 Incoherent feedforward loop

An incoherent feedforward loop carries influences from a shared input to a shared output along routes with opposite net signs. In the signaling adaptation toy, $s$ drives fast $x$ and slow $a$, which contribute with opposite signs to $r=x-a$. Despite the conventional word "loop", those routes do not return the output to an earlier stage: this arrangement is distinct from negative feedback. Opposing routes alone do not guarantee complete signaling adaptation. ^[ref]