Figure 2. Ablating Spinal Zic2 Neurons Impairs Light Touch Sensitivity.

(A) Experimental strategy to ablate Zic2cre^ER neurons in the SC. Mapt promoter; FRT and loxP, recognition sites for Flp and Cre recombinases, respectively; DTR, diphtheria toxin receptor; DTx, diphtheria toxin.

(B) Experimental paradigm time line.

(C) Adult transverse lumbar SC sections of Zic2cre^ER::DTR;Ai14 (control) and Zic2cre^ER;Cdx2FlpO::DTR;Ai14 (ablated) treated with DTx. Scale bars, 200 μm.

(D) Quantification of ablation efficiency (control: 38.4 ± 4.4 cells, n = 3/4 sections, 5 mice; ablated: 14.9 ± 5 cells, n = 4 sections, 7 mice; two-tailed Student’s unpaired t test, t₍₁₀₎ = 3.3; **p = 0.008).

(E and F) Ablated mice show a significant decrease in paw withdrawal to dynamic brush (E) (control: 82.2% ± 6.1%, n = 13; ablated: 60.5% ± 6.5%, n = 12; two-tailed Student’s unpaired t test; t₍₂₃₎ = 2.4; *p = 0.02) and static brush (F) (control: 67.9% ± 7.3%, n = 13; ablated: 44.6% ± 7.9%, n = 12; two-tailed Student’s unpaired t test; t₍₂₃₎ = 2.2; *p = 0.04).

(G) Ablated mice show a significant increase in paw withdrawal thresholds (PWTs) to von Frey (control: 0.7 ± 0.1 g, n = 13; ablated: 1.6 ± 0.4 g, n = 12; two-tailed Student’s unpaired t test, t₍₂₃₎ = 2.2, *p = 0.04).

(H) No detectable changes in response to pinprick (control: 85.1% ± 4.4%, n = 13; ablated: 85.3% ± 4.5%, n = 12; two-tailed Student’s unpaired t test, t₍₂₃₎ = 0.03, p = 1).

(I) Heat sensitivity measured by PWTs in the dynamic hot plate was not altered in ablated mice (control: 47.8° C ± 0.1° C, n = 8; ablated: 47.6° C ± 0.1° C, n = 5; two-tailed Student’s unpaired t test, t₍₁₁₎ = 1.1, p = 0.3).

(J) Cold sensitivity measured by the latency to withdraw the paw in response to dry-ice stimulation was not altered in ablated mice (control: 5.9 ± 0.5 s, n = 15; ablated: 6.7 ± 0.7 s, n = 12; two-tailed Student’s unpaired t test; t₍₂₅₎ = 0.9, p = 0.4).

(K) Scratch response to chloroquine injection over 30 mins was not altered (control: 233 ± 47 bouts, n = 11; ablated: 240 ± 49 bouts, n = 8; two-tailed Student’s unpaired t test, t₍₁₇₎ = 0.1, p = 0.9).

(L and M) Schematic of textural place preference paradigm. K30 versus K150 (L); K80 versus K150 (M).

(N and O) Heatmap of mice in experimental chambers over time. K30 versus K150 (N) and K80 versus K150 (O).

(P) Preference index for rough surfaces. Ablated mice decreased preference for the rough texture chamber when textural difference was less pronounced (K80 versus K150). (K30/K150: control: 0.3 ± 0.08, n = 11; ablated: 0.1 ± 0.04, n = 10; t₍₁₉₎ = 2.04, p = 0.06. K80/K150: control: 0.3 ± 0.06, n = 11; ablated: 0.07 ± 0.03, n = 10; two-tailed Student’s unpaired t test; t₍₁₉₎ = 3, **p = 0.007).

Data are presented as mean ± SEM; p values above 0.05 not significant (n.s.).

See Figure S2.