Image of the Day: Brainless Frogs
Image of the Day: Brainless Frogs

Image of the Day: Brainless Frogs

Without a brain, the frog embryo immune system doesn’t receive the signals it needs to mobilize macrophages and fight infections.

Amy Schleunes
Amy Schleunes

A former intern at The Scientist, Amy studied neurobiology at Cornell University and later earned her MFA in creative writing from the University of Iowa. She is a Los...

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Feb 18, 2020

ABOVE: The tail of a brainless frog embryo shows an abnormal distribution of immune cells (green) and a haphazard network of nerves (red).

Developing frog embryos without brains die of E. coli infections at higher rates than embryos with brains, report the authors of a study published on February 5 in npj Regenerative Medicine. The brain appears to send signals to the embryo’s nascent immune system, which results in macrophages moving to the site of an infection, according to a press release.

“Our results demonstrate the deep interconnections within the bacteria-brain-body axis: the early brain is able to ‘sense’ the pathogenic bacteria and to elaborate a response targeted to fight against the cellular and molecular consequences of the infection,” says coauthor Celia Herrera-Rincon of Tufts University in the statement.

A frog embryo head shows a normally developing brain and retina in the right eye (both neon green) and cranial nerves (pink).
C. Herrera-Rincon et al., NPJ REGENERATIVE MEDICINE, doi:10.1038/s41536-020-0087-2, 2020

C. Herrera-Rincon et al., “An in vivo brain-bacteria interface: the developing brain as a key regulator of innate immunity,” npj Regenerative Medicinedoi:10.1038/s41536-020-0087-2, 2020.

Amy Schleunes is an intern at The Scientist. Email her at

Correction (February 18): The article originally stated that the paper was published in Naturenpj Regenerative Medicine published the article. The Scientist regrets the error.