研究人员在11月号的《自然—神经科学》期刊上报告，两性在习惯形成方面的不同源于染色体，而不是以前认为的性荷尔蒙。大脑和行为中的绝大多数差异与荷尔蒙有关，但新研究提出了可能由染色体通过另一种途径导致的部分性别差异。
Jane Taylor和同事研究了拥有XY染色体和卵巢的雄性变异小鼠，以及拥有XX染色体和睾丸的雌性变异小鼠，了解它们的行为学习能力。与拥有XY染色体的雄性小鼠相比，拥有XX染色体的雌性小鼠，无论是否拥有卵巢或睾丸或二者都被切除，都能更快形成与食物强化刺激相关的习惯。习惯是以指数级的方式形成的，相当于从偶尔服药到药物成瘾。
新研究表明，女性比男性能更快地养成习惯。未来对这种影响机制的研究将深入了解这种差异性。（科学时报）
原始出处:
Nature Neuroscience 10, 1398 - 1400 (2007)
Published online: 21 October 2007 | doi:10.1038/nn1994
Sex chromosome complement regulates habit formation
Jennifer J Quinn1, Paul K Hitchcott1, Elizabeth A Umeda2, Arthur P Arnold2 & Jane R Taylor1
Sex differences in brain function and behavior are regularly attributed to gonadal hormones. Some brain sexual dimorphisms, however, are direct actions of sex chromosome genes that are not mediated by gonadal hormones. We used mice in which sex chromosome complement (XX versus XY) and gonadal sex (ovaries versus testes) were independent, and found that XX mice showed faster food-reinforced instrumental habit formation than XY mice, regardless of gonadal phenotype.
Division of Molecular Psychiatry, Yale University, Connecticut Mental Health Center Abraham Ribicoff Research Facilities, 34 Park Street, New Haven, Connecticut 06508, USA.
Department of Physiological Science, University of California, Los Angeles, Box 951606, 4117 Life Sciences Building, Los Angeles, California 90095-1606, USA.
Correspondence to: Jane R Taylor1 e-mail: jane.taylor@yale.edu
