Fig. 4

Examples of multi-site optical recordings of spontaneous neural activity. A An example of a single-sweep simultaneous multi-site optical recording after reduction of the pulsation artifact. The six traces surrounded with a circle (labeled a–e or with an asterisk) are shown in B. B Magnified traces obtained from the six sites (a–e and asterisk) in A. The ECoG signal was recorded using the transparent electrode spot near the asterisk. C Isochrone map for the onset time constructed from the data in A. The X indicates the initiation site of spontaneous neural activity and corresponds to trace “a” in A. Each number represents the time lag (in milliseconds) relative to this site. D Two further examples of the isochrone map of spontaneous neural activity, the initiation sites of which were located closely to that shown in A. The ECoG trace is shown at the left bottom corner in each panel