Dim light at night may cause depression-like behavior and reduce nerve cell connections in the memory area of female hamsters

Dim light at night is associated with reduced dendritic spine density in the hippocampus.

• Exposure to dim light at night resulted in more depression-like responses in behavioral tests compared to normal light/dark cycles.
• Chronic exposure to low-level nighttime illumination may influence mood and affective responses.
• In the hippocampus, specifically the CA1 region, reduced dendritic spine density was observed in hamsters exposed to dim light.
• This reduction in synaptic connections occurred without differences in baseline cortisol levels between groups.
• The findings suggest that common nighttime light exposure could contribute to the rising rates of mood disorders.

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