Fig. 6: Modeling the role of excitatory and inhibitory conductances in the L6CT synchrony-dependent bidirectional modulation of VPm ongoing activity.
From: Dynamic corticothalamic modulation of the somatosensory thalamocortical circuit during wakefulness
a The model structure consists of representative VPm and TRN neurons modeled as leaky, integrate and fire (LIF) neurons, each integrating common L6CT spike train inputs with controlled synchrony and firing rate. The VPm neuron integrated inhibitory input from the spiking of the TRN neuron. Spontaneous activity for each LIF neuron was driven by noisy, excitatory inputs. b Single trial model simulations run by holding the L6CT neurons’ firing rates fixed while varying the synchrony of the L6CT inputs result in a shift from suppression to enhancement of VPm spiking in a graded manner with increasing synchrony. Note that the spontaneous conductance has been scaled 5x for better visualization. c The mean (+/− sem across 50 trials) change in VPm firing rate with increasing L6CT population synchrony, but constant L6CT neurons’ firing rate (2.5 sp/s) replicates the experimentally observed, L6CT synchrony-dependent, bidirectional modulation of VPm. d An expanded view of the single trial components and underlying conductances in VPm highlights the key factors underlying L6CT synchrony-dependent, bidirectional modulation of VPm: (1) the relative strength of the inhibitory conductance compared to the excitatory conductance, and (2) the relative timing of the monosynaptic excitatory and disynaptic inhibitory conductances.
