<span class="fu"><a href="https://rdrr.io/pkg/oro.nifti/man/overlay-methods.html" class="external-link">overlay</a></span><span class="op">(</span><span class="va">img</span>, y <span class="op">=</span> <span class="va">img</span> <span class="op">&gt;</span> <span class="fu"><a href="https://rdrr.io/r/stats/quantile.html" class="external-link">quantile</a></span><span class="op">(</span><span class="va">img</span>, <span class="fl">0.9</span><span class="op">)</span>, z <span class="op">=</span> <span cla