共查询到20条相似文献，搜索用时 31 毫秒
1.
Lucas RJ Hattar S Takao M Berson DM Foster RG Yau KW 《Science (New York, N.Y.)》2003,299(5604):245-247
In the mammalian retina, a small subset of retinal ganglion cells (RGCs) are intrinsically photosensitive, express the opsin-like protein melanopsin, and project to brain nuclei involved in non-image-forming visual functions such as pupillary light reflex and circadian photoentrainment. We report that in mice with the melanopsin gene ablated, RGCs retrograde-labeled from the suprachiasmatic nuclei were no longer intrinsically photosensitive, although their number, morphology, and projections were unchanged. These animals showed a pupillary light reflex indistinguishable from that of the wild type at low irradiances, but at high irradiances the reflex was incomplete, a pattern that suggests that the melanopsin-associated system and the classical rod/cone system are complementary in function. 相似文献
2.
目的 研究舒肝解郁胶囊对抑郁模型大鼠脑内5-HT、DA及其代谢产物水平的影响。方法 将28只雄性SD大鼠随机分成正常对照组、模型组、舒肝解郁组、氟西汀组四组;采用慢性轻度不可预见性应激（CUMS）结合孤养方式建立抑郁大鼠模型,舒肝解郁组和氟西汀组大鼠于造模同时分别给予舒肝解郁胶囊和氟西汀干预;用库仑阵列电化学高效液相色谱法分别检测大鼠内侧前额叶皮质（mPFC）及海马CA3区 5-HT、DA及其代谢产物的含量。结果 应激21 d后,模型组与正常对照组比较,大鼠mPFC区5-HT、5－羟吲哚乙酸（5-HIAA）、DA和高香草酸（HVA）的浓度均显著降低,差异有统计学意义（P<0.01）,海马CA3区5-HT、DA和5-HIAA的浓度均显著降低,差异有统计学意义（P<0.05）;与模型组比较,舒肝解郁组和氟西汀组可显著增加大鼠mPFC区5-HT 、DA和HVA浓度,差异有统计学意义（P<0.01或P<0.05）,海马CA3区5-HT、DA和5-HIAA浓度显著升高,差异有统计学意义（P<0.05）。结论 舒肝解郁胶囊能增强抑郁模型大鼠中枢5－HT和 DA神经递质系统的功能,这可能是其抗抑郁作用的神经生化机制之一。 相似文献
3.
The prefrontal cortex is involved in the cognitive process of working memory. Local injections of SCH23390 and SCH39166, selective antagonists of the D1 dopamine receptor, into the prefrontal cortex of rhesus monkeys induced errors and increased latency in performance on an oculomotor task that required memory-guided saccades. The deficit was dose-dependent and sensitive to the duration of the delay period. These D1 antagonists had no effect on performance in a control task requiring visually guided saccades, indicating that sensory and motor functions were unaltered. Thus, D1 dopamine receptors play a selective role in the mnemonic, predictive functions of the primate prefrontal cortex. 相似文献
4.
The hippocampus is crucial for spatial memory formation, yet it does not store long-lasting memories. By combining functional brain imaging and region-specific neuronal inactivation in mice, we identified prefrontal and anterior cingulate cortices as critical for storage and retrieval of remote spatial memories [correction]. Imaging of activity-dependent genes also revealed an involvement of parietal and retrosplenial cortices during consolidation of remote memory. Long-term memory storage within some of these neocortical regions was accompanied by structural changes including synaptogenesis and laminar reorganization, concomitant with a functional disengagement of the hippocampus and posterior cingulate cortex [correction]. Thus, consolidation of spatial memory requires a time-dependent hippocampal-cortical dialogue, ultimately enabling widespread cortical networks to mediate effortful recall and use of cortically stored remote memories independently. 相似文献
5.
After learning, the medial prefrontal cortex (mPFC) gradually comes to modulate the expression of memories that initially depended on the hippocampus. We show that during this consolidation period, neural firing in the mPFC becomes selective for the acquired memories. After acquisition of memory associations, neuron populations in the mPFC of rats developed sustained activity during the interval between two paired stimuli, but reduced activity during the corresponding interval between two unpaired stimuli. These new patterns developed over a period of several weeks after learning, with and without continued conditioning trials. Thus, in agreement with a central tenet of consolidation theory, acquired associations initiate subsequent, gradual processes that result in lasting changes of the mPFC's code, without continued training. 相似文献
6.
Lezcano N Mrzljak L Eubanks S Levenson R Goldman-Rakic P Bergson C 《Science (New York, N.Y.)》2000,287(5458):1660-1664
The synergistic response of cells to the stimulation of multiple receptors has been ascribed to receptor cross talk; however, the specific molecules that mediate the resultant signal amplification have not been defined. Here a 24-kilodalton single transmembrane protein, designated calcyon, we functionally characterize that interacts with the D1 dopamine receptor. Calcyon localizes to dendritic spines of D1 receptor-expressing pyramidal cells in prefrontal cortex. These studies delineate a mechanism of Gq- and Gs-coupled heterotrimeric GTP-binding protein-coupled receptor cross talk by which D1 receptors can shift effector coupling to stimulate robust intracellular calcium (Ca2+i) release as a result of interaction with calcyon. The role of calcyon in potentiating Ca2+-dependent signaling should provide insight into the D1 receptor-modulated cognitive functions of prefrontal cortex. 相似文献
7.
As previously shown in the hippocampus and other brain areas, patterns of firing-rate correlations between neurons in the rat medial prefrontal cortex during a repetitive sequence task were preserved during subsequent sleep, suggesting that waking patterns are reactivated. We found that, during sleep, reactivation of spatiotemporal patterns was coherent across the network and compressed in time by a factor of 6 to 7. Thus, when behavioral constraints are removed, the brain's intrinsic processing speed may be much faster than it is in real time. Given recent evidence implicating the medial prefrontal cortex in retrieval of long-term memories, the observed replay may play a role in the process of memory consolidation. 相似文献
8.
【目的】探讨具有癫痫基础病变小鼠在遭受颅脑损伤时,海马和顶叶皮质中CFOS表达与损伤的相关性及其在损伤中的意义,为癫痫后颅脑损伤复合病变研究提供理论依据。【方法】用腹腔注射匹罗卡品法构建小鼠（2周龄）癫痫模型,饲养4周后（6周龄）采用自由落体法构建闭合性颅脑损伤小鼠模型和癫痫+闭合性颅脑损伤小鼠模型,同时以正常小鼠为对照,于造模后0.5,3 h及1,3,7 d取小鼠大脑,制备切片,采用尼氏染色、免疫组织化学染色方法,从形态学以及蛋白质水平上研究各组小鼠大脑海马和顶叶皮质中C-FOS的表达情况。【结果】癫痫模型、闭合性颅脑损伤模型及癫痫+闭合性颅脑损伤小鼠模型均构建成功。免疫组织化学染色结果显示,癫痫合并闭合性颅脑损伤小鼠顶叶皮质、海马均有着色深浅不同、数目不等的C-FOS阳性细胞。与对照组相比,单纯癫痫组、单纯闭合性颅脑损伤组、癫痫+闭合性颅脑损伤组C-FOS灰度值均显著（P<0.05）或极显著降低(P<0.01);癫痫+闭合性颅脑损伤组小鼠海马和顶叶皮质C-FOS阳性细胞数均显著（P<0.05）或极显著（P<0.01）高于单纯癫痫组与单纯闭合性颅脑损伤组。【结论】癫痫小鼠颅脑损伤后,海马和顶叶皮质持续高表达C-FOS,从而促进神经细胞凋亡,加重颅脑损伤后的病理变化。 相似文献
9.
[目的]探究大鼠腹内侧前额叶与胃功能活动（主要指胃运动）之间是否存在功能上的联系。[方法]采用胃内放置水囊法记录大鼠胃运动曲线,分别电刺激和化学刺激大鼠左侧腹内侧前额叶皮层（PL和IL）,观察胃运动的频率、平均时程、平均幅度和胃运动指数在刺激前后的变化。[结果]分别电刺激PL和IL两个区域,在刺激持续的5 m in内,大鼠胃运动各项指标与刺激前相比虽有变化但无统计学意义;向PL和IL两个区域内分别注射0.1 mol/L L-G lu 200 nl后,大鼠胃运动各项指标与注射前相比也没有显著性差异。[结论]正常生理状态下,大鼠腹内侧前额叶不参与对胃运动的调节,推测和胃的机能活动之间应该不存在直接的功能联系。 相似文献
10.
11.
目的 对比分析不同抑郁模型大鼠的生物学特点,为抑郁模型研究提供实验依据。方法 40只SD大鼠随机分为空白对照组、溶媒对照组、束缚应激组、慢性不可预见性温和应激（chronic unpredictable mild stress,CUMS）组,皮质酮注射组,每组8只。除对照组外,各组分别进行造模,时间均为21 d,造模结束后采用Morris水迷宫测试、旷场实验、强迫游泳实验检测大鼠的抑郁样行为,蛋白印迹法检测大鼠海马和前额叶皮质区脑源性神经营养因子（brain-derived neurotrophic factor,BDNF）、神经生长因子（nerve growth factor,NGF）的含量。结果 与对照组比较,3种模型组大鼠逃避潜伏期时间均显著增加（P<0.01）,但只有皮质酮组大鼠进入目标象限潜伏期时间增加（P<0.05）;旷场测试中活动次数显著下降,其中CUMS组和皮质酮组对比束缚组有显著差异（P<0.01）;同时,3种模型组大鼠强迫游泳中的不动时间均显著增加（P<0.01）;此外,与对照组比较,各模型组大鼠海马和前额叶皮质区BDNF、NGF表达均显著下降（P<0.01或P<0.05）,但各模型组之间相互比较,差异无统计学意义（P>0.05）。结论 慢性束缚应激、CUMS、慢性皮质酮注射均能使大鼠产生明显的抑郁样行为,且在脑内神经营养表达上差异无统计学意义。 相似文献
12.
Airan RD Meltzer LA Roy M Gong Y Chen H Deisseroth K 《Science (New York, N.Y.)》2007,317(5839):819-823
The hippocampus is one of several brain areas thought to play a central role in affective behaviors, but the underlying local network dynamics are not understood. We used quantitative voltage-sensitive dye imaging to probe hippocampal dynamics with millisecond resolution in brain slices after bidirectional modulation of affective state in rat models of depression. We found that a simple measure of real-time activity-stimulus-evoked percolation of activity through the dentate gyrus relative to the hippocampal output subfield-accounted for induced changes in animal behavior independent of the underlying mechanism of action of the treatments. Our results define a circuit-level neurophysiological endophenotype for affective behavior and suggest an approach to understanding circuit-level substrates underlying psychiatric disease symptoms. 相似文献
13.
Chronic blockade of dopamine D2 receptors, a common mechanism of action for antipsychotic drugs, down-regulates D1 receptors in the prefrontal cortex and, as shown here, produces severe impairments in working memory. These deficits were reversed in monkeys by short-term coadministration of a D1 agonist, ABT 431, and this improvement was sustained for more than a year after cessation of D1 treatment. These findings indicate that pharmacological modulation of the D1 signaling pathway can produce long-lasting changes in functional circuits underlying working memory. Resetting this pathway by brief exposure to the agonist may provide a valuable strategy for therapeutic intervention in schizophrenia and other dopamine dysfunctional states. 相似文献
14.
Whether memories can be suppressed has been a controversial issue in psychology and cognitive neuroscience for decades. We found evidence that emotional memories are suppressed via two time-differentiated neural mechanisms: (i) an initial suppression by the right inferior frontal gyrus over regions supporting sensory components of the memory representation (visual cortex, thalamus), followed by (ii) right medial frontal gyrus control over regions supporting multimodal and emotional components of the memory representation (hippocampus, amygdala), both of which are influenced by fronto-polar regions. These results indicate that memory suppression does occur and, at least in nonpsychiatric populations, is under the control of prefrontal regions. 相似文献
15.
Z Chen M Mitchell M Segev TH Coskun DN Christodoulides 《Science (New York, N.Y.)》1998,280(5365):889-892
"Dark beams" are nonuniform optical beams that contain either a one-dimensional (1D) dark stripe or a two-dimensional (2D) dark hole resulting from a phase singularity or an amplitude depression in their optical field. Thus far, self-trapped dark beams (dark solitons) have been observed using coherent light only. Here, self-trapped dark incoherent light beams (self-trapped dark incoherent wavepackets) were observed. Both dark stripes and dark holes nested in a broad partially spatially incoherent wavefront were self-trapped to form dark solitons in a host photorefractive medium. These self-trapped 1D and 2D dark beams induced refractive-index changes akin to planar and circular dielectric waveguides. The experiments introduce the possibility of controlling high-power coherent laser beams with low-power incoherent light sources such as light emitting diodes. 相似文献
16.
At synapses between cortical pyramidal neurons and principal striatal medium spiny neurons (MSNs), postsynaptic D1 and D2 dopamine (DA) receptors are postulated to be necessary for the induction of long-term potentiation and depression, respectively-forms of plasticity thought to underlie associative learning. Because these receptors are restricted to two distinct MSN populations, this postulate demands that synaptic plasticity be unidirectional in each cell type. Using brain slices from DA receptor transgenic mice, we show that this is not the case. Rather, DA plays complementary roles in these two types of MSN to ensure that synaptic plasticity is bidirectional and Hebbian. In models of Parkinson's disease, this system is thrown out of balance, leading to unidirectional changes in plasticity that could underlie network pathology and symptoms. 相似文献
17.
该试验拟考察分娩体重对母猪在泌乳期内体况变化和采食量的影响.试验采用单因子设计,选择健康的经产约克夏母猪35头,按分娩体重(190～250 kg)依次分到7个处理中进行饲养试验.结果表明,随着体重的增加,母猪泌乳期总采食量也呈不断增加的趋势,呈一定的剂量一效应关系.就体重损失而言,240 kg与250 kg处理组的母猪体重损失显著大于200 kg组的母猪(P<0.05);200 kg组(P=0.1)和220 kg组(P<0.05)也不同程度地优于190 kg组.至于采食量,结果表明,250 kg组(P<0.05)和240 kg组(P<0.1)的母猪,在采食量上超过210 kg组、高于200 kg组(P<0.1)、极显著超过190 kg组(P<0.01).试验结果说明,母猪体重与采食量变化和生产性能密切相关,母猪分娩体重对泌乳期失重和采食量的影响主要体现在整个泌乳阶段. 相似文献
18.
The primary circadian pacemaker, in the suprachiasmatic nucleus (SCN) of the mammalian brain, is photoentrained by light signals from the eyes through the retinohypothalamic tract. Retinal rod and cone cells are not required for photoentrainment. Recent evidence suggests that the entraining photoreceptors are retinal ganglion cells (RGCs) that project to the SCN. The visual pigment for this photoreceptor may be melanopsin, an opsin-like protein whose coding messenger RNA is found in a subset of mammalian RGCs. By cloning rat melanopsin and generating specific antibodies, we show that melanopsin is present in cell bodies, dendrites, and proximal axonal segments of a subset of rat RGCs. In mice heterozygous for tau-lacZ targeted to the melanopsin gene locus, beta-galactosidase-positive RGC axons projected to the SCN and other brain nuclei involved in circadian photoentrainment or the pupillary light reflex. Rat RGCs that exhibited intrinsic photosensitivity invariably expressed melanopsin. Hence, melanopsin is most likely the visual pigment of phototransducing RGCs that set the circadian clock and initiate other non-image-forming visual functions. 相似文献
19.
母猪念亲行为生理生化变化及相关性研究 总被引：2，自引：0，他引：2
对母猪念亲行为表现进行了大量的观察，同时对念亲行为与母猪体温、呼吸、脉博、红细胞、白细胞、血小板、血钠、钾、钙、镁和磷变化的相关性进行了研究。结果表明，从观察统计的2000余头母猪中具有此种行为的约占12%，其中情绪低落抑郁型母猪约占8%，情绪激怒兴奋型母猪约占4%。母猪念亲行为与体温、呼吸、脉博均呈相关性，即抑郁型母猪的体温、呼吸、脉博值均呈下降趋势，与自身断奶前和与对照比较，差异极显著；兴奋型母猪的体温、呼吸、脉博值均呈上升趋势，与自身断奶前和与对照组比较，差异极显著。念亲行为与血Na,K,Ca和Mg的变化密切相关，兴奋型组母猪其血Na,K显著升高，抑郁型组母猪其血Na,K显著降低而血Ca,Mg显著升高，RBC，WBC，BP和血P值无明显变化。 相似文献
20.
Panda S Nayak SK Campo B Walker JR Hogenesch JB Jegla T 《Science (New York, N.Y.)》2005,307(5709):600-604
In mammals, a small population of intrinsically photosensitive retinal ganglion cells (ipRGCs) plays a key role in the regulation of nonvisual photic responses, such as behavioral responses to light, pineal melatonin synthesis, pupillary light reflex, and sleep latency. These ipRGCs also express melanopsin (Opn4), a putative opsin-family photopigment that has been shown to play a role in mediating these nonvisual photic responses. Melanopsin is required for the function of this inner retinal pathway, but its precise role in generating photic responses has not yet been determined. We found that expression of melanopsin in Xenopus oocytes results in light-dependent activation of membrane currents through the Galpha(q)/Galpha(11) G protein pathway, with an action spectrum closely matching that of melanopsin-expressing ipRGCs and of behavioral responses to light in mice lacking rods and cones. When coexpressed with arrestins, melanopsin could use all-trans-retinaldehyde as a chromophore, which suggests that it may function as a bireactive opsin. We also found that melanopsin could activate the cation channel TRPC3, a mammalian homolog of the Drosophila phototransduction channels TRP and TRPL. Melanopsin therefore signals more like an invertebrate opsin than like a classical vertebrate rod-and-cone opsin. 相似文献