Figure 1.

Illustration of the experimental approach and example recording traces. (A) Left: Coronal slice of mouse barrel cortex showing opsin expression (green) and probe penetration (DiI, red). Scale bar: 200 µm. Right: Magnification of the enclosed area in the left picture. (B) Example LFP traces from one mouse (low-pass filtered at 250 Hz). Shown are selected channels from each cortical layer, averaged over 24 W1 deflections. The triangle indicates stimulus onset. (C) Example CSD profile showing allocation of cortical layers to electrode channels (32 channels, 25 µm inter-electrode spacing).