Figure 1: Sox14 is a marker of interneurons in the dLGN.

(a) Alexa-594-conjugated CTb was used to label the retinal projection to the contralateral LGN. This low-magnification image compares retinal input with the Gfp distribution in the Sox14^Gfp/+ mouse brain at P21 3 days after injection. Scale bar, 100 μm (see also Supplementary Movie 1). (b) A panel of images showing immunohistochemical detection of GABA-containing neurons in the LGN compared with the distribution of Gfp⁺ neurons in the Sox14^Gfp/+ mouse brain at P21. Scale bar, 100 μm. (c) Live-cell imaging data of Gfp⁺ and Gfp⁻ neurons in an acute slice prepared from a Sox14^Gfp/+ mouse at P27. Patch-clamp electrodes are shown during simultaneous whole-cell recording from dLGN neurons. Scale bar, 30 μm. (d) Reconstructions of Gfp⁺ and Gfp⁻ neurons following electrophysiological recording in acute slice preparations of the Sox14^Gfp/+ mouse. Scale bar, 50 μm. (e) Scatter plot of data comparing cell capacitance and input resistance in Gfp⁺ and Gfp⁻ neurons recorded from the dLGN of Sox14^Gfp/+ mice aged between P20 and 27. Mean values are shown with error bars depicting s.e.m. Averaged current–voltage curves for these Gfp⁺ and Gfp⁻ neurons is also shown. The solid lines are the average values with grey areas illustrating s.e.m. (f) Data from a simultaneous recording between a Gfp⁺ and Gfp⁻ neuron in an acute slice preparation of the Sox14^Gfp/+ mouse. The voltage traces on the top were made during a whole-cell recording from a single Gfp⁺ neuron illustrating how the action potential frequency increases at more depolarized potentials. The current traces are taken from voltage-clamp recordings made simultaneously from a neighbouring Gfp⁻ neuron indicating the increase in tonic conductance as the presynaptic neuron increases firing rate. (g) Plot of the average relationship between the AP frequency of a Gfp⁺ neuron and the tonic and phasic conductance changes recorded simultaneously from an adjacent Gfp⁻ neuron. The solid lines illustrate the result of linear regression analysis with the dashed lines demonstrating 95% confidence limits of this fit.