Subjective feeling of control during fNIRS-based neurofeedback targeting the DL-PFC is related to neural activation determined with short-channel correction

Abstract

Neurofeedback (NF) training is a promising preventive and therapeutic approach for brain and behavioral impairments, the dorsolateral prefrontal cortex (DL-PFC) being a relevant region of interest. Functional near-infrared spectroscopy (NIRS) has recently been applied in NF training. However, this approach is highly sensitive to extra-cerebral vascularization, which could bias measurements of cortical activity. Here, we examined the feasibility of a NF training targeting the DL-PFC and its specificity by assessing the impact of physiological confounds on NF success via short-channel offline correction under different signal filtering conditions. We also explored whether the individual mental strategies affect the NF success. Thirty volunteers participated in a single 15-trial NF session in which they had to increase the oxy-hemoglobin (HbO2) level of their bilateral DL-PFC. We found that 0.01–0.09 Hz band-pass filtering was more suited than the 0.01–0.2 Hz band-pass filter to highlight brain activation restricted to the NF channels in the DL-PFC. Retaining the 10 out of 15 best trials, we found that 18 participants (60%) managed to control their DL-PFC. This number dropped to 13 (43%) with short-channel correction. Half of the participants reported a positive subjective feeling of control, and the “cheering” strategy appeared to be more effective in men (p<0.05). Our results showed successful DL-PFC fNIRS-NF in a single session and highlighted the value of accounting for extra cortical signals, which can profoundly affect the success and specificity of NF training.

Towards fNIRS Hyperfeedback: A Feasibility Study on Real-Time Interbrain Synchrony

“…This means that, in particular, the bandpass filter used here needs to be exchanged by a causal filter. Also, artifact control is essential and should be improved, e.g., by utilizing short-distance channels to measure physiological artifacts online and filter them out (Godet et al, 2023; Klein et al, 2022). Note that there are already different approaches for real-time preprocessing in practice (Kohl et al 2020).…”

“…Neurofeedback is an established method, which provides participants with information about their neural state with the goal of aiding them in regulating it (e.g., Sitaram et al, 2017). It is established in EEG and fMRI and has also recently gained traction in the domain of fNIRS (Kohl et al, 2020;Soekadar et al, 2021;Godet et al, 2023;Kohl et al, 2023). During a neurofeedback session, a participant's neural state is measured in near real-time, and information about this state is then fed back to the participant in the form of, e.g., a visual 4 thermometer or an auditory tone.…”