Fig. 5: Presynaptic GABA_BRs strongly inhibit synaptic inputs to human cortical PCs.

A Recording configuration for L2/3 PCs, showing stimulus (lightning) applied to L1 or L4. B EPSCs evoked by L1 stimulation in L2/3 PCs were recorded at −70 mV for control (Ctrl) and following application baclofen (Bacl.) and CGP, the latter underlain by control (grey). Time-course of EPSC amplitude following baclofen and CGP wash-in is shown below, with baseline indicated (grey dashed line). C Data in the same form, but for L4 inputs (light grey). D Baclofen-mediated inhibition of L1 (black) and L4 (grey) inputs to L2/3 PCs during the last minute of wash-in from 6–8-month-old rats (8 cells/4 rats) and humans (L1: 15 cells/7 cases; L4: 14 cells/7 cases). E Recording configuration for L5 PCs with stimulus applied to L1 or L5. F EPSCs evoked by L1 stimulation in L5 PCs under control (Ctrl), and following baclofen, and CGP, the latter underlain by control (blue traces). Time-course of EPSC amplitude following baclofen and CGP wash-in is shown below. G Data in the same form, but for L5 inputs (light blue). H Baclofen-mediated inhibition of L1 (blue) and L5 inputs (light blue) inputs to L5 PCs during the last minute of wash-in from 6–8-month-old rat (L1: 9 cells/4 rats; L5: 9 cells/4 rats) and human (L1: 10 cells/3 cases; L5: 10 cells/3 cases). I Human EPSC recordings from L1 stimulation in L2/3 PC following L1 stimulation, before (black) and after (red) CGP wash-in for 10 EPSCs have been amplitude scaled for brevity to clarify CGP effects. J Short-term plasticity (STP) of EPSCs, normalised to the first, at 10 Hz (6 cells/3 cases). K STP of EPSCs at 20 Hz (6 cells/3 cases). Data is shown as mean ± SEM (B, C, F, G, J, K) or boxplots (25–75% range) with the median indicated and whiskers indicating maximum/minimum ranges (D, H). All statistics are shown from either LMM (D, H) or 2-way repeated measures ANOVA (2-sided, J, K). Source data are provided as a Source Data file.