Tokyo stocks were slightly lower Thursday morning, as a firmer yen prompted selling of exporter issues and a cautious mood prevailed ahead of the results of the Bank of Japan’s policy meeting. The 225-issue Nikkei Stock Average fell 45.35 points, or 0.12 percent, from Wednesday to 38,831.36. The broader Topix index was down 17.71 points, or 0.64 percent, at 2,738.73. The U.S. dollar plunged to the upper 155 yen zone in New York overnight as U.S. data showing decelerating inflation in May reinforced bets that the Federal Reserve is on track to cut interest rates this year. But the dollar quickl…