Figure 3.

ON-driven activity in the V1 cortex of newborn rat. A, Extracellular recordings of the contralateral (top red trace) and ipsilateral (bottom black trace) cortical response to electrical stimulation of the ON in a P6 rat. Note the robust direct response (1) recorded in the contralateral hemisphere followed by spindle bursts (2), and the smaller direct response (1) on the ipsilateral side. B, Topographic localization of the visual cortex determined by ON responses. Multiple-site recordings were performed on both hemispheres and each direct ON-evoked response was normalized to the maximal response and color-coded (red, 100%; blue, 0%). C, Developmental profile of the contralateral and ipsilateral ON-evoked response. D, ON-induced oscillatory activity in the visual cortex. Bar diagram displaying the relative occurrence of ON-induced spindle bursts in the ipsilateral and contralateral V1 in five investigated rats. Inset, Power spectrum of averaged ON-induced oscillations in a P5 rat. Error bars indicate SEM.