n><span  title="" class="an ">&ensp;</span>and <span  title="" class="an ">&ensp;</span>that <span  title="" class="an ">&ensp;</span>their <span  title="" class="an ">&ensp;</span>activity <span  title="" class="an ">&ensp;</span>may <span  title="" class="an ">&ensp;</span>only <span  title="" class="an ">&ensp;</span>be <span  title="" class="an ">&ensp;</span>modulated <span  title="" class="an ">&ensp;</span>by <span  title="" class="an ">&ensp;</span>synaptic <span  title="" class="an ">&ensp;</span>i