The Tactile Window to Consciousness is Characterized by Frequency-Specific Integration and Segregation of the Primary Somatosensory Cortex.
Scientific Reports February 11, 2016 Julia Natascha Frey, Philipp Ruhnau, Sabine Leske et al.
Conscious perception of a faint touch depends not only on brain activity in the sensory cortex but also on the state of larger brain networks just before the stimulus arrives. In a magnetoencephalography study, participants performed a near-threshold tactile detection task. Before correctly detected stimuli, alpha and beta power were reduced in the somatosensory region opposite the stimulated hand, and event-related responses were stronger afterward. Graph analysis revealed that the right primary somatosensory cortex showed increased integration in the theta band and decreased integration in the beta band before detection. These findings suggest that a reduction of irrelevant functional connections helps tune neural pathways for conscious perception.