Immunofluorescence-stained tadpoles visualize internal anatomy, utilizing brain-tracking devices implanted as embryos.
Hao Sheng et al. 2025, Jia Liu Lab/Harvard SEAS
Do our brains really develop from practically anything, allowing us to generate complex thoughts, actions, and even reflections on ourselves? Recent experiments with tadpoles have integrated electron implants into brain precursors during early embryonic stages, potentially bringing us closer to answering this question.
Earlier efforts to investigate neurodevelopment relied on tools like functional magnetic resonance imaging and rigid electrode wires. Unfortunately, the imaging resolution was often too low to be effective, while the rigid wires caused significant damage to the brain, yielding little more than a snapshot of specific developmental moments.
Researchers, including Jia Liu from Harvard University, discovered a material (a type of perfluropolymer) closely resembling brain tissue. They employed this to create a flexible, elastic mesh encasing an ultra-thin conductor, which was placed onto the neural plate—a flat structure that serves as the precursor to the brain—in the embryos of the African clawed frog (Axenopath Ravis).
As the neural plates folded and expanded, these ribbon-like meshes were enveloped by the developing brain, maintaining functionality amidst stretching and bending in the tissue. When the researchers sought to measure signals from the brain, they connected the meshes to computers to visualize neural activity.
The implants did not harm the brain nor provoke an immune reaction, and the tadpole embryos developed as anticipated. In fact, at least one grew into a normal frog, according to Liu.
“It’s incredible to integrate all these materials and ensure everything operates seamlessly,” said Christopher Bettinger from Carnegie Mellon University, Pennsylvania. “This tool has the potential to significantly advance basic neuroscience by enabling biologists to observe neural activity throughout development.”
The team derived two key insights from their experiments. First, the patterns of neural activity shifted as tissue differentiated into specialized structures, resulting in distinct functions. Liu noted that tracking an organism’s self-organization to a computer was previously deemed impossible.
The second area of focus was how brain activity in animals changes following amputation. Traditionally, it was believed that electrical activity would revert to its original developmental state. The research team confirmed this by utilizing implants in experiments with Axolotls.
Liu’s team is now broadening their research to include rodents. Unlike amphibians, rodent development occurs within the uterus, making the implantation of meshes more challenging. It requires in vitro fertilization and more intricate signaling measurement techniques compared to simply wiring the mesh to computers. Nonetheless, Liu is optimistic that the insights gained from observing early stages of conditions like autism and schizophrenia will justify the complexities involved.
Bettinger mentioned that similar devices could also be applied to monitor neuromuscular regeneration following injuries and during rehabilitation. “Overall, this highlights the remarkable potential of highly compliant electronic applications,” he stated.
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Source: www.newscientist.com
