Figure 10.

Cortical orientation maps during application of different levels of GABA iontophoretic current. (A) Preferred orientation (indicated by black bars) and orientation selectivity index (OSI, indicated by color scale) of each neuron in an imaging site located 260 μm below the pia. (B) Preferred orientation and OSI during iontophoresis of GABA at +5, +10, and +20 nA. (C) Mean OSI across neurons before (Ctrl.) and during iontophoresis of GABA at +5, +10, and +20 nA. Error bars: SEM, ^*p < 0.05. In each of the four conditions shown, the superimposed cell-based maps for OSI and preferred orientation were derived from responses to the presentation of stimuli at eight directions of motion (45° step size). Each map is the average of four repeats.