Effects of Kihi-to on Aβ(25–35)-induced object recognition memory deficits. Aβ(25–35) (25 nmol) was injected into the right lateral ventricle of mice. From ten days after the injection, mice were administered vehicle (V, water by p.o.; DMSO by i.v., n = 10) or Kihi-to (K, 100 mg/kg B.W., p.o., n = 9) for 3 days. The control mice (C, n = 8) were injected with a reverse peptide, Aβ(35–25) and then administered vehicle. Twelve days after the last drug administration, a novel object recognition test was performed (see drug administration schedule in Figure 1). A mouse was placed in the field, and the number of times it made contact with the two objects was recorded for 5 min (training session). Mice were placed back into the same field 10 min after the training session, in which one of the familiar objects used during the training session was replaced with a novel object. The mice were then allowed to explore the area freely for 5 min, and the amount of time spent exploring each object was recorded (test session). The preference index was defined as the ratio of the number of times a mouse made contact with any one of the objects (training session) or the novel object (test session) over the total number of times the mouse made contact with both objects. *p < 0.05 vs. Veh. (paired t-test).