Figure 2.
A tonic GABAAR-mediated conductance is only present in dLGN relay neurons and is absent from vLGN relay neurons and all interneuron populations. A–C, Representative current traces recorded at a holding potential of −60 mV from a dLGN relay neuron (A), a dLGN interneuron (B), and a vLGN relay neuron (C). In each trace, the transient inward deflections are sIPSCs that were completely abolished by the application of the GABAAR antagonist SR-95531 (open bar). In contrast, a tonic GABAAR-mediated conductance was only present in the dLGN relay neuron. In this cell, application of SR-95531 resulted in the block of a steady-state inward current and a reduction in the background noise associated with the current recording. D, Quantification of the tonic GABAAR-mediated conductance and the sIPSC frequency in all cells examined. Note that the tonic conductance is only present in the dLGN relay neuron population, but a similar sIPSC frequency is present in all neuronal populations.