Figure 4.

Photostimulation mapping of functional connections between the RFA and the CFA. (A) The four rectangles represent the regions mapped by photostimulation. In each region, 32 × 32 points were pseudo-randomly stimulated with a blue laser. The laser intensity was 2.5 mW and the illumination duration was 10 ms. The crosses represent the recording sites. Each color represents one set of recording and photostimulation. The small black square denotes the bregma. The black line represents the midline. (B) The laser was used to stimulate 32 × 32 points that are indicated as pixels throughout the RFA and the CFA. White pixels indicate points where photostimulation induced spiking activities and black pixels reflect areas that did not induce spiking activities. The gray dotted lines represent the midline. The mapping was performed in four different mice. The top panels indicate photostimuli that were presented to the RFA while simultaneous recordings were made in the CFA. The bottom panels indicate photostimuli that were presented to the CFA while simultaneous recordings were made in the RFA. The experiments in the left panels were conducted in ChR2 Tg mice, while the experiments in the right panels were conducted in AAV-ChR2 mice. The four areas mapped are indicated by the colored rectangles in (A). (C) A gray rectangle indicates the region mapped in (D). The crosses labeled as a and b represent the corresponding recording sites in (D). The recordings were made from the same ChR2 Tg mouse. The black line represents the midline. (D) Photostimulation maps of the RFA showed similar patterns of evoked activities even if the recording sites were changed within the CFA. The horizontal distance between the two recording sites shown here was 600 μm.