Kurzfassung

tDCS is a promising approach to directly manipulate the vmPFC and remote midbrain areas via efferent connections, but further studies are required to enable a precise usage of tDCS for the manipulation of fear extinction-related processes. In Chib et al. (2013), behavioral findings were that study participants found presented faces more attractive after anodal stimulation of the vmPFC and simultaneous cathodal stimulation of the DLPFC. However, this increase of attractiveness ratings was...tDCS is a promising approach to directly manipulate the vmPFC and remote midbrain areas via efferent connections, but further studies are required to enable a precise usage of tDCS for the manipulation of fear extinction-related processes. In Chib et al. (2013), behavioral findings were that study participants found presented faces more attractive after anodal stimulation of the vmPFC and simultaneous cathodal stimulation of the DLPFC. However, this increase of attractiveness ratings was supported by a relatively low test-statistic (t(18)=2.26; p=0.03). We thus intend to repeat the behavioral results of Chib et al. (2013) in a pre-study (Study 1) to confirm the stimulating effect on reward appraisal and to establish tDCS in our own laboratory environment for further experiments related to fear extinction.
Positive findings in Study 1 would strongly support the application of tDCS to enhance the processing of appetitive stimuli. Since we hypothesized that during extinction the CS will turn into an appetitive stimulus, we conclude that a tDCS-based manipulation of the DA-system may improve extinction learning and later recall. In a second behavioral study (Study 2) we thus aim to build a bridge from Chib et al. (2013) to fear extinction by testing if pre-extinction tDCS facilitates extinction learning and/or improves extinction performance at later recall.
In Haaker et al. (2013) we could show that VTA-vmPFC rsCon predicted later vmPFC activation and extinction performance. rsCon is based on estimating coactivation between slow fluctuations (<0.1 Hz) in the blood oxygen level dependent (BOLD) signal measured by fMRI. Based on Chib et al. (2013), we hypothesize that anodal vmPFC/cathodal DLPFC stimulation enhances VTA-vmPFC coupling and thus extinction performance. However, Chib et al. did no investigate rsCon but changes in task-induced vmPFC-VTA coactivation after stimulation (psychophysiological interaction = PPI (Friston, 2011)). In an fMRI study (Study 3), we thus want to examine if tDCS also induces changes in vmPFC-VTA rsCon. Therefore, resting state data will be acquired at different time points during and after tDCS to better understand the short and long-term effects on vmPFC-VTA rsCon.» weiterlesen» einklappen