A team of Austrian researchers measured the brain activity of 17 sleeping adults (14 women and 3 men, average age 22) in response to familiar and unfamiliar voices, as occurs if we leave the television on.
None of the participants had sleep disorders and received polysomnography equipment – which measures brain waves, breathing, muscle tension, movements, heart activity – during a full night of sleep.
What happened?
While they slept, they were offered auditory stimuli through loudspeakers with two unknown names, spoken by a familiar voice (such as a parent) or an unfamiliar voice (a stranger). The researchers found that unfamiliar voices elicited more K complexes, a type of brain wave linked to sensory disturbances during sleep, compared to familiar voices.
brain in sentinel mode
Thus, hearing unfamiliar voices during sleep caused the human brain to “tune in,” causing large-scale changes in brain activity associated with sensory processing, a phenomenon that could go back to the long process of human evolution and the need to wake up quickly. in the face of potential danger.
“The results suggest that voice unfamiliarity is a strong promoter of brain responses during NREM sleep,” the authors explain in their study published in the Journal of Neuroscience.
Referencia: The brain selectively tunes to unfamiliar voices during sleep
Mohamed S. Ameen, Dominik PJ Heib, Christine Blume and Manuel Schabus
Journal of Neuroscience 17 January 2022, JN-RM-2524-20; DOI: https://doi.org/10.1523/JNEUROSCI.2524-20.2021
