A cortical region consisting entirely of face-selective cells

Face perception is a skill crucial to primates. In both humans and macaque monkeys, functional magnetic resonance imaging (fMRI) reveals a system of cortical regions that show increased blood flow when the subject views images of faces, compared with images of objects. However, the stimulus selectivity of single neurons within these fMRI-identified regions has not been studied. We used fMRI to identify and target the largest face-selective region in two macaques for single-unit recording. Almost all (97%) of the visually responsive neurons in this region were strongly face selective, indicating that a dedicated cortical area exists to support face processing in the macaque.     

Clonally related cortical cells show several migration patterns

The mammalian cerebral cortex is organized into columns of cells with common functional properties. During embryogenesis, cortical neurons are formed deep, near the lateral ventricles, and migrate radially to their final position. This observation led to the suggestion that the cortex consists of radial, ontogenetic units of clonally related neurons. In the experiments reported here, this hypothesis was tested by studying cell lineage in the rat cortex with a retroviral vector carrying the Escherichia coli beta-galactosidase gene, which can be easily visualized. Labeled, clonally related cortical neurons did not occur in simple columnar arrays. Instead, clonally related neurons entered several different radial columns, apparently by migrating along different radial glial fibers.     

Visual experience without lines: effect on developing cortical neurons

Kittens were reared in a planetarium-like visual environment that lacked straight line contours. Cortical neurons were subsequently highly sensitive to spots of light but not to straight lines, in marked contrast to those from a normal cat. If linear contour processing is an innate function it appears to be subject to substantial modification by early visual experience.     

Steroscopic vision: cortical limitations and a disparity scaling effect

The spatial limitations of stereoscopic vision were studied by using vertical line stimuli containing sinusoidal disparity variations such that different parts of the line appeared at different depths. Stimuli with a finer grain than about 3 cycles per degree did not elicit depth perception, even though the sinusoidal curvature was clearly visible monocularly. At low spatial frequencies of curvature, stereoacuity was limited to the same extent as the monocular sensitivity. The limiting disparity for Panum's fusional region and the upper depth limit are subject to a scaling effect in proportion to stimulus dimensions. The disparity scaling can be characterized by a fixed maximum angular difference between the parts of the stereoscopic half-images.     

醋酸铅对体外培养大鼠大脑皮质神经细胞形态的影响

为了观察醋酸铅对神经细胞的形态学影响,通过建立体外培养大鼠大脑皮质神经细胞模型,应用不同浓度醋酸铅(0,50,100,200,400μmol/L)与神经细胞分别培养3、6、12、24 h,倒置相差显微镜观察细胞形态变化.结果显示,醋酸铅与神经细胞共同培养12~24 h,细胞密度降低,胞体变小,突起缩短;随醋酸铅浓度递增,细胞形态较对照组差异愈加显著(P<0.05).表明染铅浓度与神经细胞形态变化存在剂量效应与时间效应关系.     

Excitatory and inhibitory motoneurons in the central nervous system of the leech

The locomotion and reflex responses of the leech are brought about by inmuscles that are arranged in a regular, simple pattern in the body wall and that flatten, shorten, lengthen, or bend the animal. In the segmental ganglia, it is possible to recognize by morphological and physiological criteria the individual motoneurons that cause contractions and relaxations of these muscles.     

Nerves in cortical bone

Modified electron-microscopic techniques permit the sectioning of fully mineralized compact bone. Cortical canals in human femur are extensively innervated. Most nerves are unmyelinated and range from 0.5 to 10 micrometers in diameter. I have found a few mixed nerves (myelinated and unmyelinated fibers), one of which was 130 micrometers in diameter.     

GABAergic神经元在BARREL和VPM区组织结构及形态特点的研究

啮齿类以胡须为感觉器官,通过其摆动获取物体质地和空间位置信息。在老鼠的每一侧嘴部,有5列水平排布的机械感受器,位于胡须下面的囊泡中。胡须摆动可打开机械型离子通道,产生动作电位,经传出纤维传入位于脑干的三叉神经节中,从而使三叉核团的谷氨酸型突触产生兴奋。三叉丘脑核团在三叉核团处形成躯体代表区,称为“barrelettes”。接着脑干中的这些神经元又将信息传入丘脑的Ventral poslerior medial（VPM）核团,     

Neuraminidase activity in hela cells: effect of hydrocortisone

Homogenates of HeLa cells contain neuraminidase activity. This enzyme is particle-bound, and it has a pH optimum of 4.2. Hydrocortisone-regulated cells contain two to three times as much neuraminidase as the corresponding controls. The hydrocortisone treatment also causes an increase in the cell content of beta-glucuronidase and acid deoxyribonuclease.     

Sialic acid in HeLa cells: effect of hydrocortisone

HeLa S(3) cells grown in the presence of hydrocortisone contain more sialic acid than their corresponding untreated controls. The percentage of the total sialic acid present in the sedimentable fraction obtained from homogenates of cells treated with hydrocortisone is smaller than that of the corresponding fraction of control cells. In addition to N-acetylneuraminic acid, the chromatographic analysis suggests that HeLa S(3) cells probably contain trace amounts of N-glycolylneuraminic acid.     

GABAergic神经元在BARREL和VPM区组织结构及形态特点的研究（英文）

To understand the structure of GABAergic neurons in the VMP and "barrel",the distribution of GABAergic neurons in the two areas were studied through immunohistochemistry and Laser Scanning Confocal Microscope.The results show that the distribution of GABAergic neurons in VMP and barrel are different,and the coding of information transmission in the two areas are also dissimilar;GABAergic neurons mainly distribute among the lines asymmetrically in VMP,the somata,dendrite and axon of GABAergic neurons are restricted in the "barrel",rarely having synaptic connections with other "barrel" around.Therefore,VMP and barrel may have different roles in transmission and on processing of informatiton.     

Long-range-projecting GABAergic neurons modulate inhibition in hippocampus and entorhinal cortex

The hippocampus and entorhinal cortex play a pivotal role in spatial learning and memory. The two forebrain regions are highly interconnected via excitatory pathways. Using optogenetic tools, we identified and characterized long-range γ-aminobutyric acid-releasing (GABAergic) neurons that provide a bidirectional hippocampal-entorhinal inhibitory connectivity and preferentially target GABAergic interneurons. Activation of long-range GABAergic axons enhances sub- and suprathreshold rhythmic theta activity of postsynaptic neurons in the target areas.     

藏猪兴奋性氨基酸转运载体EAAC1基因的克隆与原核表达

兴奋性氨基酸转运载体EAAC1是肠道内谷氨酸的主要载体.本研究根据人的基因编码区设计一对特异性引物,以藏猪空肠总RNA为模板,通过RT-PCR获得一长约1600 bp的cDNA片段,T/A克隆后测序,并进行序列分析;将该基因片段连接到原核表达载体pET-32a(+)中构建融合表达质粒,转化到E.coli BL21(DE3)中进行表达.测序结果显示,获得的cDNA全长为1575 bp,编码524个氨基酸;EAAC1分子量为57 kD,等电点为5.34,GenBank登录号为GQ375513;该蛋白质具有3个N-糖基化位点、8个蛋白激酶C磷酸化位点和1个cAMP/cGMP依赖性蛋白激酶磷酸化位点,含有7个跨膜结构域和一个信号肽序列;SDS-PAGE电泳检测结果表明,表达蛋白质与预期蛋白质大小一致.上述结果为进一步研究EAAC1的功能及其调控奠定了基础.     

Neuronal oscillations in cortical networks

Clocks tick, bridges and skyscrapers vibrate, neuronal networks oscillate. Are neuronal oscillations an inevitable by-product, similar to bridge vibrations, or an essential part of the brain's design? Mammalian cortical neurons form behavior-dependent oscillating networks of various sizes, which span five orders of magnitude in frequency. These oscillations are phylogenetically preserved, suggesting that they are functionally relevant. Recent findings indicate that network oscillations bias input selection, temporally link neurons into assemblies, and facilitate synaptic plasticity, mechanisms that cooperatively support temporal representation and long-term consolidation of information.     

Synfire chains and cortical songs: temporal modules of cortical activity

How can neural activity propagate through cortical networks built with weak, stochastic synapses? We find precise repetitions of spontaneous patterns of synaptic inputs in neocortical neurons in vivo and in vitro. These patterns repeat after minutes, maintaining millisecond accuracy. Calcium imaging of slices reveals reactivation of sequences of cells during the occurrence of repeated intracellular synaptic patterns. The spontaneous activity drifts with time, engaging different cells. Sequences of active neurons have distinct spatial structures and are repeated in the same order over tens of seconds, revealing modular temporal dynamics. Higher order sequences are replayed with compressed timing.     

Sequential interplay of nicotinic and GABAergic signaling guides neuronal development

GABA (gamma-aminobutyric acid), the major inhibitory transmitter in the brain, goes through a transitory phase of excitation during development. The excitatory phase promotes neuronal growth and integration into circuits. We show here that spontaneous nicotinic cholinergic activity is responsible for terminating GABAergic excitation and initiating inhibition. It does so by changing chloride transporter levels, shifting the driving force on GABA-induced currents. The timing of the transition is critical, because the two phases of GABAergic signaling provide contrasting developmental instructions. Synergistic with nicotinic excitation, GABAergic inhibition constrains neuronal morphology and innervation. The results reveal a multitiered activity-dependent strategy controlling neuronal development.