Effects of prenatal exposure to a 50-Hz magnetic field on one-trial passive avoidance learning in 1-day-old chicks

Area of Science:

• Neuroscience
• Developmental Biology
• Bioelectromagnetics

Background:

• Prenatal exposure to electromagnetic fields is a growing concern.
• Understanding the impact of magnetic fields on developing nervous systems is crucial.
• Avian models offer insights into early-life neurodevelopmental effects.

Purpose of the Study:

• To investigate the effects of in ovo magnetic field (MF) exposure on memory formation in newly hatched chicks.
• To determine if stress levels influence MF-induced memory impairment.
• To assess memory retention at different time points post-exposure.

Main Methods:

• Embryonic chicks were exposed to a 50-Hz, 2 mT magnetic field daily from embryonic days 12-18.
• Chicks were tested in isolated or paired conditions to modulate stress.
• Memory was assessed using a learned aversion task involving a bitter-tasting bead.
• Memory retention was evaluated at 10, 30, and 120 minutes post-training.

Main Results:

• Memory was unaffected at 10 minutes post-exposure in all groups.
• Isolated chicks exposed to MF showed significantly reduced memory retention at 30 and 120 minutes.
• Paired chicks, regardless of MF exposure, maintained good memory retention.
• MF exposure impaired long-term memory, particularly under higher stress conditions.

Conclusions:

• In ovo exposure to a 50-Hz magnetic field may disrupt memory formation in chicks.
• The observed memory impairment is more evident in socially isolated (higher stress) chicks.
• These findings suggest that prenatal MF exposure could have detrimental effects on cognitive development, potentially modulated by environmental stressors.