Unveiling the Ancient Origins of Neurons Through Tiny Sea Creatures

Researchers have discovered characteristics of specialized secretory cells in placozoans, simple animals from 800 million years ago, that resemble a prelude to neurons in other organisms. These peptidergic cells in placozoans release peptide signals to coordinate their behavior, similar to how neurons function. While they have some similarities to primitive neuronal cells, they lack certain specialized components found in modern neurons. The genes of these peptide-releasing cells are highly conserved in placozoans but absent in other early animals, suggesting they may have evolved before other neuron-like cells. This finding raises questions about the evolution of neurons and the origins of brain cells.