Shehab S, Dean P, Redgrave P
Department of Anatomy, University of Glasgow, U.K.
Neuroscience. 1995 Apr;65(3):681-95. doi: 10.1016/0306-4522(94)00516-8.
Activation of the dorsal midbrain has a powerful anticonvulsant effect in the maximal electroshock model of epilepsy. The suppression of tonic seizures can be obtained most reliably from an area centred on the intercollicular nucleus overlapping into the deep layers of the superior colliculus and adjacent mesencephalic reticular formation. As part of a series of investigations to identify neural mechanisms responsible for mediating the anticonvulsant properties of the dorsal midbrain, the present study provides an anatomical description of the efferent projections of this region. Small amounts of wheatgerm agglutinin-horseradish peroxidase (10-30 nl of a 1% solution) were injected into the intercollicular nucleus and surrounding tissue. The resulting anterograde transport of the tracer was plotted on a set of standard atlas sections. Four major output pathways were identified: (i) an ipsilateral descending projection which had terminations in the microcellular tegmental nucleus, lateral and ventral pontine reticular nucleus pars oralis, ventrolateral tegmental nucleus, ventral and caudal pontine reticular nucleus pars caudalis, raphe magnus nucleus and the gigantocellular nucleus; (ii) a contralateral descending projection which for the most part targeted the same brainstem structures but with weaker terminal labelling; (iii) a projection to the contralateral dorsal midbrain with comparatively weak terminal label in the contralateral superior colliculus, intercollicular nucleus, periaqueductal gray, mesencephalic reticular formation and cuneiform area; (iv) ipsilateral ascending pathway with terminations in the red nucleus, zona incerta, peripeduncular area, parafascicular nucleus, lateral hypothalamus, parts of the pretectum and caudal thalamus. At a general level the dorsal midbrain anticonvulsant zone shares its major output projections and efferent targets with at least one of its near neighbours, including the superior colliculus, periaqueductal gray, the cuneiform nucleus and pedunculopontine nucleus. The possibility that anticonvulsant properties of the intercollicular area can simply be attributed to a unique set of efferent projections is therefore not supported by the anatomy.
在癫痫的最大电休克模型中，中脑背侧的激活具有强大的抗惊厥作用。强直发作的抑制最可靠地可从以顶盖间核为中心、延伸至上丘深层和相邻中脑网状结构的区域获得。作为确定介导中脑背侧抗惊厥特性的神经机制的一系列研究的一部分，本研究对该区域的传出投射进行了解剖学描述。将少量小麦胚凝集素 - 辣根过氧化物酶（1%溶液10 - 30 nl）注入顶盖间核及周围组织。将示踪剂产生的顺行运输绘制在一组标准图谱切片上。确定了四条主要输出通路：（i）同侧下行投射，其终末位于小细胞被盖核、脑桥外侧和腹侧网状核口部、腹外侧被盖核、脑桥腹侧和尾侧网状核尾部、中缝大核和巨细胞核；（ii）对侧下行投射，其大部分靶向相同的脑干结构，但终末标记较弱；（iii）投射至对侧中脑背侧，在对侧上丘、顶盖间核、导水管周围灰质、中脑网状结构和楔形区的终末标记相对较弱；（iv）同侧上行通路，其终末位于红核、未定带、脚周区、束旁核、外侧下丘脑、部分顶盖前区和丘脑尾部。一般而言，中脑背侧抗惊厥区与其至少一个邻近区域共享其主要输出投射和传出靶点，包括上丘、导水管周围灰质、楔形核和脚桥核。因此，顶盖间区的抗惊厥特性可简单归因于一组独特的传出投射的可能性在解剖学上并不成立。
