Synaptic Plasticity and Excitation-Inhibition Balance in the Dentate Gyrus: Insights from In Vivo Recordings in Neuroligin-1, Neuroligin-2, and Collybistin Knockouts

Figure 3

The influence of NL1 and NL2 on synaptic transmission and granule cell firing. (a) Normal granule cell firing in the NL1-deficient dentate gyrus. Population spike is a measure of granule cell firing. Input-output relationship for population spike amplitudes recorded in WT and NL1 KO mice was not changed indicating similar capability for generating action potentials. (b) EPSP-spike (ES) analysis revealed enhanced coupling between the slope of the fEPSP and the amplitude of the corresponding population spike evoked by perforant path stimulation. Inset: a significant (unpaired t-test, ) decrease in the slope generating 50% of maximal spike amplitude (v50) was found in NL1 KO as compared to WT animals (adapted from [42]). (c) The lack of NL2 leads to a dramatic increase in granule cell excitability. Increased amplitude of population spikes in the absence of NL2 implies higher number and synchrony of firing in NL2-deficient granule cells following perforant path stimulation (adapted with permission from [42, 59]).

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