Developmental changes in the amplitude reduction of cortical responses after 5-HT3 receptor activation. Thebar graph shows the slopes of linear fits to effect amplitudes (i.e., maximum amplitude under control conditions − maximum amplitude in the presence of agonist) plotted against control amplitudes for each trace to normalize for different control maximum amplitude values across slices (“normalized inhibition”). This value has been derived for each of the 100 positions recorded in each slice individually; therefore the n represents traces, not slices. Error bars represent mean values ± SEM. Recordings obtained from layers 2/3 to 6 in different slices have been pooled according to age. Data were obtained from five to eight individual slices per age group. Each bar represents the average of 480–660 data points. A significant increase in the inhibitory effect occurred between P35 and P40.
