Figure 2
<p><b>Hypothesized Propagation of Activity in Human Neocortex</b>
</p>
An action potential in a pyramidal neuron (cell 1) elicits a spike in a chandelier cell (2) via a strong connection, in turn evoking a third-order spike in a downstream pyramidal cell (3). This spike results in a trisynaptic EPSP being recorded in a postsynaptic pyramidal cell (cell 4, event A). At the same time, cell 3 drives both a basket cell (5) and chandelier cell (6) to threshold. The basket cell evokes a hyperpolarizing IPSP on the postsynaptically recorded pyramidal cell (cell 4, event B), four synapses removed from the original spike. The spiking chandelier cell (6) triggers yet another pyramidal neuron to fire (7), which produces an EPSP on the recorded neuron (cell 4, event C), five synapses away from the original spike. The result seen in the postsynaptic pyramidal neuron (cell 4) is a delayed EPSP-IPSP-EPSP sequence (events A, B, and C), traveling through three, four, and five synapses respectively. Molnár et al. propose that polysynaptic pathways similar to this one can be activated by a single action potential in a cortical pyramidal cell.
Alan Woodruff and Rafael Yuste
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<cite style="font-style:normal">Woodruff A, Yuste R (September 2008). "<a rel="nofollow" class="external text" href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2553849">Of Mice and Men, and Chandeliers</a>". <i><a href="//commons.wikimedia.org/w/index.php?title=PLoS_Biol.&amp;action=edit&amp;redlink=1" class="new" title="PLoS Biol. (page does not exist)">PLoS Biol.</a></i> <b>6</b> (9): e243. <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.pbio.0060243">10.1371/journal.pbio.0060243</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/18816168">18816168</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/PMC2553849">2553849</a>.</cite>