A study published in Nature Neuroscience highlights brain activity that happens when a sleeping person hears music. A team of UCLA researchers examined brain activity in the cerebral cortex of epilepsy patients. They discovered a significant response to sound during sleep that resembles the brain’s response during wakefulness.
The researchers observed a key difference in the level of alpha-beta waves between a sleeping state and one of wakefulness. Neural feedback from higher brain centers provides insight into understanding the impact of sound and anticipating what may come next. Study co-author and director of UCLA’s Epilepsy Surgery Program Dr. Itzhak Fried explained the sleeping brain’s neural activity. He stated that, “the neuronal orchestra is never shut from the environment when the person is deep asleep. The neurons are like musicians playing Mozart, each one with great fidelity and volume. Only the conductor, the one who monitors performance and leads expectations, is missing.” The study noted significant activity in the primary auditory cortex during sleep, but there was less neural feedback from higher brain regions responsible for regulating attention and expectation.
Patients with severe epilepsy had electrodes implanted in their brains to locate where seizures were occurring. Patients at UCLA and Tel Aviv Sourasky Medical Center were included in the study, and they were set up with bedside speakers that played words and music when the patients were awake and listening as well as when they were asleep. The team collected data from over 700 neurons during wakefulness and different stages of sleeping over a 7-year time period. This methodology allowed them to compare neuronal activity and brain waves.
Music involves every area of the brain. Music affects the brain in positive ways. Studies of children studying an instrument have demonstrated that musical learning changes brain structure. The visual cortex is engaged when reading musical sheets. Benefits such as improved cognitive skills, decision-making and social behavior are associated with specific changes in brain structures.
The findings from this study provide insights into auditory information processing by people in unconscious states. The findings have implications for developing effective treatments for comatose patients or those under anesthesia.
Source: Nature Neuroscience
