Bright light exposure during simulated night work improves cognitive flexibility

Area of Science:

• Neuroscience
• Chronobiology
• Occupational Health

Background:

• Night work is associated with sleepiness and reduced vigilant attention.
• Total sleep deprivation is known to impair cognitive flexibility, particularly reversal learning.
• The impact of night work on reversal learning and the potential mitigating effect of bright light remain unclear.

Purpose of the Study:

• To investigate whether night work impairs reversal learning task performance.
• To determine if bright light interventions can mitigate reversal learning deficits during night work.

Main Methods:

• A counterbalanced crossover study involving young healthy individuals.
• Participants completed a reversal learning task during three simulated night shifts (23:00-07:00).
• Night shifts were conducted under two light conditions: bright light (~900 lx) and standard light (~90 lx).

Main Results:

• Reversal learning performance decreased towards the end of night shifts in both light conditions.
• Bright light exposure led to improved reversal learning performance at the end of night shifts compared to standard light.
• Bright light mitigated performance deficits on the reversal learning task.

Conclusions:

• Night work impairs cognitive flexibility as measured by reversal learning.
• Bright light interventions during night work can mitigate these performance deficits.
• Bright light may be beneficial for both vigilant attention and cognitive flexibility during night shifts.