New York: A recent study conducted by researchers at Cornell University highlights the significant role pupil size plays in understanding how the brain forms and consolidates strong, long-lasting memories. The research, conducted on mice, reveals that pupil contraction and dilation during specific sleep stages are associated with the processing of new and old memories, respectively.
The study found that during a substage of non-REM sleep, when the pupil contracts, the brain actively replays and consolidates newly acquired memories. Conversely, when the pupil dilates during another substage, older memories are reactivated and integrated. This separation prevents "catastrophic forgetting," where the consolidation of one memory might erase another.
Published in the journal Nature, the findings suggest that the brain operates on an intermediate timescale to distinguish new learning from established knowledge. Azahara Oliva, an assistant professor at Cornell, stated that this mechanism ensures efficient memory processing and retention.
The study involved equipping mice with brain electrodes and miniature eye-tracking cameras. These tools monitored the animals’ neural activity and pupil changes as they engaged in various tasks, such as navigating mazes to collect water or cookie rewards. Data collected during subsequent sleep revealed that the temporal structure of mouse sleep was more complex and similar to human sleep stages than previously understood.
The researchers observed that when mice entered a specific substage of non-REM sleep, their pupils shrank, signaling the brain's reactivation and consolidation of recently learned tasks. In contrast, during periods of pupil dilation, older memories were replayed and integrated.
The study’s implications extend beyond neuroscience. The researchers believe these insights could lead to improved memory enhancement techniques for humans. Additionally, the findings may assist computer scientists in designing more efficient artificial neural networks, drawing parallels between biological memory consolidation and machine learning processes.
This research underscores the intricate relationship between sleep, pupil dynamics, and memory formation, paving the way for advancements in both human cognition and artificial intelligence.