Molecular evidence suggests that the ability to generate electric signals first appeared in evolution some 700 to 800 million years ago, during the Tonian period.

citation

Wikipedia contributors. (2024, February 11). Neuron. In Wikipedia, The Free Encyclopedia. Retrieved February 12, 2024, from https://en.wikipedia.org/w/index.php?title=Neuron&oldid=1206127096

Tonian (Wikipedia) The Tonian (from Ancient Greek: τόνος, romanized: tónos, meaning “stretch”) is the first geologic period of the Neoproterozoic Era. It lasted from 1000 to 720 Mya (million years ago). Instead of being based on stratigraphy, these dates are defined by the ICS based on radiometric chronometry. The Tonian is preceded by the Stenian Period of the Mesoproterozoic Era and followed by the Cryogenian.

Neuron (Wikipedia) Within a nervous system, a neuron, neurone, or nerve cell is an electrically excitable cell that fires electric signals called action potentials across a neural network. Neurons communicate with other cells via synapses, which are specialized connections that commonly use minute amounts of chemical neurotransmitters to pass the electric signal from the presynaptic neuron to the target cell through the synaptic gap.