Little minds, little memories: Studying the memory and sleep behaviors of 3-year olds

Sonoran UCEDD Update
Fall 2017

young girl handling cup, straw and ribbonAt the University of Arizona, a new study funded by the National Institutes of Health (NIH) and headed by Dr. Jamie Edgin is underway to develop and test a memory assessment for children with intellectual and developmental disabilities (IDD). The memory assessment is also greatly informative about memory in typically developing children, especially those under the age of 5 years, for whom the majority of tests are currently unsuitable.

Within this NIH study, undergraduate research assistant Kathryn Chung seeks to fill in the gap of understanding of the developmental link between sleep and episodic memory function in typical developing 3-year olds. Kathryn is a senior majoring in Neuroscience and Cognitive Science.

“Not only are there not a lot of memory measures for preschool-aged children, but there is also not enough research being done examining both sleep and memory in this age group, even though sleep is crucially important for memory,” Kathryn said.

To study this link, the lab designed a Deferred Imitation task - based on the gold-standard test by Patricia Bauer and Angela Lukowski’s Lab.

In this task, participants are presented with eight sets of objects. Using each set of objects, the children are shown a specific sequence of three actions that they then must immediately imitate. After a two-week delay, the participants are asked to replicate the actions they were taught before. These memory measures are thought to be reliant on a brain structure called the hippocampus.

In between these sessions, the child’s sleep is measured using actigraphy, which is essentially a watch-like device worn on the wrist that measures activity and light levels.

“Our lab is developing novel measures to assess memory retention in young children, and sleep is a big component to understanding how memories are formed,” said Edgin.

The question being asked here is: how does sleep quality affect the performance of these typical developing children on the Deferred Imitation task, or more specifically, on hippocampal encoding and retrieval of episodic memories?

For instance, take napping – many 3-year olds are still napping, while others have begun to phase out of napping, or stopped completely. The literature is mixed on the benefits and detriments of napping in this age group, as this is during the maturation of the hippocampus.

Other factors to consider are sleep duration and sleep quality. Kathryn says, “It’ll be curious to see how napping, sleep duration, or disturbance of sleep periods affects how well the children remember the task. It’s exciting to be able to explore this link between memory and sleep.”

The results of Kathryn’s project will also have implications for sleep and memory in children with IDD, such as Down Syndrome and Fragile X syndrome. Characterizing the relationship between sleep and memory function in the typically developing population may help to better understand the development of memory abilities in atypically developing populations.

Dr. Edgin is part of the Sonoran UCEDD faculty and Ms. Chung is a Sonoran UCEDD Trainee. This project is funded by the Undergraduate Biology Research Program, the LuMind Research Down Syndrome Foundation, and the National Institutes of Health.