Cortical area 8 and its thalamic projection in Macaca mulatta
Cortical area 8 and its thalamic projection in Macaca mulatta
复制标题
猕猴皮质区 8 及其丘脑投射
DOI：
10.1002/cne.901210208
复制
发表时间：
1963
影响因子：
2.5
通讯作者：
K. Akert
中科院分区：
文献类型：
--
作者：
G. Scollo;K. Akert
额眼区是由Ferrier于1874年发现的，尽管随后对人和猴的这一区域进行了大量的生理学、解剖学和临床研究（Smith，'49），但额皮质在眼活动的复杂组织中的具体作用实际上仍然未知。自Brodmann（'05）将额眼区描述为特定的皮质区（8区）以来，即使是解剖学问题的阐明也几乎没有进展，尽管组织学图一再受到脑电生理定位图的挑战。不确定性也存在关于丘脑核的传入投射到第8区的起源。然而，丘脑-皮层关系的研究对于理解给定皮层区域的解剖学和功能组织具有根本的重要性，并且它们已被证明是唯一适合于哺乳动物皮层的比较研究（Akert，'63）。例如，在几个物种中，眶额区（即额叶皮层）被定义为内侧核（nucleus medialis dor nerve salis）的接收区（Rose and Woolsey，'48），而中央前运动皮层（Brodmann's area 4）已被证明接收来自腹外侧核（nucleus ventralis lateralis）的必要丘脑传入（Akert and Woolsey，'53）。由于第8区位于中央前运动区和眶额区之间，因此无法确定地预测其丘脑对应部分。Hassler（'49）认为，第8区接受来自腹外侧核（最内侧部分）的传入似乎更合理，因为他认为视野主要是一个运动皮层，与锥体系统的起源区域相当。似乎有证据支持这一假设，从人类病例与病变的前眼域（斯特恩，'42; Nor Barman，'45;弗里曼和瓦茨，'47）。另一方面，步行者（'40 b）和Mettler（'47）以及Pribram、Chow和Semmes（'53）在恒河猴中进行了实验观察，他们发现到第8区的传入来自背内侧核（最外侧部分）。在这种两难境地中，很难借助消融-变性技术做出决定，因为在高等灵长类动物中，第8区的相当大一部分位于脑沟深处。在猕猴中，第8区部分位于脑沟深处，手术切除可能会对支配第8区以外皮质区域的皮质下纤维系统造成意外损伤。相同的错误来源存在于大多数（如果不是所有）人类病例中，区域8受损。这可能导致错误的解释逆行丘脑的变化和对比的结论可能会得出不同的研究者。为了消除此类误差因素，本研究纳入了对照病例，其中对8区的吻侧和尾侧区域进行消融，而不损伤8区本身。试验和对照系列关于丘脑退行性变的结果是一致的，并表明区域8接收来自背内侧核的前板部分的投射。
The frontal eyefields were discovered in 1874 by Ferrier and though considerable research has subsequently been done on physiological, anatomical and clinical as pects of this area in man and monkey (Smith, ’49), the specific role of the fron tal cortex in the complex organization of oculomotor activity is still virtually un known. Even the elucidation of anatom ical problems has made little progress since Brodmann ( ’05) characterized the area of the frontal eyefield as a specific cortical area (area 8), though histological maps were repeatedly challenged by elec tro-physiological localization charts. Un certainty also exists about the thalamic nucleus of origin of afferent projections to area 8. Yet, thalamo-cortical relation ship is of fundamental importance for the understanding of the anatomical and functional organization of a given cortical field, and they have proved to be uniquely suited for comparative studies of mam malian cortex (Akert, ’63). For example the Orbitofrontal region (i.e. frontal gran ular cortex) has been defined as the re ceiving area of the nucleus medialis dor salis in several species (Rose and Woolsey, ’48), and the precentral motor cortex (Brodmann’s area 4 ) has been shown to receive essential thalamic afferents from nucleus ventralis lateralis (Akert and Woolsey, ’53). Since area 8 is situated between the precentral motor and the Orbitofrontal regions its thalamic counter part could not have been predicted with certainty. To Hassler ( ’49) it seemed more reasonable to assume that area 8 receives afferents from nucleus ventralis lateralis (the most medial portion) be cause he considered the eyefields primarily a motor cortex comparable to the fields of origin of the pyramidal system. Seem ingly, there is supporting evidence for this hypothesis from human cases with lesions of the frontal eyefields (Stern, ’42; Nor man, ’45; Freeman and Watts, ’47). On the other hand, there are experimental observations in the Rhesus monkey by Walker ( ’40b) and Mettler ( ’47) as well as by Pribram, Chow and Semmes ( ’53) who have found that the afferents to area 8 arise from nucleus medialis dorsalis (the most lateral portion). A decision in this dilemma with the aid of ablation-degeneration techniques is dif ficult because in the higher primates a considerable portion of area 8 is situated in the depth of a sulcus. In the species Macaca mulatta, area 8 is partially situ ated in the depth of sulcus arcuatus, and its surgical removal may entail unintended damage to Subcortical fiber systems which innervate cortical areas other than area 8. The same source of errors exists in most if not all human cases with damage to area 8. This can lead to errors in the interpretation of retrograde thalamic changes and contrasting conclusions may be drawn by different investigators. In order to eliminate error factors of this kind control cases have been included in this study in which the areas rostrally as well as caudally to area 8 were ablated without injuring area 8 itself. The results of the test and control series in respect to retrograde thalamic degeneration were consistent and have shown that area 8 receives projections from the paralamellar portion of nucleus medialis dorsalis.