Inhibitory Gating in the Dentate Gyrus

Electrophysiological recordings have demonstrated a tight inhibitory control of hilar interneurons over Dentate Gyrus granule cells (DGgc) (Bragin et al. 1995; Permía-Andrade et al. 2014). This excitation/inhibition balance is crucial for information transmission (Bartos et al, 2001) and likely relies on inhibitory synaptic plasticity (Vogels et al, 2011).Our experiments show that LTP induction in perforant pathway, not only potentiates glutamatergic synapses, but unexpectedly decreases feed-forward inhibition in the DG, facilitating activity propagation in the circuit. To investigate this phenomenon we propose a population model based on the Izhikevich’s neuronal equations. Overall, our findings suggest that LTP of the EC input increases the excitation/inhibition balance and facilitates activity propagation to the next station in the circuit by recruiting an interneuron-interneuron network that inhibits the tight control of basket cells over DGgc firing. Currently, we are performing in vitro experiments in mice to validate this theoretical prediction.