Line Plot from Scientific Research

Top: illustration of anin vitropaired recording experiment to assess DSI. Note that in CCKBCs, but not in PVBCs, IPSPs in postsynaptic PCs are suppressed following PC depolarization (solid lines) compared with baseline (dashed lines). This suppression is mediated by eCBs, as indicated by its sensitivity to CB1receptor antagonists. Middle: illustration ofin vivoimaging experiments to assess DSI. GRABeCB2.0imaging shows eCB release following calcium transients in PCs (left). All-optical interrogation of IPSPs shows suppressed IPSP following PC depolarization (right). CCKBCs were optogenetically stimulated using blue light, while a genetically encoded voltage indicator was imaged to record changes in the membrane potential of postsynaptic PCs. Blue bar illustrates photoactivation of presynaptic CCKBCs. Optically evoked IPSPs were detected when the PC was quiet before the light pulse (dashed line), while IPSPs were suppressed if the light pulse followed a spontaneous plateau-driven complex spike in the PC (solid line). The depolarization associated with such events may release eCBs and induce DSI. IPSPs are not drawn to scale with action potentials. Bottom: immediate-early gene expression in PCs leads to BC type-specific inhibitory plasticity: while Fos activation leads to increased PVBC and decreased CCKBC synapse strength, Npas4 activation leads to increased inhibition by CCKBCs. Red nuclei symbolize activated cells (dark colors) compared with neighboring inactive cells (light colors). Round markers symbolize synapses.

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