Figure 3.

Tonic GABA_A conductances differentially affect responses to bAP/EPSP pairing and EPSP burst in the model pyramidal neuron. a, The synapse location (green dots) on the simulated pyramidal neuron. Two electrodes indicate where V_m was obtained: red, on soma; blue, on a second-order dendritic branch. The somatic electrode also indicates where the current injection used to elicit bAP occurred. b, The Ca²⁺ transients in the dendrite (top row); V_m in the dendrite (middle row) and the soma (bottom row). Left column, EPSP. Middle column, bAP. Right column, bAP/EPSP pairing. [Ca²⁺]_i, Intracellular Ca²⁺ concentration. c, The ΔV_m to bAP/EPSP pairing in control (Ctrl, gray), on an increase in the tonic GABA_A conductance (GABA, green), and subsequent blockade of NMDARs (GABA + APV, orange). d, The Ca²⁺ transient in response to bAP/EPSP pairing in control (gray), and on an increase in the tonic GABA_A conductance (green), and subsequent blockade of NMDARs (orange). e, The summary of data on the effect of tonic GABA_A conductances (GABA) on the amplitude of the Ca²⁺ transient induced by bAP/EPSP pairing (empty bar) and EPSP burst (filled bar). f, The summary of data on the effect of subsequent NMDAR blockade (GABA + APV) on the amplitude of the Ca²⁺ transient induced by bAP/EPSP pairing (empty bar) and EPSP burst (filled bar). g, The ΔV_m to EPSP burst in control (gray), and on an increase in the tonic GABA_A conductance (green), and subsequent blockade of NMDARs (orange). h, The Ca²⁺ transient in response to EPSP burst in control (gray), and on an increase in the tonic GABA_A conductance (green), and subsequent blockade of NMDARs (orange).