Visual responses of dLGN neurons in mice lacking thalamic Gabra1.

A, Recording electrodes were placed in the ipsilateral projection zone of dLGN (see green fluorescent trace of actual electrode penetration in dLGN). All receptive field centers of multi-units recorded in wild-type (WT, blue) and knockout (KO, green) mice (n=61 units from 13 non-deprived or monocularly deprived (MD) mice and n=80 units from 18 NO MD or MD mice). Nose position is at 0 degrees horizontally and vertically. The black dashed lines indicate −30 degree and +30 degree horizontal angles. B, Experimental setup to measure receptive field (RF) and single eye responses. C, RF sizes of multi-units in NO MD and MD (shaded area) KO and WT mice do not differ (interaction of genotype with MD: two-way ANOVA, P=0.07). D, Examples of dLGN neuron responses to full screen OFF-ON flash stimuli in WT (blue) and KO (green) mice. Colored and black lines indicate responses of contra- and ipsilateral eyes, respectively. Waveforms of each unit responding to the contra- or ipsilateral eye are shown in the upper right corner. E, Left, average responses of contralateral eye in WT (blue) and KO (green) mice. Middle, areas under curve (AUC) of early (0-150ms, left) and late responses (150-300ms, mid). Right, attenuation index of visual responses in WT and KO mice.

Reduced OD plasticity in dLGN of mice lacking thalamic synaptic inhibition.

A, Illustration of the experiment design. In experiments, four groups of animals were used: deprived (MD) or non-deprived (NO MD) wild-type and knockout mice. Mice in the MD group had the eyelids of the eye contralateral to the recording side sutured 7 for days. B, 7 days of MD reduces the ODI in WT mice but not in KO animals (interaction of genotype with MD: two-way ANOVA, P=0.046, Tukey’s post-hoc test; WT NO MD vs. WT MD, P=0.040; WT NO MD, n=40 units, 7 mice; WT MD, n=22 units, 6 mice; KO NO MD, n=45 units, 9 mice; KO MD, n=34 units, 9 mice). C, In WT mice, responses to the ipsilateral eye are significantly increased after 7-d MD. Responses to the contralateral eye are unchanged (Mann-Whitney; contralateral, NO MD vs. MD, P=0.29; ipsilateral, NO MD vs. MD, P=0.032). D, In KO mice, MD causes no significant changes in responses to either the contralateral or the ipsilateral eye (Mann-Whitney; contralateral, NO MD vs. MD, P=0.73; ipsilateral, NO MD vs. MD, P=0.59).

Reduced OD plasticity in adult V1 lacking thalamic OD plasticity.

A, Recording electrodes are located in binocular V1. All receptive field centers of multi-units recorded in WT (blue) and KO (green) mice (n=112 units from 13 NO MD or MD mice and n=138 units from 18 NO MD or MD mice). Nose position is at 0 degrees horizontally and vertically. The black dashed lines indicate −30 degree and +30 degree horizontal angles. B, RF sizes of units in KO and KO mice do not differ (interaction of genotype with MD: two-way ANOVA, P=0.07). C, Two examples of single unit responses in V1 of a WT (blue) and KO (green) mouse to the contra- and ipsilateral eyes to ON and OFF visual stimuli. Each stimulus lasted 3s. Colored and black lines indicate contra- and ipsilateral eye responses, respectively. D, Attenuation index of contralateral eye responses in V1 of WT and KO mice. E, 7 days of MD reduces the ODI in WT but not KO mice (interaction of genotype with MD: two-way ANOVA, P<0.001, Tukey’s post-hoc test; WT NO MD vs. WT MD, P<0.001; WT NO MD, n=71 units, 7 mice; WT MD, n=42, 6 mice; KO NO MD, n=63 units, 9 mice; KO MD, n=78 units, 9 mice). F, In WT mice, responses to the contralateral eye are significantly reduced after 7-d MD, while those to the ipsilateral eye are significant increased (Mann-Whitney; contralateral, NO MD vs. MD, P=0.0043; ipsilateral, NO MD vs. MD, P=0.0062). G, In KO mice, MD causes no significant changes in responses to either the contralateral or the ipsilateral eye (Mann-Whitney; contralateral, NO MD vs. MD, P=0.17; ipsilateral, NO MD vs. MD, P=0.66.).

Effect of feedback from V1 to dLGN responses.

A, Left, illustration of corticothalamic-thalamocortical feedback network. dLGN is innervated by V1 and receives glutamatergic feedback. All these projections send excitatory colaterals to the thalamic reticular nucleus (TRN) which sends inhibitory inputs to dLGN. By muscimol injection in V1, corticothalamic projections are silenced. Right, V1 is effectively silenced by muscimol injection (Wilcoxon signed rank, P<0.001, n=31 mice). B, Examples of dLGN responses before and after muscimol injection in V1 of non-deprived WT mice. Waveforms of each unit are shown in upper right corner. Left and right panels correspond to contralateral and ipsilateral eye responses respectively. Dark and light lines represent responses before and after muscimol injection respectively. C & D, Silencing V1 feedback has no significant effect on contralateral (C) or ipsilateral (D) responses in WT mice (Wilcoxon signed rank; contralateral, WT NO MD vs. WT NO MD with muscimol, P=0.62; ipsilateral, WT NO MD vs. WT NO MD with muscimol, P=0.94, n=40 units, 7 mice). E, Examples of dLGN responses before and after muscimol injection in V1 of non-deprived KO mice. Waveforms of each unit are shown in upper right corner. Left and right panels correspond to contralateral and ipsilateral eye responses respectively. Dark and light lines represent responses before and after muscimol injection respectively. F & G, There is no significant effect of V1 silencing on contralateral (F) or ipsilateral (G) eye responses in KO mice, but a trend towards decreased ipsilateral eye responses is present (Wilcoxon signed rank; contralateral, KO NO MD vs. KO NO MD with muscimol, P=0.19; ipsilateral, KO NO MD vs. KO NO MD with muscimol, P=0.059, n=45 units, 9 mice).

The OD shift in dlGN is independent from V1 feedback in adult mice but not in critical period mice.

A & B, Muscimol injection in V1 has no effect on the ODI in dLGN of adult non-deprived WT (A) and KO (B) mice (Wilcoxon signed rank; WT NO MD vs. WT NO MD with muscimol, P=0.86, n=40 units, 7 mice; KO NO MD vs. KO NO MD with muscimol, P=0.45, 45 units, 9 mice). C, D & E, Muscimol injection in V1 has no significant effect on the ODI (C), or contralateral (D) or ipsilateral (E) eye responses in dLGN of monocularly deprived WT mice (Wilcoxon signed rank; ODI, WT MD vs. WT MD with muscimol, P=0.89; contralateral, WT MD vs. WT MD with muscimol, P=0.21; ipsilateral, WT MD vs. WT MD with muscimol, P=0.10, n=22 units, 6 mice). F, G & H, During the critical period, V1 silencing has a significant influence on the ODI (F) and ipsilateral eye responses (H) in dLGN of monocularly deprived WT mice, but not on contralateral eye responses in these mice (G) (Wilcoxon signed rank; ODI, WT MD vs. WT MD with muscimol, P<0.001; contralateral, WT MD vs. WT MD with muscimol, P=0.46; ipsilateral, WT MD vs. WT MD with muscimol, P=0.003, n=41 units, 10 mice). I, J & K, Muscimol injection in V1 has no significant influence on the ODI and contralateral eye responses in KO MD mice, but significantly modulates dLGN ipsilateral eye responses (Wilcoxon signed rank; ODI, KO MD vs. KO MD with muscimol, P=0.13; contralateral, KO MD vs. KO MD with muscimol, P=0.97; ipsilateral, KO MD vs. KO MD with muscimol, P=0.004, n=34 units, 9 mice).

A, Examples of immunohistochemical staining for GAD67 in dLGN of adult WT and KO mice. B, Quantification of the density, number, and sizes of GAD67 puncta (putative inhibitory boutons). No differences were detected between WT and KO mice (T-test; puncta density, P=0.85; puncta number, P=0.82; puncta size, P=0.80. n=3 mice per group, 3 slices were imaged per mouse). C, Examples of immunohistochemical staining for VAChT puncta (putative cholinergic boutons) in dLGN of adult WT and KO mice. D, Quantification of the density, number, and sizes of VAChT. No differences were detected between WT and KO mice (T-test; puncta density, P=0.29; puncta number, P=0.35; puncta size, P=0.22. n=3 mice per group, 3 slices were imaged per mouse).

A, MD induces ocular dominance plasticity in dLGN of WT mice during the critical period (Mann-Whitney; WT NO MD vs. WT MD, P=0.0015; WT NO MD, n=36, 10 mice; WT MD, n=41, 10 mice). B, During the critical period, V1 feedback has no effect on OD in non-deprived WT mice (Wilcoxon signed rank; ODI, WT NO MD vs. WT MD with muscimol, P=0.20).