Continuous vs. Intermittent Rt-fMRI Neurofeedback Training of the Anterior Insula

A double-blinded, placebo-controled, between-subject design is employed in this study. A total of 90 healthy subjects will be recruited and randomly assigned into the intermittent experimental group (EG1; N=30), which receives intermittent feedback from the left anterior insula after each block, the control group (CG; N=30) after each block, which receives sham feedback from the middle temporal gyrus (MTG), and the continuous expermiental group (EG2; N=30), which receives real-time feedback from the left anterior insula. Comparisons between the EG1 and the CG are used to validate the efficacy of intermittent neurofeedback and comparisons between the EG2 and the CG are used to determine the better neurofeedback type (intermittent vs. continuous).

The neurofeedback training task consists of 4 training sessions with real-time feedback and 1 transfer session without feedback. Each session comprises 5 regulation blocks and 5 rest blocks. At the end of each block, participants are presented with pain-related images and asked to rate their level of pain empathy, which was used to determine the effects of neurofeedback training on empathic responses. A heartbeat detection task is performed pre- and post-training to measure interoceptive accuracy changes induced by neurofeedback training. A functional localizer task (heartbeat counting task) before training was used to localise the anterior insula. Personality traits of subjects are assessed using validated Chinese version questionnaires, including the Toronto Alexithymia Scale (TAS), Multidimensional Assessment of Interoceptive Awareness (MAIA), Bermond-Vorst Alexithymia Questionnaire (BVAQ),Interoceptive Confusion Questionnaire (ICQ), Beck Depression Inventory (BDI), State-Trait Anxiety Inventory (STAI), Autism Spectrum Quotient (ASQ), Interpersonal Reactivity Index (IRI), and Cognitive Flexibility Inventory (CFI). Subjects are asked to complete Positive and Negative Affect Schedule (PANAS) twice before and after the neurofeedback training task to measure mood changes.

Inclusion criteria

Healthy subjects without any past or present psychiatric or neurological disorders

Exclusion criteria

History of brain injury medical or mental illness

Contraindication to MRI scanning (e.g., metal implants, claustrophobia or other --conditions that make them inappropriate for MRI scanning)