Non-specific increase in alpha power during a neurofeedback session targeting its downregulation

Area of Science:

• Neuroscience
• Cognitive Science
• Neurofeedback Research

Background:

• Electroencephalographic (EEG) neurofeedback aims to achieve volitional control over neural oscillations.
• The alpha rhythm is frequently targeted in neurofeedback protocols.
• Evidence for single-session alpha modulation is limited due to insufficient controls for non-specific effects.

Purpose of the Study:

• To investigate if individuals can downregulate alpha parietal-scalp power in a single neurofeedback session.
• To control for feedback veracity and targeted modulation direction.
• To assess the specificity of neurofeedback interventions.

Main Methods:

• Healthy participants underwent three training blocks with visual feedback reflecting real-time alpha power (Alpha-Down), opposite direction (Alpha-Up), or prerecorded data (Sham).
• Feedback update frequency was manipulated (1, 5, or 10 Hz).
• A transfer block without feedback followed training.

Main Results:

• Significant increases in alpha power were observed across all groups, irrespective of feedback condition or update frequency.
• Theta and sensorimotor rhythm bands also increased, while beta power remained stable.
• No specific modulation of alpha power was achieved.

Conclusions:

• Apparent alpha modulation in single-session neurofeedback likely stems from spontaneous, non-specific increases in oscillatory activity.
• Time-dependent factors like arousal or fatigue may influence outcomes more than volitional control.
• Rigorous methodological controls are essential for evaluating neurofeedback specificity.