Episodic memory consolidation during sleep across development

• Applicants: Professor Dr. Jan Born, since 3/2020; Marion Inostroza, Ph.D.
• Subject Area: Developmental and Educational Psychology ; Developmental Neurobiology ; Human Cognitive and Systems Neuroscience
• Term: from 2018 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 401829341

• Final Report Year: 2024

Final Report Abstract

This project explored how sleep contributes to the development of episodic memory, the type of memory that helps us remember what happened, where, and when. The research involved both rodents and humans to gain insights into how these memory systems develop over time and how they benefit from sleep. The project had two main goals. First, we wanted to investigate at what age children and young rats, respectively, start showing signs of episodic memory and how sleep helps strengthen these memories. We examined the relationships between the emergence of behavioral indicators of episodic memory components and specific brain oscillatory signatures of memory processing during sleep, such as slow oscillations and sleep spindles. The second goal was to examine whether the development of episodic memory and its related brain oscillatory signatures during sleep could be accelerated by exposing young rats to specific learning experiences. In our studies in rats, we found that allocentric spatial memory, a key part of episodic memory, has a rather protracted developmental trajectory with an adult-like expression of behavioral and associated sleep oscillatory features of a consolidated spatial memory achieved only in adolescence. We also discovered that prior exposure to spatial experiences could accelerate maturation of episodic memory functioning, i.e., after these experiences the rats showed earlier adult-like behavioral expression of spatial memory and a more fine-tuned synchronization of brain oscillatory signatures of episodic memory processing during sleep. In our studies in humans, we similarly observed that children have the capability to form long-term memory already at a very early age of 3 months. However, with increasing age their abilities improve to remember both specific details and more general schema-like memories. And these improvements were linked to changes in sleep oscillatory patterns, specifically to an increase in sleep spindles and their coupling to slow oscillations, which is associated with better memory retention. In combination, our findings in rodent and humans highlight the importance of sleep in memory development. Sleep not only helps consolidate specific memories but also supports the early development of memory systems.

Publications

• The expression of allocentric object-place recognition memory during development. Behavioural Brain Research, 372, 112013.
  Contreras, María P.; Born, Jan & Inostroza, Marion
  
• Accelerating Maturation of Spatial Memory Systems by Experience: Evidence from Sleep Oscillation Signatures of Memory Processing. The Journal of Neuroscience, 43(19), 3509-3519.
  Contreras, María P.; Fechner, Julia; Born, Jan & Inostroza, Marion
  
• Sleep electroencephalogram (EEG) oscillations and associated memory processing during childhood and early adolescence.. Developmental Psychology, 59(2), 297-311.
  Kurz, Eva-Maria; Zinke, Katharina & Born, Jan
  
• Long-term memory formation for voices during sleep in three-month-old infants. Neurobiology of Learning and Memory, 215, 107987.
  Bastian, Lisa; Kurz, Eva-Maria; Näher, Tim; Zinke, Katharina; Friedrich, Manuela & Born, Jan
  
• Sleep-slow oscillation-spindle coupling precedes spindle-ripple coupling during development. SLEEP, 47(5).
  Fechner, Julia; Contreras, María P.; Zorzo, Candela; Shan, Xia; Born, Jan & Inostroza, Marion