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Englisch

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Cerebral Cortex/physiopathology

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Abstracts

Stewart, J. L., Connolly, C. G., May, A. C., Tapert, S. F., Wittmann, M., & Paulus, M. P. (2014). Cocaine dependent individuals with attenuated striatal activation during reinforcement learning are more susceptible to relapse. Psychiatry Research, 223(2), 129–139. https://doi.org/10.1016/j.pscychresns.2014.04.014

Cocaine-dependent individuals show altered brain activation during decision making. It is unclear, however, whether these activation differences are related to relapse vulnerability. This study tested the hypothesis that brain-activation patterns during reinforcement learning are linked to relapse 1 year later in individuals entering treatment for cocaine dependence. Subjects performed a Paper-Scissors-Rock task during functional magnetic resonance imaging (fMRI). A year later, we examined whether subjects had remained abstinent (n=15) or relapsed (n=15). Although the groups did not differ on demographic characteristics, behavioral performance, or lifetime substance use, abstinent patients reported greater motivation to win than relapsed patients. The fMRI results indicated that compared with abstinent individuals, relapsed users exhibited lower activation in (1) bilateral inferior frontal gyrus and striatum during decision making more generally; and (2) bilateral middle frontal gyrus and anterior insula during reward contingency learning in particular. Moreover, whereas abstinent patients exhibited greater left middle frontal and striatal activation to wins than losses, relapsed users did not demonstrate modulation in these regions as a function of outcome valence. Thus, individuals at high risk for relapse relative to those who are able to abstain allocate fewer neural resources to action-outcome contingency formation and decision making, as well as having less motivation to win on a laboratory-based task.
Gard, T., Hölzel, B. K., Sack, A. T., Hempel, H., Lazar, S. W., Vaitl, D., & Ott, U. (2012). Pain attenuation through mindfulness is associated with decreased cognitive control and increased sensory processing in the brain. Cerebral Cortex (New York, N.Y. : 1991), 22(11), 2692–2702. https://doi.org/10.1093/cercor/bhr352

Pain can be modulated by several cognitive techniques, typically involving increased cognitive control and decreased sensory processing. Recently, it has been demonstrated that pain can also be attenuated by mindfulness. Here, we investigate the underlying brain mechanisms by which the state of mindfulness reduces pain. Mindfulness practitioners and controls received unpleasant electric stimuli in the functional magnetic resonance imaging scanner during a mindfulness and a control condition. Mindfulness practitioners, but not controls, were able to reduce pain unpleasantness by 22% and anticipatory anxiety by 29% during a mindful state. In the brain, this reduction was associated with decreased activation in the lateral prefrontal cortex and increased activation in the right posterior insula during stimulation and increased rostral anterior cingulate cortex activation during the anticipation of pain. These findings reveal a unique mechanism of pain modulation, comprising increased sensory processing and decreased cognitive control, and are in sharp contrast to established pain modulation mechanisms.
Schienle, A., Schäfer, A., Stark, R., & Vaitl, D. (2009). Long-term effects of cognitive behavior therapy on brain activation in spider phobia. Psychiatry Research, 172(2), 99–102. https://doi.org/10.1016/j.pscychresns.2008.11.005

This functional magnetic resonance imaging study investigated long-term effects of cognitive behavior therapy (CBT) in individuals suffering from spider phobia. Ten female patients who had shown positive immediate CBT effects were invited to take part in a 6-month follow-up investigation. Here, the patients, along with eight non-phobic females, were presented with the same pictures depicting spiders, generally disgust-inducing, generally fear-inducing and neutral content, which they had viewed 6 months earlier. Patients' self-report and overt behavior indicated a positive long-term clinical improvement. Related hemodynamic changes included an increase in medial orbitofrontal cortex (OFC) activity. As the medial OFC is involved in emotion-related learning, especially in the representation of positive stimulus-outcome associations, we conclude that the medial OFC effect constitutes the neuronal basis of the lasting positive CBT outcome. Activity to disorder-irrelevant pictures decreased across the sessions in the lateral OFC and in the insula, which most likely reflects general habituation.
Hermann, A., Schäfer, A., Walter, B., Stark, R., Vaitl, D., & Schienle, A. (2007). Diminished medial prefrontal cortex activity in blood-injection-injury phobia. Biological Psychology, 75(2), 124–130. https://doi.org/10.1016/j.biopsycho.2007.01.002

We examined the effects of symptom induction on neural activation in blood-injection-injury (BII) phobia. Nine phobic and 10 non-phobic subjects participated in an fMRI study in which they were presented with disorder-relevant, generally disgust-inducing, generally fear-evoking and neutral pictures. We observed diminished medial prefrontal cortex (MPFC) activity in patients compared to controls for phobia-relevant and disgust-inducing pictures. The MPFC has been shown to be critically involved in the automatic and effortful cognitive regulation of emotions. Therefore, the results might reflect reduced cognitive control of emotions in BII phobics during the experience of phobic symptoms as well as during states of disgust. The latter response component might be a result of the elevated disgust sensitivity of BII phobics.
Wittmann, M., & Szelag, E. (2003). Sex differences in perception of temporal order. Perceptual and Motor Skills, 96(1), 105–112. https://doi.org/10.2466/pms.2003.96.1.105

On duration judgments lasting seconds to minutes, which are thought to be cognitively mediated, women typically perceive time intervals as longer than men do. On a perceptual level in the milliseconds range, few reports indicate higher acuity of temporal processing in men than in women. In this study, sex differences in the perception of temporal order of two acoustic stimuli were identified in neurologically healthy subjects, as well as in brain-injured patients with lesions in either the left or the right hemisphere. Women needed longer interstimulus intervals than men before they were able to indicate the correct temporal order of two clicks. Neurobiological evidence and findings on cognitive strategies are discussed to explain the apparent psychophysical sex differences.

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Last update from database: 04.06.25, 15:35 (UTC)

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