The brain regulates and integrates a wide variety of endocrine, autonomic and behavioral processes which are essential for the organism’s survival and reproduction. The hypothesis guiding our research is that disturbances of the functional activity of the human brain may develop into neurological, psychiatric or neuroendocrine disorders. We focus on aging, hypertension, depression, multiple sclerosis, Alzheimer’s disease, anorexia, schizophrenia and thyroid disorders. Sexual differentiation of the brain and the interaction between sex hormones and the adult brain are investigated in relation to the disorders mentioned and to transsexuality. The aim of our research is to find putative factors and targets for therapeutic strategies.
HUMAN BIOLOGICAL CLOCK AND AGING
In humans, age-related changes have been described for hormonal rhythms, body temperature, sleep-wakefulness, and several other behavioral cycles. Disruption of circadian rhyth-micity and increased incidence of disturbed sleep during aging are paralleled by a degeneration of the suprachiasmatic nucleus (SCN) and pineal gland, critical components of the biological clock in our brain. Damage to this clock is the underlying neural substrate for the clinically often-observed disturbances in circadian rhythmicity in mood disorders and Alzheimer’s disease.
Structural and functional sex differences are studied in the human brain in relation to gender-identity (the feeling to be male or female) and sexual orientation (homo- and heterosexuality). A reversal of sex differences is found in transsexuals. The size of the central part of the bed nucleus of the stria terminalis (BSTc) is independent of sexual orientation (similar size in heterosexual (A) and homosexual (C) male). But it is smaller in a heterosexual woman (B) and has a female size in an XY male-to-female transsexual (D).