e="" class="an ">&ensp;</span>reward <span  title="" class="an ">&ensp;</span>processing <span  title="" class="an ">&ensp;</span>monoaminergic <span  title="" class="an ">&ensp;</span>nuclei <span  title="" class="an ">&ensp;</span>express <span  title="" class="an ">&ensp;</span>hyperpolarization <span  title="" class="an ">&ensp;</span>activated <span  title="" class="an ">&ensp;</span>cyclic <span  title="" class="an ">&ensp;</span>nucleotid <span  title="" class="an ">&ensp;</span>gated <span  title=""