[Strategies and methods for research on sex- and gender-differences in the rat and human brain]

Strategies and methods for experiments on sex and gender-differences in the rat and human brain are discussed taking our experiments as examples. As sex differences that should be biologically present in "the old brain", control mechanism for the GnRH secretion in the rat, nicotine effects on pulsatile LH secretion in the human and feeding behavior in the rat are mentioned. Then, the absence of sex-difference in the spatial learning memory in the rat that has been fed soft diet, instead of ordinary hard diet, and also the absence of sex-difference in the overall cognitive function in the aged human, in accordance with our concept that gender-differences are produced in response to environmental stimuli in "the new brain", are mentioned.