Together with evidence that psychotic features are highly recurrent, these data show 1) that psychotic features denote a lifetime illness of greater severity and 2) that within individuals, psychotic features may emerge in only the more severe episodes.
Highlights We found neurofeedback-specific attenuation of amygdala responses. Trauma symptoms and the affective state improved in patients at one-month follow-up. Reduced amygdala responses were associated with improved well-being at follow-up. 75% of individuals with PTSD used the learned strategies in daily life. Left lateral prefrontal cortex responses were reduced during neurofeedback training.
The autonomic nervous system (ANS) receives modulatory input from high-level supra-tentorial brain structures, which affects peripheral physiological measures such as heart rate variability (HRV), respiration, and electrodermal activity (see Beissner, Meissner, Bär, & Napadow, 2013 for a meta-analysis). For instance, in the neurovisceral integration model for HRV (Thayer & Lane, 2009), neocortical areas such as the prefrontal and cingulate cortex exert tonic inhibitory control over brainstem circuitry underlying the ANS regulation. A similar cortico-limbic model has been proposed for sensorimotor integration of respiration (Evans, 2010), with an interplay of volitional respiratory control (pre-motor and supplementary motor area (SMA)) and interoceptive integration areas (anterior cingulate cortex (ACC), insula, and amygdala). These models overlap in core autonomic network areas, including the cingulate cortex, insula, and amygdala
Affective disorders are associated with maladaptive emotion regulation strategies. In particular, the left more than the right ventrolateral prefrontal cortex (vlPFC) may insufficiently regulate emotion processing, e.g., in the amygdala. A double-blind cross-over study investigated NF-supported cognitive reappraisal training in major depression (n = 42) and age- and gender-matched controls (n = 39). In a randomized order, participants trained to upregulate either the left or the right vlPFC during cognitive reappraisal of negative images on two separate days. We wanted to confirm regional specific NF effects with improved learning for left compared to right vlPFC (ClinicalTrials.gov NCT03183947). Brain responses and connectivity were studied with respect to training progress, gender, and clinical outcomes in a 4-week follow-up. Increase of vlPFC activity was stronger after NF training from the left- than the right-hemispheric ROI. This regional-specific NF effect during cognitive reappraisal was present across patients with depression and controls and supports a central role of the left vlPFC for cognitive reappraisal. Further, the activity in the left target region was associated with increased use of cognitive reappraisal strategies (r = 0.48). In the 4-week follow-up, 75% of patients with depression reported a successful application of learned strategies in everyday life and 55% a clinically meaningful symptom improvement suggesting clinical usability.
Distributed cutaneous tissue blood volume oscillations contain information on autonomic nervous system (ANS) regulation of cardiorespiratory activity as well as dominating thermoregulation. ANS associated with low-frequency oscillations can be quantified in terms of frequencies, amplitudes, and phase shifts. The relative order between these faculties may be disturbed by conditions colloquially termed ‘stress’. Photoplethysmography imaging, an optical non-invasive diagnostic technique provides information on cutaneous tissue perfusion in the temporal and spatial domains. Using the cold pressure test (CPT) in thirteen healthy volunteers as a well-studied experimental intervention, we present a method for evaluating phase shifts in low- and intermediate frequency bands in forehead cutaneous perfusion mapping. Phase shift changes were analysed in low- and intermediate frequency ranges from 0.05 Hz to 0.18 Hz. We observed that time waveforms increasingly desynchronised in various areas of the scanned area throughout measurements. An increase of IM band phase desynchronization observed throughout measurements was comparable in experimental and control group, suggesting a time effect possibly due to overshooting the optimal relaxation duration. CPT triggered an increase in the number of points phase-shifted to the reference that was specific to the low frequency range for phase-shift thresholds defined as π/4, 3π/8, and π/2 rad, respectively. Phase shifts in forehead blood oscillations may infer changes of vascular tone due to activity of various neural systems. We present an innovative method for the phase shift analysis of cutaneous tissue perfusion that appears promising to assess ANS change processes related to physical or psychological stress. More comprehensive studies are needed to further investigate the reliability and physiological significance of findings.
Virtual environments (VEs), in the recent years, have become more prevalent in neuroscience. These VEs can offer great flexibility, replicability, and control over the presented stimuli in an immersive setting. With recent developments, it has become feasible to achieve higher-quality visuals and VEs at a reasonable investment. Our aim in this project was to develop and implement a novel real-time functional magnetic resonance imaging (rt-fMRI)–based neurofeedback (NF) training paradigm, taking into account new technological advances that allow us to integrate complex stimuli into a visually updated and engaging VE. We built upon and developed a first-person shooter in which the dynamic change of the VE was the feedback variable in the brain–computer interface (BCI). We designed a study to assess the feasibility of the BCI in creating an immersive VE for NF training. In a randomized single-blinded fMRI-based NF-training session, 24 participants were randomly allocated into one of two groups: active and reduced contingency NF. All participants completed three runs of the shooter-game VE lasting 10 min each. Brain activity in a supplementary motor area region of interest regulated the possible movement speed of the player’s avatar and thus increased the reward probability. The gaming performance revealed that the participants were able to actively engage in game tasks and improve across sessions. All 24 participants reported being able to successfully employ NF strategies during the training while performing in-game tasks with significantly higher perceived NF control ratings in the NF group. Spectral analysis showed significant differential effects on brain activity between the groups. Connectivity analysis revealed significant differences, showing a lowered connectivity in the NF group compared to the reduced contingency-NF group. The self-assessment manikin ratings showed an increase in arousal in both groups but failed significance. Arousal has been linked to presence, or feelings of immersion, supporting the VE’s objective. Long paradigms, such as NF in MRI settings, can lead to mental fatigue; therefore, VEs can help overcome such limitations. The rewarding achievements from gaming targets can lead to implicit learning of self-regulation and may broaden the scope of NF applications.
ObjectiveReticular brain activity described by intermediate (IM) band physiology exhibits parallels to controversial concepts of cranial osteopathy (CO), the primary respiratory mechanism or cranial rhythmic impulse (CRI). Interestingly, evidence for PRM/CRI activity has been reported using manual palpation, yet with questionable validity. Validation is tested combining manual palpation, instrumented tracking, and algorithmic objectivation of frequencies and phases.MethodsUsing a standard CO intervention, Vault Hold (VH), two CO experts palpated and digitally marked CRI frequencies in 25 healthy adults. IM band autonomic nervous system activity was examined as momentary frequency of highest amplitude (MFHA) in examiner and participant forehead photoplethysmography (PPG). Palpation errors and frequency expectation bias during VH were examined using MFHA and CRI phases.FindingsPalpated CRI frequencies matched those reported in the literature. Mean MFHA and CRI frequencies were highly correlated and showed constant low deviating 1:1 coupling in 77% of participants (responders), and high deviating 1:2 coupling in 23% of participants (non-responders). Both groups showed harmonic waves in (very) low and IM bands in >98% of palpated intervals. Phase analyses suggested synchronization between MFHA and CRI in responders but not in non-responders confirming that examiners palpated CRI activity in participants.ConclusionsDecreases in forehead PPG of responders from IM activity (~0.14 Hz) to LF activity (0.072 Hz) suggest successful palpation may be explained by IM and LF activity, whereas CRI in non-responders was not associated with PPG activity.
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