大鼠大脑运动皮质向脑干运动前神经元的谷氨酸能投射

为观察大鼠大脑运动皮质向脑干运动前神经元所在区域的谷氨酸能投射。用逆行追踪和免疫荧光组织化学染色相结合掇标技术，将四甲基罗达明分别注入臂上侧核，三叉上核或延髓网状结构外侧部后，ＴＭＲ逆神经元分别见于额叶２区，额叶１区域额叶１区和２区的Ｖ层；磷磷酸激活的谷氨酸胺酶，样阳性神经元见于大脑运动皮质Ⅱ－Ⅵ层的锥体细胞；ＴＭＲ逆标神经元几乎均呈ＰＡＧ样阳性。结果提示，大脑运动皮质发出的皮质脑干束主要终止干运     

大鼠大脑皮质运动区投射到扣带回的神经元分布

目的　探讨大鼠大脑皮质运动区投射到扣带回的神经元分布。方法　在对大脑皮质运动区进行机能定位的基础上 ,将逆行性示踪标记物荧光蓝 (FB)或荧光黄 (DY)注入到扣带回 ,观察投射到扣带回的神经元的分布。结果　扣带回接受来自支配前肢和颜面部的运动区皮质以及额叶和躯体感觉区皮质的神经元投射。结论　扣带回可能具有将来自运动、感觉皮质及额叶皮质的情报进行处理 ,参与调控机体的运动机能 ,为进一步明确扣带回在运动调节中的作用提供了组织学依据     

大鼠大脑运动皮质与脑干面口部运动前神经元的突触联系

目的 观察大脑运动皮质发出的下行投射终末或谷氨酸能终末与脑干面口部运动核内运动神经元的间接突触联系。方法 顺行与逆行追踪相结合及免疫组织化学染色与逆行追踪相结合的双重标记技术。结果 将ＰＨＡ－Ｌ电泳入大鼠额叶１区和／或２区和将ＨＲＰ分别注入三叉神经运动核（Ｖｍ）、面神经核（Ⅶ）或舌下神经核（Ⅻ）,ＰＨＡ－Ｌ顺标终末和ＨＲＰ逆标神经元的重叠分布区主要见于臂旁核族、三叉上核、Ｖｍ内侧的脑桥网状结构、延     

恒河猴大脑与人类大脑的比较解剖学研究

目的:探讨恒河猴与人大脑的进化差异。方法:18～19岁老年恒河猴4只,观测恒河猴大脑重量、半球各径线及比较大脑各叶的沟回的发育状况。结果:恒河猴大脑的重量为(93.40±5.8)g,枕颞极径、枕额极径、内外径、上下径、背内侧缘径分别为(56.64±0.72)、(72.95±1.25)、(29.13±0.89)、(42.83±0.67)和(97.10±1.73)mm。结论:与人类大脑比较,恒河猴大脑(无论是重量、半球各径线及各叶沟、回进化方面)远远不如人类大脑发育完善。     

脓毒症对小鼠内侧隔区-内侧前额叶皮质胆碱能投射的影响

目的:观察脓毒症对小鼠内侧隔区-内侧前额叶皮质(MS-mPFC)胆碱能投射的影响.方法:选取6周龄雄性C57BL/6小鼠,于mPFC区注射逆向跨单突触狂犬病毒,通过神经元示踪,观察MS区病毒表达情况,明确mPFC的投射来源.于8周龄雄性C57BL/6小鼠侧脑室注射脂多糖(LPS)诱导急性脓毒症相关性脑病模型,使用递质探...     

脑干神经元向前扣带回皮质中部区域的投射(英文)

目的:用逆行标记方法观察脑干神经元向皮质扣带回中部(the middle portion of the cingulate cortex,MCC)的纤维投射。方法:立体定位注射法将0.06~0.08μl的4%荧光金(Fluoro-gold,FG)注射至MCC(Bregmma:+0.2,-0.3,-0.8 mm)部位,7 d后处死大鼠,含4%多聚甲醛的磷酸缓冲液(PB)灌注固定,取脑组织,制作30μm厚度的冰冻切片,荧光显微镜下观察FG逆行标记神经元的定位分布并计数。结果:MCC与皮质间有广泛的联系,包括与同侧、对侧和扣带回内部的联系。在脑干中缝核簇、蓝斑、被盖腹侧区、被盖背内侧区及中脑中央灰质(α部)均可观察到FG逆标神经元的分布,以上FG标记神经元以同侧为主,对侧较少。结论:以上核团向MCC的投射表明MCC接受来自脑干神经元的广泛投射,提示MCC神经元的活动受到脑干众多结构的调控。     

家兔皮质脊髓束向脊髓长下行固有束神经元的投射—HRP逆行…

用成年家兔１１只，在脊髓腰膨大部注射ＨＲＰ或麦芽凝集素结合的辣根过氧化物酶，逆行追踪长下行脊髓固有束神经元在颈髓和部分髓的分布，其中５例动物在腰膨大注射ＨＲＰ的同时进行大脑皮质脊髓束起始区的损毁，电镜观察皮质脊髓束在颈髓的溃变末梢与ＨＲＰ逆行标记神经元的关系，结果表明，长下行脊髓固有束神经元在脊髓灰质内可分为背腹两群，背侧群主要集中在Ｖ层，细胞较少；腹侧群位于Ⅶ、Ⅷ层，细胞数较多，电镜下可观察与标     

前庭刺激激活大鼠内侧前额叶皮质神经元Fos表达

目的:分析对比加伐尼刺激(Galvanic stimulation)与双轴旋转运动分别作用于大鼠前庭器官对内侧前额叶皮质(mPFC)神经元活动的影响。方法:将雄性SD大鼠随机分为4组：电刺激组、对照组、双轴旋转运动组和对照组。电刺激组动物以100～200μA电流强度刺激前庭感受器1 h后休养1 h;双轴旋转组动物以双轴旋转运动刺激2 h。应用包含mPFC的25μm脑冠状切片,以免疫组织化学抗生物素蛋白-生物素复合物(ABC)技术进行Fos蛋白免疫反应并以3,3′-二氨基联苯胺(DAB)显色。最后,对mPFC内标记神经元进行计数和统计分析。结果:动物经两种类型分别刺激后,mPFC均见到大量Fos样免疫阳性反应神经元细胞核;曼-惠特尼U检验统计表明每种刺激条件下,刺激组较对照组动物mPFC内Fos阳性神经元数目都有显著增加(P<0.05)。半定量统计显示两种类型刺激后,接受刺激组和对照组动物mPFC内Fos阳性神经元数目激活的神经元数目分别是1053±240.50 vs 44.25±3.64和509.80±54.40 vs 128.30±7.66。结论:诱发晕动病的双轴旋转刺激和伽伐...     

小鼠脑干交感运动前区前阿黑皮素能神经传入投射的实验研究

目的:研究脑干交感运动前区的前阿黑皮素能神经纤维的分布及其传入投射。方法:以免疫组化法检测前阿黑皮素能神经纤维在脑干交感运动前区的分布;将霍乱毒素B微量注入小鼠脑干交感运动前区进行逆行追踪。结果:α-MSH(α-melanocyte-stimulating hormone)能神经终末密集分布于交感运动前区内,同时则未见AgRP(agouti-related protein)能神经终末,显示交感运动前区仅接受前阿黑皮素(POMC)能神经的单向调节。逆行追踪实验显示脑干交感运动前区的POMC能纤维投射来自于下丘脑弓状核/视交叉后区,而非孤束核尾侧部;统计结果表明下丘脑弓状核/视交叉后区向脑干交感运动前区的神经投射中有近一半为POMC能投射。结论:小鼠下丘脑的POMC能神经元可直接投射到脑干交感运动前区,该神经通路在能量平衡的调节中可能发挥重要的作用。     

Differential Distribution Patterns From Medial Prefrontal Cortex and Dorsal Raphe to the Locus Coeruleus in Rats

Locus coeruleus (LC) consists of a densely packed nuclear core and a surrounding plexus of dendritic zone, which is further divided into several subregions. Whereas many limbic‐related structures topographically target specific subregions of the LC, the precise projections from two limbic areas, that is, medial prefrontal cortex (mPFC) and dorsal raphe (DR), have not been investigated. The goal of the present study is to identify and compare the distribution patterns of mPFC and DR afferent terminals to the LC nuclear core as opposed to specific pericoerulear dendritic regions (Peri‐LC). To address these issues, anterograde tracer injections were combined with dopamine‐β‐hydroxylase (DBH) immunofluorescent staining to reveal the distribution patterns around the LC nuclear complex. Our data suggest that both mPFC‐LC and DR‐LC projections exhibit selective afferent terminal patterns. More specifically, mPFC‐LC projecting fibers mainly target the rostromedial Peri‐LC, whereas DR‐LC projecting fibers demonstrate a preference to the caudal juxtaependymal Peri‐LC. Thus, our present findings provide further evidences that afferents to the LC are topographically organized. Understanding the relationship among different inputs to the LC may help to elucidate the organizing principle which likely governs the interactions between the broad afferent sources of the LC and its global efferent targets. Anat Rec, 2012. © 2012 Wiley Periodicals, Inc.     

Specific Functions of the Motor Cortex in Reorganizing Coordinations during Motor Training in Animals and Humans

The involvement of the motor cortex in learning movements has recently attracted much attention. One aspect of motor learning is the inhibition of innate synergies which interfere with performance of the acquired movement. Various models of operant responses in dogs have demonstrated the critical role of the motor cortex in the reorganization and inhibition of interfering synergies during learning. The role of the motor cortex and corticospinal influences in the formation of new coordinations in humans was studied here in patients with organic lesions of the cerebral circulation involving the internal capsule, using postural coordination and movements in a bimanual unloading response as an example. Formation of the forearm stabilization response was deeply lesioned on the afflicted side. Some degree of impairment was also seen on the ipsilateral side, but it was no different from the level of learning impairment in patients with lesions not involving the internal capsule or in patients with parkinsonism. The existence of specific contralateral influences of the motor cortex and non-specific descending influences on the process of motor learning is proposed.     

重复电刺激前肢神经引起成年大鼠运动皮层的可塑性改变

为了了解成年大鼠运动皮层的功能可塑性，利用皮层内微刺激方法测定ＭＩ代表区并观察重复电刺激前肢神经对ＭＩ代表区的影响。实验组大鼠（９例）持续１．２－２小时的前肢神经电刺激导致前肢运动区与面部触须运动区边界向ＶＩ方向，移动２６３．３±９０．９μｍ并同时伴有运动阈值的改变；ＦＬ内ＭＴ降低５．０±１３．３μＡ，而在ＶＩ内ＭＴ升高９．６±１１．６μＡ对照组大鼠间隔１．５－２小时的两次测定结果，ＦＬ－ＶＩ边界     

The Range of Motor Activation in the Normal Human Cortex Using Bold fMRI

Summary Understanding and documenting the nature of normal human brain functional motor activation using functional Magnetic Resonance Imaging (fMRI) is necessary, if valid statements are to be made about normal and disease functional states using fMRI activation maps. The present study examines activation maps in ’normal‘ adults. Six healthy adult volunteers performed three motor tasks isolating the tongue, non-dominant foot, and non-dominant thumb during a single magnetic resonance imaging (MRI)/(fMRI) scanning session. Group maps demonstrated discrete areas of activation that were task dependent. The degree of variability between the anatomical central location of global maximum intensity for each individual may mean extra care should be applied when using the global maximum to define the area of activation. These differences may represent anatomical variability among individuals, task complexity, paradigm design, data analysis techniques or a combination thereof, which form the basis of our ongoing research endeavors. Standard notions of strongly associated functions as related to anatomic foci may need to be revised.     

Dopaminergic Modulation of Motor Maps in Rat Motor Cortex: An In Vivo Study

While the primary motor cortex (M1) is know to receive dopaminergic projections, the functional role of these projections is poorly characterized. Here, it is hypothesized that dopaminergic signals modulate M1 excitability and somatotopy, two features of the M1 network relevant for movement execution and learning.     

握力刺激强度与运动皮层激活相关性的fMRI研究

目的研究握力刺激强度与运动皮层激活程度的相关性。方法16例正常右利手受试者根据视觉刺激提示右手进行固定频率的三种不同握力运动,同时进行BOLD fMRI扫描,用spm5计算得到不同握力的脑激活区并比较差异。结果在三种不同握力运动中,对侧主运动区、对侧躯体感觉区、对侧辅助运动区(SMA)和对侧运动前区(PMC)明显激活;同侧激活区较小或者未见激活区;同侧小脑激活区较对侧明显激活。随着握力强度的增高,M1和S1激活强度、范围都提高;小脑激活程度有所降低。结论正常人手握力运动时脑皮质运动网络被激活,握力刺激强度与M1、S1的激活程度呈正相关。     

To move or not to move: imperatives modulate action-related verb processing in the motor system

It has been suggested that the processing of action-related words involves activation of the motor circuitry. Using fMRI (functional magnetic resonance imaging), the current study further explored the interaction between action and language by investigating whether the linguistic context, in which an action word occurs, modulates motor circuitry activity related to the processing of action words. To this end, we examined whether the presentation of hand action-related verbs as positive or negative imperatives, for example, “Do grasp” or “Don't write,” modulates neural activity in the hand area of primary motor cortex (M1) or premotor cortex (Pm). Subjects (n = 19) were asked to read silently the imperative phrases, in which both meaningful action verbs and meaningless pseudo-verbs were presented, and to decide whether they made sense (lexical decision task). At the behavioral level, response times in the lexical decision task were significantly longer for negative, compared to positive, imperatives. At the neural level, activity was differentially decreased by action verbs presented as negative imperatives for the premotor and the primary motor cortex of both hemispheres. The data suggest that context (here: positive vs. negative imperatives), in which an action verb is encountered, modulates the neural activity within key areas of the motor system. The finding implies that motor simulation (or motor planning) rather than semantic processing per se may underlie previously observed motor system activation related to action verb processing. Furthermore, the current data suggest that negative imperatives may inhibit motor simulation or motor planning processes.     

Spatial and Temporal Characteristics of Set-Related Inhibitory and Excitatory Inputs from the Dorsal Premotor Cortex to the Ipsilateral Motor Cortex Assessed by Dual-Coil Transcranial Magnetic Stimulation

The capacity to produce movements only at appropriate times is fundamental in successful behavior and requires a fine interplay between motor inhibition and facilitation. Evidence in humans indicates that the dorsal premotor cortex (PMCd) is involved in such preparatory and inhibitory processes, but how PMCd modulates motor output in humans is still unclear. We investigated this issue in healthy human volunteers, using a variant of the dual-coil transcranial magnetic stimulation (TMS) technique that allows testing the short-latency effects of conditioning TMS to the left PMCd on test TMS applied to the ipsilateral orofacial primary motor cortex (M1). Participants performed a delayed cued simple reaction time task. They were asked to produce a lip movement cued by an imperative GO-signal presented after a predictable SET-period, during which TMS was applied at different intervals. Results showed that the area of motor evoked potentials (MEPs) to test TMS was modulated by conditioning TMS. A transient inhibition cortico-bulbar excitability by PMCd stimulation was observed around the middle of the SET-period. Conversely, a ramping excitatory effect of PMCd stimulation appeared towards the end of the SET-period, as the time of the predicted GO-signal approached. The time-course of PMCd–M1 activity scaled to the varying SET-period duration. Our data indicate that inhibition and excitation of motor output during a delayed reaction time task are two distinct neural phenomena. They both originate in PMCd and are conveyed via cortico–cortical connections to the ipsilateral M1, where they are integrated to produce harmonic fluctuations of motor output.     

The neural response to transcranial magnetic stimulation of the human motor cortex. I. Intracortical and cortico-cortical contributions

We investigated the properties of the neural response to transcranial magnetic stimulation (TMS) applied over the human primary motor cortex. Consistent with our previous findings, single pulses of TMS induce a characteristic negative deflection at 45 ms (N45) and a transient oscillation in the beta frequency-range (15–30 Hz), as measured using electroencephalograpy (EEG). Here we show the relative specificity of the beta oscillation and the N45; both are stronger when elicited by stimulation applied over the primary motor cortex, as compared with stimulation over the dorsal premotor cortex. We also provide a quantitative analysis of the beta responses to single pulses of TMS and show that the responses are highly phaselocked to the TMS pulses within single subjects; this phaselocking is similar from subject to subject. A single pulse of TMS applied over the primary motor cortex thus appears to reset the ongoing oscillations of the neurons, bringing them transiently into synchrony. Finally, we examine the effect of local or distal modulation of the excitability of the primary motor cortex on the beta oscillation and the N45 in response to single-pulse TMS. We applied low-frequency subthreshold repetitive TMS either over the primary motor cortex (local modulation) or, on a separate day, over the dorsal premotor cortex (distal modulation). The modulation was evaluated with single suprathreshold test pulses of TMS applied over the primary motor cortex before and after the subthreshold low-frequency rTMS. We recorded the EEG response throughout the testing session, i.e. to both the subthreshold and the suprathreshold pulses. After repetitive TMS applied over the primary motor cortex, but not the dorsal premotor cortex, the amplitude of the N45 in response to suprathreshold pulses tended to decrease (not significant), and subsequently increased (significant); neither type of repetitive TMS affected the amplitude of the beta oscillation. We conclude that (1) the N45 depends on circuits intrinsic to the primary motor cortex; (2) the beta oscillation is specific to stimulation of the primary motor cortex, but is not affected by modulation of either cortical area and; (3) the beta oscillatory response to pulses of TMS arises from resetting of ongoing oscillations rather than their induction.The first author was funded by a fellowship from the Canadian Institute of Health Research (CIHR).