关键词： hereditary canine spinal muscular atrophy (HCSMA)   neurophysiology   homozygotes   pathology  

关键词： review   digestive enzymes   crustacean larvae  

摘要： While most copepods are holoplanktonic, decapod larvae are meroplanktonic with a pelagic larval development ranging from days (Penaeidae) to weeks (most Palaemonidae, Palinuridae). Reproductive strategies result in either the early release of larvae in large numbers of small planktonic forms (Penaeidae) or smaller numbers of advanced larvae after parental incubation (Brachyura, Palaemonidae, Nephropidae, Palinuridae). Commercially-cultured decapod larvae exhibit a wide range of feeding strategies exploiting most of the trophic levels found within the planktonic ecosystem. Studies on these crustacean larvae demonstrate how their digestive physiology is adapted to different feeding strategies during larval development, and provide an insight into the design of appropriate artificial feeds for commercial culture. Comparative measurements of digestive enzyme levels reveal that trypsin-like protease appears to dominate in all larvae investigated. Highest levels occur in herbivorous penaeid and brachyuran larval stages. In contrast, carnivorous lobster and caridean larvae show low protease activity at first feeding and appear to rely upon high-energy digestible live prey for their nutrition. Ontogenetic changes in enzyme type, activity and content are displayed during the penaeid mysis and caridean, brachyuran late zoeal stages as larvae transfer to higher trophic levels. The range and extent of these changes are reviewed for the commercial larval groups of commercially important species. (C) 1997 Elsevier Science B.V.

关键词： 脑   事件相关电位   心理生理学   心率变异性  

摘要： 目的探讨心理生理学方法在双重任务脑力负荷评定中的意义。方法采用事件相关电位Ｐ３波潜时（ＬＡＴ）和波幅（ＡＭＰ）、逐次心跳间期（ＩＢＩ）及心率变异性（ＨＲＶ）、逐次呼吸间期（ＩＲＩ）及呼吸变异性（ＲＲＶ）、眨眼率（ＢＲ）等心理生理学指标，评定了１６名男性青年受试者完成三种不同难度双重任务时的脑力负荷。双重任务由视觉追踪主任务和Ｓｔｅｒｎｂｅｒｇ副任务组成，其难度由主任务目标运动的速度和维度控制。结果①随任务难度增加，Ｐ３波ＬＡＴ延长（Ｐ＜０．０１），ＡＭＰ无显著性变化（Ｐ＞０．０５）；②ＩＢＩ及ＨＲＶ在中等难度任务时最小，其中ＩＢＩ在任务间有显著性差异（Ｐ＜０．０１）；③ＩＲＩ随任务难度增加而减小（Ｐ＜０．０５），ＲＲＶ任务间无显著性差异（Ｐ＞０．０５）；④ＢＲ在三种任务条件与对照条件时相比显著降低（Ｐ＜０．０１）。结论各指标与脑力负荷均有一定关系，但单一指标评定脑力负荷有局限性，多种心理生理学指标综合评定是双重任务条件下脑力负荷评定更为适宜的方法。

关键词： 飞行模拟器   心理生理储备   双重任务   心理生理学  

摘要： 目的旨在建立飞行员心理生理功能的客观评价方法。方法采用飞行模拟技术与实验心理学和职业医学相结合的方法，建立一套飞行员心理生理储备的检测设备和评价方法，并对其有效性和合理性进行验证。结果健康飞行员心理生理储备值呈正态分布，其平均值（０．６１±０．１７）明显高于康复及有病飞行员的心理生理储备值（０．４３±０．１５，Ｐ＜０．０５）。且健康飞行员的储备值与其多种飞行技能有明显相关（ｒ＝０．２７～０．４０，Ｐ＜０．０５）。结论飞行中技能水平与该飞行员的心理生理储备值有关。经重复性测量，该系统设计合理，且稳定性良好。

关键词： far-field potentials   near-field potentials   volume conduction   modeling   bioelectric sources  

摘要： It is possible to appreciate the production of far-field potentials by considering constant current dipolar source voltage distributions in bounded volumes, especially when they are stretched in one direction, e.g., a cylinder. An essentially nondeclining voltage is detected when the recording electrodes are on opposite sides of, and relatively far from, the dipolar source. This voltage maintains its (a) latency, (b) amplitude, (c) morphology, and (d) polarity even if recordings are performed a whole body length away. These four criteria define far-field potentials. A propagating action potential (AP) can be conceptualized as a linear quadrupole or the summation of two dipoles "back-to-back" (+ - - +). The far-field components of the summated dipoles cancel resulting in the anticipated triphasic waveform for APs with only near-field characteristics, not meeting the first three criteria above. Far-field potentials can be transiently generated when any propagating AP constitutes a net "real" or "virtual" dipolar source. "Real" dipolar sources can occur if an AP encounters the termination of excitable tissue, an alteration in conduction velocity, curvature in excitable tissue resulting in a change in propagation direction, or an abrupt change in resistance of the excitable tissue. Virtual dipolar sources may be produced if an AP encounters a change in the size or shape of the extracellular medium or a transition in extracellular conductivity.

关键词： 符号学   人工智能机   认识论   符号识别   符号学研究   信息处理过程   人类智能   感觉器   认知过程   神经生理学  

摘要： AI符号学（人工智能符号学）是本世纪60年代以来随着信息科学、认知科学、生物控制论和物理学操作主义等学科的兴起而产生的一个符号学研究的新领域。当代许多符号学家，如加拿大的P·Ouell、法国的J·C、加了等人，都曾涉足这一领域。国内符号学研究专家李幼燕先生认为：“AI理论虽然属于控制论和信息论的科学与技术领域，然而由于它直接处理语言记号系统问题，故在某些方面与语言符号学和一般符号学有重要的交接面，是今日一般符号学家不能不关注的新学科。”（《理论符号学导论》，中国社会科学出版社1993年版，第474页。以下该书引文，只注页码）也就是说，AI符号学可能以间接的和隐喻的形式暗示着我们进一步理解人类符号认知过程的方向。因此，比较机器符号处理过程与人类符号认知过程的异同，便既可以应用AI符号学的研究成果探索人脑符号处理过程的奥秘，又可以利用人类符号认知的研究成果促进机器符号“认知”的研究，无论在理论上还是实践上，都是有益的。从认识论的角度看，AI符号学研究中值得注意的问题主要有两个：一是关于智能机的符号模式识别问题；二是关于智能机信息处理过程和人类传讯思维过程的关系问题。本来，符号感知是人类独有的能力，但AI符号学的研...

关键词： 晕厥   心理生理学   信息处理  

摘要： 目的了解晕厥后飞行员心理生理储备能力的变化特点。方法用飞行员心理生理储备能力评定系统,测量了15名晕厥飞行员和22名健康飞行员在模拟飞行条件下完成双重任务时的心理生理反应。结果晕厥飞行员在单纯和双重任务飞行中的正确保持率分别为35.0％和9.3％,心率分别为76.7次/min和80.0次/min,飞行中信息处理速度为0.44 bit/s,此三项与健康组相比均有显著性差异。飞行中心率与安静时比较无显著差异。结论晕厥飞行员心理生理储备能力和操纵行为质量低于健康飞行员,机体应激反应能力明显降低。

关键词： Brain/physiology*   Brain Mapping   Brain Mapping   Electroencephalography/methods*   Humans  

摘要： A. Digital EEG is an established substitute for recording, reviewing, and storing a paper EEG record. It is a clear technical advance over previous paper methods. It is highly recommended. (Class III evidence, Type C recommendation). B. EEG brain mapping and other advanced QEEG techniques should be used only by physicians highly skilled in clinical EEG, and only as an adjunct to and in conjunction with traditional EEG interpretation. These tests may be clinically useful only for patients who have been well selected on the basis of their clinical presentation. C. Certain quantitative EEG techniques are considered established as an addition to digital EEG in: C.1. Epilepsy: For screening for possible epileptic spikes or seizures in long-term EEG monitoring or ambulatory recording to facilitate subsequent expert visual EEG interpretation. (Class I and II evidence, Type A recommendation as a practice guideline). C.2. OR and ICU monitoring: For continuous EEG monitoring by frequency-trending to detect early, acute intracranial complications in the OR or ICU, and for screening for possible epileptic seizures in high-risk ICU patients. (Class II evidence, Type B recommendation as a practice option). D. Certain quantitative EEG techniques are considered possibly useful practice options as an addition to digital EEG in: D.1. Epilepsy: For topographic voltage and dipole analysis in presurgical evaluations. (Class II evidence, Type B recommendation). D.2. Cerebrovascular Disease: Based on Class II and III evidence, QEEG in expert hands may possibly be useful in evaluating certain patients with symptoms of cerebrovascular disease whose neuroimaging and routine EEG studies are not conclusive. (Type B recommendation). D.3. Dementia: Routine EEG has long been an established test used in evaluations of dementia and encephalopathy when the diagnosis remains unresolved after initial clinical evaluation. In occasional clinical evaluations, QEEG frequency analysis may be a useful adjun

关键词： .larval   descending   locomotor activity   Lamprey   Hagevik  

摘要： The purpose of the present study was to examine the mechanisms that produce natural spontaneous turning, maneuvers in larval lamprey. During swimming, spontaneous turning movements began with a larger-than-normal bending of the head to one side. Subsequently, undulations propagated down the body with greater amplitude on the side ipsilateral to the turn. During turning to one side, which usually occurred within one cycle, the amplitude and duration of ipsilateral muscle burst activity as well as overall cycle time increased significantly with increasing turn angle. In in vitro brain/spinal cord preparations, brief electrical stimulation applied to the left side of the oral hood at the onset of locomotor burst activity on the right side of the spinal cord produced turninglike motor activity. During the perturbed cycle, the duration and amplitude of the burst on the right as well as cycle time were significantly larger than during preceding control cycles. In several lower vertebrates, unilateral stimulation in brain stem locomotor regions elicits asymmetric, turninglike locomotor activity. In the lamprey, unilateral chemical microstimulation in brain stem locomotor regions elicited continuous asymmetric locomotor activity, but there was little change in cycle time, as occurs during the single turning cycles In whole animals. The descending mechanisms responsible for producing turning locomotor activity were examined with the use of a computer model consisting of left and right phase oscillators in the spinal cord that were coupled by net reciprocal inhibition. With relatively weak reciprocal coupling, a brief unilateral descending excitatory input to one oscillator produced effects ipsilaterally, but there was little effect on the contralateral oscillator. Turninglike patterns could be produced by each of the following modifications of the model: 1) unilateral descending input and relatively strong reciprocal coupling, 2) unilateral descending input that phase shifte

关键词： 加速度   心率   催乳素   儿茶酚胺类   垂体-肾上腺功能试验  

摘要： 前言 研究了在战斗机飞行员生态环境中线和角加速度对下丘脑-垂体-肾上腺和心肺轴水平体内平衡改变的复合作用。方法 试验被分成:①Mirage和Pucara飞机=大的情绪应激:40名飞行员。②道格拉斯A4B和A4C飞机=小的情绪应激:22名飞行员。每次任务平均80 min。在每次飞行中产生约+3 Gz,最大+5 Gz的惯性力。连续24 h记下读数。