大鼠前庭—丘脑投射——HRP法研究

用 HRP 法研究了41只大鼠的前庭—丘脑投射。在丘脑腹前核(腹外侧核)、腹内侧核、中央外侧核、腹后核、丘脑后核、内侧膝状体大细胞部及外侧膝状体腹侧核等处分别注入 HRP 后,在前庭核簇的不同亚核中观察到标记细胞。证实了大鼠和猫及猴同样也有前庭—丘脑投射。并依前庭—丘脑投射的细胞起源和终止部位不同,可将前庭—丘脑投射大致分为两大类。第一类起自前庭核簇所有四个亚核,投射到丘脑的“非特异”核群,包括腹前核(可能还有腹外侧核),腹内侧核及中央外侧核,可能与维持并改变大脑皮层的兴奋性以及完成运动功能有关。第二类仅起自前庭内侧核和降核,投射到丘脑的腹后核及后核群(包括丘脑后核、内侧膝状体大细胞部及外侧膝状体腹侧核),可能和前庭感觉的传递以及前庭感觉和其它感觉的会聚有关。     

听源性惊厥易感大鼠惊厥和点燃后听觉核团内的c—fos表达

为探讨听源性惊厥点燃和听觉核团的关系，用免疫细胞化学方法结合体视学分析，研究了Ｗｉｓｔａｒ种系的听源性惊厥易感大鼠惊厥和点燃后听觉核团内ｃ－ｆｏｓ表达的差异。在内侧膝状体背侧核和蜗神经背核，Ｆｏｓ标记细胞无显著变化。本研究结果表明，听源性惊厥导的display status     

P77PMC大鼠听源性惊厥神经回路──核团损毁研究

采用立体定位直流电损毁法,分别损毁双侧下丘、脑桥吻侧网状核、内侧膝状体、黑质,观察核团损毁对大鼠听源性惊厥行为的影响,以寻找与P77PMC大鼠听源性惊厥有关的神经核团。结果表明：双侧下丘损毁后能完全阻断强直阵挛性惊厥,脑桥吻侧网状核损毁能明显减少惊厥发生（P＜0．05）,而双侧内侧膝状体及黑质损毁对惊厥无明显影响（P＜0．05）。提示下丘是P77PMC大鼠听源性惊厥的关键核团,而脑桥吻侧网状核可能参与了惊厥回路,内侧膝状体可能并未参与惊厥回路,黑质在此惊厥中的作用尚不明确。     

猫外侧膝状体腹核至上丘和顶盖前区的定位投射——HRP法

本文采用HRP方法观察了猫外侧膝状体腹核至上丘和顶盖前区的定位投射,HRP注射在上丘深层后,可见同侧较吻端的外侧膝状体腹核内侧部腹侧半的许多细胞被标记,这些细胞成团分布,多为圆形或卵圆形。注射在吻端顶盖前区以后,二侧较尾端的外侧膝状体腹核外侧部的细胞被标记,以对侧为主。注射至尾端顶盖前区(部分扩散至上丘)后,同侧较尾端的外侧膝状体腹核外侧部腹侧半的细胞被标记。与注射于上丘者相比,细胞密度较低,亦为圆形或卵圆形,提示外侧膝状体腹核至上丘或顶盖前区的投射具有较明显的局部组构关系。     

大鼠小脑—丘脑投射的起源和终止——HRP法研究

本实验用HRP法研究了大鼠小脑—丘脑投射的起源和终止。大鼠所有小脑核(齿状核DN、间位核前部 AIN、间位核后部 PIN 及顶核 FN)都发出纤维投射到丘脑,其中 DN 投射的范围最广,其次是PIN及AIN,FN较小。大鼠小脑—丘脑投射终止在对侧丘脑的腹侧核群(腹前核VA、腹外侧核VL、腹内侧核VM及腹后外侧核VPL),内侧核群(中央外侧核CL、束旁核Pf及背内侧核MD)以及后核群(内侧膝状体MGB、丘脑后核PO)。小脑DN到丘脑腹侧核群的投射有相应的颅尾局部定位关系,但有部分重叠。FN到丘脑的投射仅起自FN的尾侧部,投射到丘脑的VM、VPL、CL、Pf及PO。除AIN外,小脑的DN、PIN及FN均有少量纤维投射到同侧的丘脑VM、CL及Pf。     

大鼠前庭脊核和X细胞群向脑桥核的直接投射

目的:应用菜豆白细胞凝集素(PHA-L)顺行追踪和荧光金(FG)逆行追踪技术研究前庭脊核和X细胞群向脑桥核的直接投射.方法:SD大鼠随机分为PHA-L注射组和FG注射组.将顺行神经追踪剂PHA-L电泳至前庭脊核和X细胞群,逆行神经追踪剂FG分别电泳至脑桥核的外侧亚核和内侧亚核,动物存活7 d,灌流固定后,脑干作冠状冷冻切片,然后进行免疫组织化学显色.结果:PHA-L注射于前庭脊核后,顺行标记纤维和终末主要分布在对侧脑桥核的外侧亚核、内侧亚核及脑桥网状被盖核;FG分别注射于脑桥核的外侧和内侧亚核后,逆行标记细胞仅分布在对侧前庭脊核和X细胞群.结论:前庭脊核和X细胞群向对侧脑桥核的外侧和内侧亚核有直接的纤维投射,该投射可能与前庭-眼反射的调节有关.     

猫背海马和齿状回的传入纤维来源——HRP法研究

本文借助脑立体定位仪,在11只猫背海马和齿状回,分内、中及外侧三个区域内注入HRP,在以下主要部位见到酶标细胞:中缝背核、中央上核、兰斑核;丘脑前背核、丘脑前腹核、丘脑前内侧核、丘脑背内侧核、丘脑连合核、下丘脑外侧核、下丘脑内侧核、下丘脑后核、乳头上间质核、缰核及外侧膝状体核;内侧隔核、斜角带核及旁海马回。     

大鼠下丘脑催产素及加压素样神经元与脑啡肽样传入纤维末梢的关系

用免疫组织化学ABC双标记法,显示大鼠下丘脑各大细胞神经分泌核团中催产素样免疫反应(OT-li)、加压素样免疫反应(VP-li)神经元、亮-脑啡肽样免疫反应(L-ENK-li)和甲-脑啡肽样免疫反应(M-ENK-li)纤维末梢,并对不同神经分泌核团内脑啡肽样传入纤维末梢与OT-li及VP-li神经元的关系加以分析。结果发现,L-ENK-li及M-ENK-li纤维末梢在下丘脑各神经分泌核团中,与OT-li及VP-li神经元均有一定程度的接触关系。L-ENK-li与M-ENK-li纤维末梢在第三脑室周、前连合核、背内侧和背外侧副核、穹窿前和后核的OT-li及VP-li神经元周围最密集,在视上核、室旁核次之,在血管周细胞群内的OT-li及VP-li神经元周围密度较低。这些神经分泌性核团内L-ENK-li纤维末梢,均较M-ENK-li纤维末梢密集。表明脑啡肽能传入纤维末梢,与视上核、室旁核及各神经分泌副核(除血管周细胞群外)中的OT-li及VP-li神经元,均有不同程度的接触关系。因此,脑啡肽能传入纤维末梢可能在大细胞神经分泌系统OT-li及VP-li神经元分泌活动的调节中,起较广泛的重要作用。     

剥夺性弱视猫外侧膝状体c-fos基因及Fos蛋白表达

为研究生后关键期内,正常猫及剥夺性弱视猫外侧膝状体神经元功能形态的变化规律,对正常视发育敏感期的幼猫行左眼睑缝合术,造成剥夺性弱视模型,采用Nissl染色法及电镜观察正常猫及剥夺性弱视猫外侧膝状体神经元的形态改变,并用免疫组化和原位杂交技术检测Fos蛋白及cfos基因的表达情况。结果显示:(1)剥夺猫剥夺层外侧膝状体神经元的截面积比非剥夺层及正常猫的明显变小,差异有显著性(P<0.05);(2)超微结构显示:剥夺性弱视猫的剥夺层出现大量变性的细胞,剥夺4周时最为显著;(3)正常猫外侧膝状体神经元Fos蛋白和cfos原位杂交的阳性细胞数及OD值随着时间的延长而降低。同龄猫剥夺层外侧膝状体Fos蛋白和cfos原位杂交阳性细胞数及OD值较正常猫减少(P<0.05)。结果提示:猫视觉的可塑性敏感期为生后4周到8周。剥夺性弱视猫外侧膝状体剥夺层及非剥夺层神经元形态及功能与正常猫相比较均发生改变。Fos法可以成为衡量弱视猫外侧膝状体兴奋性状态与形态学定位相结合的实验方法,但必须注意神经可塑性对其的影响。     

金黄地鼠上丘和外侧膝状体之间的联系

本实验采用了顺行和逆行追踪技术,对金黄地鼠上丘与丘脑视核团的纤维联系进行了实验观察。一、用尼氏和Loyez染色法,对4只正常金黄地鼠上丘和外侧膝状体背核和腹核的正常结构做了观察。二、3~H-亮氨酸和3~H-脯氨酸注入动物上丘不同部位(4只,存活期一天)后,可见神经末梢标记于同侧的外侧膝状体背核和腹核的外侧部位。若注射部位在上丘外侧,其投射部位在外侧膝状体背核和腹核的尾外侧;注射部位移向内侧,投射部位移向吻外侧。三、将HRP注入外侧膝状体背核(4只,存活期一天)或腹核(2只,存活期一天)或后外侧核(2只,存活期一天)后,在同侧上丘浅层见有标记神经元。在上丘深层则未见。本实验说明了上丘浅层的神经元对同侧的外侧膝状体背核和腹核有局部定位的投射,并按视野和视网膜将该投射作定位排列。     

Thalamic projections to the auditory cortex in the rufous horseshoe bat (Rhinolophus rouxi). II. Dorsal fields

In this study, we analyzed the thalamic connections to the parietal or dorsal auditory cortical fields of the horseshoe bat, Rhinolophus rouxi. The data of the present study were collected as part of a combined investigation of physiologic properties, neuroarchitecture, and chemoarchitecture as well as connectivity of cortical fields in Rhinolophus, in order to establish a neuroanatomically and functionally coherent view of the auditory cortex. Horseradish peroxidase or wheat-germ-agglutinated horseradish peroxidase deposits were made into cortical fields after mapping response properties. The dorsal fields of the auditory cortex span nearly the entire parietal region and comprise more than half of the non-primary auditory cortex. In contrast to the temporal fields of the auditory cortex, which receive input mainly from the ventral medial geniculate body (or "main sensory nucleus"), the dorsal fields of the auditory cortex receive strong input from the "associated nuclei" of the medial geniculate body, especially from the anterior dorsal nucleus of the medial geniculate body. The anterior dorsal nucleus is as significant for the dorsal fields of the auditory cortex as the ventral nucleus of the medial geniculate body is for the temporal fields of the auditory cortex. Additionally, the multisensory nuclei of the medial geniculate body provide a large share of the total input to the nonprimary fields of the auditory cortex. Comparing the organization of thalamic auditory cortical afferents in Rhinolophus with other species demonstrates the strong organizational similarity of this bat's auditory cortex with that of other mammals, including primates, and provides further evidence that the bat is a relevant and valuable model for studying mammalian auditory function.     

Thalamic projections to the auditory cortex in the rufous horseshoe bat (<Emphasis Type="Italic">Rhinolophus rouxi)</Emphasis>

In this study, we analyzed the thalamic connections to the parietal or dorsal auditory cortical fields of the horseshoe bat, Rhinolophus rouxi. The data of the present study were collected as part of a combined investigation of physiologic properties, neuroarchitecture, and chemoarchitecture as well as connectivity of cortical fields in Rhinolophus, in order to establish a neuroanatomically and functionally coherent view of the auditory cortex. Horseradish peroxidase or wheat-germ-agglutinated horseradish peroxidase deposits were made into cortical fields after mapping response properties. The dorsal fields of the auditory cortex span nearly the entire parietal region and comprise more than half of the nonprimary auditory cortex. In contrast to the temporal fields of the auditory cortex, which receive input mainly from the ventral medial geniculate body (or “main sensory nucleus”), the dorsal fields of the auditory cortex receive strong input from the “associated nuclei” of the medial geniculate body, especially from the anterior dorsal nucleus of the medial geniculate body. The anterior dorsal nucleus is as significant for the dorsal fields of the auditory cortex as the ventral nucleus of the medial geniculate body is for the temporal fields of the auditory cortex. Additionally, the multisensory nuclei of the medial geniculate body provide a large share of the total input to the nonprimary fields of the auditory cortex. Comparing the organization of thalamic auditory cortical afferents in Rhinolophus with other species demonstrates the strong organizational similarity of this bat’s auditory cortex with that of other mammals, including primates, and provides further evidence that the bat is a relevant and valuable model for studying mammalian auditory function.     

"Ventral" area in the rat auditory cortex: a major auditory field connected with the dorsal division of the medial geniculate body

The rat auditory cortex is made up of multiple auditory fields. A precise correlation between anatomical and physiological areal extents of auditory fields, however, is not yet fully established, mainly because non-primary auditory fields remain undetermined. In the present study, based on thalamocortical connection, electrical stimulation and auditory response, we delineated a non-primary auditory field in the cortical region ventral to the primary auditory area and anterior auditory field. We designated it as "ventral" area after its relative location. At first, based on anterograde labeling of thalamocortical projection with biocytin, ventral auditory area was delineated as a main cortical terminal field of thalamic afferents that arise from the dorsal division of the medial geniculate body. Cortical terminal field (ventral auditory area) extended into the ventral margin of temporal cortex area 1 (Te1) and the dorsal part of temporal cortex area 3, ventral (Te3V), from 3.2-4.6 mm posterior to bregma. Electrical stimulation of the dorsal division of the medial geniculate body; evoked epicortical field potentials confined to the comparable cortical region. On the basis of epicortical field potentials evoked by pure tones, best frequencies were further estimated at and around the cortical region where electrical stimulation of the dorsal division of the medial geniculate body evoked field potentials. Ventral auditory area was found to represent frequencies primarily below 15 kHz, which contrasts with our previous finding that the posterodorsal area, the other major recipient of the dorsal division of the medial geniculate body; projection, represents primarily high frequencies (>15 kHz). The posterodorsal area is thought to play a pivotal role in auditory spatial processing [Kimura A, Donishi T, Okamoto K, Tamai Y (2004) Efferent connections of "posterodorsal" auditory area in the rat cortex: implications for auditory spatial processing. Neuroscience 128:399-419]. The ventral auditory area, as the other main cortical region that would relay auditory input from the dorsal division of the medial geniculate body to higher cortical information processing, could serve an important extralemniscal function in tandem with the posterodorsal area. The results provide insight into structural and functional organization of the rat auditory cortex.     

Topography of projections from the primary and non-primary auditory cortical areas to the medial geniculate body and thalamic reticular nucleus in the rat

The functional significance of parallel and redundant information processing by multiple cortical auditory fields remains elusive. A possible function is that they may exert distinct corticofugal modulations on thalamic information processing through their parallel connections with the medial geniculate body and thalamic reticular nucleus. To reveal the anatomical framework for this function, we examined corticothalamic projections of tonotopically comparable subfields in the primary and non-primary areas in the rat auditory cortex. Biocytin was injected in and around cortical area Te1 after determining best frequency at the injection site on the basis of epicortical field potentials evoked by pure tones. The rostral part of area Te1 (primary auditory area) and area temporal cortex, area 2, dorsal (Te2D) (posterodorsal auditory area) dorsal to the caudal end of area Te1, which both exhibited high best frequencies, projected to the ventral zone of the ventral division of the medial geniculate body. The caudal end of area Te1 (auditory area) and the rostroventral part of area Te1 (a part of anterior auditory field), which both exhibited low best frequencies, projected to the dorsal zone of the ventral division of the medial geniculate body. In contrast to the similar topography in the projections to the ventral division of the medial geniculate body, collateral projections to the thalamic reticular nucleus terminated in the opposite dorsal and ventral zones of the lateral and middle tiers of the nucleus in each pair of the tonotopically comparable cortical subfields. In addition, the projections of the non-primary cortical subfields further arborized in the medial tier of the thalamic reticular nucleus. The results suggest that tonotopically comparable primary and non-primary subfields in the auditory cortex provide corticofugal excitatory effects to the same part of the ventral division of the medial geniculate body. On the other hand, corticofugal inhibition via the thalamic reticular nucleus may operate in different parts of the ventral division of the medial geniculate body or different thalamic nuclei. The primary and non-primary cortical auditory areas are presumed to subserve distinct gating functions for auditory attention.     

Cytoarchitecture of the medial geniculate body and thalamic projections to the auditory cortex in the rufous horseshoe bat (Rhinolophus rouxi). I. Temporal fields

The auditory cortex in echolocating bats is one of the best studied in mammals, yet the projections of the thalamus to the different auditory cortical fields have not been systematically analyzed in any bat species. The data of the present study were collected as part of a combined investigation of physiological properties, neuroarchitecture, and chemoarchitecture as well as connectivity of cortical fields in Rhinolophus in order to establish a neuroanatomically and functionally coherent view of the auditory cortex in the horseshoe bat. This paper first describes the neuroanatomic parcellation of the medial geniculate body and then concentrates on the afferent thalamic connections with auditory cortical fields of the temporal region. Deposits of horseradish peroxidase and wheatgerm-agglutinated horseradish peroxidase were made into neurophysiologically characterized locations of temporal auditory cortical fields; i.e., the tonotopically organized primary auditory cortex, a ventral field, and a temporal subdivision of a posterior dorsal field. A clear topographic relationship between thalamic subdivisions and specific cortical areas is demonstrated. The primary auditory cortex receives topographically organized input from the central ventral medial geniculate body. The projection patterns to the temporal subdivision of the posterior dorsal field suggest that it is a "core" field, similar to the posterior fields in the cat. Projections to the ventral field arise primarily from border regions of the ventral medial geniculate body. On the whole, the organization of the medial geniculate body projections to the temporal auditory cortex is quite similar to that described in other mammals, including cat and monkey.     

Afferent fibers to the anterior suprasylvian gyrus from the medial geniculate body of cat

Afferents to the anterior suprasylvian gyrus (ASG) from the medial geniculate body of cat were demonstrated by means of autoradiography. [3H]Glycine was injected stereotactically into the medial division of the medial geniculate body (mMGB). After a 3-day survival period, the auditory cortices and the ASG were excised. Labelled terminals were found in the ASG, in the anterior auditory field (AAF) and in the acoustic cortex (AI). The density of labelling was highest in the ASG and lower in the AAF and AI. The afferents from the mMGB made synaptic contacts in the 3rd layer of the cortices examined.     

Cytoarchitecture of the medial geniculate body and thalamic projections to the auditory cortex in the rufous horseshoe bat (<Emphasis Type="Italic">Rhinolophus rouxi)</Emphasis>

The auditory cortex in echolocating bats is one of the best studied in mammals, yet the projections of the thalamus to the different auditory cortical fields have not been systematically analyzed in any bat species. The data of the present study were collected as part of a combined investigation of physiological properties, neuroarchitecture, and chemoarchitecture as well as connectivity of cortical fields in Rhinolophus in order to establish a neuroanatomically and functionally coherent view of the auditory cortex in the horseshoe bat. This paper first describes the neuroanatomic parcellation of the medial geniculate body and then concentrates on the afferent thalamic connections with auditory cortical fields of the temporal region. Deposits of horseradish peroxidase and wheatgerm-agglutinated horseradish peroxidase were made into neurophysiologically characterized locations of temporal auditory cortical fields; i.e., the tonotopically organized primary auditory cortex, a ventral field, and a temporal subdivision of a posterior dorsal field. A clear topographic relationship between thalamic subdivisions and specific cortical areas is demonstrated. The primary auditory cortex receives topographically organized input from the central ventral medial geniculate body. The projection patterns to the temporal subdivision of the posterior dorsal field suggest that it is a “core” field, similar to the posterior fields in the cat. Projections to the ventral field arise primarily from border regions of the ventral medial geniculate body. On the whole, the organization of the medial geniculate body projections to the temporal auditory cortex is quite similar to that described in other mammals, including cat and monkey.     

Topographic organization of the auditory thalamocortical system in the albino rat

Summary The organization of the auditory thalamocortical connections was studied in rats. Retrograde transport of horseradish peroxidase conjugated to wheat germ agglutinin following injections into parietal, occipital and temporal cortex was used. The medial geniculate body, the suprageniculate, the lateral part of the nucleus posterior thalami, the posterior part of the nucleus lateralis thalami, and the nucleus ventroposterior project to the investigated part of the neocortex. Corresponding to different patterns of labeling, five areas of auditory neocortex were distinguished: 1. The rostral area is innervated by neurons of the nucleus ventroposterior, the lateral part of the nucleus posterior thalami, and the medial division of the medial geniculate body. 2. The dorsal area is innervated by neurons of the suprageniculate, the posterior part of the nucleus lateralis thalami and the rostral region of the dorsal division of the medial geniculate body. 3. The caudal area is innervated by neurons of the posterior part of the nucleus lateralis thalami, the suprageniculate, the medial division, the caudal region of the dorsal division and the ventrolateral nucleus of the medial geniculate body. 4. The ventral area is innervated by neurons of the suprageniculate, the medial division, the caudal region of the dorsal division, and the ventrolateral nucleus of the medial geniculate body. 5. The core area of the temporal cortex is exclusively connected to the caudal region of the medial division and the ventral division of the medial geniculate body.The findings of the present study indicate topographic organizations of the ventral division of the medial geniculate body and of the corea area. Four segments (a-d) of the ventral division each show a different set of topographic axes. They correspond to sets of topographic axes in the core area of the auditory cortex. These topographies characterize the segments which are each exclusively connected to one of the four fields of the core area.Abbreviations AC Auditory Cortex - c Caudal - d Dorsal - FR Fissura rhinalis, Rhinal Fissure - l Lateral - LTP Nucleus lateralis thalami, pars posterior - m Medial - MGB Medial geniculate body - MGBd Medial geniculate body, dorsal division - MGBm Medial geniculate body, medial division - MGBmc Medial geniculate body, caudal third of MGBm - MGBv Medial geniculate body, ventral division - MGBvl Medial geniculate body, ventrolateral nucleus - NPT Nucleus posterior thalami, pars lateralis - r Rostral - SG Suprageniculatum - VP Nucleus ventroposterior     

Effects of medial geniculate lesions on sound localization by the rat

Rats with bilateral lesions of the medial geniculate body were tested on a two-choice sound-localization task that required a directional response to a distant sound source. Stimuli included both broadband and filtered noise bursts presented singly or in repetitive trains. Separate tests were conducted with loudspeakers 180 and 60 degrees apart, centered around 0 degree azimuth. With complete bilateral destruction of the medial geniculate, rats could localize both trains and single bursts of noise and were capable of high levels of performance even at small angles of speaker separation. Some evidence of impaired performance was noted with high-frequency noise bursts, but generally the deficits were not severe. Animals with lesions that extended caudally into the brachium of the inferior colliculus and lateral tegmentum were severely impaired in their ability to localize sounds even at large angles of speaker separation. Three of the four animals in this group were incapable of localizing single bursts even with loudspeakers separated by 180 degrees, and the fourth was unable to perform above chance at 60 degrees. The effects of medial geniculate lesions were very similar to those reported previously for rats with lesions of the auditory cortex, but contrasted with reports of severe impairments in sound localization following damage to the auditory cortex in other mammalian species.     

老年人内侧膝状体形态、血供和来源动脉的病理学改变

目的 :研究老年人内侧膝状体的形态、毗邻及供血动脉来源、分支、分布和病理改变。方法 :体视及手术显微镜下观察 60～ 80岁年龄的脑内侧膝状体的形态、毗邻和血供情况 ;取内侧膝状体来源动脉 (大脑后动脉 )光镜下观察动脉壁的病理改变情况。结果 :内侧膝状体呈半球形 ,动脉来源于大脑后动脉的分支 ,即丘脑膝状体动脉 ,脉络丛后内、外动脉和丘体动脉 ,每侧有小动脉 ( 6.8± 1 .5 )支 ,大脑后动脉粥样硬化改变者占 88.3 %。结论 :内侧膝状体动脉细小 ,仅由大脑后动脉供血 ,动脉硬化可致小动脉管腔狭窄 ,供血不足 ,可能是老年人听力下降的原因之一。