Stimulus Presentation at Specific Neuronal Oscillatory Phases Experimentally Controlled with tACS: Implementation and Applications

In recent years it has become increasingly clear that both the power and phase of oscillatory brain activity can influence the processing and perception of sensory stimuli. Transcranial alternating current stimulation (tACS) can phase-align and amplify endogenous brain oscillations and has often been used to control and thereby study oscillatory power. Causal investigation of oscillatory phase is more difficult, as it requires precise real-time temporal control over both oscillatory phase and sensory stimulation. Here, we present hardware and software solutions allowing temporally precise presentation of sensory stimuli during tACS at desired tACS phases, enabling causal investigations of oscillatory phase. We developed freely available and easy to use software, which can be coupled with standard commercially available hardware to allow flexible and multi-modal stimulus presentation (visual, auditory, magnetic stimuli, etc.) at pre-determined tACS-phases, opening up a range of new research opportunities. We validate that stimulus presentation at tACS phase in our setup is accurate to the sub-millisecond level with high inter-trial consistency. Conventional methods investigating the role of oscillatory phase such as magneto-/electroencephalography can only provide correlational evidence. Using brain stimulation with the described methodology enables investigations of the causal role of oscillatory phase. This setup turns oscillatory phase into an independent variable, allowing innovative and systematic studies of its functional impact on perception and cognition

The vaginal pressure inducer: a new device to test the (un)pleasurableness and tolerance of vaginal pressure and the influence of sexual stimuli

To better understand the impact of sexual stimuli on genital pain, a new instrument was developed: the Vaginal Pressure Inducer (VPI). We administered gradually increasing vaginal pressure with the VPI to sexually functional women while watching a neutral, erotic or explicit sex film. Women had higher unpleasantness thresholds in a sexual context compared to a non-sexual context. Moreover, ratings of pleasurableness were higher in the sexual compared to neutral context and most so during the explicit sexual film. These results provide initial support for the suitability of the VPI to study determinants of pleasant and unpleasant appraisal of vaginal pressure

Toward a More Valid Assessment of Behavioral Aggression:An Open Source Platform and an Empirically Derived Scoring Method for Using the Competitive Reaction Time Task (CRTT)

While the Competitive Reaction Time Task (CRTT) is the most used behavioral aggression paradigm, it is characterized by methodological heterogeneity and quantification strategies for its' outcome are unstandardized. Therefore, the standards of measuring aggression should be improved. This article contributes on such an improvement by providing: (a) a freely available CRTT online administration program, and (b) a factor-analytically derived scoring method. Based on a combined sample (n = 423), a two-factor model was fit to the 30-trial CRTT version. The first factor included all trial scores subsequent to the first time the participant received aversive feedback (i.e., provoked factor) and the second factor included all trial scores prior to this first aversive feedback (i.e., unprovoked factor). Construct validity was evidenced based on the factors` differential relationship with self-reported aggression and narcissism. Our factor analytic findings empirically support the superiority of one of the existing CRTT scoring methods, that is, separately averaging all preprovocation versus all postprovocation trials. We discuss practical recommendations for CRTT users and outline future empirical avenues. This article aims at stimulating joint efforts to move toward standardization of CRTT implementation and outcome measure analysis

Stimulus Presentation at Specific Neuronal Oscillatory Phases Experimentally Controlled with tACS: Implementation and Applications Stimulus Presentation at Specific Neuronal Oscillatory Phases Experimentally Controlled with tACS: Implementation and Applic

In recent years, it has become increasingly clear that both the power and phase of oscillatory brain activity can influence the processing and perception of sensory stimuli. Transcranial alternating current stimulation (tACS) can phase-align and amplify endogenous brain oscillations and has often been used to control and thereby study oscillatory power. Causal investigation of oscillatory phase is more difficult, as it requires precise real-time temporal control over both oscillatory phase and sensory stimulation. Here, we present hardware and software solutions allowing temporally precise presentation of sensory stimuli during tACS at desired tACS phases, enabling causal investigations of oscillatory phase. We developed freely available and easy to use software, which can be coupled with standard commercially available hardware to allow flexible and multi-modal stimulus presentation (visual, auditory, magnetic stimuli, etc.) at pre-determined tACS-phases, opening up a range of new research opportunities. We validate that stimulus presentation at tACS phase in our setup is accurate to the sub-millisecond level with high inter-trial consistency. Conventional methods investigating the role of oscillatory phase such as magneto-/electroencephalography can only provide correlational evidence. Using brain stimulation with the described methodology enables investigations of the causal role of oscillatory phase. This setup turns oscillatory phase into an independent variable, allowing innovative, and systematic studies of its functional impact on perception and cognition