Current progress in real-time functional magnetic resonance-based neurofeedback: Methodological challenges and achievements

Abstract

Neurofeedback (NF) is a research and clinical technique, characterized by live demonstration of brain activation to the subject. The technique has become increasingly popular as a tool for the training of brain self-regulation, fueled by the superiority in spatial resolution and fidelity brought along with real-time analysis of fMRI (functional magnetic resonance imaging) data, compared to the more traditional EEG (electroencephalography) approach. NF learning is a complex phenomenon and a controversial discussion on its feasibility and mechanisms has arisen in the literature. Critical aspects of the design of fMRI-NF studies include the localization of neural targets, cognitive and operant aspects of the training procedure, personalization of training, and the definition of training success, both through neural effects and (for studies with therapeutic aims) through clinical effects. In this paper, we argue that a developmental perspective should inform neural target selection particularly for pediatric populations, and different success metrics may allow in-depth analysis of NF learning. The relevance of the functional neuroanatomy of NF learning for brain target selection is discussed. Furthermore, we address controversial topics such as the role of strategy instructions, sometimes given to subjects in order to facilitate learning, and the timing of feedback. Discussion of these topics opens sight on problems that require further conceptual and empirical work, in order to improve the impact that fMRI-NF could have on basic and applied research in future.

Improved emotion regulation after neurofeedback. A single-arm trial in patients with borderline personality disorder

“…However, we highlight the explorative fashion of this finding and we stress that only the original data showed significant reductions. Nonetheless, our results are in line with a recent study showing that amygdala electrical fingerprint neurofeedback resulted in a larger reduction of alexithymia scores compared to a control group (Keynan et al, 2019). Conversely, neurofeedback studies to increase the amygdala response showed that the ability to identify or describe one's own emotions (as indicated by a subscale of the Toronto alexithymia scale; TAS), was correlated with the effectivity to increase amygdala activity (Young et al, 2017(Young et al, , 2014Zotev et al, 2011), which suggests that individuals with less symptoms of alexithymia might have better prerequisites to learn increasing their amygdala activity with neurofeedback.…”

“…Improvements in emotion regulation, assessed with the emotion-modulated startle, however, faded to the follow-up test; that is, some training effects did not persist for 6 weeks. Future studies must gain more stable effects, such as adding booster sessions or homework between sessions (Paret et al, 2019).…”

“…We quantified downregulation success by creating two different indices: First deltas of amygdala amplitudes/AUCs ('view' minus 'down') between the first and last neurofeedback run were created. However, as this index assumes linear improvement and may misrepresent actual learning slopes, we complemented this by calculating the best performance (Paret et al, 2019) of each participant. That is, we determined the largest delta between the 'view' and 'down' condition for each participant across all four neurofeedback runs.…”

The potential of functional near-infrared spectroscopy-based neurofeedback – a systematic review and recommendations for best practice

“…Whether immediate or delayed feedback is superior or whether they are equally effective is a matter of ongoing debate and there is only limited and as yet unclear evidence from a few comparative fMRI-neurofeedback studies (see Paret et al, 2019). In case of the noisier fNIRSneurofeedback, feeding back mean or median activity at the end of each block may avoid confusing participants due to noisy fluctuations of the feedback signal and may also be beneficial with regard to timing (see above).…”

“…Given the advantages of fNIRS over other neuroimaging modalities, this technique has been increasingly used as a tool for neurofeedback (Ehlis et al, 2018). During neurofeedback training, participants are trained to self-regulate their brain activity, generally with the ultimate goal of changing behavior or cognitive/emotional functions (for reviews see Paret et al, 2019;Sitaram et al, 2017;. Figure 0.2 (upper part) shows a typical fNIRS-neurofeedback setup.…”