Perceived stress in obsessive-compulsive disorder is related with obsessive but not cmpulsive symptoms

Obsessive–compulsive disorder (OCD) is achronic psychiatric disorder characterized by recurrent intrusive thoughts and/or repetitive compulsory behaviors. This psychiatric disorder is known to be stress responsive, as symptoms increase during periods of stress but also because stressful events may precede the onset of OCD. However, only a few and inconsistent reports have been published about the stress perception and the stress-response in these patients. Herein, we have characterized the correlations of OCD symptoms with basal serum cortisol levels and scores in a stress perceived questionnaire (PSS-10). The present data reveals that cortisol levels and the stress scores in the PSS-10 were significantly higher in OCD patients that in controls. Moreover, stress levels self-reported by patients using the PSS-10 correlated positively with OCD severity in the Yale–Brown Obsessive–Compulsive Scale (Y–BOCS). Interestingly, PSS-10 scores correlated with the obsessive component, but not with the compulsive component, of Y–BOCS. These results confirm that stress is relevant in the context of OCD, particularly for the obsessive symptomatology.Pedro Morgado is supported by a fellowship “SFRH/SINTD/60129/2009” funded by FCT – Foundation for Science and Technology. Supported by FEDER funds through Operational program for competitive factors – COMPETE and by national funds through FCT –Foundation for Science and Technology to project “PTDC/SAU-NSC/111814/2009.

Stress Transiently Affects Pavlovian-to-Instrumental Transfer

Stress has a strong impact in the brain, impairing decision-making processes as a result of changes in circuits involving the prefrontal and orbitofrontal cortices and the striatum. Given that these same circuits are key for action control and outcome encoding, we hypothesized that adaptive responses to which these are essential functions, could also be targeted by stress. To test this hypothesis we herein assessed the impact of chronic stress in a Pavlovian-to-instrumental transfer (PIT) paradigm, a model of an adaptive response in which a previously conditioned cue biases an instrumental goal-directed action. Data reveals that rats submitted to chronic unpredictable stress did not display deficits in pavlovian conditioning nor on the learning of the instrumental task, but were impaired in PIT; importantly, after a stress-free period the PIT deficits were no longer observed. These results are relevant to understand how stress biases multiple incentive processes that contribute to instrumental performance

A novel risk-based decision-making paradigm

This paper presents a novel rodent decision-making task that explores uncertainty, independently of expectation and predictability. Using a 5-hole operating box, adult male Wistar rats were given choices between a small certain (safe) food reward and a large uncertain (risk) food reward. We found that animals strongly preferred the safe option when it had a fixed position or was cued with a light in a random placement scheme, but had no preference for safe or risk options when the latter were associated with light. Importantly, when the reward was manipulated animals could perceive alterations in the outcome value and biased their choice pattern to the most profitable option. In addition, we found that the D2/D3 agonist quinpirole biased all decisions toward risk in this paradigm. Finally, a c-fos analysis revealed that several brain areas known to be involved in decision-making mechanisms, including the medial prefrontal cortex, the orbitofrontal cortex, the nucleus accumbens and the striatum, were activated by the task. In summary, this paradigm is a useful and highly reliable tool to explore decision-making processes in contexts of uncertainty.Pedro Morgado is supported by a fellowship "SFRH/SINTD/60129/2009" funded by FCT-Foundation for Science and Technology. Supported by FEDER funds through Operational program for competitive factors-COMPETE and by national funds through FCT-Foundation for Science and Technology to project "PTDC/SAU-NSC/111814/2009.

Musical expertise and foreign speech perception

The aim of this experiment was to investigate the influence of musical expertise on the automatic perception of foreign syllables and harmonic sounds. Participants were Cuban students with high level of expertise in music or in visual arts and with the same level of general education and socio-economic background. We used a multi-feature Mismatch Negativity (MMN) design with sequences of either syllables in Mandarin Chinese or harmonic sounds, both comprising deviants in pitch contour, duration and Voice Onset Time (VOT) or equivalent that were either far from (Large deviants) or close to (Small deviants) the standard. For both Mandarin syllables and harmonic sounds, results were clear-cut in showing larger MMNs to pitch contour deviants in musicians than in visual artists. Results were less clear for duration and VOT deviants, possibly because of the specific characteristics of the stimuli. Results are interpreted as reflecting similar processing of pitch contour in speech and non-speech sounds. The implications of these results for understanding the influence of intense musical training from childhood to adulthood and of genetic predispositions for music on foreign language perception is discussed