Phase-space structure of a thermoreceptor

We analyze the phase-space structure of a model for thermoreceptors in fish and mammals. As a function of the temperature we identify a period doubling scenario at low temperatures, a regime where an unstable stationary fixed point collides with the attractor and blocks the thermoreceptor, and a transition from period n+1 to period n as the temperature is further increased. The period reduction phenomenon is due to an autoresonance between fast and slow ion channels and shows the features typical for mode locking.