RECEPTIVE FIELDS OF CONES IN RETINA OF TURTLE
RECEPTIVE FIELDS OF CONES IN RETINA OF TURTLE
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DOI：
10.1113/jphysiol.1971.sp009432
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发表时间：
1971-01-01
影响因子：
5.5
通讯作者：
OBRYAN, PM
中科院分区：
文献类型：
--
作者：
BAYLOR, DA;FUORTES, MGF;OBRYAN, PM
1.细胞内记录已作出的反应，光的单一锥在视网膜的海龟。对闪光的超极化反应的形状取决于视网膜照明的模式以及刺激强度。虽然刺激模式的变化可以产生有效刺激强度的变化，但对某些模式的反应不能通过刺激强度的任何调整来匹配。对大或小刺激点的反应的初始部分与光强度成比例;这允许当锥体上的光量保持恒定但周围锥体上的光改变时的反应进行比较。对于圆锥上相同的光强，对半径为2或4 μ的光斑的响应小于对半径为70 μ的光斑的响应.对半径为70和600 μ的点的反应在它们的上升阶段和峰值上一致，而不需要任何刺激强度的调整。然而，对较大光斑的响应包含较小光斑不存在的延迟去极化。在具有小中心光斑的圆锥体的稳定照明期间，对叠加在相同区域上的瞬态照明的响应大大降低。然而，在近距离环境中的视锥细胞的照明产生超极化响应，并且在更远距离环境中的视锥细胞的照明产生延迟的去极化。上述结果表明，突触信号可能撞击锥细胞。这种可能性通过电极化一个视网膜细胞同时记录另一个来测试。电流通过40 μ内的一个锥体可以改变另一个锥体的膜电位。然而，并非在该距离内的所有视锥都显示出相互作用，并且在大于50 μ s的距离处从未检测到。水平细胞在外加电流作用下的超极化可以在附近产生锥体的去极化。在这种去极化过程中，锥体对闪光的反应在尺寸上减小，在形状上改变。它的结论是，锥光的反应可能被修改的突触机制，激活周边照明。
1. Intracellular recordings have been made of the responses to light of single cones in the retina of the turtle. The shape of the hyperpolarizing response to a flash depends on the pattern of retinal illumination as well as the stimulus intensity.2. Although changes in the stimulus pattern can produce changes in the effective stimulus intensity, the responses to certain patterns cannot be matched by any adjustment of stimulus intensity.3. The initial portion of responses to large or small stimulating spots is proportional to light intensity; this allows comparison of responses when the amount of light on a cone is kept constant but the light on surrounding cones is changed. For equal light intensity on the cone, the response to a spot 2 or 4 μ in radius is smaller than that to a spot 70 μ in radius.4. Responses to spots 70 and 600 μ in radius coincide over their rising phases and peaks without any adjustment of stimulus intensity. The responses to the larger spot, however, contain a delayed depolarization not present with the smaller spot.5. During steady illumination of a cone with a small central spot, the response to transient illumination superimposed on the same area is greatly reduced. Illumination of cones in the near surround, however, produces a hyperpolarizing response, and illumination of cones in the more distant surround generates a delayed depolarization.6. The results described above suggested that synaptic signals might impinge on cones. This possibility was tested by electrically polarizing one retinal cell while recording from another.7. Currents passed through a cone within 40 μ of another cone can change the membrane potential of the latter. Not all cones within this distance show the interaction, however, and it has never been detected at distances greater than 50 μ.8. Hyperpolarization of a horizontal cell with applied current can produce a depolarization of a cone in the vicinity. During this depolarization, the response of the cone to a flash is reduced in size and altered in shape.9. It is concluded that the response of a cone to light may be modified by synaptic mechanisms which are activated by peripheral illumination.