Figure 5.

Characteristics of bursting: input–output functions, time dependence, and voltage-dependence. (A) Left: example of a low-threshold bursting neuron's response to increasing depolarizing pulse amplitude. Right: example of a regular spiking neuron's response to increasing depolarizing pulse amplitude. Both neurons are layer 5 corticothalamic neurons. Spikes are truncated in height for clarity. (B) Mean input–output functions for low-threshold bursting (blue) and regular spiking (red) layer 5 corticothalamic neurons. Error bars represent the standard deviation (SD). The y-axis shows number of spikes expressed as a percentage of the maximum number of spikes fired in a 25-ms window after response onset. (C) Response of low-threshold bursting neurons to paired-pulse stimulation. Shown in an overlay of 4 traces of a single neuron in response to interstimulus intervals of 62.5, 125, 250, and 500 ms. Action potential heights are truncated for clarity. (D) Interpulse interval versus average of the ratio of spike output in response to the second pulse to spike output in response to the first pulse. Error bars represent the SD at each point. (E) Response of a low-threshold bursting neuron to a depolarizing prepulse. This neuron responded to a 100 pA depolarizing pulse with a typical low-threshold burst. (F) After this cell is depolarized by about 10 mW by a 300 pA depolarizing pulse and rechallenged with 100 pA positive current pulse, this cell fired only individual spikes rather than a burst.