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Figure supplement 1. Schematic of layer-specic inputs to IS3 cells in hippocampal CA1. IS3 cell have dendrites that extend into RAD and L-M and receive excitatory inputs from entorhinal cortex and CA3. They also receive inhibitory input from various local inhibitory cell types. Acronyms: CA3 -Cornu Ammonis area 3; IS3 -Interneuron Specic type 3 cell; OLM -Oriens Lacunosum Moleculare cell; PC -Pyramidal cell; L-M -stratum lacunosum moleculare; RAD -stratum radiatum; PYR -stratum pyramidale; O/A -stratum orians/alveus.
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Brain coding strategies are enabled by the balance of synaptic inputs that individual neurons receive as determined by the networks in which they reside. Inhibitory cell types contribute to brain function in distinct ways but recording from specific, inhibitory cell types during behaviour to determine their contributions is difficult. In particular...
Citations
... The weights used here predicted a biologically realistic range of receptors per synapse (Figure 3, Figure Supplement 1A). The model also predicted an increase in the measured reversal potential with distance from soma (Figure 3 We next used these realistic synaptic parameters (Guet-McCreight et al., 2017) to simulate in vivo-like conditions in our IS3 cell model (Guet-McCreight and Skinner, 2018), where the model was bombarded with synaptic inputs. In our computational explorations, we tested two IS3 cell model variants that did (SDprox1) or did not (SDprox2) have dendritic A-type potassium channels (Guet-McCreight et al., 2016). ...
... From the simulations done for Figure 4 and Figure 5, we did not observe any consequential differences between our two model variants (SDprox1 and SDprox2) with theta and SWR timed recruitment. This could be because the addition of synaptic inputs needed to generate baseline in vivo-like electrophysiological outputs was dependent on the model variant (Guet-McCreight and Skinner, 2018). Thus this lack of difference in recruitment cannot be directly explained by the inclusion (SDprox1) or exclusion (SDprox2) of dendritic A-type potassium channels. ...
... In vivo-like excitatory and inhibitory inputs (i.e. spike rates and numbers of active synapses) were estimated previously (Guet-McCreight and Skinner, 2018). In all simulations, the baseline in vivo-like synaptic locations and presynaptic spike trains were chosen randomly according to a set of random seeds. ...
In the hippocampus, a highly specialized population of vasoactive intestinal peptide-expressing interneuron-specific (IS) inhibitory cells coordinates the activity of GABAergic interneurons. While disinhibition may play a critical role in hippocampal learning, the synaptic properties and recruitment of IS cells remain unknown. Here, we found that the CA1 type 3 IS cells (IS3) receive excitatory inputs through the Schaffer collateral and the temporoammonic pathways with synapse-specific properties. The computational models predicted that these synaptic inputs could rhythmically drive the IS3 cell firing during theta oscillations and sharp-wave ripples. However, recordings in awake mice revealed a large variability in IS3 cell recruitment, with preferential recruitment of these cells in relation to theta-run epochs and silence during sharp-wave ripples. Taken together, these data indicate that, while synaptic properties of IS3 cells predict a particular output, additional factors may modulate the cell recruitment during different behavioral and network states.
