The Paleoamygdala: Cytoarchitectonics,Organization, and the Cytological Characteristics of Its Neurons

The aim of the present work was to compare the cytoarchitectonics, neuronal organization, and cytological characteristics of the dorsomedial, posterior medial, and posterior cortical nuclei of the amygdaloid body (AB) of the rat brain. Series of frontal brain sections stained with cresyl violet and silver nitrate impregnation by the Golgi method were studied. The results showed that rearrangements of the nuclear principle of organization of the gray matter of the nervous system into the screened organization occur within the territory of this complex of nuclei; it consists of a sparsely branched neuron system and contains neuroendocrine cells. It is concluded that this complex of nuclei is unique in terms of its structural organization and the mechanism of development of this part of the AB, which forms in the earliest stages of AB development; it is termed the “paleoamygdala.”__________Translated from Morfologiya, Vol. 126, No. 5, pp. 15–19, September–October, 2004.     

Collateral Projections from the Lateral Parabrachial Nucleus to the Central Amygdaloid Nucleus and the Ventral Tegmental Area in the Rat

Lateral parabrachial nucleus (LPB) is a critical region in the integration and transmission of peripheral nociceptive information. The parabrachio-amygdaloid (P-Amy) pathway and parabrachio-ventral tegmental area (P-VTA) pathway is thought to be significant in regulation of pain-related negative emotions. In present study, retrograde tract tracers Fluoro-gold (FG) and tetramethylrhodramine-dextran (TMR) were stereotaxically injected into the right central amygdaloid nucleus (CeA) and right VTA, respectively. Then, part of these rats were performed with the spare nerve injury (SNI) in the controlateral side of FG and TMR injection. Afterwards, double- or triple-immunofluorescent histochemistry was used to examine FG/TMR double- and FG/TMR/FOS or FG/TMR/CGRP triple-labeled neurons in the LPB. The results showed that all of FG, TMR single- and FG/TMR double-labeled neurons were distributed in the LPB bilaterally with an ipsilateral predominance. The proportion of FG/TMR double-labeled neurons to the total number of FG- and TMR-labeled neurons was 10.78% and 13.07%, respectively. Nearly all of the FG/TMR double-labeled neurons (92.67%) showed calcitonin gene-related peptide (CGRP) immunopositive. On the other hand, in the SNI rats, about 89.49% and 77.87% of FG- and TMR-labeled neurons were FG/FOS- and TMR/FOS-positive neurons; about 93.33% of the FG/TMR double-labeled neurons were FOS-LI. Our results suggest that the part of CGRP immunopositive neurons in the LPB send projection fibers to both the CeA and VTA by the way of axon collaterals, which are activated by the nociceptive stimulation in the SNI condition, and may play an important role in the transmission of peripheral nociceptive information. Anat Rec, 302:1178–1186, 2019. © 2018 The Authors. The Anatomical Record published by Wiley Periodicals, Inc. on behalf of American Association of Anatomists.     

Structural Organization of the Amygdaloid Complex of the Rat Brain

The amygdaloid complex, traditionally regarded as part of the system of basal endbrain nuclei, has a unique structure in that it combines the two major principles of organization of the gray matter--the nuclear and the screening. Working from the studies of Zavarzin on the nuclear and screening centers, the authors suggest a classification of its structures into nuclei, paleocortex, and intermediate formations.     

薄层脑横断面上的杏仁体及相关结构

目的观察杏仁体、侧脑室和海马结构在脑的薄层横断面上的表现及变化,为影像学提供解剖学依据。方法采用薄层冰冻铣切技术做颅脑标本的横切面,并用数码相机逐层照相。结果从杏仁体出现到消失,共获得72张高清晰数码照片。结论薄层冰冻铣切技术和820万相素数码照片能清晰显示杏仁体、侧脑室和海马结构的位置关系及形态变化。     

Structural and Quantitative Characteristics of the Dendrites of Neurons in the Posterior Zone of the Amygdaloid Body in the Rat Brain

The aim of the present work was to study the structure of the dendritic tree of the main groups of neurons in the posterior zone of the amygdaloid body and to analyze their quantitative characteristics. Frontal sections of rat brain impregnated with Golgi silver nitrate were used to study the characteristics of neuronal organization. Classification of neurons was based on criteria developed by Leontovich (1978) and Polyakov (1973). The main groups of neurons were long-axon, rarely branched cells, long-axon, densely branched subcortical cells, and long-axon, densely branched cortical cells. Quantitative studies of seven measures of the dendrite tree showed that the most informative parameters for differences between the main groups of neurons were the number of branching points and the number of free dendrite tips. The contents of rarely and densely branched neuron systems in the nuclei, paleocortex, and intermediate formations are described.     

Cytoarchitectonics,neuronal organization,and the effects of gender on the dendroarchitectonics of neurons in the posterior medial nucleus of the amygdaloid body in rats

The aim of the present work was to analyze the cytoarchitectonics, neuronal organization, and effects of gender on the dendroarchitectonics of neurons in the posterior medial nucleus of the amygdaloid body of the brain. Studies were performed using 50 mature Wistar rats (25 male, 25 female) using the Nissl and Golgi methods. The nucleus was found to consists of large neurons, which on silver nitrate impregnation had the characteristics typical of long-axon sparsely branched and densely-branched neurons. In males, the dendrites of long-axon sparsely-branched neurons had higher levels of branching, while the dendrites of long-axon densely-branched neurons were longer than in females. __________ Translated from Morfologiya, Vol. 132, No. 6, pp. 17–21, November–December, 2007.     

Effects of the gender factor and neonatal androgenization on the dendroarchitectonics of neurons in the dorsomedial nucleus of the amygdaloid body of the brain

The aim of the present work was to identify gender-related differences in the dendroarchitectonics of neurons in the dorsomedial nucleus of the amygdaloid body and the role of androgens in their formation during period of sexual differentiation of the brain in rats. Studies using the Golgi method showed that the quantitative characteristics of long-axon sparsely branched neurons of all classes - neuroblast-like, short-dendrite, and reticular - reflected the influences of gender. In particular, long-axon sparsely branched neurons were found to have more abundant branching primary dendrites and greater total dendrite lengths in adult males than in females. Adult females subjected to neonatal androgenization by administration of testosterone propionate at a dose of 1250 microg showed different neuron characteristics five days after birth as compared with normal females, and these were more marked than in males.     

Dendroarchitectonics of neurons in the posterior cortical nucleus of the amygdaloid body of the rat brain as influenced by gender and neonatal androgenization

The aim of the present work was to identify gender-related differences in the dendroarchitectonics of neurons in the posterior cortical nucleus of the amygdaloid body and the role of androgens in forming the dendroarchitectonics during the period of sexual differentiation of the rat brain. Golgi staining showed that long-axon, sparsely branched neurons in males had large numbers of primary dendrites, while long-axon densely branched neurons had a greater total dendrite length in females. Administration of testosterone propionate (1250 µg) to females on postnatal day 5 increased the number of primary dendrites in long-axon, sparsely branched neurons in adults as compared with the number in control females; treatment also produced a significant increase in dendrite length in long-axon, densely branched neurons, leading to an increase in the area of the dendritic field.Translated from Morfologiya, Vol. 125, No. 2, pp. 22–25, March–April, 2004.     

大鼠脊髓向中央颈核和外侧颈核的投射——PHA-L顺行追踪研究

将菜豆白细胞凝集素(PHA-L)分别注入下颈髓、胸髓、腰髓和骶髓等不同脊髓节段,顺行追踪脊髓向中央颈核和外侧颈核的投射。观察结果表明,脊髓不同节段注入PHA-L,在中央颈核和外侧颈核均可见到标记末梢;比较各节段脊髓的投射分布,未能发现明显的定位关系。一侧脊髓灰质注入,在两侧中央颈核均观察到标记末梢,但主要见于同侧;外侧颈核的标记末梢仅见于同侧。结果提示,各节段脊髓均发出纤维投射到同侧中央颈核和外侧颈核。     

Electron-microscopic characteristics of neuroendocrine neurons in the amygdaloid body of the brain in male rats and female rats at different stages of the estral cycle

The ultrastructural features of neuroendocrine neurons in the dorsomedial nucleus (DMN) of the amygdaloid body of the brain — one of the major zones of sexual dimorphism — in 12 Wistar rats weighing 250–300 g were studied in three males and nine females at different stages of the estral cycle. On the basis of ultrastructural characteristics, analysis of the functional states of an average of 50 DMN neurons were studied in each animal. A morphofunctional classification reflecting hormone-dependent variations in neuron activity is proposed. DMN neurons were found to be in different structural-functional states, which could be classified as the states of rest, moderate activity, elevated activity, tension (maximal activity), decreased activity (types 1 and 2, depending on prior history), return to the initial state, and apoptosis. At the estrus stage, there was a predominance of neurons in the states of elevated activity (40% of all cells) and maximal activity (26%). At the metestrus stage, neurons in the state of decreased activity type 1 (with increased nuclear heterochromatin content) predominated (30% of cells), while 25% and 20% of cells were in the states of maximal activity and elevated activity respectively. In diestrus, neurons in the resting state, in moderate and elevated activity, in maximal activity, and in decreased activity type 1 were present in essentially identical proportions (18%, 21%, 18%, 20%, and 16% respectively). In males, 35% and 22% of neurons were in the states of elevated and maximal activity respectively. Neuron death was seen only in males. __________ Translated from Morfologiya, Vol. 130, No. 6, pp. 25–29, November–December, 2006.     

家兔延髓巨细胞网状核内突触复合体的超微结构

目的　探讨哺乳动物延髓巨细胞网状核内突触的超微结构及其功能。方法　本研究用透射电镜对家兔延髓巨细胞网状核的超微结构进行了观察和研究。结果　巨细胞网状核内轴突终末和树突密集 ,轴突终末内突触小泡和线粒体含量丰富。最为显著的是 ,巨细胞网状核内存在两种典型的突触复合体 :一是以一个中央树突为中心 ,同周围若干轴突终末、数个树突构成的聚合型突触复合体 ;另一个是以一个中央轴突为中心 ,与周围若干树突、数个轴突终末构成的辐散型突触复合体。结论　延髓巨细胞网状核内密集多样的突触联系表明其复杂的神经调节功能 ,特别是突触复合体的结构可能是延髓巨细胞网状核在脑干 -脊髓的神经联系中起整合作用的形态学基础。     

Thalamocortical Connections between the Mediodorsal Nucleus of the Thalamus and Prefrontal Cortex in the Human Brain: A Diffusion Tensor Tractographic Study

Purpose

The elucidation of thalamocortical connections between the mediodorsal nucleus (MD) of thalamus and the prefrontal cortex (PFC) is important in the clinical fields of neurorehabilitation and psychiatry. However, little is known about these connections in human brain. We attempted to identify and investigate the anatomical characteristics of the thalamocortical connection between MD and PFC in human brain using diffusion tensor tractography (DTT).

Materials and Methods

Thirty-two healthy volunteers were recruited for this study. Diffusion tensor images were scanned using a 1.5-T. A seed region of interest was placed at the MD of the thalamus on coronal images, and target regions of interest were placed on the dorsolateral prefrontal cortex (DLPFC), the ventrolateral prefrontal cortex (VLPFC), and the orbitofrontal cortex (OFC), respectively. The three thalamocortical connections found were reconstructed using Functional Magnetic Resonance Imaging of the Brain (FMRIB) software.

Results

The three thalamocortical connections were arranged in subcortical white matter in the following order from upper to lower levels: the DLPFC, the VLPFC, and the OFC. In terms of fractional anisotropy and mean diffusivity values, no significant differences were observed between the DLPFC, VLPFC and OFC (p>0.05). In contrast, the OFC tract volume was higher than those of the DLPFC and the VLPFC (p<0.05).

Conclusion

Three thalamocortical connections were reconstructed between MD and PFCs in human brain using DTT. We believe that the results of this study would be helpful to clinicians in treating frontal network syndrome and psychiatric diseases.     

Neuronal Nitric Oxide Synthase Activation Is Involved in Insulin-Mediated Cardiovascular Effects in the Nucleus Tractus Solitarii of Rats

Neuronal nitric oxide synthases (nNOS) is distributed throughout the central nervous system (CNS) and has been proposed to modulate neuronal activity in the nucleus tractus solitarii (NTS). Here, we investigated whether the activation of nNOS is involved in insulin-induced cardiovascular responses in the NTS. Insulin (100 IU/ml) was unilaterally microinjected into the NTS, and the cardiovascular effects were evaluated before and after microinjection of the nNOS inhibitors 7-nitroindazole (7-NI) (5 pmol) and N(5)-(1-imino-3-butenyl)-l-ornithine (vinyl-L-NIO) (600 pmol). Western blot and immunohistochemical analyses were performed to determine nNOS phosphorylation levels after insulin or phosphoinositide 3-kinase (PI3K) inhibitor LY294002 microinjection into the NTS. Unilateral microinjection of insulin into the NTS produced prominent depressor and bradycardic effects in WKY rats. Pretreatment with the nNOS inhibitors 7-NI and Vinyl-L-NIO attenuated the cardiovascular response evoked by insulin in Wistar-Kyoto (WKY) rats. Moreover, Western blot analysis showed a significant increase in nNOS (16.5±0.4-fold; P<0.05; n=4) phosphorylation after insulin injection, whereas the PI3K inhibitor LY294002 abolished the insulin-induced effects. In situ nNOS phosphorylation was found to be increased in the NTS after insulin injection. Furthermore, co-immunoprecipitation assay showed Akt and nNOS can bind to each other as detected by phospho-Akt^S473 and phospho-nNOS^S1416 antibodies. In vitro kinase assay showed insulin activated Akt can directly phosphorylate nNOS^S1416. These results demonstrated that nNOS may couple with the activation of the insulin receptor, via the liberation of NO, in order to participate in central cardiovascular regulation of WKY rats.     

Organization of Efferent Projections of the Pedunculopontine Nucleus of the Tegmentum of the Striatum in the Dog Brain

A method based on retrograde axonal transport was used to undertake detailed studies of the efferent projections of individual substructures of the pedunculopontine nucleus of the midbrain tegmentum to functionally diverse segments of striatal structures in dogs. The compact and diffuse zones of this nucleus were found to project to segments of the putamen, caudate nucleus, and nucleus accumbens, which are components of the limbic and motor systems. The medial part of the diffuse zone, adjacent to the decussation of the superior cerebellar peduncles (presumptively the mesencephalic extrapyramidal field) projected only to the dorsal segments of the caudate nucleus and putamen, which are parts of the motor system. __________ Translated from Morfologiya, Vol. 126, No. 6, pp. 11–15, November–December, 2004. Director: Doctor of Biological Sciences V. T. Shuvaev     

The Role of the Septal Nuclei in Controlling the Activity of Vagosensitive Neurons in the Solitary Tract Nucleus in Cats

Studies on cats anesthetized with a mixture of Nembutal and chloralose were performed to study the descending influences of single, paired, and frequent stimulation of the lateral septal nucleus (LSN) and bed nucleus of the stria terminalis (BNST) on the activity of viscerosensory neurons in the solitary tract nucleus, identified by stimulation of the cervical part of the vagus nerve. Of 70 units recorded in the solitary tract nucleus, 50 were identified as primary and secondary input vagus neurons. Single stimuli applied to the septal nuclei induced initial excitation in 30% (15 units) of vagus neurons. The latent period of these responses was 5-25 msec. Presentation of paired stimuli showed that loss of the ability to respond to the second stimulus occurred at interstimulus intervals of 10-200 and sometimes 300 msec. A total of 34% (17 units) of solitary tract nucleus neurons showed tonic changes in spontaneous activity in response to rhythmic stimulation. Increasing the stimulation frequency to 10-20 Hz led to very different changes in the spontaneous rhythm, i.e., wave-like changes (decreases and increases in frequency, secondary suppression) or complete inhibition, sometimes lasting up to 10 sec after stimulation ended. A small number of units (five) showed a blocking effect of septal discharges on the visceral afferent input in conditions of paired stimulation. These results lead to the conclusion that the LSN and BNST are involved in modulating the activity of bulbar viscerosensory neurons, though their influences are mediated mainly via oligo- and polysynaptic pathways via other limbic structures (hypothalamus, amygdala).     

大鼠帕金森综合征模型脑的黑质、尾状核及中缝核的超微结构变化

目的　观察大鼠帕金森综合症模型脑的黑质、尾状核及中缝核神经元超微结构变化。方法　应用透射电镜。结果　上述核团神经元的超微结构均发生病理性改变 :神经细胞核膜皱缩 ,核膜凹凸不整 ,并有局部断裂 ;线粒体变性 ,基质浓度降低及空泡化 ;粗面内质网和高尔基复合体囊腔扩张变性 ;大量初级溶酶体及脂褐素集聚 ;出现了髓样体和多泡体等变性结构。结论　黑质、尾状核及中缝核神经元超微结构的病理性变化从而导致纹状体 黑质 纹状体锥体外路系环路功能障碍 ,是引发帕金森氏综合症的结构基础。     

杏仁中央核NMDA受体对急性吗啡依赖大鼠戒断诱发条件性位置厌恶的影响

目的:研究杏仁中央核(Central nucleus of the amygdala,CeA)N-甲基-D-天冬氨酸(N-methyl-D-aspartate,NMDA)受体在纳络酮诱发急性吗啡依赖大鼠戒断性情绪反应中的作用.方法:吗啡、纳络酮间隔4小时皮下注射,通过两轮纳络酮匹配训练建立条件性位置厌恶(Conditioned place aversion,CPA),作为急性吗啡依赖戒断诱发的情绪反应模型.观察纳络酮匹配训练前CeA微量注射NMDA受体拮抗剂地卓西平(MK801)对大鼠训练后在纳络酮匹配侧停留时间的影响.结果:戒断组大鼠经过两轮训练后在纳络酮匹配侧停留时间(230.4±32.8s)比假手术组(457.6±47.8s)显著缩短(P＜0.01),训练前CeA微量注射MK801大鼠在纳络酮匹配侧停留时间(447.0±51.8s)比戒断组(230.4±32.8s)显著延长(P＜0.01),非戒断组大鼠(急性吗啡依赖组,未接触吗啡组)训练前CeA注射MK801训练前后在处理侧停留时间差异无显著性(P＞0.05).结论:CeA注射MK801既无奖赏效应也无厌恶效应,但能阻断CPA的建立,提示CeA的NMDA受体参与急性吗啡依赖戒断诱发的情绪反应.