Figure 6.

A, Simulated firing of BGMT thalamocortical neuron to somatic current injection (350 pA; 2 s of duration) for control (black trace) and after I_M blockade (red trace). For both, membrane potential was held at ∼−64 mV to inactivate T calcium channels and evoke tonic firing on depolarization. I_M blockade increases the model firing rate (compare black and red traces). B, Injected current-firing rate relationship of the model (F-I plot) for control (black), after 50% reduction (pink) and full blockade (red) of I_M current, with current intensities of 30–360 pA. I_M reduction and blockade shifts the F-I curve leftward, resulting in a decrease in spike threshold as well as an increase in firing rate. C, Rebound bursts in the model neuron evoked by hyperpolarizing current steps (−100 pA) of different durations (200, 500, 2000 ms), for control (black) and after I_M blockade (red). Insets show an expanded wave forms of a burst (green, purple). Membrane potential was held at ∼−71 mV. I_M reduction increases the rebound burst duration, i.e., spike count (compare green and purple wave form). D, Spike count in rebound bursting as in C, evoked by current steps of 200 ms (top), 500 ms (center), and 2000 ms (bottom), for control (black), after 50% reduction (pink) and full blockade (red) of I_M conductance. E, Sag generated in response to hyperpolarizing current pulses of increasing intensities (50–200 pA; no holding current) for control (black), after I_M blockade (red), and 200% increase of I_H (blue). F, Sag amplitude versus hyperpolarizing current intensity for control (black), after I_M blockade, 200% increase of I_H (blue), or combination of both changes (white). I_M blockade makes a small increase in sag amplitudes (compare red and black), while I_H increase brings the amplitudes to similar levels as observed in 6-OHDA-lesioned condition (compare blue, white, and black), combination of both changes allows to replicate the increase in the sag observed experimentally (compare white and black).

 Figure Contributions: Francesco Cavarretta conducted simulations, performed analysis, and prepared figure. Dieter Jaeger reviewed data and analysis.