Local removal of Acan in V1 reactivates juvenile OD plasticity. a, Injection of the retrograde tracer cholera toxin subunit B (CtxB) conjugated to different fluorophores, at two closely aligned sites in V1 of nontargeted Acan-loxP+/+ mice. Representative wide-field image from V1 (top) and confocal images from the dorsal part of the lateral geniculate nucleus (dLGN) of the thalamus. Labeled projections stem from adjacent patches of neurons in dLGN, indicating a normal connectivity pattern with retinotopic organization. Sections were counterstained with DAPI to distinguish brain areas, and data were reproduced in two mice. b, Experimental time line for optical imaging of intrinsic signals before and after MD of adult mice. c, ODI calculated for responses to stimulating the ipsilateral and contralateral eye separately, before and after 4 d of MD. Positive ODI indicates contralateral bias while negative ODI indicates ipsilateral bias. Four days of MD did not affect ocular dominance in noninjected Acan-loxP+/+ mice (p = 0.21, paired t test, n = 4 mice) or in heterozygous AAV9.Cre-injected Acan-loxP+/− mice (p = 0.32, paired t test, n = 3 mice). In AAV9.Cre-injected Acan-loxP+/+ mice, MD caused a significant shift in activation toward the open eye (p = 0.003, paired t test, n = 7 mice). d, Stimulus-evoked responses of intrinsic signals through the open or closed eye before and after 4 d of MD. The MD in AAV9.Cre injected Acan-loxP+/+ caused both increased responses to ipsilateral stimulation (p = 0.02, paired t test, n = 7 mice) and reduced responses to contralateral stimulation (p = 0.009, paired test, n = 7 mice), while no effect was observed in controls. Acan-loxP+/+: deprived eye responses, p = 0.73 (Wilcoxon signed rank test); open eye responses, p = 0.48 (paired t test); Acan-loxP+/− AAV9.Cre injected: deprived eye responses, p = 0.46 (paired t test); open eye responses, p = 0.70 (paired t test) *p < 0.05, **p < 0.01. Open circles and gray lines indicates individual animals, solid circles and thick lines indicate population mean ± SD.
