Hippocampal activities in young subject. A Task paradigm. B Significant signal increases associated with photograph encoding before and after gum chewing. Hip, hippocampus. Color scale: t value.
Hippocampal activities in an aged subject. A, Significant signal increases are associated with photograph encoding before and after gum chewing. Color scale: t value. B, Changes in signal intensity on an image-by image basis for 64 successive images during four cycles of encoding of photographs: brown (without chewing) and pink (with chewing) boxes
Effect of chewing during prenatal stress on learning ability and cell proliferation in the hippocampal dentate gyrus. Spatial learning in the water maze test (A) and BrdU-positive cells (B). The results are expressed as the mean score (mean ± SD, n=6 for each group) of four trials per day (A). The results are presented as the mean ± SD (n=5 for each group). C, control; S, restraint stress; S/C, restraint/chewing. *P<0.05 (B). Note that prenatal stress induced learning and memory deficits, and decreased cell proliferation in the hippocampal dentate gyrus. Maternal chewing during stress inhibits the stress- induced learning and memory deficits, and suppression of cell generation.