鸽丘脑听觉中继核团传出神经投射的研究

应用神经示踪物生物素标记的葡聚糖对环鸽丘脑听觉中继核团的传出神经投射进行了研究。结果发现：（１）丘脑卵圆核的传出纤维投射至端脑新纹状体内侧的Ｌ２听区;（２）卵圆核壳的传出纤维投射至Ｌ１、Ｌ３和部分Ｌ２听区,在Ｌ区周围亦存在许多标记终末;（３）尾侧卵圆核壳的传出投射参与了卵圆核壳的形成并发出二束纤维分别投射至下丘脑腹内侧核和端脑新纹状体Ｌ区外侧的旁听区。本实验结果首次揭示在鸟类丘脑听中继核团、端脑新     

大鼠杏仁基底外侧核腹侧部向杏仁中央核的纤维投射──HRP逆行示踪结合免疫组织化学法研究

本实验采用ＨＲＰ逆行示踪结合免疫组织化学方法,对大鼠杏仁底基底外侧核腹侧部向中央杏仁核的纤维投射特征及其化学特性进行了研究。一侧杏仁中央核（Ｃｅ）内注射ＨＲＰ后,于双侧杏仁基底外侧核腹侧部（ＢＬＶ）观察到大量ＨＲＰ标记神经元,以对侧为主;在杏仁基底外侧核前（ＢＬＡ）、后（ＢＬＰ）部及梨状皮质内侧部（ＰＣＭ）第Ⅱ、Ⅲ层仅观察到少量ＨＲＰ标记神经元。当注射范围局限于杏仁中央核内侧部（ＣｅＭ）,ＢＬＶ的标记神经元相对多．当注射范围局限于杏仁中央核外侧部（ＣｅＬ）,ＢＬＶ的标记神经元相对少。将有ＨＲＰ标记神经元的切片分别与生长抑素（ＳＯＭ）、脑啡呔（ＥＮＫ）、Ｐ物质（ＳＰ）抗血清按ＡＢＣ法完成免疫组织化学反应,结果在ＢＬＶ、ＰＣＭ第Ⅱ、Ⅲ层观察到ＨＲＰ－ＳＯＭ免疫阳性双标记神经元,但未发现ＨＲＰ－ＳＰ、ＨＲＰ－ＥＮＫ免疫阳性双标记神经元;在ＢＬＡ和ＢＬＰ未发现ＨＲＰ－ＳＯＭ、ＨＲＰ－ＥＮＫ、ＨＲＰ－ＳＰ免疫阳性双标记神经元。本文着重讨论了ＢＬＶ与内脏功能活动的关系,认为ＢＬＶ不同于ＢＬＡ与ＢＬＰ,它参与“内脏环路”。此外,还分析了ＰＣＭ投射到Ｃｅ的神经元的功能学意义。     

环鸽丘脑听区传入神经投射的研究

应用神经示踪物ＰＨＡＬ和ＢＤＡ对环鸽丘脑听区的传入神经投射进行了研究。结果发现中脑外侧核背部和丘间核交界内缘区的神经元发出纤维投射至丘脑卵形核周围形成卵形壳;尾部Ｏｖ壳和Ｏｖ交界面区域接受前峡核浅区的投射;尾部Ｏｖ壳不但接受ＩＣＭ神经元的传出投射,而且有神经发出的传出纤维参与了Ｏｖ壳的形成。     

THE IMMUNOHISTOCHEMICAL STUDIES OF PROJECTIONS LINKING THE AUDITORY THALAMUS AND NEUROSE- CRETORY HYPOTHALAMUS IN THE BRAIN OF NON - SONGBIRD

应用神经示踪物ＢＤＡ（ｂｉｏｔｉｎｙｌａｔｅｄｄｅｘｔｒａｎａｍｉｎｅ）和免疫组织化学方法对环鸽（ｓｔｒｅｐｔｏｐｅｌｉａｒｉｓｏｒｉａ）丘脑听区和下丘脑内分泌脑区间的神经通路进行了研究。结果发现,丘脑卵形核壳（Ｏｖｓｈｅｌ）及周围区域存在丰富脑啡肽免疫反应神经元。丘脑卵形核尾侧（Ｏｖｐ）有传出纤维直接投射至Ｏｖ壳和下丘脑腹内侧核（ＶＭＮ）。卵形核壳周围和下丘脑内分泌脑区间的传出神经通路显示了丰富的脑啡肽阳性免疫反应细胞和终末标记,在下丘脑腹内侧核中亦存在大量脑腓肽终末标记。结果提示Ｏｖ周围的部分脑啡肽神经元发出的传出纤维可能参与了鸽丘脑听区向内分泌下丘脑区投射的神经通路。     

大鼠下橄榄复合体至小脑旁绒球和绒球的投射：HRP逆行追踪的研究

应用辣根过氧化物酶（ＨＲＰ）做逆行标记,以四甲基联苯胺（ＴＭＢ）,为呈色剂,对成年大鼠下橄榄复合体到小脑分级球和线球的纤维投射进行了详细的研究。结果显示旁线球和线球接受对侧下橄榄复合体的纤维投射。其中,绒球只接受背帽（ＤＣ）和内侧副橄榄核（ＭＡＯ）嘴段的投射;旁绒球接受ＭＡＯ、橄榄主核（ＰＯ）及少量腹外延伸（ＶＬＯ）的投射。但是,未观察到由下橄榄复合体的背侧副橄榄核（ＤＡＯ）到旁绒球或绒球的投射。此外,对大鼠橄榄旁绒球和橄榄绒球投射的带型以及下橄榄与绒球和旁线球的功能做了相关的讨论。     

黄雀中脑及丘脑听性核团的纤维联系

本文用ＨＲＰ顺、逆行追踪方法，研究黄雀中脑下丘中央核（ＩＣｃ）及丘脑卵圆核（ＯＶ）的传入联系及ＯＶ向端脑的投射。将ＨＲＰ微电泳入ＩＣｃ，在延髓角状核、层状核及脑桥外侧丘系核复合体出现了密布的标记细胞，在ＯＶ及卵圆核的腹内侧部见到密集的标记终末，在对侧ＩＣｃ有许多的标记细胞及终末。将ＨＲＰ微电泳入ＯＶ，除在ＩＣｃ有大量的标记细胞外，在端脑Ｌ听区等处见到密集的标记终末。结果表明，ＩＣｃ接受角状核、层状核和外侧丘系核复合体的传入投射，由它发出的纤维投射到ＯＶ及卵圆核的腹内侧部，双侧ＩＣｃ间有往返联系，从ＯＶ发出的纤维投射至端脑的Ｌ听区。Ｌ听区可能是听觉的高位中枢。     

大鼠延髓至下丘脑腹内侧核的儿茶酚胺能投射神经元在胃伤害性刺激后的Fos表达

本实验用ＨＲＰ注入下丘脑腹内侧核结合逆行追踪与抗ＦＯＳ蛋白和抗酪氨酸羟化酶（ＴＨ）抗血清双重免疫细胞化学相结合的三重标记方法,对大鼠孤束核和延髓腹外侧区至下丘脑腹内侧核的儿茶酚胺能投射神经元在胃伤害性刺激后的ｃ－ｆｏｓ表达进行了观察。本文发现孤束核和延髓腹外侧区有七种不同的标记细胞：ＨＲＰ、Ｆｏｓ、ＴＨ单标细胞Ｆｏｓ／ＨＲＰ、Ｆｏｓ／ＴＨ、ＨＲＰ／ＴＨ双标细胞和Ｆｏｓ／ＨＲＰ／ＴＨ三标细胞。上述七种标记细胞主要分布在延髓中段和尾段孤束核的内侧亚核和延髓腹外侧区以及两者之间的网状结构。ＨＲＰ标记细胞以注射侧为主,对侧有少量分布。本文结果证明,大鼠孤束核、延髓腹外侧区和网状结构内儿茶酚胺能神经元有些至下丘脑腹内侧核的投射,其中一部分儿茶酚胺能神经元参与了胃伤害性刺激的传导和调控。     

大鼠膀胱初级传入纤维向中枢的定位投射──CB－HRP跨神经节追踪研究

本文用大鼠１７只，将ＣＢ－ＨＲＰ注入一例膀胱壁内，ＴＭＢ法反应，明暗视野对照观察。结果：１）标记的初级传入神经元在脊神经节的分布节段为Ｔ１２－Ｓ２节，以注射侧为主。最集中的节段是Ｌ６－Ｓ１，其标记细胞数占标记细胞总数５２．５％，并集中分布在节内的背远侧端，有较明确的局部定位；２）初级传入神经元的中枢突进入脊髓后，其大部分纤维（外侧径束）终于网状核和中间外侧核形成终末区。小部分纤维（内侧径束）进入中央管背外侧区和灰质后连合形成终末区。灰质后连合被一横行的白质带分为背、腹两部，外侧径束分布在腹部并可越过中线，内侧径束分布在背部。     

鸣禽栗 新纹状体L复合区与发声控制系统的神经联系

利用辣根过氧化物酶顺、逆行追踪的方法对鸣禽栗端脑新纹状体Ｌ复合区的神经联系进行了研究。结果表明,新纹状体Ｌ复合区中的Ｌ２区主要接受来自丘脑卵圆核的传入,并与Ｌ１和Ｌ３区有纤维联系;而Ｌ１和Ｌ３区传出纤维投射至高级发声中枢腹侧的架区、古纹状体粗核喙背侧的杯区以及上纹状体腹部尾外侧等处;Ｌ复合区亦接受来自新纹状体前部巨细胞核内侧部的传入投射。     

鸣禽栗Wu新纹状体L复合区与发声控制系统的神经联系

利用辣根过氧化物酶顺、逆行追踪的方法对鸣禽栗Ｗｕ端脑新纹状体Ｌ复合区的神经联系进行了研究。结果表明,新纹状体Ｌ复合区中的Ｌ２区主要接受来自丘脑卵圆核的传入,并与Ｌ１和Ｌ３区有纤维联系;而Ｌ１和Ｌ３区传出纤维投射至高级发声中枢腹侧的架区、１古纹状体粗核 背侧的杯区以及上纹状体腹部尾外侧等处;Ｌ复合区亦接受一自新纹状体前部巨细胞核内侧部的传入投射。     

Proposed pathways for vocal self-stimulation: Met-enkephalinergic projections linking the mibrain vocal nucleus,auditory-responsive thalamic vocal nucleus,auditory-responsive thalamic regions and neurosecretory hypothalamus

In this study, we have investigated the neuroanatomical pathways that may underlie the influence of a female bird's vocal behavior upon her own reproductive endocrine response. We traced the ascending efferent projections of the midbrain vocal control nucleus, the intercollicularis (ICo), using an anterograde tracer, PHAL, delivered by iontophoretic application. We found labelled terminal fields in the anterior regions of the hypothalamus that contained luteinizing hormone releasing hormone- (LHRH) immunoreactive neurons. We injected into the LHRH-rich anterior medial hypothalamus (AM) the retrograde tracer, fluorogold, to verify the results of PHAL anterograde tracing and exmine whether retrogradely labelled neurons in the ICo can be stained with met-enkephalin antiserum by the immunohistochemical method. Of the retrogradely labelled neurons in the medial division of ICo (mICo), between 5% and 15% were found to be met-enkephalin-immunoreactive positive perikarya. Our data suggest that axonal projections into the anterior medial hypothalamus may arise in part from enkephalin-immunoreactive neurons in the medial ICo. The mICo neurons distributed along the medial border of the midbrain auditory nucleus give rise to projections into the posterior medial hypothalamus (PMH) via synapses within the shell region of thalamic auditory nucleus, ovoidalis (Ov). We conclude that in the ring dove, the medial division of the vocal control nucleus, by virtue of its connection with the auditory thalamus and neurosecretory hypothalamus, is in a position to exert influence on endocrine response partly through enkephalinergic systems. Implications of similar connections in other species are discussed. 1994 John Wiley & Sons, Inc.     

Afferent and efferent connections of the sexually dimorphic medial preoptic nucleus of the male quail revealed by in vitro transport of DiI

The medial preoptic nucleus of the Japanese quail is a testosterone-sensitive structure that is involved in the control of male copulatory behavior. The full understanding of the role played by this nucleus in the control of reproduction requires the identification of its afferent and efferent connections. In order to identify neural circuits involved in the control of the medial preoptic nucleus, we used the lipophilic fluorescent tracer DiI implanted in aldheyde-fixed tissue. Different strategies of brain dissection and different implantation sites were used to establish and confirm afferent and efferent connections of the nucleus. Anterograde projections reached the tuberal hypothalamus, the area ventralis of Tsai, and the substantia grisea centralis. Dense networks of fluorescent fibers were also seen in several hypothalamic nuclei, such as the anterior medialis hypothalami, the paraventricularis magnocellularis, and the ventromedialis hypothalami. A major projection in the dorsal direction was also observed from the medial preoptic nucleus toward the nucleus septalis lateralis and medialis. Afferents to the nucleus were seen from all these regions. Implantation of DiI into the substantia grisea centralis also revealed massive bidirectional connections with a large number of more caudal mesencephalic and pontine structures. The substantia grisea centralis therefore appears to be an important center connecting anterior levels of the brain to brain-stem nuclei that may be involved in the control of male copulatory behavior.     

The efferent connections of the lateral septal nucleus in the guinea pig: intrinsic connectivity of the septum and projections to other telencephalic areas

Summary The distribution of efferent fibers originating in the lateral septal nucleus was investigated in guinea pigs by means of anterograde tracing with Phaseolus vulgaris-leucoagglutinin (PHA-L). Special emphasis was placed on the intraseptal fiber systems. The fibers originating from the different subnuclei of the lateral septal nucleus formed massive horizontal connections in the rostrocaudal axis. Projections to the contralateral, congruent subnuclei were also detected. In the medial septum/diagonal band of Broca complex the largest number of PHA-L-stained fibers was found after application of the tracer into the dorsal subnucleus of the lateral septal nucleus; the density of the efferent fibers decreased progressively after injection into the intermediate or ventral subnuclei. In all cases the diagonal band contained a much higher number of efferent fibers from the lateral septal nucleus than from the medial septal nucleus. In the medial septal nucleus, terminal labeling was generally sparse. Other telencephalic areas (organum vasculosum of the lamina terminalis, nucleus accumbens, bed nucleus of the stria terminalis, amygdala, hippocampal complex, and other cortical areas) contained varying numbers of labeled projections. In double-labeling experiments, a close spatial relationship between PHA-L-stained fibers and vasoactive intestinal polypeptide-immunoreactive perikarya was observed in several of these target areas.     

Efferent Projections of Prokineticin 2 Expressing Neurons in the Mouse Suprachiasmatic Nucleus

The suprachiasmatic nucleus (SCN) in the hypothalamus is the predominant circadian clock in mammals. To function as a pacemaker, the intrinsic timing signal from the SCN must be transmitted to different brain regions. Prokineticin 2 (PK2) is one of the candidate output molecules from the SCN. In this study, we investigated the efferent projections of PK2-expressing neurons in the SCN through a transgenic reporter approach. Using a bacterial artificial chromosome (BAC) transgenic mouse line, in which the enhanced green fluorescence protein (EGFP) reporter gene expression was driven by the PK2 promoter, we were able to obtain an efferent projections map from the EGFP-expressing neurons in the SCN. Our data revealed that EGFP-expressing neurons in the SCN, hence representing some of the PK2-expressing neurons, projected to many known SCN target areas, including the ventral lateral septum, medial preoptic area, subparaventricular zone, paraventricular nucleus, dorsomedial hypothalamic nucleus, lateral hypothalamic area and paraventricular thalamic nucleus. The efferent projections of PK2-expressing neurons supported the role of PK2 as an output molecule of the SCN.     

Distribution of trigeminothalamic and spinothalamic lamina I terminations in the cat

The distribution in the thalamus of terminal projections from lamina I neurons of the trigeminal, cervical, and lumbosacral dorsal horn was investigated with the anterograde tracer Phaseolus vulgaris leucoagglutinin (PHA-L) in the cat. Iontophoretic injections were guided by single- and multi-unit physiological recordings. The injections in particular cases were essentially restricted to lamina I, whereas in others they spread across laminae I-III or laminae I-V. The trigemino- and spinothalamic (TSTT) terminations were identified immunohistochemically. In all cases, regardless of the level of the injections, terminal fibers were consistently distributed in three main locations: the submedial nucleus; the ventral aspect of the basal ventral medial nucleus and ventral posterior nuclei; and, the dorsomedial aspect of the ventral posterior medial nucleus. The terminal fields in the submedial nucleus and the ventral aspect of the ventral posterior group were topographically organized. Terminations along the ventral aspect of the ventral posterior group extended posterolaterally into the caudal part of the posterior nucleus and anteromedially into the ventromedial part of the ventral lateral nucleus. In several cases with trigeminal lamina I injections, a terminal labeling patch was observed within the core of the ventral posterior medial nucleus. In cases with spinal lamina I injections, terminations were also consistently found in the lateral habenula, the parafascicular nucleus, and the nucleus reuniens. Isolated terminal fibers were occasionally seen in the zona incerta, the dorsomedial hypothalamus, and other locations. These anatomical observations extend prior studies of TSTT projections and identify lamina I projection targets that are important for nociceptive, thermoreceptive, and homeostatic processing in the cat. The findings are consistent with evidence from physiological (single-unit and antidromic mapping) and behavioral studies. The novel identification of spinal lamina I input to the lateral habenula could be significant for homeostatic behaviors.     

Intramedullary projections of the rostral nucleus of the solitary tract in the rat: gustatory influences on autonomic output

The efferent connections of the rostral nucleus of the solitary tract (NTS) in the rat were studied by anterograde transport of Phaseolus vulgaris leucoagglutinin. Rostral to the injection site, fibers travel through the rostral parvocellular reticular formation and deflect medially or laterally around the motor trigeminal nucleus, giving off few terminals in these nuclei and terminate in the parabrachial nucleus. Moderate projections to the peritrigeminal zone, including the intertrigeminal nucleus and the dorsal subcoeruleus nucleus, were observed. Caudally to the injection site, dense innervations from the rostral nucleus of the solitary tract were detected in the parvocellular reticular formation ventral and caudal to the injection site and in the intermediate and ventral medullary reticular formation. The rostral central and ventral subdivisions of the NTS up to the level where the nucleus of the solitary tract abuts the fourth ventricle and the hypoglossal nucleus, receive moderate input from the rostral nucleus of the solitary tract. In general, the projections from the rostral nucleus of the solitary tract were bilateral with an ipsilateral predominance. The caudal part of the nucleus of the solitary tract, the dorsal motor nucleus of the vagus and the facial nucleus were not labeled. It is concluded that medullary rNTS projections participate in oral motor behavior and autonomic control of abdominal organs.     

Divergent axon collaterals originate in the estrogen receptive ventromedial nucleus of hypothalamus in the rat

The ventromedial nucleus of the hypothalamus (VMH) plays a crucial role in the mediation of lordosis by integrating predominantly inhibitory limbic signals with cyclic variation of ovarian steroids and sending a stimulatory output to the midbrain, especially the periaqueductal gray (PAG). Tract-tracing studies have established projections of the VMH and Golgi studies have shown these neurons to frequently give rise to axon collaterals, but the anatomical pattern of shared projections has not been explored. We have used a combination of retrograde tracers to map VMH projections to the medial division of the medial preoptic nucleus (MPNm), posterodorsal division of the medial nucleus of the amygdala (MeApd), and the PAG. Neurons with dual projections were mainly confined to the VMHvl and represented 31%–37% of each projection subset. Neurons simultaneously projecting to the MPNm, MeApd, and PAG represented 7%–9% of each projection subset. By combining tract-tracing with steroid autoradiography, we found that approximately one-quarter of each projection subset in the VMHvl concentrated ³H-estradiol. Thus, some of the VMHvl neurons that communicate a facilitatory signal to the PAG may also act to stimulate lordosis through a feedback suppression of the net inhibition formed by efferent signals from the forebrain. The even distribution of estrogen binding among projection subsets suggests a lack of compartmentalization of estrogen-regulated processes that are relevant to lordosis. 1994 John Wiley & Sons, Inc.     

Centrally administered GABA and GABA-selective agonist and antagonist in rats: histoenzymological cytophotometric study

In the present study, the effect of intracerebroventricular (icv) injection of GABA, its agonist--muscimol, and antagonist--picrotoxin, has been studied on histoenzymological alterations of acetylcholinesterase (AChE). butyrylcholinesterase (BuChE), monoamine oxidase (MAO), and succinic dehydrogenase (SDH) by cytophotometric technique. This study was conducted on medial preoptic area (mPOA), nucleus paraventricularis hypothalami (PVH), area lateralis hypothalami (LHA), nucleus dorsomedialis hypothalami (DMH), and nucleus ventromedialis hypothalami (VMH). Results showed that GABA and muscimol inhibited AChE, BuChE, MAO, and SDH in all the areas while picrotoxin stimulated these enzymes. These changes in enzyme activity by GABA, muscimol, and picrotoxin and their possible mode of action are discussed.