Fig. 6

AMPA/KA receptor-mediated excitatory synaptic transmission in both pyramidal neurons and interneurons in the ACC. A Representative traces of a single neuron in the presence of ACSF, picrotoxin (100 µM) and AP5 (50 µM) (top). Perfusion of GYKI 53655 (50 µM) decreases EPSC amplitude and reveals KA receptor mediated EPSCs (middle). Perfusion of CNQX (20 µM) blocked all residual currents (bottom). B Plotting the time course of GYKI 53655 and CNQX perfusion and its effect on EPSCs recorded in the patched neuron. C Statistical results comparing the percentage of EPSCs during baseline, GYKI, and GYKI + CNQX perfusion (41 channels, n = 6 neurons/3 mice). Differences in percent amplitude were found to be significant *p < 0.05, SEM is represented by error bars. D Pharmacological isolation of AMPA and KA receptors on interneurons using GYKI 53655 (50 µM) and CNQX (20 µM) on both FS-INs and RS-INs shown as a percent of the baseline amplitude. In FS-INs, GYKI 53655 resulted in a 94.3 ± 1.4% decrease from 105.5 ± 17.3 pA to 6.1 ± 0.6 pA (**p < 0.01). In RS-INs, GYKI 53655 resulted in a 94.2 ± 1.6% decrease from 60.3 ± 10.6 pA to 3.5 ± 0.4 pA (***p < 0.001). E A bar graph showing the proportion of mono to polysynaptic connections in pyramidal neurons, FS, and RS interneurons (70.2% monosynaptic; n = 16, 5, and 3 neurons respectively, 24 mice total). F A bar graph re-examining response kinetics of neurons based on neuron type and not distance shows that rise time is significantly larger only in regulars-spiking interneurons (Rise time; RS IN: 10.2 ± 3.6 ms; PN Mono: 2.7 ± 0.1 ms; PN Poly: 3.3 ± 0.3 ms; FS IN: 2.6 ± 0.4 ms; ***p < 0.001; one-way ANOVA). The shortest average decay time was observed in monosynaptic pyramidal neurons followed by polysynaptic pyramidal neurons (***p < 0.001; Welch t-test). Both fast-spiking and regular-spiking interneurons had larger decay times than that of pyramidal neurons (Decay time; PN Mono: 16.4 ± 0.7 ms; PN Poly: 22.2 ± 1.9 ms; FS IN: 35.5 ± 5.2; RS IN: 29.3 ± 4.7; ***p < 0.001; one-way ANOVA). G Sample traces depicting mono and polysynaptic responses in pyramidal neurons, polysynaptic responses in interneurons, and typical undetectable responses