Limulus lateral eye: properties of receptor units in the unexcised eye

Single receptor units in the compound eye of the horseshoe crab were illuminated, and their impulse discharges were recorded without removing the eye from the animal. The receptors were spontaneously active in darkness and responded without saturation over a light intensity range of 10(10) to 1. When the eye was excised, the receptors did not discharge in darkness and had an intensity range of 10(5) to 1, as is usually found. Experiments show that these and other differences result from cutting off the blood supply to the eye when it is excised. In addition, the range and shape of the intensity characteristic suggest that more than one receptor mechanism encodes light intensity in this eye.     

Corollary discharge provides accurate eye position information to the oculomotor system

The saccadic system accurately compensates for perturbations of eye position produced by microstimulation of the superior colliculus. This requires that information about the stimulation-induced change in eye position be provided by an extraretinal source--either proprioceptive endings in extraocular muscles or a centrally generated corollary discharge. It is shown that compensation remains intact after elimination of extraocular muscle proprioception, demonstrating that corollary discharge provides accurate eye position information.     

A pathway in primate brain for internal monitoring of movements

It is essential to keep track of the movements we make, and one way to do that is to monitor correlates, or corollary discharges, of neuronal movement commands. We hypothesized that a previously identified pathway from brainstem to frontal cortex might carry corollary discharge signals. We found that neuronal activity in this pathway encodes upcoming eye movements and that inactivating the pathway impairs sequential eye movements consistent with loss of corollary discharge without affecting single eye movements. These results identify a pathway in the brain of the primate Macaca mulatta that conveys corollary discharge signals.     

Superior colliculus cell responses related to eye movements in awake monkeys

Single cell responses were recorded from the superior colliculus of awake monkeys trained to move their eyes. A class of cells that discharged before eye movements was found in the intermediate and deep layers of the colliculus. The response of the cells was most vigorous before saccadic eye movements within a particular range of directions. These cells had no visual receptive fields, and visually guided eye movements were not necessary for their discharge, since they responded in total darkness before spontaneous eye movements and vestibular nystagmus.     

比目鱼类的眼睛移位和不对称的进化起源

比目鱼类外形不对称产生的机制引起人们兴趣已逾一个多世纪。从比目鱼类(鲽形目)的类群和分布、变态过程中眼睛移位机械力的来源、甲状腺激素调控眼睛移位的信号通路、比目鱼类外形左右不对称与内脏左右不对称两者调控机制之间的关系以及比目鱼类眼睛左右不对称的进化起源等5个方面,系统地介绍了比目鱼类变态发育过程中眼睛移位的研究历史。重点介绍了本实验室提出的关于眼睛移位的组织学模型,以及眼睛移位信号调控途径的最新研究进展。发现并证明眶下皮肤组织细胞分裂导致眼睛移动,而眼睛移动进一步导致额骨变形,纠正了以往假说的谬误。最后,对比目鱼类眼睛移位和不对称进化起源进行了探讨,提出了解释比目鱼类不对称进化起源的新假说。     

Visual cortex neurons: response to stimuli during rapid eye movements

While awake, unanesthetized monkeys held their eyes stationary, a motionless or slowly moving stimulus falling on the receptive field of striate cortex neurons produced an excitatory response. When a rapid eye movement was made across the same stimulus, many of these neurons continued to give an excitatory response. But the discharge of other neurons was unchanged or was suppressed during the eye movement.     

Reinnervated eye muscles do not respond to impulses in foreign nerves

Normal movements return to carp eyes after section and regeneration of the IIIrd and IVth nerve trunks. Two months after reinnervation, records of impulses in the inferior oblique nerve during tilting of the body show activity of the normal motoneurons to that muscle, together with discharge patterns characteristic of the antagonistic superior oblique and some of the rectus muscles. These axons must have found their way into the inferior oblique trunk during sprouting at the lesion and must be maintained after reinnervation. Impulses from foreign axons are without detectable effect on eye movement and therefore must be blocked at their termination in the muscle. Previous study of cross-innervated and doubly innervated fish eye muscles revealed only structurally normal neuromuscular junctions. Transmission from foreign junctions in multiply innervated muscle is blocked by competitive molecular recognition and control mechanisms that do not cause degeneration.     

Presence of lateral eye lens crystallins in the median eye of the american chameleon

With the use of immunofluorescence techniques, gamma globulin antibody specific for the crystallins of Anolis carolinensis lateral eye lens was applied to sections through the median (parapineal) eye of Anolis carolinensis. Only the median eye lens exhibited fluorescence specific for the crystallins; other structures were negative. These results indicate that the lens of the reptilean median eye shares tissue-specific antigenic determinants with the lens of the lateral eye. This suggests a possible evolutionary relation between the two structures, based on biochemical, as well as previously reported anatomical, criteria.     

Photoelectric technique for measuring eye movements

By the system described, the movement of a stimulus and the correlated tracking movements of the eye are recorded simultaneously. The technique for measuring the eye movements consists of detecting and amplifying by photomultiplication the total amount of light passing through a small slit upon which is imaged a small portion of the light-dark field represented by the iris and sclera of the eye. This total amount of light varies directly with the angular position of the eye.     

Optics of arthropod compound eye

The extent to which light can escape from one ommatidium into its neighbors in the compound eye has been examined by recording from single receptors during stimulation of single facets. In the "apposition" eye of the drone honeybee and locust, optical interaction is extremely small. In the "superposition" eye of the crayfish, more than half the light captured by the average cell gets in through neighboring facets, even when screening pigments are in the fully lightadapted position.     

Scanpaths in eye movements during pattern perception

Subjects learned and recognized patterns which were marginally visible, requiring them to fixate directly each feature to which they wished to attend. Fixed "scanpaths," specific to subject and pattern, appeared in their saccadic eye movements, both intermittently during learning and in initial eye movements during recognition. A proposed theory of pattern perception explains these results.     

鱼类眼睛晶体信息分析与应用研究进展

眼睛晶体作为鱼类的硬组织之一,具有结构稳定、耐腐蚀、易获取的特性,其含有大量的蛋白质,蕴含着丰富的化学信息,并在鱼类的年龄鉴定中得到了一定程度的应用。近年来,随着生物地球化学技术的不断创新与进步,鱼类眼睛晶体的微量元素、稳定同位素信息也越来越受到国内外学者的重视。本文将依据国内外学者的研究成果,从眼睛晶体的直径与重量、微结构、微量元素和稳定同位素等方面,对鱼类的年龄鉴定、栖息环境重建、摄食生态的追踪等方面的应用进行综述,并通过分析鱼类眼睛晶体的组成成分与生长模式,比较眼睛晶体与其他组织做稳定同位素分析的优势,着重归纳总结了眼睛晶体碳氮稳定同位素在鱼类生活史信息,尤其在摄食生态、栖息环境重建等方面的研究方法、应用现状及发展前景,为以后开展相关的研究提供参考。     

Retinoscopy and eye size

Retinoscopy was performed on animals with different sized eyes, all of whom appeared hypermetropic. The data were well fitted by an equation of the form y = kx(-2) where y is refractive error in diopters, and x is the corneo-retinal length of the eye. Apparent hypermetropia may be due to the reflection from the inner surface of the retins.     

Human amygdala responsivity to masked fearful eye whites

The amygdala was more responsive to fearful (larger) eye whites than to happy (smaller) eye whites presented in a masking paradigm that mitigated subjects' awareness of their presence and aberrant nature. These data demonstrate that the amygdala is responsive to elements of.     

Rapid eye movement sleep deprivation: a central-neural change during wakefulness

Three adult cats were deprived of rapid eye movement sleep for six separate periods of up to 32 days. Animals were allowed normal amouints of sleeping time during which rapid eye movement sleep was interrupted, whenever it occurred, by human observers who continually monitored the animals and their electrocortical activity. Cortical responses evoked by pairs of acoustic clicks were recorded during wakefulness. Recovery functions derived from these data were facilitated during periods of deprivation of rapid eye movement sleep and returned to base-line values when animals were allowed normal amounts of this sleep phase. This change was noted repeatedly within, as well as between, subjects. It did not occur during control periods when non-rapid eye movement sleep was interrupted on identical schedules, nor did it occur when the cats were deprived of all sleep for 22 hours a day for 5 days.     

Gating of retinal transmission by afferent eye position and movement signals

Vision in most vertebrates is an active process that requires the brain to combine retinal signals with information about eye movement. Eye movement information may feed forward from the motor control areas of the brain or feed back from the extrinsic eye muscles. Feedback signals elicited by passive eye movement selectively gate retinal outflow at the first relay, the dorsal lateral geniculate nucleus. The gating predominantly facilitates retinogeniculate transmission immediately after eye movement and inhibits transmission when a new steady-state eye position is achieved. These two gating effects are distributed in a complementary fashion across the dorsal lateral geniculate nucleus such that the spatiotemporal activity profile could contribute to object detection and localization.     

An eagle's eye: quality of the retinal image

The optical quality of a living eagle's eye was determined by an ophthalmoscopic method. The performance of the eye was substantially better than that reported for humans, but did not confirm some of the wilder claims made for such birds.     

Central role for the lens in cave fish eye degeneration

Astyanax mexicanus is a teleost with eyed surface-dwelling and eyeless cave-dwelling forms. Eye formation is initiated in cave fish embryos, but the eye subsequently arrests and degenerates. The surface fish lens stimulates growth and development after transplantation into the cave fish optic cup, restoring optic tissues lost during cave fish evolution. Conversely, eye growth and development are retarded following transplantation of a surface fish lens into a cave fish optic cup or lens extirpation. These results show that evolutionary changes in an inductive signal from the lens are involved in cave fish eye degeneration.     

橘小实蝇成虫复眼结构及感光机制

【目的】研究橘小实蝇Bactrocera dorsalis成虫复眼外部形态、内部显微结构和光感受机制。【方法】利用扫描电镜观察橘小实蝇成虫复眼外部形态,组织切片研究成虫复眼内部显微结构及在不同光环境下小眼结构的变化。【结果】橘小实蝇成虫复眼位于头部两侧,正面观呈半球形,表面光滑平坦;小眼间隙有感觉毛,单个小眼由角膜、晶锥、网膜细胞及其特化的视杆、基膜等构成,晶锥、视杆周围和色素细胞内均含有大量的色素颗粒。不同单色光处理后,小眼内的附属色素细胞色素颗粒沿小眼纵轴移动。白光、绿光和黄光处理后,附属色素细胞色素颗粒沿小眼纵轴均匀分布;紫光、蓝光和红光处理后,附属色素细胞色素颗粒主要集中在视网膜细胞远端和角膜的近端。【结论】橘小实蝇雌、雄成虫复眼在外形和内部结构上无差异,均属于并置像眼,屏蔽色素颗粒的移动是其复眼适应外界光环境变化的重要机制,该研究结果为筛选橘小实蝇成虫敏感光波并对其进行灯光诱杀提供了理论依据。     

Retrograde amnesia: electroconvulsive shock effects after termination of rapid eye movement sleep deprivation

Mice that were deprived of rapid eye movement sleep for 2 days immediately after one-trial training in an inhibitory avoidance task and were given an electroconvulsive shock after deprivation displayed retrograde amnesia on a retention test given 24 hours later. Electroconvulsive shock produced no amnesia in comparable groups of animals that were not deprived of rapid eye movement sleep.