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131.
Latency to respond to an aversive thermal stimulus and the degree of analgesia induced by morphine were examined in mice injected with either isotonic saline or morphine sulfate (10 mg/kg) during midscotophase of a 12:12 h LD cycle. When mean response latencies were compared to the degree of geomagnetic disturbance (Ap index) present on test days, it was found that during the geomagnetic storm on December 17th, 1982, a significant reduction (P<0.01) in response latency was evident in both saline- and morphine-treated mice. The reduction in response latencies was greater, and lasted longer in the morphine-treated animals. It is suggested that the pineal gland may mediate this biomagnetic effect. 相似文献
132.
133.
Lomber SG Payne BR Hilgetag CC Rushmore J 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2002,142(4):463-474
A contralateral hemineglect of the visual field can be induced by unilateral cooling deactivation of posterior middle suprasylvian (pMS) sulcal cortex of the posterior parietal region, and this neglect can be reversed by additional cooling deactivation of pMS cortex in the opposite hemisphere. The purpose of the present study was to test whether an enduring hemianopia induced by removal of all contiguous visual cortical areas of one hemisphere could be reversed by local cooling of pMS cortex in the opposite hemisphere. Two cats sustained large unilateral ablations of the contiguous visual areas, and cooling loops were placed in the pMS sulcus, and in contact with adjacent area 7 or posterior ectosylvian (PE) cortex of the opposite hemisphere. In both instances cooling of pMS cortex, but neither area 7 nor PE, restored a virtually normal level of orienting performance to stimuli presented anywhere in the previously hemianopic field. The reversal was highly sensitive to the extent of cooling deactivation. In a third cat, cooling deactivation of the superficial layers of the contralateral superior colliculus also restored orienting performance to a cortical ablation-induced hemianopia. This reversal was graded from center-to-periphery in a temperature-dependent manner. Neither the cortical ablation nor any of the cooling deactivations had any impact on an auditory detection and orienting task. The deactivations were localized and confirmed by reduced uptake of radiolabeled 2-deoxyglucose to be limited to the immediate vicinity of each cooling loop. The results are discussed in terms of excitation and disinhibition of visual circuits. 相似文献
134.
尾加压素II(urotensin II,UII)最早是从鱼尾部下垂体中分离出的调节肽,近来已从人体中克隆出来,并发现体内一种孤立的G蛋白偶联受体GPR14是其特异性受体。UII与GPR14结合后,参与许多生物学效应,如调节内分泌,调节渗透压平衡,调节胃肠道平滑肌及心血管收缩功能等,是迄今体内最强的缩血管活性肽。UII不仅与许多人类心血管疾病如高血压,充血性心力衰竭(CHF),冠心病和动脉粥样硬化有关,而且研究发现,糖尿病患者血液中UII含量升高。初步研究表明,UII的基因多态性和2型糖尿病的发生有关;尾加压素II还可抑制胰岛素的释放。 相似文献
135.
R. Shafiq Geoffrey W. Stuart Jennifer Sandbach Paul Maruff Jon Currie 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1998,118(2):221-229
Latencies of eye movements to peripheral targets are reduced when there is a short delay (typically 200 ms) between the offset
of a central visual fixation point and the target onset. This has been termed the gap effect. In addition, some subjects, usually with practice, exhibit a separate population of very short latency saccades, called express saccades. Both these phenomena have been attributed to disengagement of visual attention when the fixation point is extinguished. A
competing theory of the gap effect attributes it to disengagement of oculomotor fixation during the temporal gap. It is known
that auditory targets are effective in eliciting saccadic eye movements, and also that covert attention operates in the auditory
modality. If the gap effect and express saccades are due to disengagement of spatial attention, both should persist in the
auditory modality. However, fixation of gaze is largely under visual control. If the gap effect results from disengagement
of fixation, then at least a reduced effect should be seen in the auditory modality. Human subjects performed the gap task
and a control task in the dark, using auditory fixation points and saccadic targets, on five successive days. Despite this
practice, express saccades were not observed. There was a reliable gap effect, but the reduction in saccadic latency was only
17 ms, compared with 32 ms for the same subjects in the visual modality. This suggests that about half the gap effect is due
to disengagement of visual fixation. The remainder was not due to non-specific warning effects and could be attributed to
offset of the auditory fixation stimulus.
Received: 1 March 1996 / Accepted: 11 July 1997 相似文献
136.
Ferrarin M Gironi M Mendozzi L Nemni R Mazzoleni P Rabuffetti M 《Medical & biological engineering & computing》2005,43(3):349-356
Cerebellar ataxia is a complex motor disturbance that involves the planning and execution of movements and reduces movement
accuracy and co-ordination. The quantification of ataxic signs is commonly realised through visual examination of motor tasks
performed by the patient and assignment of scores to specific items composing the international co-operative ataxia rating
scale (ICARS). The present work studied an experimental procedure to characterise specific aspects of motor disturbances in
ataxia objectively. Four tests belonging to the ICARS were considered: walking, knee-tibia test, finger-to-nose and finger-to-finger
test. Through a kinematic analysis performed during the above tests, specific indices were defined to quantify velocity, linearity,
asymmetry, tremor, instability and smoothness of movement or posture. The procedure was applied to five patients with cerebellar
ataxia and to ten healthy adult subjects. Results demonstrated that the patients moved significantly more slowly than the
healthy subjects (0.67 against 0.97 m s−1 and 0.81 against 1.02 m s−1, respectively, for straight walk and finger-to-nose tests) and showed poorer linearity and smoothness behaviour. Velocity,
linearity, tremor, smoothness and instability indices showed moderate to good correlation with the corresponding ICARS score.
Some of these indices can separately evaluate aspects that are combined in single ICARS subscores. It is concluded that the
combination of clinical assessments and instrumental evaluations allows a better insight into ataxic patients' motor disturbances
and is a useful tool for the definition and follow-up of rehabilitation programmes. 相似文献
137.
The ethanol extract of potato tubers (Solanum tuberlosum L.) has been evaluated for antinociceptive and anti-inflammatory activities in mice. The acute treatment of mice with an ethanolic extract from the potato tuber at doses of 100 and 200 mg/kg, by oral administration, produced a significant anti-nociceptive effect in the acetic acid-induced writhing, formalin-induced pain licking and hot plate-induced pain. Also, the ethanolic extract of potato tubers significantly inhibited both carrageenan- and formalin-induced inflammation in mice as well as arachidonic acid-induced ear edema in mice. These inhibitions were statistically significant (p<0.05). These results provide support for the use of the ethanol extract of potato tuber in relieving inflammatory pain, and insight into the development of new agents for treating inflammatory diseases. 相似文献
138.
Summary An increased base binding power of the blood induced by alkali administration to subjects performing a supramaximal exercise has no appreciable effect neither on the maximal performance time nor on the total amount of lactic acid or its rate of appearance in blood.This work has been supported by a grant from the Italian National Research Council. Thanks are due also to Laboratory Glaxo, S.p.A. for facilities and financial support in the course of the experiments. 相似文献
139.
Functional magnetic resonance imaging evidence for binocular interactions in human visual cortex 总被引:3,自引:0,他引:3
Büchert M Greenlee MW Rutschmann RM Kraemer FM Luo F Hennig J 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》2002,145(3):334-339
Using functional magnetic resonance imaging (fMRI), we explored the binocular interactions occurring when subjects viewed dichoptically presented checkerboard stimuli. A flickering radial checkerboard was presented to each eye of the subject, while T2*-weighted images were acquired over the visual cortex with gradient-echo, echoplanar sequences. We compared responses in striate and extrastriate visual cortex under four conditions: both eyes were stimulated at the same time (binocular condition), each eye was stimulated in alternation (monocular condition) or first the one eye then the other eye was stimulated (left eye first - right eye trailing, or vice versa). The results indicate that only the striate area, in and near the calcarine fissure, shows significant differences for these stimulation conditions. These differences are not evident in more remote extrastriate or associational visual areas, although the BOLD response in the stimulation-rest comparison was robust. These results suggest that the effect could be related to inhibitory interactions across ocular dominance columns in striate visual cortex. 相似文献
140.
毫米波辐射对植入前小鼠胚胎及早期胚胎的影响 总被引:3,自引:0,他引:3
本文报道小鼠受精卵体外及在体受毫米波辐照后一些改变。毫米波源为36.11GHz固态微波连续发生器,波长8mm,功率密度为10mW/cm~2、8mW/cm~2、4mW/cm~2及2mW/cm~2。结果发现2-4mW/cm~2毫米波辐照即可使体外培养之受精卵细胞表面微绒毛减少、脱落,细胞表面形成许多囊泡。透射电镜下可见细胞间隙扩大、胞浆中线粒体膨胀、空化,用FITC-ConA试验可见细胞表面结合荧光减少。酶试验证明辐照后卵胚细胞表面AKP,ATPase,5′-Nase均有降低。在体受精卵细胞经辐射后证明,辐射可使胎儿体重增长减慢,囊胚形成数量下降,植入率降低,而表面酶下降不明显。 相似文献