Chicks reared in the absence of light and rat pups reared without extra stimulation fail to exhibit behavioral laterality, implying that a threshold amount of environmental stimulation is necessary for the brain to follow an asymmetry pathway. Reverse asymmetry has been reported in the chick, but not the rat, though a sex difference resembling reverse asymmetry has been found in the rat.

Mazur & Booth have shown an association between testosterone and dominance behavior, but the strength of the relationship is not given. In addition to being statistically significant, it is also necessary that testosterone account for a meaningful proportion of the variance; a multivariate model is probably necessary. A cautionary tale from the animal literature is related.

Historically, studies of the role of endogenous hormones in developmental differentiation of the sexes have suggested that mammalian sexual differentiation is mediated primarily by testicular androgens, and that exposure to androgens in early life leads to a male brain as defined by neuroanatomy and behavior. The female brain has been assumed to develop via a hormonal default mechanism, in the absence of androgen or other hormones. Ovarian hormones have significant effects on the development of a sexually dimorphic cortical structure, the (...) corpus callosum, which is larger in male than in female rats. In the females, removal of the ovaries as late as Day 16 increases the cross-sectional area of the adult corpus callosum. Treatment with low-dose estradiol starting on Day 25 inhibits this effect. Female callosa are also enlarged by a combination of daily postnatal handling and exogenous testosterone administered prior to Day 8. The effects of androgen treatment are expressed early in development, with males and testosterone-treated females having larger callosa than control females as early as Day 30. The effects of ovariectomy do not appear until after Day 55. These findings are more consistent with other evidence of a later sensitive period for ovarian feminization as compared to androgenic masculinization. (shrink)

A number of commentators agree that the evidence reviewed in the target article supports a previously unrecognized role for ovarian hormones in feminization of the brain. Others question this view, suggesting that the traditional model of sexual differentiation already accounts for ovarian influence. This position is supported by various reinterpretations of the data presented (e.g., ovarian effects are secondary to the presence/absence of androgen, ovarian effects are smaller than testicular effects, ovarian effects are not organizational). We discuss these issues, and (...) reiterate our position that evidence of neurobehavioral ovarian effects is incompatible with the currently accepted model of sexual differentiation. Other points regarding species generalizations, the direct versus indirect action of estrogen, and nonhormonal mechanisms of sexual differentiation are also discussed. Finally, we address the controversial issue of using ratio scores in the assessment of the human corpus callosum (where CC scores are divided by an index of brain size). Future applications to human research are also discussed. (shrink)

Das hier angezeigte Buch stellt sich dar als eine repräsentative Studie zur byzantinischen Buchkunst über einen Zeitraum von mehr als anderthalb Jahrtausenden. In einem knappen Vorwort reiht Peter Schreiner es in eine bedeutende Forschungstradition ein und zugleich in die Abfolge einer „unübersehbar gewordenen Literatur“. Dabei wird zu Recht hervorgehoben, daß im Unterschied zu vielen anderen Veröffentlichungen des Faches die Buchkunst aus dem slawisch-orthodoxen Bereich voll einbezogen wird, an dessen Erforschung die Verf. mit zahlreichen Arbeiten beteiligt ist. Sie stellt in ihrer (...) eigenen Einleitung dem Leser das vorwiegend liturgische Buch als wesentliches Fundament der byzantinischen Kultur vor Augen. Skizzenhaft erläutert sie seine religiös bestimmte Würde, aus der sich zugleich seine Zierate und Illustrationen rechtfertigen. Es ist einer der Vorzüge der Darstellung, daß dem politischen und kulturellen Zentrum des Reiches Provinzen und Nachbarländer mit vollem Gewicht an die Seite treten: – Syrien, das koptische Ägypten und Äthiopien, Armenien und Georgien, Bulgarien, Rumänien, die Walachei und nicht zuletzt Rußland. (shrink)

In this article, Latin American identity is analyzed from an anthropological and holistic perspective. Dynamic contradictions are offered as a contribution towards understanding the process of construction-deconstruction of our identity, within the global historical context of its emergence an..

Stone and Dung, Oil and Spit: Jewish Daily Life in the Time of Jesus. By Jodi Magness. Grand Rapids, Mich.: William B. Eerdmans Publishing Co., 2011. Pp. xv + 335, illus. $25.