Manganese Enhanced Magnetic Resonance Imaging reveals light-induced brain asymmetry in embryo

The idea that sensory stimulation to the embryo ( in utero or in ovo ) may be crucial for brain development is widespread. Unfortunately, up to now evidence was only indirect because imaging of embryonic brain activity in vivo was not viable. Here we applied for the first time Manganese Enhanced Magnetic Resonance Imaging (MEMRI) to the eggs of domestic chicks. We revealed light-induced brain asymmetry by comparing embryonic brain activity in vivo of eggs that were stimulated by light or maintained in the darkness. Our protocol paves the way to investigation of the effects of a variety of sensory stimulations on brain activity in embryo. Significance Sensory stimulation in embryo may be crucial for many aspects of brain and behavioral development (e.g., mother language in humans). However, direct evidence of this is lacking because imaging of embryonic brain activity in vivo is not viable. Here we established a new protocol for measuring embryonic brain activity in vivo in domestic chick eggs. We were able to visualize in vivo the effect of light stimulation on the development of structural brain asymmetries of the embryo. The protocol established paves the way for collecting further evidence on the effects of sensory stimulation on embryonic brain activity. ### Competing Interest Statement The authors have declared no competing interest.