, 1980) in spherical coordinates (Supplemental Experimental Procedures, available online). Second, we used low-magnification two-photon calcium imaging to measure the retinotopic organization of visual cortex at high resolution. This resulted in a retinotopic map which was continuous within the extent of visual cortex and allowed us to precisely define borders between several areas based on visual field sign reversals at peripheral representations (Sereno et al., 1995; Figure 1 and Figure 2). A representative intrinsic imaging map from one animal is shown in Figure 1. Several features of previous

map schema are present in the map (for a direct comparison, see Wagor et al., 1980, Figure 4, and Wang and Burkhalter, 2007, Figure 10). Our data are most consistent with the map predicted primarily from anatomy by Wang

and BVD-523 cost Burkhalter (2007), and thus all further analyses and discussion are made in reference to their schema and area selleck kinase inhibitor names. Intrinsic imaging maps were sufficient to detect activation in V1, LM, LI, AL, RL, A, AM, PM, P, and POR, but often could not resolve fine-scale details in the maps of relatively small areas (such as LI, RL, A, AM, and PM) that were necessary to precisely define area boundaries. Using the intrinsic imaging maps as a guide, several calcium dye loadings were performed to load a volume of cortex spanning several millimeters and encompassing several visual areas (Experimental Procedures). We then systematically imaged Oxalosuccinic acid the extent of the loaded area by moving the objective in ∼500–700 μm steps to tile the whole loaded region. At each position, we displayed the retinotopic mapping stimulus (identical to that used for intrinsic imaging) to the animal, and mapped the retinotopy of that ∼800–1000 μm2 patch of cortex

with a 16× objective. Mosaics of these individual maps resulted in a complete high-resolution map of the region, often spanning several millimeters and encompassing the full visuotopic extent of several extrastriate visual areas (Figure 2 and Figure S2). At this resolution, we observed several features in the maps that were not seen with intrinsic imaging, revealing the fine-scale organization of each of eight extrastriate visual areas predicted previously (LM, LI, AL, RL, AM, PM, P, and POR; Figure 2 and Figure S2). We observed some retinotopic structure in the putative location of area A, but did not target this area for population analysis because its retinotopic map was ambiguous in relation to its predicted organization (Wang and Burkhalter, 2007; Figure 2 and Figure S2). It was also difficult to obtain complete maps of areas P and POR given their cortical location (Figure S2). Using this method, we located the region of cortex representing the central visual field within each confidently identified area (∼0 degrees azimuth, ∼20 degrees altitude) for further analysis.