Investigations into the neural underpinnings and biological correlates of asexuality

很少有研究存在于人类无性恋，定义为“缺乏性吸引力。”虽然无性恋研究表面上似乎是一个非常具体的研究领域，但无性恋的特殊性质可能为研究大脑，认知和行为的性别分化提供了独特的人类模型。因此，无性恋可能是解开我们对所有性行为（典型的和非典型的）理解的钥匙。在我的实验室里，十年的研究已经验证了无性恋是一种独特的性取向的原则。具体来说，我已经排除了无性恋是性功能障碍、心理障碍和性欲倒错的理论。此外，我的工作表明，终身缺乏性吸引力，对无性恋至关重要，可能是一种先天的生物学特征。一般来说，激素、遗传和免疫过程被假设影响大脑的性分化，并导致性吸引和性取向的变化，这似乎也是无性恋的情况。在这里，我们建议进一步探讨这一点。*在5年多的时间里，我们提出了3项研究，每项研究都采用了以前不适用于无性恋的性取向研究中经过验证的方法。在研究1中，我们将使用性吸引力的自动测量（观看视觉刺激时的眼球运动和瞳孔放大）来评估对性偏好和非偏好线索的视觉注意和认知处理。** 在研究2中，我们将使用一系列神经成像技术对比无性和有性群体（包括性欲亢进和对照参与者），以研究包括大脑结构和功能在内的神经解剖学特征。这将是有史以来第一次对无性恋者进行神经成像研究。大脑活动将被记录在90分钟的大脑扫描会议，而参与者是在休息，而他们正在观看色情刺激。** 研究3将通过调查身体生长模式来复制和扩展我早期对无性恋生物标志物的研究;例如，身高、指长比和用手习惯。这些变量被认为是性取向发展变化的生物标志物（特别是在同性恋参与者中），并被认为反映了雄激素的产前影响。我们还将研究兄弟出生顺序效应，另一个性取向的生物标志物，通过调查无性个体的生物兄弟姐妹的数量和性别是否与有性个体显著不同。总的来说，拟议的研究计划将直接回答有关无性恋的神经相关性的令人困惑的问题，并将完善我们关于无性恋以及其他性取向发展的病因学途径的概念模型。它将改变我们对大脑、认知和行为的性别差异的理解。

Very little research exists on human asexuality, defined as “absence of sexual attraction.” While asexuality research seems on the surface to be a very specific field of research, the exceptional nature of asexuality may provide a unique human model for studying sexual differentiation of the brain, cognition, and behaviour. Thus, asexuality may be the key that unlocks our understanding of all the sexualities (typical and atypical).******A decade of research in my lab has tested the tenet that asexuality is a unique sexual orientation. Specifically, I have ruled out theories that asexuality is a sexual dysfunction, a psychological disorder, and a paraphilia. Furthermore, my work suggests that the lifelong lack of sexual attraction, essential to asexuality, may be an innate biological characteristic. In general, hormonal, genetic, and immunological processes have been hypothesized to influence sexual differentiation of the brain and to lead to variations in sexual attraction and orientation, and this seems also to be the case in asexuality. Here, we propose to probe this further.******Over 5 years we propose 3 studies, each employing validated methodologies in sexual orientation research not previously applied to asexuality. In Study 1, we will use automatic measures of sexual attraction (eye-movements and pupil dilations while viewing visual stimuli) to assess visual attention to and cognitive processing of sexually preferred and non-preferred cues. ******In Study 2, will we use a series of neuroimaging techniques to contrast asexual and sexual groups (including hypersexual and control participants) to investigate neuroanatomic features including brain structure and function. This will be the first-ever study of neuroimaging in asexuals. Brain activity will be recorded in a 90-min brain scanning session, while participants are at rest and while they are viewing erotic stimuli. ******Study 3 will replicate and expand my earlier study of biological markers of asexuality by investigating physical growth patterns; e.g., height, finger-length ratio, and handedness. These variables are considered biomarkers of variations in sexual orientation development (specifically among gay participants) and are thought to reflect prenatal influence of androgens. We will also investigate the fraternal birth order effect, another biomarker of sexual orientation, by investigating whether the number and sex of biological siblings of asexual individuals significantly differs from that of sexual individuals. ******Overall, the proposed research program will directly answer puzzling questions about the neural correlates of asexuality, and will refine our conceptual models of etiological pathways of the development of asexuality as well as other sexual orientations. It will transform our understanding of the sexual differentiation of the brain, cognition, and behaviour.