Holstege Gert, Georgiadis Janniko R, Paans Anne M J, Meiners Linda C, van der Graaf Ferdinand H C E, Reinders A A T Simone
Department of Anatomy and Embryology, University of Groningen, 9713 AV Groningen, The Netherlands.
J Neurosci. 2003 Oct 8;23(27):9185-93. doi: 10.1523/JNEUROSCI.23-27-09185.2003.
Brain mechanisms that control human sexual behavior in general, and ejaculation in particular, are poorly understood. We used positron emission tomography to measure increases in regional cerebral blood flow (rCBF) during ejaculation compared with sexual stimulation in heterosexual male volunteers. Manual penile stimulation was performed by the volunteer's female partner. Primary activation was found in the mesodiencephalic transition zone, including the ventral tegmental area, which is involved in a wide variety of rewarding behaviors. Parallels are drawn between ejaculation and heroin rush. Other activated mesodiencephalic structures are the midbrain lateral central tegmental field, zona incerta, subparafascicular nucleus, and the ventroposterior, midline, and intralaminar thalamic nuclei. Increased activation was also present in the lateral putamen and adjoining parts of the claustrum. Neocortical activity was only found in Brodmann areas 7/40, 18, 21, 23, and 47, exclusively on the right side. On the basis of studies in rodents, the medial preoptic area, bed nucleus of the stria terminalis, and amygdala are thought to be involved in ejaculation, but increased rCBF was not found in any of these regions. Conversely, in the amygdala and adjacent entorhinal cortex, a decrease in activation was observed. Remarkably strong rCBF increases were observed in the cerebellum. These findings corroborate the recent notion that the cerebellum plays an important role in emotional processing. The present study for the first time provides insight into which regions in the human brain play a primary role in ejaculation, and the results might have important implications for our understanding of how human ejaculation is brought about, and for our ability to improve sexual function and satisfaction in men.
人们对总体上控制人类性行为，尤其是射精的大脑机制了解甚少。我们利用正电子发射断层扫描技术，测量了异性恋男性志愿者在射精过程中相较于性刺激时局部脑血流量（rCBF）的增加情况。手动阴茎刺激由志愿者的女性伴侣进行。主要激活区域位于中脑间脑过渡区，包括腹侧被盖区，该区域参与多种奖赏行为。研究发现射精与海洛因快感有相似之处。其他被激活的中脑间脑结构包括中脑外侧中央被盖区、未定带、束旁下核以及丘脑腹后核、中线核和板内核。外侧壳核和毗邻的屏状核也出现了激活增强。新皮层活动仅在右侧的布罗德曼7/40区、18区、21区、23区和47区被发现。基于对啮齿动物的研究，内侧视前区、终纹床核和杏仁核被认为与射精有关，但在这些区域均未发现rCBF增加。相反，在杏仁核和相邻的内嗅皮层观察到激活减少。在小脑中观察到显著强烈的rCBF增加。这些发现证实了近期关于小脑在情绪处理中起重要作用的观点。本研究首次揭示了人类大脑中哪些区域在射精中起主要作用，其结果可能对我们理解人类射精的产生方式以及改善男性性功能和性满意度的能力具有重要意义。
