Figure 6: Restoration of thalamocortical VEP amplitude during recovery from chronic monocular deprivation.

(a) Representative VEP and unit activity (in 50 ms bins) evoked by visual stimulation before cortical silencing (pre; 0.04 cycle per degree. 96% contrast gratings at preferred orientation, reversing at 1 Hz, arrows). Intracortical infusion of muscimol+SCH50911 silences cortical spiking and reduces VEP amplitude (post). Cortical spiking and VEP amplitude recover following washout (∼10 h; wash). Scale bars, 50 ms, 50 μV. (b) Significant reduction in VEP amplitude following cortical silencing in subjects that received chronic monocular deprivation (cMD average deprived eye VEP±s.e.m.; *P=0.004, paired t-test, n=4). (c) Significant reduction in VEP amplitude following cortical silencing in subjects that received chronic monocular deprivation followed by dark exposure and reverse deprivation (DE-RD average deprived eye VEP±s.e.m.; *P=0.005, paired t-test; n=4). (d) Increase in the thalamocortical VEP amplitude following recovery from chronic monocular deprivation (normalized total VEP average±s.e.m.; *P=0.027, unpaired t-test). (e) Inhibition of cortical spiking does not modify the VEP contralateral bias in subjects that received chronic monocular deprivation, or chronic monocular deprivation followed by dark exposure and reverse deprivation.