Deficits in acquisition and extinction of conditioned responses in mGluR7 knockout mice

Metabotropic glutamate receptor 7 (mGluR7) is expressed in brain regions implicated in emotional learning and working memory, and previous behavioral experiments indicated contributions of mGluR7 to various complex behaviors. In the present study, we investigated the specific effects of mGluR7 deletion on a variety of conditioning paradigms that model crucial neurocognitive and psychopathological behavioral phenomena. Null-mutant mGluR7^−/− mice displayed defects during scheduled appetitive conditioning, acquisition and extinction of appetitive odor conditioning, extinction of response suppression-based conditioned emotional responding (CER), acquisition of discriminative CER, and contextual fear conditioning. mGluR7^−/− animals were slower to acquire the association between a conditioned stimulus and a positive or negative reinforcer, but eventually reached similar performance levels to their wildtype littermates. Notably, extinction learning of conditioned responses was slower in mGluR7^−/− compared to wildtype animals. The observed delays in the acquisition of complicated stimulus associations across conditioning procedures may suggest a critical role for mGluR7 in neurocognitive functions and psychopathology.     

Non-ruminative processing reduces overgeneral autobiographical memory retrieval in students

It has been suggested that overgeneral memory (OGM) represents a vulnerability marker for depression [Williams, J. M. G., Barnhofer, T., Crane, C., Hermans, D., Raes, F., Watkins, E., et al. (2007). Autobiographical memory specificity and emotional disorder. Psychological Bulletin, 133, 122-148]. One important underlying mechanism involved is rumination [e.g., Watkins, E., & Teasdale, J. D. (2001). Rumination and overgeneral memory in depression: Effects of self-focus and analytic thinking. Journal of Abnormal Psychology, 110, 353-357; Watkins, E., & Teasdale, J. D. (2004). Adaptive and maladaptive self-focus in depression. Journal of Affective Disorders, 82, 1-8]. It is as yet unclear to what extent the relationship between rumination and OGM also applies to nonclinical groups. The present study investigated this relationship in a nonclinical student sample, using an innovative sentence completion procedure to assess OGM. As hypothesized, the experimental induction of a concrete, process-focused (or non-ruminative) thinking style (n=102) led to less OGMs as compared to the experimental induction of an abstract, evaluative (or ruminative) thinking style (n=93). The present results add to the accumulating body of evidence that abstract, evaluative (or ruminative) thinking is a crucial underlying process of OGM, and expand prior literature by extending this idea to nonclinical individuals and by using a new procedure to assess OGM.     

Cognitive confidence in obsessive-compulsive disorder: distrusting perception, attention and memory

Previous studies have established that obsessive-compulsive disorder (OCD) is characterised by significant levels of distrust in memory (e.g. for actions). Ironically, this lowered confidence is at least in part due to repeated checking, which is assumed to lower perceptual processing and thereby reduces vividness and detail of the recollections. In a previous study, Hermans, D., Martens, K., De Cort, K., Pieters, G., and Eelen, P. [(2003). Reality monitoring and metacognitive beliefs related to cognitive confidence in OCD. Behaviour Research and Therapy, 41, 383-401] observed that OCD is not only characterised by reduced confidence in memory, but also by a similar distrust in attention (Hermans et al., 2003). The present study aimed at replicating and extending this finding. It was observed (a) that patients suffering from OCD showed less confidence in attention and memory than a clinical and a nonclinical control group; (b) that confidence in attention was uniquely related to checking behaviour, and (c) that repeated checking caused increased levels of distrust in attention. In addition, it was observed that cognitive distrust while performing OCD-related actions not only extends to attention, but also to perception. It is argued that research on metacognition in OCD should move beyond the study of memory.     

Affective priming with subliminally presented pictures.

Affective priming studies have demonstrated that subliminally presented prime words can exert an influence on responses towards positive or negative target stimuli. In the present series of experiments, it was investigated whether these findings can be extended to pictorial stimuli. Ideographically selected positive, neutral, and negative picture primes that were sandwich-masked immediately preceded positive or negative target pictures (Experiment 1) or words (Experiments 2 & 3). Evaluative categorization responses to these target stimuli were significantly influenced by the valence of the prime. First, it was demonstrated that high anxious participants were selectively slowed when the subliminally presented prime was negative (Experiments 1 & 2). Second, the affective congruence between primes and targets also exerted an influence on the responses, but in a direction that is opposite to what is typically observed in affective priming research. These reverse priming effects are situated within a series of recent similar findings, and implications for theories of affective priming are discussed.     

On the replicability of the affective priming effect in the pronunciation task

Bargh, Chaiken, Raymond, and Hymes (1996) and Hermans, De Houwer, and Eelen (1994) showed that a valenced target word is pronounced faster after the presentation of an affectively related prime word than after the presentation of an affectively unrelated prime word. This finding is important because it provides crucial evidence for the hypotheses that stimulus evaluation (a) is goal-independent and (b) facilitates the encoding of stimuli that have the same valence. However, recent studies indicate that the affective priming effect is not a reliable finding in the standard pronunciation task. We report the results of a nearly exact replication of Bargh et al.'s (1996) Experiment 2. In line with previous replication studies, we failed to detect the affective priming effect.     

Autobiographical memory specificity and affect regulation: an experimental approach

This study investigated J. M. G. Williams's (1996) affect-regulation hypothesis that level of specificity of autobiographical memory (AM) is used to minimize negative affect. It was found that a negative event leads to more reports of subjective stress in high- as compared with low-specific participants. Also, afterward, high-specific participants rated their unprompted memories for the event as more unpleasant. The results indicate that, relative to high specificity, being less specific in the retrieval of AMs is associated with less affective impact of a negative event. Results are discussed within the affect-regulation model. It is suggested that future research take a more functional perspective on AM specificity.     

Verbal, behavioural and physiological assessment of the generalization of exposure-based fear reduction in a spider-anxious population

Clinical fear of spiders was assessed in 39 patients before and after exposure treatment and at a 3-month follow-up. The assessment included behavioral, physiological and self-report measures. Some patients were tested in the treatment context (group Same), while others were tested in a different context (group Different). Both groups demonstrated a significant fear reduction from pre- to post-treatment in all measures, which persisted at the 3-month follow-up. Contrary to our expectations, no clear difference was observed between the groups at any moment. However, a 1-year follow-up test of the self-report measure revealed a return of fear in group Same, but not in group Different. These results show (1) that the effects of exposure treatment persisted over contexts and time in the short term, and (2) that conducting treatment and tests in different contexts enhanced efficiency of exposure treatment in the long term.     

Non-differential return of fear in humans after a reinstatement procedure

The present experiment investigated reinstatement of fear in humans using a differential fear conditioning preparation. In this experiment, one neutral stimulus (conditioned stimulus; CS+) was paired with an aversive stimulus (unconditioned stimulus; US) during the acquisition phase, while another neutral stimulus was not (CS−). This procedure led to a difference in responding between the CS+ and the CS− (i.e., differential conditioning). After this acquisition phase, an extinction phase followed, during which both CSs were presented without the US, resulting in a decrease in differential conditioned responding. Reinstatement refers to the return of extinguished conditioned responses due to the experience of US-only trials after the extinction phase. This phenomenon was investigated by presenting half of the participants (reinstatement group) with unpredictable USs after the extinction phase. The control group did not receive these USs after the extinction procedure. The results show that return of fear was clearly apparent after the reinstating USs. This return of fear was, however, not limited to the CS+. An increase in ‘conditioned’ responding was also observed for the control stimulus. This interesting observation will be discussed against the background of a number of recent theoretical conceptualizations of reinstatement.     

The Penn State Worry Questionnaire—Past Day: Development and Validation of a Measure Assessing Daily Levels of Worry

Based on the widely used Penn State Worry Questionnaire for trait worry, a scale was developed to measure the level of worry experienced during the past 24 h. This instrument, the Penn State Worry Questionnaire—Past Day (PSWQ-PD), was administered to a student sample and two clinical samples. The PSWQ-PD demonstrated high internal consistency, good convergent validity and adequate test-retest reliability. A confirmatory factor analysis revealed that a unifactorial solution provided the best fit. Moreover, it was shown that the PSWQ-PD is a more state-like worry measure than the original PSWQ. The PSWQ-PD is a promising, brief tool for daily worry assessment, which is apt for frequent administration.