Author response image 3. Long-lasting potentiation can be induced at glutamatergic inputs targeting somatostatin-expressing interneurons (SOMIs) in the presence of the group II mGluR agonist DCG-IV.
EPSCs were evoked by extracellular stimulation with a pipette positioned at thegranule cell layer to hilus border. Plot summarizes the time course of EPSC peak amplitudes evoked at glutamatergic input synapses targeting SOMIs before and after associative pairing as indicated by the arrow. EPSCs were averaged over 30 sec intervals and normalized to baseline values. Long-term potentiation (LTP) was determined 15-20 min after plasticity induction. Note, DCG-IV was bath-applied throughout the entire experiment to block mossy fiber-mediated EPSCs (4 SOMIs). These data together with our finding that LTP can be induced at glutamatergic inputs onto SOMIs that are strongly DCG-IV sensitive and therefore mediated by mossy fibers (blocking effect >40%; see Figure 3F left in the main manuscript), suggests that LTP induction in SOMIs is independent on the nature of the input synapse.