Brain imaging studies of lucid dreaming have revealed correlations with neural activity, but causal methods are needed to understand the role of the dorsolateral prefrontal cortex in metacognitive insight during dreams. The authors propose using transcranial magnetic stimulation, transcranial direct current stimulation, and galvanic vestibular stimulation to directly interfere with neural functioning during sleep. They argue that aspects of dream lucidity can be investigated in ordinary, nonlucid dreams, enabling more comprehensive and efficient experiments. This approach would deepen understanding of self-consciousness in dreams and integrate dream research into broader neurophilosophical theories of consciousness and the self.
Applying transcranial direct current stimulation (tDCS) over the sensorimotor cortex during REM sleep reduces reported dream movement, particularly repetitive actions, without affecting other bodily sensations like touch or balance. This effect coincides with reduced interhemispheric coherence in parietal areas and altered muscle activity correlation between arms. The findings indicate that tDCS causally interferes with the neural mechanisms underlying dream movement, confirming the spatial specificity of the stimulation site and suggesting a reorganization of the motor network during dreaming.