Visual responses with and without fixation: neurons in premotor cortex encode spatial locations independently of eye position

 The ventral premotor cortex (PMv) of the macaque monkey contains neurons that respond both to visual and to tactile stimuli. For almost all of these “bimodal” cells, the visual receptive field is anchored to the tactile receptive field on the head or the arms, and remains stationary when the eyes fixate different locations. This study compared the responses of bimodal PMv neurons to a visual stimulus when the monkey was required to fixate a spot of light and when no fixation was required. Even when the monkey was not fixating and the eyes were moving, the visual receptive fields remained in the same location, near the associated tactile receptive field. For many of the neurons, the response to the visual stimulus was significantly larger when the monkey was not performing the fixation task. In control tests, the presence or absence of the fixation spot itself had little or no effect on the response to the visual stimulus. These results show that even when the monkey’s eye position is continuously changing, the neurons in PMv have visual receptive fields that are stable and fixed to the relevant body part. The reduction in response during fixation may reflect a shift of attention from the visual stimulus to the demands of the fixation task. Received: 8 April 1997 / Accepted: 16 July 1997     

Voluntary smooth eye movements with foveally stabilized targets

Summary We investigated the capacity of 6 humans to make voluntary smooth eye movements with a horizontally stabilized foveal point target. When the target was viewed on a dark field, all subjects were able to make smooth oscillatory eye movements when they attempted to imitate their own normal pursuit of sinusoidal target movement (0.2–0.7 Hz) directly preceding the stabilization on the fovea. The frequency of the imitating eye movement was in general lower than the frequency of normal pursuit by 2–35%. While fixating a foveally stabilized point target superimposed on a large, sinusoidally moving non-stabilized background, all subjects were able to make either no eye movements, eye movements nearly in phase with or eye movements nearly in counterphase with the background movement depending on the instruction to imagine the target as head-stationary, moving in phase, or moving in counterphase with the background. The accuracy of the frequency of the smooth eye movement with the stabilized target on the moving background was higher than during imitation of pursuit on the dark field but the precision of the frequency was lower than during normal pursuit. When the background moved pseudo-randomly all subjects could voluntarily inhibit their smooth eye movements or could make smooth eye movements in phase with the background. Only 2 subjects showed a limited ability to make smooth eye movements opposite to the pseudo-random background movement. The results suggest that with predictable background movement the volition of the subject rather than the movement of the background determines the eye movements when the subject looks at the foveally stabilized target.     

顺行交锁髓内钉治疗肱骨骨折

目的探讨顺行交锁髓内钉治疗肱骨骨折的手术要点和治疗效果。方法回顾性分析2003年10月～2005年10月23例顺行肱骨交锁髓内钉治疗肱骨干中上段骨折。结果全部病例随访6个月～1年3个月,平均11个月。所有病例均骨性愈合,平均临床愈合时间为2.4个月。所有关节活动度均可。结论顺行交锁髓内钉治疗肱骨中段或中上段骨折,效果良好。     

对99例髋臼骨折内固定治疗的分析

从1972年11月到1994年3月,401例髋臼骨折病人中的99例经手术治疗并获随访,包括30例双柱骨折,13例横骨折伴后壁骨折,9例后壁骨折,9例后柱骨折,9例前往骨折伴前壁骨折,13例T形骨折和16例横骨折.平均随访时间为7年(2～14).外科手术入路的选择,后入路53次,髂腹股沟入路23次,延长的髂股骨入路11次,放射状入路9次和结合性入路6次.复位情况用X线平片来评判,解剖复位的有59例(59.6%),接近解剖复位(<2mm的错位)的有19例(19.2%).总结果用Harris Hip Score来评判,优秀的有53例(53.5%),良好的有25例(25.3%),一般的有14例(14.1%),差的有7例(7%).并发症中,有10例(53%)为感染,7例(37%)为静脉栓塞.这些结果表明,对于错位严重的髋臼骨折,切开复位内固定是一种可以选择的治疗方法.     

What is normal binocular vision?

The vergence position of the eyes is determined by the near fixation-accommodationmiosis synkinesis and the fusion mechanism. The contribution of both systems was analysed in 30 normal subjects and 16 subjects with abnormal binocular vision. Prism fixation disparity curves were determined in three different experimental situations: the routine method according to Ogle, a method to stimulate the synkinetic convergence (Experiment I, with one fixation point as sole binocular stimulus) and a method to stimulate the fusion mechanism (Experiment II, with random dot stereograms). Experiment I produced flat curves and Experiment II steep curves. The mean diameter of the horizontal Panum area was 5 minutes of arc in Experiment I and 2 in Experiment II. On the basis of these findings, it was postulated that the synkinetic system operates in the absence of fixation disparity and the fusion system in the presence of fixation disparity. In Experiment II, esodisparities of 100 minutes of arc occur in a number of normal subjects.The dividing line between normal and abnormal binocular vision therefore is blurred. Normal persons can display disparities, the order of magnitude of which is equal to that of the angle of squint in micro-strabismus.     

胸骨上举术的固定方式与结果

目的：分析胸骨上举术的不同固定方式与手术效果的关系。方法：１４８例经胸骨上举术治疗的漏斗胸患儿，术中分别用自制金属支杠、三点式悬吊和塑料及金属制成的支架背心悬吊固定胸骨。结果：其中８４例患儿获术后６个月至６年（平均２年）随访观察，绝大部分效果满意，仅２例复发。２７例保留金属支杠于术后１０～１２个月拔除者，无复发，外观更满意。结论：胸骨上举术治疗漏斗胸的效果肯定，手术安全。用自制金属支杠固定上举的胸骨操作简便，术后护理方便。保持金属支杠于手术后１０～１２个月才拔除，有利于防止复发，胸廓外形更满意。三点式悬吊固定对较小的轻度患儿适用。支架背心悬吊固定法术后护理不便，影响患儿日常生活，使用受限     

病灶清除一期前路植骨钛板内固定治疗胸腰椎结核

目的　探讨胸腰椎结核病灶清除,一期前路植骨钛板内固定的手术方法与疗效。方法　对1997年5月~2003年6月收治的23例胸腰椎结核患者,术前常规应用异烟肼、链霉素、利福平和乙胺丁醇四联抗痨治疗最少3周,并纠正贫血及低蛋白血症。血沉恢复正常或连续观察低于50mm/h后进行手术。采取病灶清除、一期前路植骨、“K”形钛板内固定。术后继续抗痨治疗10-12个月。结果　手术时间2-3 5h,平均2 6h。输血400~1200ml,平均600ml。伤口一期愈合,随访时间18 -61个月,植骨融合时间为4~9个月,平均6个月。5例截瘫患者均恢复,术后脊柱后凸角度平均矫正19°。结论　采取病灶清除、一期前路植骨钛板内固定治疗胸腰椎结核,具有矫正后凸畸形,稳定脊柱,并发症少,术后早期离床活动的优点。是较安全有效的治疗方法。     

骶髂关节不同固定方式对骶部影响的生物力学研究

背景:长节段固定治疗腰椎退变性侧凸取得了良好的矫形效果.目前对于骶髂关节不同固定方式对骶部影响的生物力学研究尚少..目的:研究骶髂关节不同固定方式对S1螺钉应力分布的影响,为腰椎退变性手术方式的选择提供依据.方法:抽取6具成人新鲜尸体按照三种不同固定方式分成T12-S1组(T12-S1固定)、T12-S2组(T12-S...     

直肠骶骨岬固定治疗直肠脱垂

目的 探讨一种操作简便、创伤小的治疗直肠脱垂的术式。方法 采用直肠骶骨岬固定,直肠下端盆底腹膜成角固定治疗直肠脱垂54例。结果 本术式创伤小,并发症少,经长期观察均无复发。结论 直肠骶骨岬固定,直肠下端盆底腹膜成角固定是治疗直肠脱垂的一种理想术式。     

经皮椎弓根钉内固定治疗高龄患者腰椎退变性滑脱所致腰痛的临床研究

目的观察经皮椎弓根钉治疗高龄老人腰椎退变性滑脱所致腰痛的临床疗效。方法201O年4月～2013年8月28例腰椎退变性滑脱所致腰痛的高龄老人,采用经皮椎弓根钉内固定实施治疗,对比术前、术后1周、术后6个月视觉模拟评分（VAS）和功能障碍指数（ODI）,记录手术时间及术中出血量,评价临床疗效。结果本组28例患者,术前视觉模拟评分（VAS）为（7．61±1．22）分,功能障碍指数（OO!）为（53．12±3．32）分：采用经皮椎弓根钉内固定治疗,术后1周内均带护腰支具下地活动,下地后术前腰痛症状消失或明显缓解,术后2周伤口甲级愈合并拆线。术后1周VAS为（2．30±0．98）分,0DI为（7．64±1．23）分;平均手术时间130分钟,平均出血量110ml。所有患者均获得随访,随访时间6个月,随访时VAS为（2．12±1．33）分,ODI为（8．46±2．20）分。结论经皮椎弓根钉内固定治疗高龄老人腰椎退变性滑脱所致腰痛疗效确切。