Roeling T A, Veening J G, Peters J P, Vermelis M E, Nieuwenhuys R
Department of Anatomy and Embryology, Faculty of Medical Sciences, University of Nijmegen, The Netherlands.
Neuroscience. 1993 Sep;56(1):199-225. doi: 10.1016/0306-4522(93)90574-y.
The efferent connections of the hypothalamic area, where grooming can be elicited by local electrical stimulation or injection of various substances, were studied using iontophoretic injections of Phaseolus vulgaris leucoagglutinin. This hypothalamic "grooming area" consists of parts of the hypothalamic paraventricular nucleus and of the dorsal hypothalamic area. The specificity of these efferents for the hypothalamic "grooming area" was investigated by comparison with efferents of hypothalamic sites adjacent to this area. In addition, the distribution of oxytocinergic fibres was studied, since oxytocinergic neurons are present in the hypothalamic "grooming area" and oxytocin is possibly involved in grooming behaviour. The efferents of the hypothalamic "grooming area" as well as of hypothalamic sites surrounding this area and the oxytocinergic fibres studied do not form well determined bundles, but rather spread out throughout the hypothalamus. Clusters of fibres could be traced rostrally and caudally, forming diffuse fibre "streams". Three rostral, two thalamic and three caudal fibre "streams" have been distinguished along which efferent fibres innervate different brain areas. The many varicosities on labelled fibres "en passant" suggest that hypothalamic fibres are able to influence many parts of the brain along their way. The anterior periventricular area, the median preoptic nucleus, the ventral tegmental area and nucleus of the solitary tract were found to be more or less specifically innervated by hypothalamic "grooming area" fibres and oxytocinergic fibres. Other brain areas, like the septum, the medial amygdaloid nucleus, the central gray and the paraventricular nucleus of the thalamus were found to receive efferent projections from the hypothalamic "grooming area" and hypothalamic loci outside this area, as well as from the oxytocinergic system. Within the septum and the mesencephalic central gray, differences in the spatial organization of terminating fibres from the hypothalamic "grooming area" and hypothalamic "non-grooming" sites have been found. Fibres from the grooming area clustered in the ventral part of the lateral septal nucleus, while fibres from surrounding hypothalamic loci innervated other parts of that brain area. In the central gray, fibres from the hypothalamic "grooming area" clustered in rostrodorsal and caudoventral parts. A number of brain areas, that are innervated by hypothalamic "grooming area" fibres and oxytocinergic fibres, like central gray, ventral tegmental area and the noradrenergic A5 area, have been reported previously to be involved in grooming behaviour. It is concluded from the present findings, that the hypothalamic "grooming area" has preferential connections with a number of brain sites, not shared with hypothalamic projections from outside the "grooming area".(ABSTRACT TRUNCATED AT 400 WORDS)
采用离子电渗法注射菜豆白细胞凝集素，研究了下丘脑区域的传出联系，该区域可通过局部电刺激或注射各种物质引发梳理行为。这个下丘脑“梳理区”由下丘脑室旁核的部分区域和下丘脑背侧区组成。通过与该区域相邻下丘脑部位的传出联系进行比较，研究了这些传出联系对下丘脑“梳理区”的特异性。此外，还研究了催产素能纤维的分布，因为下丘脑“梳理区”存在催产素能神经元，且催产素可能参与梳理行为。下丘脑“梳理区”以及该区域周围下丘脑部位的传出联系和所研究的催产素能纤维并未形成明确的束状结构，而是散布于整个下丘脑。纤维束可向头端和尾端追踪，形成弥散的纤维“流”。已区分出三条头端、两条丘脑和三条尾端纤维“流”，传出纤维沿这些纤维“流”支配不同的脑区。标记纤维上众多的膨体表明，下丘脑纤维在其行程中能够影响脑的许多部位。发现室周前区、视前正中核、腹侧被盖区和孤束核或多或少地特异性接受下丘脑“梳理区”纤维和催产素能纤维的支配。其他脑区，如隔区、杏仁内侧核、中央灰质和丘脑室旁核，发现接受来自下丘脑“梳理区”和该区域外下丘脑位点的传出投射，以及来自催产素能系统的投射。在隔区和中脑中央灰质内，已发现来自下丘脑“梳理区”和下丘脑“非梳理”位点终末纤维的空间组织存在差异。来自梳理区的纤维聚集在外侧隔核的腹侧部分，而来自周围下丘脑位点的纤维支配该脑区其他部分。在中央灰质中，来自下丘脑“梳理区”的纤维聚集在头背侧和尾腹侧部分。先前有报道称，一些受下丘脑“梳理区”纤维和催产素能纤维支配的脑区，如中央灰质、腹侧被盖区和去甲肾上腺素能A5区，参与梳理行为。从目前的研究结果得出结论，下丘脑“梳理区”与一些脑位点有优先联系，这些联系是“梳理区”外的下丘脑投射所不具备的。（摘要截选至400字）
