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1.
Masaru Kato Rie Kobayashi Ikuo Watanabe 《Documenta ophthalmologica. Advances in ophthalmology》1993,84(1):71-81
An unusual form of scotopic electroretinogram with a bright white stimulus, which consisted of a rectangular a-wave of normal amplitude and a b-wave of supernormal amplitude, was recorded in three patients with cone dysfunction. In addition to poor visual acuity, abnormal color vision and reduced amplitude of the photopic electroretinogram, these patients showed a 2-log unit elevation of the dark-adaptation threshold. Funduscopic examination and fluorescein angiography revealed fine granular pigment disturbances at the mascula. The relationship between the response of the dark-adapted electroretinogram versus stimulus intensity was unique to these patients. The b-wave thresholds were elevated by 1 log unit. The b-waves were reduced in amplitude and markedly delayed in implicit time to dim stimuli, but supernormal in amplitude and normal in implicit time to bright stimuli.Abbreviations GMP
guanosine monophosphate 相似文献
2.
指数曲线电刺激对周围神经移植的组织学影响 总被引:1,自引:0,他引:1
目的 :研究指数曲线电刺激对周围神经移植修复后神经再生的影响。方法 :将 1 2 0只Wistar成年雄性大鼠制成坐骨神经移植模型 ,随机分为A组 (对照组 )、B组 (弥可保组 )、C组(指数曲线电刺激组 ) ,给予不同的治疗 ,在不同时段观察步态、毛发、展爪反射 ,测定SFI、神经传导速度、小腿三头肌湿重等指标。结果 :指数曲线电刺激有助于神经传导的恢复 ,减慢小腿三头肌失神经的废用 ,加快SFI及神经远段变性的恢复。结论 :指数曲线电刺激有利于神经再生。 相似文献
3.
P. Apicella Eric Legallet Elisabeth Trouche 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1997,116(3):456-466
In the primate striatum, the tonically discharging neurons respond to conditioned stimuli associated with reward. We investigated
whether these neurons respond to the reward itself and how changes in the behavioral context in which the reward is delivered
might influence their responsiveness. A total of 286 neurons in the caudate nucleus and putamen were studied in two awake
macaque monkeys while liquid reward was delivered in three behavioral situations: (1) an instrumental task, in which reward
was delivered upon execution of a visually triggered arm movement; (2) a classically conditioned task, in which reward was
delivered 1 s after a visual signal; (3) a free reward situation, in which reward was delivered at irregular time intervals
outside of any conditioning task. The monkeys′ uncertainty about the time at which reward will be delivered was assessed by
monitoring their mouth movements. A larger proportion of neurons responsive to reward was observed in the free reward situation
(86%) than in the classically conditioned (57%) and instrumental tasks (37%). Among the neurons tested in all situations (n = 78), 24% responded to reward regardless of the situation and 65% in only one or two situations. Responses selective for
one particular situation occurred exclusively in the free reward situation. When the reward was delivered immediately after
the visual signal in the classically conditioned task, most of the neurons reduced or completely lost their responses to reward,
and other neurons remained responsive. Conversely, neuronal responses invariably persisted when reward was delivered later
than 1 s after the visual signal. This is the first report that tonic striatal neurons might display responses directly to
primary rewards. The neuronal responses were strongly influenced by the behavioral context in which the animals received the
reward. An important factor appears to be the timing of reward. These neurons might therefore contribute to a general aspect
of behavioral reactivity of the subject to relevant stimuli.
Received: 16 September 1996 / Accepted: 1 April 1997 相似文献
4.
Joseph V. Hajnal Ralph Myers Angela Oatridge Jane E. Schwieso Ian R. Young Graeme M. Bydder 《Magnetic resonance in medicine》1994,31(3):283-291
To assess the effect of stimulus correlated motion on the appearance of functional magnetic resonance images, conventional visual and motor protocols were each performed by four normal volunteers and an image co-registration technique was used to retrospectively monitor subject motion. In three studies synthetic data sets were constructed from single baseline images using the positional information obtained from the co-registration procedure. Cumulative difference images were then created from both the synthetic and functional image sets. Stimulus correlated motion was detected in all eight studies and the synthetic cumulative difference images showed striking similarities to the equivalent functional images in each case. 相似文献
5.
Single neuron activity was recorded in the monkey anterior putamen to compare visuomotor-related responses during operant bar-press behavior with visual discrimination of objects. Of 615 neurons recorded 9.8% (
) responded to the presentation of food during forced delay of access to the bar. Of these 60 neurons, 38 were also tested with nonfood, and 19 of these responded to the nonfood objects regardless of the following movement. The amplitude of the visual-related responses of some differential neurons was graded for different objects to reflect the relative degree of preference for the food presented. However, these responses disappeared in reaction time tasks in which the bar could be accessed for pressing immediately upon presentation of an object. The visual response latency of differential neurons ranged from 50 to 700 ms (mean ± SD, 386 ±211 ms), which was longer than that of the nondifferential responses (207 ± 204 ms). These results suggest that anterior putamen neurons might participate in estimation of visual information that could be related to forecasting movement. 相似文献
6.
Gerard A. Riley 《Journal of developmental and physical disabilities》1998,10(2):153-165
The use of stimulus modifications in teaching involves altering the materials of a task in order to simplify its execution. Though their use in teaching stimulus discriminations to people with developmental disabilities has been extensively investigated, less attention has been given to their utilization in teaching response topography. This paper offers some general guidelines about their use for this purpose. In relation to their design, it is suggested that the aim should be to reduce the demands made by task components, to eliminate components, and/or to increase the attentional value of the discriminating features of the response topography. In relation to their application, guidelines are suggested about when they should be employed in conjunction with response prompts; when they should be used, either alone or in conjunction with response prompts, in preference to response prompts alone; whether one or a series of modifications is required; and at what point during teaching should probe trials on the unmodified task be introduced. 相似文献
7.
This study was conducted to assess the involvement of N-methyl-d-aspartate (NMDA) and γ-aminobutyric acid (GABA) receptor systems, located in specific limbic brain regions, in the discriminative
stimulus effects of ethanol. Male Long-Evans rats were trained to discriminate between intraperitoneal (IP) injections of
ethanol (1 g/kg) and saline on a two-lever drug discrimination task. The rats were then implanted with bilateral injector
guides aimed at the nucleus accumbens core (AcbC), prelimbic cortex (PrLC), hippocampus area CA1 (CA1), or extended amygdala
(i.e., at the border of the central and basolateral nuclei). Infusions of the non-competitive NMDA antagonist MK 801 in the
AcbC or CA1 resulted in dose-dependent full substitution for IP ethanol. MK 801 infusion in the PrLC or amygdala failed to
substitute for ethanol. Injection of the competitive NMDA antagonist CPP in the AcbC also failed to substitute for ethanol.
Co-infusion of MK 801 in the hippocampus potentiated the effects of MK 801 in the AcbC, whereas NMDA infusion in the hippocampus
attenuated the ability of MK 801 in the AcbC to substitute for ethanol. The direct GABAA agonist muscimol resulted in dose-dependent full substitution for IP ethanol when it was injected into the AcbC or amygdala,
but failed to substitute when administered in the PrLC. Co-infusion of MK 801, but not CPP, potentiated the effects of muscimol
in the AcbC. These results demonstrate that ethanol’s discriminative stimulus function is mediated centrally by NMDA and GABAA receptors located in specific limbic brain regions. The data also suggest that the discriminative stimulus effects of ethanol
are mediated by interactions between ionotropic GABAA and NMDA receptors in the nucleus accumbens, and by interactions among brain regions.
Received: 2 December 1997 / Final version: 24 January 1998 相似文献
8.
目的 探究腰椎间盘突出症(LDH)与阻塞性睡眠呼吸暂停(OSA)之间的关联,为LDH的临床诊治策略及治疗方案提供参考依据。方法 选取2018年1月—2020年3月中国医科大学附属第一医院骨科行外科手术治疗的485例LDH患者,按是否合并OSA进行分组研究。结果 485例LDH患者中合并OSA的307例,发生率为63.3%。LDH合并OSA组主观症状、临床症状、日常活动受限程度日本骨科协会(JOA)腰痛评分低于单纯LDH组(P <0.05);两组膀胱功能JOA评分比较,差异无统计学意义(P> 0.05);LDH合并OSA组视觉模拟评分法(VAS)评分高于单纯LDH组(P <0.05)。Pfirrmann 5级评分法中4、5级例数构成比LDH合并OSA组较单纯LDH组高(P <0.05)。两组患者的硬膜撕裂率、神经受损率、血肿率、切口感染率等并发症发生率比较,差异无统计学意义(P>0.05)。单纯LDH组与LDH合并OSA组术后3、6、12和24个月静息状态下JOA和VAS评分比较,采用重复测量设计的方差分析,结果:(1)不同时间点的JOA和VAS评分有差异(... 相似文献
9.
MASAOMI CHINUSHI YOSHIFUSA AIZAWA TOSHIKAZU FUNAZAKI MAKOTO TAMURA AKIRA SHIBATA 《Pacing and clinical electrophysiology : PACE》1992,15(5):756-761
In a patient with sustained ventricular tachycardia, we obtained two different paced QRS morphologies from a single pacing site. In one QRS morphology the stimulus to the QRS complex was long, 150 msec, and in the other it was 100 msec. At the paced cycle length of 600 msec and the stimulus output of 4 V, one QRS morphology with the stimulus to the onset of QRS activation (St-QRS) interval of 150 msec was observed. At the paced cycle length of 400 msec, the other QRS morphology with a St-QRS interval of 100 msec was observed alternatively with the former. At the paced cycle length of 353 msec or 316 msec, the latter with a shorter St-QRS interval was exclusively observed. When the stimulus output was increased from 4 to 10 V, keeping with the paced cycle length at 400 msec, the St-QRS interval was shortened from 100 to 80 msec. For the two QRS morphologies with two St-QRS intervals, two slowly conducting pathways would be responsible. The site of the block in the faster pathway must be located at the proximity of the pacing site and the conduction at a shorter paced cycle length would be explained by "supernormal conduction." 相似文献
10.
电针对大鼠丘脑腹后外侧核痛反应神经元放电的影响 总被引:2,自引:0,他引:2
在大鼠丘脑腹后外侧核(VPL)中可同时记录到对躯体和内脏伤害性刺激起反应的痛兴奋神经元(PEN)和痛抑制神经元(PIN)。注射吗啡和电针“足三里”穴能使VPL中PEN电活动减弱,PIN电活动加强。这表明,VPL通过其中的PEN和PIN同时电活动参与对疼痛和吗啡及电针镇痛的调制作用。 相似文献