# Math Insight

### Image: Neuron firing rate with kink and nicotine

A fictitious representation of the firing rate $r(i,s)$ of a neuron in response to an input $i$ and nicotine level $s$. As nicotine increases from $s=0$ to $s=2$ and $s=4$, the location of the kink moves to lower input levels and the curve flattens.

Image file: neuron_firing_rate_kink_nicotine.png