anxiety disorder (GAD). College undergraduates (N=284) completed measures of depression, GAD, and rated their certainty that a given set of positive and negative outcomes were or were not likely to happen in their future. Participants also completed measures of hopelessness and intolerance of uncertainty (IU). Individuals (N=263) completed the same measures again 6 weeks later. Certainty in an absence of positive future outcomes was associated with symptoms of depression but not GAD, and hopelessness mediated this relationship - concurrently and when examining change scores over 6 weeks. Certainty in negative outcomes was concurrently associated with both symptoms of depression and GAD, and hopelessness partially mediated these relationships. IU predicted concurrent increases in depression and GAD symptoms, and negative-outcome certainty partially mediated the IU-depression but not the IU-GAD symptom relationship. Change in certainty did not mediate the relationship between changes in IU and GAD symptoms but partially mediated the relationship between change in IU and depression symptoms over time. Hopelessness appears to play a unique role in the relationship between reduced anticipation of positive future outcomes and depression. Although less clearly suggested by the data, IU may contribute to both depression and GAD symptoms but may do so through different pathways.