On the afternoon of March 18th, Dr. Xia Tao, a postdoctoral researcher from Dr. Hu Xiaoqing's research group at the Department of Psychology, the University of Hong Kong, delivered a lecture titled “Unraveling Human Cognition During Sleep: From Active Stimulation to Behavioral Response” at the School of Psychology, Shenzhen University. Dr. Xia shared his series of studies on sleep cognition with the faculty and students, providing students with expanded insights on sleep stimulation and memory-related research, and revealing the effects and potential mechanisms of sleep stimulation intervention on human cognitive functions.
Dr. Xia introduced the traditional method of studying cognition by comparing the behavioral performance of the Sleep Group and the Wake Group, and pointed out the limitations of these methods. He proposed that targeted reactivation, sleep learning, and real-time behavioral response monitoring could be used to effectively intervene in negative memories through sleep stimulation. Dr. Xia detailed three studies in this sharing session.
Firstly, in the Targeted Memory Reactivation (TMR) experiment, the research team played sound stimuli related to memory cues during sleep and recorded electrophysiological indicators such as slow oscillations and spindles using electroencephalography (EEG). The study found that these neural signals could predict the effect of memory consolidation, with theta oscillations playing a key role in the regulation of emotional memories. The results showed that the activation of positive memory cues could significantly weaken the emotional response to negative memories.
Secondly, in the sleep learning experiment, the study found that presenting positive words during sleep could successfully weaken the emotional response to negative memories. The experimental results showed that the presentation of positive words significantly improved emotional judgment, especially during the upstate phase of slow oscillations, when the emotional updating effect was the best.
Next, through real-time behavioral response monitoring, the research team conducted arithmetic decision-making and word judgment tasks during the Lucid Dreaming state, recording the participants' reaction times and accuracy using electroencephalography (EEG) and electromyography (EMG). This revealed differences in cognitive strategies across different sleep stages, such as NREM and REM sleep. The experiment found that during the NREM stage, participants' reactions to real words were significantly faster than to pseudowords, while in the REM stage, due to the competition between internal and external processes, overall cognitive efficiency declined. These research results indicate that neural oscillations during sleep, such as slow waves and spindles, play an important role in memory consolidation and emotional regulation.
Finally, Dr. Xia proposed future research plans, including establishing an objective nightmare detection system, developing olfactory and auditory interventions, and studying the comorbidity of mental illnesses and sleep disorders.
