Fig. 7. Effects of age and sensory deprivation on the responses evoked with minimal stimulation. All responses were recorded at −80 mV in the presence of 20 μm CNQX and 100 μm APV. A, Examples of responses evoked with minimal stimulation. The superimposed traces are 20 consecutive responses evoked with two stimulation intensities, 2.8 μA (left) and 3.0 μA (right). In each case, the thick traces correspond to the average of the successful responses. The amplitude histogram of the responses is displayed on the right. The noise level, calculated from the prestimulus baseline, is also plotted (in gray), but at a different scale (2×). B, Examples of responses evoked with minimal stimulation in a 3-week-old cell (3W, left), a 5-week-old cell (5W, center), and a 5-week-old dark-reared cell (5W DR, right). In each case, 20 consecutive responses are superimposed.C, Probability distribution of the average amplitude responses (excluding failures) evoked in 3-week-old cells (thin line), 5-week-old cells (thick line), and dark-reared cells (thick gray line). D, Relationship between the 10–90% rise time and the decay constant (top graph) and amplitude (bottom graph) for the responses evoked in 3-week-old cells (×), 5-week-old cells (○), and dark-reared cells (●). Solid linescorrespond to the best linear fit of the data. E, Normalized averaged responses recorded in all 3-week-old cells (thin line), 5-week-old cells (black thick line), and dark-reared cells (gray thick line). Each of the superimposed traces represents the average of all different cell responses normalized by their amplitude and aligned by their rise time.