ss="comment">%     value SPIKES.OPTIONS.REFRACTORY_PERIOD with units of seconds (e.g.,</span>
0022 <span class="comment">%     set to 0.0017 to indicate an expected refractory period of 1.7 msec).</span>
0023 <span class="comment">%</span>
0024 <span class="comment">%     The SPIKES.HIERARCHY.TREE output is a matrix describing the aggregation.</span>
0025 <span class="comment">%     Each aggregation step entry produces a row, listed in the order they</span>
0026 <span class="comment">%     were performed.  