Stimulation of axons in a channel back-propagating to somas in chambers and along axonal branches. Colors correspond to spike amplitudes with red representing the most positive (50 μV and above) and blue the most negative (-20 μV and below) voltage amplitudes. The characteristic signature of a propagating triphasic signal was a positive (red) peak followed quickly by a negative (blue) peak, and then another smaller positive peak at the end. The signals were especially large in amplitude in the channels. Outside of the channels, somatic activity was also readily apparent but smaller in amplitude, while axonal signals were yellow in color, and generally hard to detect in the noise.
Lewandowska M, Bakkum D, Rompani S, Hierlemann A
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<a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4348166/bin/pone.0118514.s002.avi">S1 Movie</a> from <cite style="font-style:normal">Lewandowska M, Bakkum D, Rompani S, Hierlemann A (2015). "<a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4348166">Recording Large Extracellular Spikes in Microchannels along Many Axonal Sites from Individual Neurons</a>". <i>PLOS ONE</i>. <a href="https://en.wikipedia.org/wiki/Digital_object_identifier" class="extiw" title="w:Digital object identifier">DOI</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1371/journal.pone.0118514">10.1371/journal.pone.0118514</a>. <a href="https://en.wikipedia.org/wiki/PMID" class="extiw" title="w:PMID">PMID</a> <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pubmed/25734567">25734567</a>. <a href="https://en.wikipedia.org/wiki/PubMed_Central" class="extiw" title="w:PubMed Central">PMC</a>: <a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4348166">4348166</a>.</cite>