大鼠额前皮质的脑干传入纤维联系

用ＣＢ－ＨＲＰ及ＨＲＰ法研究了２７只大鼠额前皮质的脑干传入纤维联系。观察结果发现，额前皮质各区中以岛叶无颗粒皮质胶部接受的脑干传入投射的核团最广泛，且多为植物性神经核；黑质致密部，被盖腹侧区与额前皮质有局部定位的投射关系；脚底视核向额前皮质内侧部投射；脑干中有大量接触脑脊液神经元投射到额前皮质；孤束核可不经其他核团中继直接投射到额前皮质的外侧部。实验对进一步研究额前皮质的功能提供了形态学依据。     

大鼠丘脑背内侧核的传出联系——WGA-HRP法研究

将WGA-HRP微电泳导入19只大鼠的丘脑背内侧核(DM),又将WGA-HRP注射于17只大鼠前额叶皮质的前扣带回背部,前边缘叶和岛叶无颗粒皮质背部,观察DM的传出投射。 DM投射到前额叶皮质的范围广泛,并有一定的局部定位。DM外侧部主要投射到前扣带回背部,其次为中央前区内侧皮质、前边缘叶、岛叶无颗粒皮质背部及腹外侧眶区等。DM内侧部主要投射到岛叶无颗粒皮质背部,其次为前边缘叶、下边缘叶、内侧眶区及腹侧眶区等。DM中间部主要投射到岛叶无颗粒皮质背部。 DM还投射到某些皮质下核团,如丘脑网状核、外侧视前区、尾壳核、伏隔核、苍白球、丘脑下部外侧区及束旁核等。此外,DM和前额叶皮质的前扣带回背部、中央前区内侧皮质、前边缘叶、下边缘叶及岛叶无颗粒皮质背部以及和丘脑网状核、外侧视前区及丘脑下部外侧区之间均有交互投射。     

扣带皮质各区与丘脑局部定位的联系——HRP法、放射自显影法及Nauta法研究

采用HRP法、放射自显影及Nauta法研究了大鼠扣带皮质各区与丘脑诸核团的纤维联系及局部定位。结果表明:扣带皮质与丘脑核团有较广泛的纤维联系,并多数为往返性联系;一侧扣带皮质只接受同侧丘脑发出的纤维,但也有双侧性地投射到丘脑某些核团,如束旁核、带旁核、网状核和前内侧核等;扣带皮质的不同区域与丘脑核团的联系具有一定的局部定位关系。     

大鼠脑干中缝核群向额前皮质的传入投射──HRP法研究

本实验用ＨＲＰ法研究了２７只大鼠脑干中缝核群向额前皮质的传入联系。结果如下：向额前皮质各区泳注ＨＲＰ后，标记细胞出现于上位脑干的中缝核，即吻侧、尾侧线形核，中缝背核，正中中缝核；下位脑干的中缝核中，除中缝苍白核外，中缝桥核、中缝大核、中缝隐核中也见到标记细胞。各中缝核中，以中缝背核标记为最多，其次是正中中缝核、中缝桥核和中缝大核，较少的是中缝隐核，吻、尾侧线形核．标记细胞大部分为中、小型，偶见大型，形态为多极形、梭形或三角形．另外，发现中缝核向额前皮质不同区域投射的细胞数量不同，正中中缝核、中缝桥核和中缝大校主要投射到额前皮质的内侧部分、而中缝背核，吻、尾侧线形核主要投射到额前皮质的外侧部分．     

丘脑、屏状核及蓝斑向扣带皮质不同区域的分支投射—荧光双标法研究

采用荧光双标记法，研究了18只SD大鼠丘脑、屏状核及蓝斑向扣带皮质不同区域的分支投射。结果表明丘脑内侧核外侧部发出少量侧枝投射到扣带皮质的23区和29区；丘脑外侧核发出少量侧枝投射到扣带皮质的24区和23区以及23区和29区；屏状核发出侧技投射到扣带皮质较广泛的区域；蓝斑偶见有细胞发出侧支投射到扣带皮质32区和23区。     

大白鼠扣带回3区向杏仁体及其他核群的纤维投射——菜豆白细胞凝集素顺行示踪研究

本文用菜豆自细胞凝集素免疫组织化学顺行示踪技术,观察大白鼠扣带回3区(Cg3)向皮质下核团的纤维投射。其投射区自前向后主要有:伏核、尾壳核内侧1/3、终纹床核、外侧视前区、带旁核、丘脑前内侧核、背内侧核、前室旁核、网状核、外侧缰核、后室旁核、束旁核及丘脑筛状核等。在丘脑下方,标记纤维密集于未定带、内囊的内侧边缘区和乳头丘脑束的周围。自这些区域,有纤维投射至下丘脑外侧区。本文着重分析了标记纤维在杏仁体的分布情况,标记纤维密集于基底外侧前核和外侧核的腹内侧亚核。从而证实Cg3皮质的纤维投射参与基底外侧核一边缘系环路,即所谓记忆环路。而杏仁体中央核仅偶见极稀疏的标记纤维。所以我们认为,Cg3皮质未参与“内脏环路”。标记纤维自注射侧经胼胝体膝至对侧半球,其投射区与注射侧的投射区一致,但标记纤维比较稀疏。     

大鼠间脑和皮质下端脑到前额叶皮质的传入投射——WGA-HRP法研究

本研究将 WGA-HRP 注射于25只大鼠前额叶皮质的前扣带回背部、前边缘区及岛叶无颗粒皮质背部,观察其间脑和皮质下端脑的传入联系。间脑的传入主要来自丘脑背内侧核,并有一定的局部定位。此外,丘脑的板内核群(中央外侧核、旁中央核、中央内侧核及束旁核)、腹侧核群(腹外侧核、腹内侧核、腹前核及腹后核)、中线核群(菱形核、连合核、带旁核及室旁核)、前内侧核、外侧缰核、后核及外侧核亦有到前额叶皮质的传入投射,且投射到前额叶皮质不同部位的数量不同。丘脑下部的传入主要来自外侧区、外侧视前区、尾侧大细胞核及乳头体上核,少量传入也可见于丘脑下部后区、背内侧核、腹内侧核及未定带。皮质下端脑的传入主要来自苍白球,其次为斜角带核、隔核、杏仁核及屏状核。在隔核中,除内侧隔核外还观察到外侧隔核,繖隔核及三角隔核亦投射到前额叶皮质。杏仁核中除杏仁外侧核、杏仁基底核外侧部及内侧部外,还观察到杏仁内侧核及杏仁皮质核亦有少量到前额叶皮质的传入。     

大鼠间脑到前额叶皮质的传入投射——FG逆行追踪法

目的：探讨间脑中神经核向前额叶中央外侧区的投射。方法：用荧光金（ＦＧ）逆行追踪法对１５只Ｗｉｓｔａｒ大鼠进行研究。结果：大鼠前额叶中央外侧区接受同侧丘脑前内侧核，丘脑前腹核；丘脑腹内侧核，丘脑腹外侧核，丘脑腹后内侧核，丘脑腹后外侧核；丘脑内侧背核中间部、外侧部、内侧部、丘脑外侧背核；丘脑后核，丘脑外侧一核；丘胲板内核的中央内核的中央内侧核，中央旁核，中央外侧核，丘脑束旁核；丘脑中线核的丘脑带旁核，     

大白鼠海马下托的皮质和皮质下核团的传入纤维联系——HRP法研究

使用HRP逆行轴浆运输技术观察了大白鼠海马下托的皮质和皮质下核团传入纤维联系。向腹侧下托和背侧下托投射的皮质区包括:Brodmann's 28、27、35、13、25、51b区前份和29区后份;向下托投射的皮质下核团包括:Broca's斜角带、内侧隔核、上乳头体核,下乳头体丘脑束核、中缝背核、正中中缝核、蓝斑核、丘脑连合核,皮质杏仁核及对侧海马结构的CA_3、CA_4亚区。这些结果表明,大白鼠海马下托是皮质向海马结构投射的主要接受区。但是在实验中没有观察到新皮质区向下托的纤维投射。在啮齿类动物这个进化等极上,新皮质区似乎尚未与海马结构建立纤维联系。实验结果还说明,皮质下核团向海马下托和CA_1亚区均有纤维投射,但是向腹侧下托投射的皮质下核团数目更多。     

杏仁复合体皮质内侧核群与基底外侧核群的皮质下传入性联系——逆行HRP法

用逆行HRP标记法研究了大白鼠杏仁复合体皮质内侧核群及基底外侧核群的皮质下传入性联系。分别对丘脑、下丘脑、中脑、脑桥等部向此二核群投射的核团做了观察和讨论。     

Subcortical projections to the prefrontal cortex in the rat as revealed by the horseradish peroxidase technique

The sources and distribution of subcortical afferents to the anterior neocortex were investigated in the rat using the horseradish peroxidase technique. Injections into the prefrontal cortex labelled, in addition to the mediodorsal thalamic nucleus, neurons in a total of fifteen subcortical nuclei, distributed in the basal telencephalon, claustrum, amygdala, thalamus, subthalamus, hypothalamus, mesencephalon and pons. Of these, the projections from the zona incerta, the lateroposterior thalamic nucleus, and the parabrachial region of the caudal mesencephalon to the prefrontal cortex have not previously been described.Different parts of the mediodorsal thalamic nucleus project to different areas of the frontal cortex. Thus, horseradish peroxidase injections in the most ventral pregenual part of the medial cortex labelled predominantly neurons in the medial anterior and dorsomedial posterior parts of the mediodorsal nucleus; injections into the more dorsal pregenual area labelled only neurons in the lateral and ventral parts of the nucleus; injections placed supragenually labelled neurons in the dorsolateral posterior part of the nucleus; and injections into the dorsal bank of the anterior rhinal sulcus labelled neurons in the centromedial part of the nucleus.Several other subcortical nuclei had projections overlapping with that of the mediodorsal thalamic nucleus. Five different types of such overlap were distinguished: (1) cell groups labelled after horseradish peroxidase injections into one of the subfields of the projection area of the mediodorsal nucleus (defined as the prefrontal cortex), but not outside this area (parataenial nucleus of the thalamus); (2) cell groups labelled both after injection into a subfield of the projection area of the mediodorsal nucleus and after injections in a restricted area outside this area (anteromedial, ventral and laterposterior thalamic nuclei); (3) cell groups labelled after injections into all subfields of the mediodorsal nucleus projection area, but not outside this area (ventral tegmental area, basolateral nucleus of amygdala); (4) cell groups labelled after injections into any area of the anterior neocortex, including the mediodorsal nucleus projection area (parabrachial neurons of the posterior mesencephalon); (5) cell groups labelled after all neocortical injections investigated (claustrum, magnocellular nuclei of the basal forebrain, lateral hypothalamus, zona incerta, intralaminar thalamic nuclei, nuclei raphe dorsalis and centralis superior, and locus coeruleus).We can draw the following conclusions from these and related findings. First, because of the apparent overlap of projections of the mediodorsal, the anteromedial and ventral thalamic nuclei in the rat, parts of the prefrontal cortex can also be called ‘cingulate’ and ‘premotor’. Second, on the basis of projections from parts of the mediodorsal nucleus, the prefrontal cortex of the rat can be subdivided into areas corresponding to those in other species. Third, the neocortex receives afferents from a large number of subcortical cell groups outside the thalamus, distributed from the telencephalon to the pons; however, the prefrontal cortex seems to be the only neocortical area innervated by the ventral tegmental area and amygdala. Finally, neither the prefrontal cortex nor the mediodorsal thalamic nucleus receives afferents from regions directly involved in sensory and motor functions.     

大鼠间脑到前额叶皮质的传入投射——FG逆行追踪法

目的:探讨间脑中神经核向前额叶中央外侧区的投射.方法:用荧光金(FG)逆行追踪法对15只Wistar大鼠进行研究.结果:大鼠前额叶中央外侧区接受同侧丘脑前内侧核,丘脑前腹核;丘脑腹内侧核,丘脑腹外侧核,丘脑腹后内侧核,丘脑腹后外侧核;丘脑内侧背核中间部、外侧部、内侧部,丘脑外侧背核;丘脑后核,丘脑外侧后核;丘脑板内核的中央内侧核,中央旁核,中央外侧核,丘脑束旁核;丘脑中线核的丘脑带旁核,丘脑菱形核,丘脑连结核,丘脑室旁核;丘脑网状核,膝上核;下丘脑的室旁核,室周核,下丘脑后区,下丘脑外侧区,乳头体上核,乳头体内侧核.下丘脑外侧大细胞核,外侧视前区,内侧视前区及丘脑底部中的未定带,Forel区,丘脑底核的投射纤维.结论:前额叶中央外侧区接受广泛的间脑核团的投射,并存在着局部定位的关系.     

Organization of amygdaloid projections to the prefrontal cortex and associated striatum in the rat.

The organization of connections between the amygdala, prefrontal cortex and striatum was studied using anterograde and retrograde tract tracing techniques in the rat. The anterograde transport of Phaseolus vulgaris leucoagglutinin and wheat germ agglutinin conjugated to horseradish peroxidase was used to examine the striatal projections of the prefrontal cortex. These studies revealed that the prelimbic area of the medial prefrontal cortex projects mainly to the medial part of the striatum, whereas the dorsal agranular insular area of the lateral prefrontal cortex projects mainly to the ventrolateral part of the striatum. The organization of amygdaloid projections to the prefrontal cortex and its associated portions of the striatum was investigated using the fluorescence retrograde tract tracing technique. Different color fluorescent dyes, True Blue and Diamidino Yellow, were injected into the prefrontal cortex and striatum. These studies demonstrated that medial portions of the basolateral nucleus, and adjacent portions of the lateral, basomedial and amygdalo-hippocampal nuclei, project to both the medial prefrontal cortex and its associated medial striatal region. The rostral pole and lateral portions of the basolateral nucleus project to both the lateral prefrontal cortex and its associated lateral striatal region. Many neurons in the basolateral amygdaloid nucleus, and to a lesser extent other amygdaloid nuclei, were double-labeled in these experiments, indicating that these cells send collaterals to both the prefrontal cortex and striatum. These findings indicate that discrete areas of the amygdala, and in some cases individual amygdaloid neurons, can modulate information processing in the first two links of distinct cortico-striato-pallidal systems arising in the medial and lateral prefrontal cortex.     

The prefrontal cortex of a prosimian (Galago senegalensis) defined as the cortical projection area of the thalamic mediodorsal nucleus

In the lesser bush baby (Galago senegalensis) small amounts of horseradish peroxidase were injected into different areas of the frontal cortex and respective distributions of labelled cells in the mediodorsal nucleus of the thalamus were charted. The results show that the medial part of this nucleus projects to the most ventrolateral portions of the frontal lobe (no injections into ventromedial portions of the frontal lobe were made); the lateral part projects to a more dorsally located belt extending from the medial surface over the frontal tip and to the lateral surface; whereas the most lateral (paralamellar) portion projects to an even more dorsal belt also on all three sides of the frontal lobe. Neither more posterior dorso-lateral cortex in the vicinity of the sulcus reclus, nor the supra- and infragenual areas receive any innervation from this thalamic nucleus.These results show that in the bush baby the topographical position of the prefrontal cortex and/or its subdivisions differs both from the positions obtained with other techniques in the same species, and from the positions found in several other species, including monkeys. The present picture of the prefrontal cortex in the bush baby resembles the cytoarchitectural maps of another prosimian—the lemur.Also in the bush baby the frontal eye field, defined as the cortical target of the paralamellar portion of the mediodorsal thalamic nucleus, occupies the position between the other subdivisions of the prefrontal cortex and the motor-premotor complex.     

Afferent connections of the subparafascicular area in rat

The subparafascicular nucleus and the subparafascicular area are the major sites of synthesis of the recently discovered neuropeptide, tuberoinfundibular peptide of 39 residues (TIP39). Better knowledge of the neuronal inputs to the subparafascicular area and nucleus will facilitate investigation of the functions of TIP39. Thus, we have injected the retrograde tracer cholera toxin B subunit into the rostral, middle, and caudal parts of the rat subparafascicular nucleus. We report that the afferent projections to the subparafascicular nucleus and area include the medial prefrontal, insular, and ectorhinal cortex, the subiculum, the lateral septum, the anterior amygdaloid area, the medial amygdaloid nucleus, the caudal paralaminar area of the thalamus, the lateral preoptic area, the anterior, ventromedial, and posterior hypothalamic nuclei, the dorsal premamillary nucleus, the zona incerta and Forel's fields, the periaqueductal gray, the deep layers of the superior colliculus, cortical layers of the inferior colliculus, the cuneiform nucleus, the medial paralemniscal nucleus, and the parabrachial nuclei. Most of these regions project to all parts of the subparafascicular nucleus. However, the magnocellular subparafascicular neurons, which occupy the middle part of the subparafascicular nucleus, may not receive projections from the medial prefrontal and insular cortex, the medial amygdaloid nucleus, the lateral preoptic area, and the parabrachial nuclei. In addition, double labeling of cholera toxin B subunit and TIP39 revealed a remarkable similarity between input regions of the subparafascicular area and the brain TIP39 system. Neurons within regions that contain TIP39 cell bodies as well as regions that contain TIP39 fibers project to the subparafascicular area. Overall, the afferent connections of the subparafascicular nucleus and area suggest its involvement in central reproductive, visceral, nociceptive, and auditory regulation.     

Organization of the thalamo-cortical connexions to the frontal lobe in the rhesus monkey

Summary In 25 rhesus monkeys horseradish peroxidase was injected in different parts of the frontal cortex. The retrogradely labelled thalamic neurons formed longitudinal bands, some of which crossed the internal medullary lamina, and extended from one thalamic nucleus into another. On the basis of these findings the frontal cortex was subdivided into seven transverse cortical strips which receive afferents from seven longitudinal bands of thalamic neurons. The most rostral transverse strip receives afferents from the most medial thalamic band which is oriented vertically and extends through the most medial part of the MD into the medial pulvinar. Progressively more caudally located transverse strips receive afferents from progressively more laterally located thalamic bands which in part are situated in the VL and show an increasing tilt towards the horizontal. Moreover, those parts of the various bands which are situated along the dorsal and lateral margin of the thalamus project to the medial portions of the transverse cortical strips, i.e. along the medial margin of the frontal lobe, while the other parts situated ventromedially in the thalamus project to the lateral portions of these strips, i.e. along the lateral margin of the frontal lobe.These data provide an alternative view of the organization of the thalamus and suggest that this structure contains a matrix of longitudinal cell columns which in some cases extend across specific nuclear borders and may represent the basic thalamic building blocks in respect to the thalamo-cortical connexions.     

Some topographical connections of the striate cortex with subcortical structures in Macaca fascicularis

Summary Subcortical connections of the striate cortex with the superior colliculus (SC), the lateral pulvinar (Pl), the inferior pulvinar (Pi) and the dorsal lateral geniculate nucleus (LG) were studied in the macaque monkey, Macaca fascicularis, following cortical injections of tritiated proline and/or horseradish peroxidase. All four structures were shown to receive topographically organized projections from the striate cortex. The exposed surface of the striate cortex was found to be connected to the rostral part of the SC and the caudal part of the LG. Injections of the exposed striate cortex close to its rostral border resulted in label in adjoining parts of the Pl and Pi. The ventral half and dorsal half of the calcarine fissure were connected with the medial and lateral parts of the SC, the ventrolateral and dorsomedial portions of the Pl and Pi and the lateral and medial parts of the LG, respectively. Injections located at the lateral posterior extreme of the calcarine fissure resulted in label at the optic disc representation in the LG. The horseradish peroxidase material demonstrated that LG neurons in all laminae and interlaminar zones project to the striate cortex.Abbreviations BIC brachium of the inferior colliculus - BSC brachium of the superior colliculus - C cerebellum - CG central grey - i interlaminar zone(s) of the dorsal lateral geniculate nucleus - IC inferior colliculus - ICc central nucleus of the inferior colliculus - LG dorsal lateral geniculate nucleus - m magnocellular layer(s) of the dorsal lateral geniculate nucleus - MG medial geniculate body - p parvocellular layer(s) of the dorsal lateral geniculate nucleus - P pulvinar complex - Pi inferior pulvinar - PG pregeniculate nucleus - Pl lateral pulvinar - Pm medial pulvinar - s superficial layer(s) of the dorsal lateral geniculate nucleus - SC superior colliculus - sgs stratum griseum superficiale of the superior colliculus - R reticular nucleus of the thalamus - VP ventroposterior group - 17 Area 17 Supported by NEI Grants EY-07007 (J. Graham) and EY-02686 (J.H. Kaas)     

Restricted cortical termination fields of the midline and intralaminar thalamic nuclei in the rat.

The projections from the midline and intralaminar thalamic nuclei to the cerebral cortex were studied in the rat by means of anterograde tracing with Phaseolus vulgaris-leucoagglutinin. The midline and intralaminar nuclear complex taken as a whole projects to widespread, predominantly frontal, cortical areas. Each of the constituent thalamic nuclei has a restricted cortical projection field that overlaps only slightly with the projection fields of adjacent midline and intralaminar nuclei. The projections of the intralaminar nuclei cover a larger cortical area than those of the midline nuclei. The laminar distributions of fibres from individual midline and intralaminar thalamic nuclei are different and include both deep and superficial cortical layers. The parataenial, paraventricular and intermediodorsal midline nuclei each project to circumscribed parts of the prefrontal cortex and the hippocampal and parahippocampal regions. In the prefrontal cortex, the projections are restricted to the medial orbital, infralimbic, ventral prelimbic and agranular insular fields, and the rostral part of the ventral anterior cingular cortex. In contrast to the other midline nuclei, the rhomboid nucleus projects to widespread cortical areas. The rostral intralaminar nuclei innervate dorsal parts of the prefrontal cortex, i.e. the dorsal parts of the prelimbic, anterior cingular and dorsal agranular insular cortical fields, the lateral and ventrolateral orbital areas, and the caudal part of the ventral anterior cingular cortex. Additional projections are aimed at the agranular fields of the motor cortex and the caudal part of the parietal cortex. The lateral part of the parafascicular nucleus sends fibres predominantly to the lateral agranular field of the motor cortex and the rostral part of the parietal cortex. The medial part of the parafascicular nucleus projects rather sparsely to the dorsal part of the prelimbic cortex, the anterior cingular cortex and the medial agranular field of the motor cortex. Individual midline and intralaminar thalamic nuclei are thus in a position to directly influence circumscribed areas of the cerebral cortex. In combination with previously reported data on the organization of the midline and intralaminar thalamostriatal projections and the prefrontal corticostriatal projections the present results suggest a high degree of differentiation in the convergence of thalamic and cortical afferent fibres in the striatum. Each of the recently described parallel basal ganglia-thalamocortical circuits can thus be expanded to include projections at both the cortical and striatal levels from a specific part of the midline and intralaminar nuclear complex. The distinctive laminar distributions of the fibres originating from the different nuclei emphasize the specificity of the midline and intralaminar thalamocortical projections.