Repetitive Brain Injury of Juvenile Mice Impairs Environmental Enrichment-Induced Modulation of REM Sleep in Adulthood

Neuroscience, 2018 · DOI: 10.1016/j.neuroscience.2018.01.064 · Published: April 1, 2018

Simple Explanation

This study investigates the long-term effects of repeated mild traumatic brain injuries (TBIs) during adolescence on sleep patterns in adulthood. It also explores whether providing an enriched environment can prevent any sleep disturbances caused by these injuries. The researchers found that while TBIs during adolescence didn't significantly alter basic sleep patterns, they did prevent the positive effects of environmental enrichment on REM sleep. Environmental enrichment typically enhances REM sleep, but this effect was not seen in mice with prior TBIs. This suggests that TBIs during development can have lasting effects on how the brain responds to environmental factors known to promote recovery and plasticity, particularly in relation to sleep regulation.

Study Duration

9 weeks

Participants

41 Swiss-Webster mice (male pups)

Evidence Level

Level 2: Animal Study

Key Findings

1
Repeated mild TBIs in juvenile mice did not significantly alter basal or homeostatic sleep responses in adulthood under standard laboratory conditions.
2
Environmental enrichment enhanced REM sleep and pro-melanin concentrating hormone expression in sham-injured mice, but this effect was blocked in TBI mice.
3
Silver staining revealed mTBI-induced axon damage that persisted at 9 weeks following injury, and did not differ as a function of housing condition

Research Summary

The study aimed to determine if multiple mild traumatic brain injuries in juvenile mice lead to disrupted sleep cycles in adulthood, and if this effect is prevented by an enriched environment (EE). The results indicated that repeated juvenile traumatic brain injuries did not significantly impair basal sleep physiology or the homeostatic response to sleep deprivation. However, traumatic brain injury blocked the REM sleep-modulatory effects of EE. The findings suggest that even mild TBIs during development can persistently alter sleep responses into adulthood, highlighting the importance of addressing sleep dysfunction in TBI patient populations.

Practical Implications

Rehabilitation Strategies

The findings suggest that TBI patients may not benefit from environmental enrichment strategies to improve sleep, indicating the need for alternative or tailored interventions.

Clinical Management

The study highlights the importance of monitoring and addressing sleep disturbances in TBI patients, even those with mild injuries, as these disturbances can have long-term consequences.

Further Research

Future studies should investigate the mechanisms underlying the interaction between TBI and environmental enrichment on sleep regulation, as well as explore potential interventions to restore plasticity in the sleep system.

Study Limitations

1
The study may not have detected transient sleep disruptions that occurred in the early post-injury period.
2
The implantation of sleep recording devices may have differentially produced inflammatory responses in mice with a history of brain injury.
3
The study was not designed to determine whether observed sleep changes in adulthood were also present earlier in life.

Your Feedback

Was this summary helpful?

Back to Sleep Medicine