Artificial light at night impairs visual lateralisation in a fish

Area of Science:

• Neuroscience
• Developmental Biology
• Environmental Science

Background:

• Environmental light exposure during early development is crucial for brain lateralisation.
• Artificial light at night (ALAN) is a pervasive form of environmental pollution with unknown effects on neurodevelopment.
• Lateralisation, or brain hemisphere specialization, influences information processing and behavior.

Purpose of the Study:

• To investigate the impact of artificial light at night (ALAN) on the lateralisation of zebrafish larvae.
• To assess whether ALAN affects motor and visual processing lateralisation in developing fish.

Main Methods:

• Zebrafish eggs and larvae were exposed to either control light conditions or artificial light at night (ALAN).
• Motor lateralisation was assessed using a rotational test.
• Visual stimulus lateralisation was evaluated with a mirror test.

Main Results:

• Control zebrafish larvae exhibited significant population-level lateralisation bias, favoring right-hemisphere processing.
• Zebrafish larvae exposed to ALAN showed a significant reduction in this lateralisation bias.
• ALAN exposure also led to decreased individual differences in lateralisation among fish.

Conclusions:

• Artificial light at night (ALAN) disrupts natural brain lateralisation in zebrafish larvae.
• This disruption may have implications for fish behavior, adaptation, and survival.
• Environmental light pollution is a potential threat to neurodevelopment in aquatic organisms.