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"Wittmann, Marc"

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Brain Mapping

Ergebnisse 4 Einträge

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Jo, H.-G., Hinterberger, T., Wittmann, M., & Schmidt, S. (2016). Rolandic beta-band activity correlates with decision time to move. Neuroscience Letters, 616, 119–124. https://doi.org/10.1016/j.neulet.2016.01.051

Research findings link rolandic beta-band activity to voluntary movements, but a linkage with the decision time to move remains unknown. We found that beta-band (16-28Hz) activity shortly before the movement onset is relevant for the decision time to move: the more pronounced the decrease in beta-band synchronization, the earlier the subjective experience of the decision to move. The linkage was relevant regarding 'decision', but not regarding 'intention' timing that has been often applied in the study of free will. Our findings suggest that oscillatory neural activity in the beta-band is an important neural signature pertaining to the subjective experience of making a decision to move.
Wittmann, M., Burtscher, A., Fries, W., & von Steinbüchel, N. (2004). Effects of brain-lesion size and location on temporal-order judgment. Neuroreport, 15(15), 2401–2405. https://doi.org/10.1097/00001756-200410250-00020

We assessed the effect of size and localization of a brain lesion on patients' abilities to perceive the temporal order of two acoustic stimuli. In those patients who had performed with impaired order thresholds, local overlaps of lesions as analyzed with CT were found in specific left-hemispheric regions of the temporal and parietal lobe. However, a moderate association of lesion size and temporal-order threshold was found among all brain-injured patients (n = 30), a correlation that was most pronounced in patients with right-hemispheric lesions. This non-specific effect of lesion size has to be discussed critically with respect to behavioral findings of an association between temporal-processing abilities and language competence.
Gowin, J. L., Harlé, K. M., Stewart, J. L., Wittmann, M., Tapert, S. F., & Paulus, M. P. (2014). Attenuated insular processing during risk predicts relapse in early abstinent methamphetamine-dependent individuals. Neuropsychopharmacology : Official Publication of the American College of Neuropsychopharmacology, 39(6), 1379–1387. https://doi.org/10.1038/npp.2013.333

There is some evidence that neuroimaging can be used to predict relapse among abstinent methamphetamine-dependent (MD) individuals. However, it remains unclear what cognitive and neural processes contribute to relapse. This investigation examined whether insula activation during risk-taking decisions-a process shown to be disrupted in MD-is able to predict susceptibility for relapse. Sixty-eight MD enrolled in a treatment program during early abstinence completed a risk-taking task during functional magnetic resonance imaging. Sixty-three of the sixty-eight individuals were followed up 1 year after the study. Of these, 18 MD reported relapse. The 45 abstinent MD showed patterns of insula activation during risky decisions that resembled those found in prior studies of healthy controls, consisting of lower insula activation during safe decisions paired with higher activation during risky decisions. In contrast, the 18 relapsed MD showed similar insula activation during safe and risky decisions. An increase in one standard deviation in the difference in insula activation between risky and safe choices was associated with a 0.34 odds ratio for relapse at any given time. A median split of insula activation (difference between risky and safe) showed that individuals in the bottom half were two times more likely to relapse. In addition, a model that included several other brain regions increased prediction accuracy compared with insula-based model alone. These results suggest that failure to differentially activate the insula as a function of risk is a part of an altered risk-processing network associated with an increased susceptibility to relapse.
Gutyrchik, E., Churan, J., Meindl, T., Bokde, A. L. W., von Bernewitz, H., Born, C., Reiser, M., Pöppel, E., & Wittmann, M. (2010). Functional neuroimaging of duration discrimination on two different time scales. Neuroscience Letters, 469(3), 411–415. https://doi.org/10.1016/j.neulet.2009.12.040

Analyses of neural mechanisms of duration processing are essential for the understanding of psychological phenomena which evolve in time. Different mechanisms are presumably responsible for the processing of shorter (below 500 ms) and longer (above 500 ms) events but have not yet been a subject of an investigation with functional magnetic resonance imaging (fMRI). In the present study, we show a greater involvement of several brain regions - including right-hemispheric midline structures and left-hemispheric lateral regions - in the processing of visual stimuli of shorter as compared to longer duration. We propose a greater involvement of lower-level cognitive mechanisms in the processing of shorter events as opposed to higher-level mechanisms of cognitive control involved in longer events.

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

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