The paper/source linked at the end of the article describes this newly discovered type of signal called "calcium-mediated dendritic action potentials".<p>Dendritic action potentials and computation in human layer 2/3 cortical neurons<p><a href="https://science.sciencemag.org/content/367/6473/83" rel="nofollow">https://science.sciencemag.org/content/367/6473/83</a>