Developmental effects of neonatal sex hormones on spatial and activity skills in the white rat

Spatial Ability and Prenatal Androgens: Meta-Analyses of Congenital Adrenal Hyperplasia and Digit Ratio (2D:4D) Studies

“…This interpretation accords with research on rats, in which males exhibit superior spatial performance to females (Jonasson, 2005), and testosterone treatment improves spatial ability in females (Dawson et al, 1975;Isgor & Sengelaub, 1998Joseph et al, 1978;Roof, 1993;Roof & Havens, 1992;Stewart et al, 1975) but worsens it in males (Roof, 1993;Roof & Havens, 1992). This interpretation is also consonant both with studies finding behavioral masculinization in CAH females (Berenbaum, 1999) and with studies suggesting that human spatial ability is related to prenatal androgens.…”

“…Hines et al (2003) suggested that this period may occur as late as the first six months of postnatal life, but the fact that CAH is detected and treated soon after birth, especially in females, would seem to argue against differentiation occurring much after birth. In rats, spatial ability sexually differentiates during the first two of weeks after birth (Dawson et al, 1975;Joseph et al, 1978;Stewart et al, 1975). Because rats are born relatively underdeveloped, this corresponds approximately to the end of the third trimester of gestation in humans (Nunez & McCarthy, 2003), which would appear to be a likely time frame for the sexual differentiation of human spatial ability.…”

“…In rats, spatial ability is masculinized perinatally by testicular hormones. Several studies have shown that neonatal castration impairs maze learning in males (Dawson, Cheung, & Lau, 1975;Isgor & Sengelaub, 2003;Joseph, Hess, & Birecree, 1978; C. L. Williams, Barnett, & Meck, 1990), and neonatal testosterone treatment improves maze performance in females (Dawson et al, 1975;Isgor & Sengelaub, 1998Joseph et al, 1978;Roof, 1993;Roof & Havens, 1992;Stewart, Skvarenina, & Pottier, 1975). However, there may be an optimal level of early androgen exposure beyond which spatial ability declines.…”

Neurobehavioral effects of dietary soy phytoestrogens

“…Generally, VSM refers to the ability to imagine what irregular figures would look like if they were rotated in space, the ability to discern the relationship between shapes and objects or the ability to recall the location of objects or places [74]. In learning and memory tasks that require the use of visual spatial cues, males typically acquire and exhibit performance superior to females [28,30,76,98,99]. This sex difference in rats has been attributed to the hormonal influence of estrogens.…”

“…This sex difference in rats has been attributed to the hormonal influence of estrogens. For example, exogenous estradiol administered to intact male rats inhibited memory, whereas estrogen replacement to ovariectomized rats enhanced memory [27,28,30,76,125]. Since estrogen hormone action appears to influence VSM, we studied the influence of phytoestrogens on VSM utilizing radial arm maze methods to examine varying aspects of memory.…”