Figure 2.

Arteriolar diameter change in response to contra and ipsilateral stimulation. White traces show percentage diameter change relative to the baseline (Δd/d) at different locations indicated by arrows. At every location, the upper and lower trace in a pair represents the response to the contra and ipsilateral stimulation, respectively. Dilation is plotted upward; constriction, downward. The center of the neuronal response was mapped on the cortical surface using a ball electrode. Surface potential recordings from different locations are shown in red. The strongest amplitude and fastest rise time indicate the center. The traces are overlaid on a two-photon image of vasculature within the exposure. The image was calculated as a maximum intensity projection of an image stack 0–300 μm in depth. Individual images were acquired every 10 μm. The horizontal dimension is 3.2 mm.