Figure 1.

Differential effects of focal inactivation of corticothalamic feedback by iontophoretic application of GABA on overlapping and nonoverlapping LGN cell locations. A, Schematic summary of experimental method. Drug inactivation electrode is shown inserted in either an overlapping (O) or nonoverlapping (NO) retinotopic location with respect to that of the LGN. B, C, Population summary histograms plot the mean percentage change in LGN cell responses for overlapping (B, n = 14) and nonoverlapping (C, n = 12) recording sites for smaller than optimal (left), optimal (middle), and larger than optimal (right) stimuli, across our sample. Error bars indicate SEM. Significant response changes (see Results) denoted by filled bars, nonsignificant changes by open bars.