正常成年猫多导程视觉诱发电位研究

用平面均匀闪光和棋盘格图形翻转刺激,研究了１７只正常猫的多导程视觉诱发电位（ＶＥＰｓ）,主要结果为：１．图形刺激引起的Ｐ－ＶＥＰ波形为两个正相成份（Ｐ１和Ｐ２）夹着一个负相成份（Ｎ１）组成“Ｗ”型的波复合;而平面均匀闪光引起的Ｆ－ＶＥＰ则为两个负相成分（Ｎ１和Ｎ１）成分夹着一个正相成分（Ｐ１）构成“Ｍ”型的波复合。这两种ＶＥＰ均表现出明显的双眼总和现象,而且Ｐ－ＶＥＰ的总和率大于Ｆ－ＶＥＰ的。２．     

鸡减蛋综合征病毒（EDSV—76）基因组E1区结构特点分析

ＥＤＳＶ－７６病毒中国株ＡＡ－２经常规方法提取其病毒ＤＮＡ后,建立了限制性内切酶ＰｓｔＩ水解片段的全基因文库。对其中ＰｓｔＩ－Ｇ片段和ＰｓｔＩ－Ａ片段的正反链进行序列测定,获得ＥＤＳＶ Ｅ１区（０－８．８ｍ．ｕ）的核苷酸序列。经分析,ＥＤＳＶ Ｅ１区具有与其他腺病毒Ｅ１区类似的结构。以大于６０个氨基酸残基为标准,ＥＤＳＶ Ｅ１区共有７个开放读码框架（ＯＲＦ）,其中Ｒ１、Ｒ２、ＥｌｂｓＴ和Ｅ１ｂ１Ｔ     

新生大鼠脊髓薄片中的运动神经元对腹外侧索刺激的反应

在新生大鼠脊髓薄片细胞内记录了２５个经送行刺激鉴定的运动神经元（ＭＮ）,发现腹外侧索刺激可在８０％的ＭＮ诱发去极化反应（ＥＰＳＰ）。在静息电位水平ＥＰＳＰ的潜伏期、达峰时间、幅度、半衰时间和时程分别为１．２±０．２ｍｓ,２．６±０．４ｍｓ,１３±３ｍＶ,５．３±１．６ｍｓ和３１±８ｍｓ。ＥＰＳＰ呈等级性和膜电位依赖性,平均翻转电位为－８ｍＶ,潜伏期在０．—５Ｈｚ频率的刺激时相对恒定,但刺激频率＞２０Ｈｚ时ＥＰＳＰ变小或被取消。ＥＰＳＰ在低钙高镁溶液中被阻抑叵在无镁溶液中增强。犬尿烯酸（０．５—１ｍｍｏｌ／Ｌ）可逆地阻断ＥＰＳＰ,但氯胺酮（５０—１００μｍｏｌ／Ｌ）仅部分抑制之。结果表明腹外侧索中的下行纤维可能释放兴奋性氨基酸而激活ＭＮ。     

人脐静脉内皮细胞的生物学特性及细胞内信号转导机制

本实验对人脐静脉内皮细胞（ＨＵＶＥＣ）合成与释放篾这活性多肽（ＶＰｓ）及其作用机制进行了研究。结果表明：（１）无神经支配的人脐血管内皮细胞（ＶＥＣ）所含ＶＰｓ较有神经支配的肠系膜血管ＶＥＣ多;（２）这些ＶＰＳ是ＶＥＣ自身合成且能释放到胞外;（３）血管活性肠肽（ＶＩＰ）和Ｐ物质（ＳＰ）使ＨＵＶＥＣ膜上Ｃａ＾２＋通道开放概率明显增加,生长抑制（ＳＯＭ）使其明显降低,但它们均使胞浆内「Ｃａ＾２＋」和ＣＡ     

侵染西番莲属(Passiflora)植物的五个黄瓜花叶病毒分离物的特性比较

从紫果西番莲（Ｐａｓｉｆｌｏｒａｅｄｕｌｉｓ）、杂交种西番莲（Ｐ．ｅｄｕｌｉｓＸＰ．ｅｄｕｌｉｓｖａｒ．ｆｌａｖｉｃａｒｐａ）、黄果西番莲（Ｐ．ｅｄｕｌｉｓｖａｒ．ｆｌａｖｉｃａｒｐａ）、转心莲（Ｐ．ｃａｅｒｕｌｅａ）及龙珠果（Ｐ．ｆｏｅｔｉｄａ）分离到的５个黄瓜花叶病毒（ＣＭＶ）分离物（ＰＥ、ＰＥ２、ＰＥｆ、ＰＣ、ＰＦ）所作的生物学性质、理化特性和血清学关系的比较研究结果表明,５个分离物在寄主反应及血清学性质上存在不同,而在病毒粒体形态、体外抗性、蚜虫传毒和病毒外壳蛋白分子量方面无明显差异。根据５个分离物的寄主反应和血清学关系,可将其区分为ＣＭＶ的两个亚组,其中ＰＥ、ＰＥ２、ＰＣ和ＰＦ属ＣＭＶ亚组Ｉ,ＰＥｆ属ＣＭＶ亚组Ｉ。     

番茄花叶病毒外壳蛋白基因及3′端非编码区的克隆、序列分析及其表达

根据已报道的番茄花叶病毒Ｌ株系（ＴｏＭＶＬ）序列人工合成引物,经ＲＴＰＣＲ扩增并克隆了我国番茄花叶病毒分离物（ＴｏＭＶＳ１）的外壳蛋白ＣＰ基因及３′端非编码区。序列测定结果表明,所得ｃＤＮＡ共长６８２个核苷酸,其中ＣＰ基因含４８０个核苷酸,编码１５８个氨基酸,３′端非编码区含２０２个核苷酸,其核苷酸序列与ＴｏＭＶＬ株系具有９９．５％的同源率。将该基因片段克隆到ｐＧＥＭＥＸ１载体中,转入Ｅ．ｃｏｌｉ后诱导表达,经Ｗｅｓｔｅｒｎｂｌｏｔ检测证明,该基因已在大肠杆菌中正确表达。这是我国首次报道ＴｏＭＶＣＰ基因序列。     

应激引起血压升高大鼠血管升压素V1受体mRNA水平改变

实验在雄性ＳｐｒａｇｕｅＤａｗｌｅｙ 大鼠上进行。实验动物被随机分为对照组和应激组, 应激组大鼠每天给予电击足底结合噪声的应激刺激, 每日２ 次, 每次２ ｈ 。应激组大鼠在接受连续１５ ｄ 的慢性应激刺激后, 其尾动脉收缩压与对照动物相比有显著升高。对照组为１６－２５ ±０－６３ｋＰａ （ｎ ＝ ７） ; 应激组为１９－５５ ±１－４５ ｋＰａ （ｎ ＝ ８, Ｐ＜ ０－０５） 。用ＲＴＰＣＲ 结合Ｓｏｕｔｈｅｒｎ 印迹核酸分子杂交技术观察到, 血管升压素（ｖａｓｏｐｒｅｓｓｉｎ, ＡＶＰ）Ｖ１ 受体ｍＲＮＡ 广泛存在于大鼠下丘脑、皮质、延髓等部位以及心脏、肝脏、肾脏等组织中。用定量ＰＣＲ 方法观察到, 大鼠在接受慢性应激刺激之后, 其大脑顶叶皮质、下丘脑及延髓组织中ＡＶＰＶ１ 受体ｍＲＮＡ 水平均显著低于正常大鼠（ 顶叶皮质： Ｐ＜ ０－０５ ; 下丘脑： Ｐ＜ ０－０１ ; 延髓： Ｐ＜ ０－００１） , 而心脏、肝脏及肾脏组织中的ＡＶＰＶ１ 受体ｍＲＮＡ水平与正常大鼠相比均无明显差别（ 心脏： Ｐ＞ ０－０５ ; 肝脏： Ｐ＞ ０－０５ ; 肾脏：Ｐ＞ ０－０５） 。上述结果提示, 慢性应激刺激可引起大鼠不同部位脑组织ＡＶＰＶ１ 受体合成水平下调, 可能导致     

幼猫单眼视剥夺和反缝过程中显示的双眼竞争机制

本研究以光栅为刺激所同时产生的图形视觉诱发电位和图形视网膜电图为指标,测定了单眼视剥夺和缝的新生幼猫个体在发育不同阶段的空间频率调谐曲线,并与同龃正常猫,成年正常猫进行了比较研究。结果显示,在０．１２－１．５ｃ／ｄ空间频率范围内,正常幼猫单独刺激其左眼和右眼所驱动的Ｐ－ＶＥＰ振幅相近,但都明显地比双眼驱动的为小。在单眼剥夺的幼猫,由剥夺眼所驱动的Ｐ－ＶＥＰ振幅大幅度下降,健康眼所驱动的Ｐ－ＶＥＰ则     

广东两株人免疫缺陷病毒的分离和鉴定

从我省两名经性途径感染艾滋病的病人中采血,分离外周血单核细胞（ＰＢＭＣｓ）,将其与正常人ＰＢＭＣｓ共培养分离人免疫缺陷病毒（ＨＩＶ）,３周后检测上清ＨＩＶ－１ｐ２４抗原（ＥＬＩＳＡ法）超过阈值。将共培养第四周细胞和上清分别感染Ｈ９细胞（Ｔ细胞淋巴瘤传代细胞）,一周后检测ＨＩＶ－１ ｐ２４怕,证明有病毒生长。用ＨＩＶ－１ ＥＮＶ基因引物的套式聚合酶链反应（Ｎｅｓｔｅｄ ＰＣＲ）证实,两株新分离的病毒     

VNP减弱NE刺激的心肌细胞c-fos表达

目的：研究血管利钠肽（ＶＮＰ）对去甲贤上腺素（ＮＥ）刺激的心肌细胞ｃ－ｆｏｓ表达的影响。方法：分离纯化ＳＤ乳鼠心肌细胞,随机分为四组：对照组、ＮＥ组、ＶＮＰ组和ＶＮＰ＋ＮＥ组。以免疫组织化学染色方法观察各组ｃ－ｆｏｓ的表达情况,采用放射免疫方法测定了细胞内ｃＧＭＰ水平。结果：ＮＥ（１０＾－６ｍｏｌ／Ｌ）可以显著升高Ｆｏｓ样免疫阳性细胞数及染色强度（Ｐ〈０．０５,ｖｓ对照组）,ＶＮＰ（１０＾－７ｍｏ     

Characteristics of functional asymmetry in small premature infants at an age of 13–14 months

Delayed consequences of a sharp shortening of the prenatal period for the formation of handedness and the function of visuospatial attention were analyzed. The test group consisted of 16 small premature (SP) children at a corrected age of 13–14 months. The functional asymmetry was assessed by means of the A-not-B neuropsychological task, which is arranged in such a way that a child has to look for an attractive object in either a left or a right location. As compared to healthy children of the same age, the functional asymmetry of SP children was characterized by the absence of right-handedness. During the performance of the A-not-B trials, the SP children displayed a distinct left-side asymmetry: trials with an object hidden to the right of the child were significantly more frequently erroneous than those with a left-side position of the object. It is suggested that SP children have problems with disengagement of the attentional focus from an object located in the left half-field of vision under the conditions of shifting the attention to the right half-field. Probably, one of the consequences of a sharp decrease in the period of prenatal development is abnormal lateralization of some brain functions.     

Visual evoked potentials in response to dichoptic presentation of sinusoidal grating and noise background

Dichoptic stimulation was used in comparison of visual evoked potentials (VEPs) with those obtained with monocular stimulation (recordings made from the occipital area). 16 subjects viewed sinusoidal gratings with the right eye while a visual noise was added via a mirror for the left eye. In presence of the noise, amplitude of the early VEP components' N1, P1b, and the late component P2 decreased, P1a is not changed in presence of the noise, and the late negative wave N2 increased for all spatial frequencies. The effect of noise on the amplitude of VEPs obtained for monocular and dichoptic stimulation was similar. The data suggest that external noise is filtered by the V1 cortical neurons--matched filters for the gratings.     

Hemispheric asymmetry of visual evoked potentials during human recognition of facial emotional expressions

Visual evoked potentials (VEP) in standard 16 EEG derivations were recorded in 26 young men and 20 women during recognition of facial emotional expressions and geometric figures. The stimuli were presented on a computer screen in the center of the visual field or randomly in the right or left vision hemifields. Peak VEP latency and mean amplitude in 50-ms epochs were measured; spatiotemporal VEP dynamics was analyzed in a series of topographic maps. The right hemisphere was shown to be more important in processing emotional faces. The character of the asymmetry was dynamic: at earlier stages of emotion processing the electrical activity was higher in the right inferior temporal region compared to the left symmetrical site. Later on the activity was higher in the right frontal and central areas. The dynamic mapping of "face-selective" component N180 of VEPs revealed the onset of activation over the right frontal areas that was followed by the fast activation of symmetrical left zones. Notably, this dynamics didn't correlate with the hemifield of stimuli exposition. The degree of asymmetry was lower during presentation of figures, especially in the inferior temporal and frontal regions. The prominent asymmetry of information processes in the inferior temporal and frontal areas was suggested to be specific for recognition of facial expression.     

Lateralization of saccadic latency during monocular presentation of stimuli to a leading and non-leading eye

Saccadic latencies were studied in ten healthy subjects. Peripheral targets were presented monocularly to a leading and nonleading eyes in the right and left hemifields. SS (single step) and OVERLAP (200 ms) schemes of visual stimulation were used. Under OVERLAP conditions, the saccadic latency was longer by 30-39 ms and the number of long-latency saccades was higher than under SS conditions, especially in subjects with mixed asymmetry profiles. In the majority of subjects with right asymmetry profile, the latencies of saccades during stimulation of the leading eye were by 12 ms shorter than during stimulation of the nonleading eye, and the latencies of right saccades were by 24 ms shorter than that of the left saccades independently of the stimulated eye. The obtained results explain some characteristic features of hemyspheric asymmetry in organization of saccadic movements.     

Nonlinear effects in subthreshold virtual electrode polarization

Introduction of the virtual electrode polarization (VEP) theory suggested solutions to several century-old puzzles of heart electrophysiology including explanation of the mechanisms of stimulation and defibrillation. Bidomain theory predicts that VEPs should exist at any stimulus strength. Although the presence of VEPs for strong suprathreshold pulses has been well documented, their existence at subthreshold strengths during diastole remains controversial. We studied cardiac membrane polarization produced by subthreshold stimuli in 1) rabbit ventricular muscle using high-resolution fluorescent imaging with the voltage-sensitive dye pyridinium 4-[2-[6-(dibutylamino)-2-naphthalenyl]-ethenyl]-1-(3-sulfopropyl)hydroxide (di-4-ANEPPS) and 2) an active bidomain model with Luo-Rudy ion channel kinetics. Both in vitro and in numero models show that the common dog-bone-shaped VEP is present at any stimulus strength during both systole and diastole. Diastolic subthreshold VEPs exhibited nonlinear properties that were expressed in time-dependent asymmetric reversal of membrane polarization with respect to stimulus polarity. The bidomain model reveals that this asymmetry is due to nonlinear properties of the inward rectifier potassium current. Our results suggest that active ion channel kinetics modulate the transmembrane polarization pattern that is predicted by the linear bidomain model of cardiac syncytium.     

躯体传入冲动抑制中枢性心肌缺血的脊髓机制

本工作在58只尿酯-氯醛糖麻醉,三碘季铵酚制动,人工呼吸,切断迷走神经的兔上进行。结果显示:电刺激正中神经(MN)和腓深神经(DPN)均能抑制或部分抑制下丘脑背内侧核(DMH)诱发的缺血性心电 ST 段偏移,以刺激 MN 的抑制作用更为明显。蛛网膜下腔注射(ith)吗啡(40μg)也能抑制这种缺血性心电变化。ith 纳洛酮(20μg)则可阻断刺激 MN 对中枢性心肌缺血的抑制作用。完整兔在刺激左侧 MN 或 DPN 后,用放射免疫技术测得胸 2—5(T_2-5)节段两侧中间外侧柱(IML)中亮氨酸脑啡肽(LENK)含量明显增加。在颈1(C_1)水平横断脊髓,以同样参数刺激左侧 MN,同侧胸髓 IML 中 LENK 含量明显增加,而对侧胸髓 IML 中 LENK 含量无明显改变;刺激一侧 DPN,T_(2-5)的两侧 IML 中 LENK 含量均无明显变化。上述结果表明,刺激 MN 与 DPN 均能抑制 DMH 诱发的中枢性心肌缺血,但以MN 作用较明显。我们推测这种抑制作用可能与通过脊上机制双侧性增加 IML 中 LENK 含量有关,MN 的抑制作用可能尚包括直接激活胸髓内的脑啡肽系统,增加同侧 IML 中 LENK含量,加强了对交感输出活动的抑制作用。     

Understanding Actions of Others: The Electrodynamics of the Left and Right Hemispheres. A High-Density EEG Neuroimaging Study

Background

When we observe an individual performing a motor act (e.g. grasping a cup) we get two types of information on the basis of how the motor act is done and the context: what the agent is doing (i.e. grasping) and the intention underlying it (i.e. grasping for drinking). Here we examined the temporal dynamics of the brain activations that follow the observation of a motor act and underlie the observer''s capacity to understand what the agent is doing and why.

Methodology/Principal Findings

Volunteers were presented with two-frame video-clips. The first frame (T0) showed an object with or without context; the second frame (T1) showed a hand interacting with the object. The volunteers were instructed to understand the intention of the observed actions while their brain activity was recorded with a high-density 128-channel EEG system. Visual event-related potentials (VEPs) were recorded time-locked with the frame showing the hand-object interaction (T1). The data were analyzed by using electrical neuroimaging, which combines a cluster analysis performed on the group-averaged VEPs with the localization of the cortical sources that give rise to different spatio-temporal states of the global electrical field. Electrical neuroimaging results revealed four major steps: 1) bilateral posterior cortical activations; 2) a strong activation of the left posterior temporal and inferior parietal cortices with almost a complete disappearance of activations in the right hemisphere; 3) a significant increase of the activations of the right temporo-parietal region with simultaneously co-active left hemispheric sources, and 4) a significant global decrease of cortical activity accompanied by the appearance of activation of the orbito-frontal cortex.

Conclusions/Significance

We conclude that the early striking left hemisphere involvement is due to the activation of a lateralized action-observation/action execution network. The activation of this lateralized network mediates the understanding of the goal of object-directed motor acts (mirror mechanism). The successive right hemisphere activation indicates that this hemisphere plays an important role in understanding the intention of others.     

Hypergravity decreases carbonic anhydrase-reactivity in inner ear maculae of fish

Previous investigations revealed that fish inner ear otolith growth depends on the amplitude and the direction of gravity. Both otolith total size, otolith bilateral size-asymmetry and the total and bilateral calcium-incorporation are also affected by gravity. Hypergravity, e.g., slows down otolith growth and diminishes bilateral otolith asymmetry as compared to 1 g control specimens raised in parallel. Since the enzyme carbonic anhydrase (CA) plays a prominent role in otolithic calcification, the reactivity of inner ear CA during otolith growth under hypergravity was investigated. CA-reactivity was demonstrated histochemically and densitometrically on sections of inner ear maculae of larval cichlid fish (Oreochromis mossambicus), that were kept for 6 hrs in a 3 g hypergravity centrifuge. The total unilateral macular CA-reactivity and the bilateral difference in CA between the left and the right maculae were significantly lower in 3 g animals than in 1g controls. The result is in complete agreement with previous studies indicating that a regulatory mechanism, which adjusts otolith size and asymmetry towards the gravity vector, acts via activation/deactivation of macular CA.     

Asymmetry in size, shape, and color impairs the protective value of conspicuous color patterns

The received view of protective coloration in animals is thatconspicuous colors and patterns have evolved because they elicitavoidance behavior in potential predators. In the present study,we examine the spontaneous response of naive predators (Gallusgallus domesticus) to artificial prey to test the hypothesisthat deviations from bilateral symmetry of signaling patternelements may negatively influence the avoidance-inducing effectof conspicuous color patterns. Chicks displayed stronger aversionsto artificial "butterfly" prey items possessing symmetric colorpattern elements than to those possessing asymmetric signalswith pattern elements of different color or shape. Althoughthey attacked signals with a size asymmetry of 5% at the samerate as symmetric signals, signals with a size asymmetry of7.5% or more were attacked more often than were symmetric signals.These results suggest that the protective value of conspicuouscolor patterns is impaired by asymmetry in color, shape, andsize of color pattern elements. Our findings also argue againstthe notion that animals have inherent preferences for symmetricover asymmetric objects, and demonstrate the existence of athreshold for asymmetry detection, beyond which further incrementsin asymmetry have no influence on signal efficacy.     

Facilitating Access to Emotions: Neural Signature of EMDR Stimulation

Background

Eye Movement Desensitisation and Reprocessing (EMDR) is a method in psychotherapy effective in treating symptoms of posttraumatic stress disorder. The client attends to alternating bilateral visual, auditory or sensory stimulation while confronted with emotionally disturbing material. It is thought that the bilateral stimulation as a specific element of EMDR facilitates accessing and processing of negative material while presumably creating new associative links. We hypothesized that the putatively facilitated access should be reflected in increased activation of the amygdala upon bilateral EMDR stimulation even in healthy subjects.

Methods

We investigated 22 healthy female university students (mean 23.5 years) with fMRI. Subjects were scanned while confronted with blocks of disgusting and neutral picture stimuli. One third of the blocks was presented without any additional stimulation, one third with bilateral simultaneous auditory stimulation, and one third with bilateral alternating auditory stimulation as used in EMDR.

Results

Contrasting disgusting vs. neutral picture stimuli confirmed the expected robust effect of amygdala activation for all auditory stimulation conditions. The interaction analysis with the type of auditory stimulation revealed a specific increase in activation of the right amygdala for the bilateral alternating auditory stimulation. Activation of the left dorsolateral prefrontal cortex showed the opposite effect with decreased activation.

Conclusions

We demonstrate first time evidence for a putative neurobiological basis of the bilateral alternating stimulation as used in the EMDR method. The increase in limbic processing along with decreased frontal activation is in line with theoretical models of how bilateral alternating stimulation could help with therapeutic reintegration of information, and present findings may pave the way for future research on EMDR in the context of posttraumatic stress disorder.