ORIENTATION-SENSITIVE AMACRINE AND GANGLION-CELLS IN THE RABBIT RETINA
ORIENTATION-SENSITIVE AMACRINE AND GANGLION-CELLS IN THE RABBIT RETINA
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DOI：
10.1152/jn.1994.71.5.1672
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发表时间：
1994-05-01
影响因子：
2.5
通讯作者：
BLOOMFIELD, SA
中科院分区：
文献类型：
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作者：
BLOOMFIELD, SA
1.细胞内记录获得从无长突和神经节细胞的分离，灌流视网膜眼杯制备的兔子，以测试其响应的方向敏感性。在注射辣根过氧化物酶（HRP）或N-（2-氨乙基）-生物素酰胺盐酸盐（Neurobiotin）以可视化胞体-树突状结构之后，基于形态学标准进行细胞鉴定。根据其敏感性产生的生理机制，我们发现了两种方向敏感无长突细胞和一种方向敏感神经节细胞，它们被称为方向选择性细胞和方向偏向性细胞。细胞进一步分为中心或偏离中心的感受野类别。方向选择性无长突细胞和神经节细胞的感受野由两个抑制野组成，它们沿着在兴奋中心感受野的两侧。这些抑制侧翼产生了一个中心接收场各向异性，其主轴对应于首选的方向：平行或正交的视觉条纹。当刺激被定向为正交于优选取向（即，在零方向），抑制场被刺激，导致阻断中心介导的兴奋的零抑制。刺激这些抑制侧翼是绝对必要的，以唤起这些细胞的方向选择性。零反应反映了与电导增加相关的抑制，而不是障碍。取向偏置无长突细胞显示中心感受野各向异性，其主轴取向平行或正交的视觉条纹。这些细胞更喜欢光刺激取向沿着主轴的中心感受野。然而，当刺激从优选方向旋转时，这些细胞的兴奋性反应降低，没有相应的超极化。即使用外源性电流调节膜电位后也没有检测到无效抑制.虽然取向偏置无长突细胞形态异质，他们都显示树突状乔木，显着延长沿着轴对应于他们的生理首选方向。因此，似乎这些细胞的伸长的树突状野可以提供它们的中心感受野的各向异性，进而提供它们的取向敏感性。取向选择性无长突细胞形成了一个相当均匀的形态组的细胞。这些神经元显示出大的、径向对称的树突状乔木，直径平均为1,100 μ m。在它们的树突区域中没有不对称性，因此它们的取向选择性没有明确的结构基础。相反，方向选择性神经节细胞显示不同的胞体树突状结构，因此不能被放置到一个单一的形态类。虽然有些细胞表现出不对称的树突状乔木，有没有明确的对应关系，它们的结构和方向选择性。
1. Intracellular recordings were obtained from amacrine and ganglion cells in the isolated, superfused retina-eyecup preparation of the rabbit to test the orientation sensitivity of their responses. Cell identification was based on morphological criteria following injection of horseradish peroxidase (HRP) or N-(2-aminoethyl)-biotinamide hydrochloride (Neurobiotin) to visualize soma-dendritic architectures.2. In terms of the physiological mechanisms generating their sensitivity, two types of orientation-sensitive amacrine cell and a single type of orientation-sensitive ganglion cell were found. These cell types were termed orientation selective and orientation biased. Cells were subtyped further into on- or off-center receptive-field categories.3. The receptive fields of orientation-selective amacrine and ganglion cells were composed of two inhibitory fields that flanked the excitatory center receptive field along the preferred orientation. These inhibitory flanks produced a center receptive-field anisotropy with its major axis corresponding to the preferred orientation: either parallel or orthogonal to the visual streak. When a stimulus was oriented orthogonal to the preferred orientation (i.e., at the null orientation), the inhibitory fields were stimulated, resulting in a null inhibition that blocked the center-mediated excitation. Stimulation of these inhibitory flanks was absolutely essential to evoke the orientation selectivity of these cells. The null response reflected inhibition associated with a conductance increase and not disfacilitation.4. Orientation-biased amacrine cells displayed a center receptive-field anisotropy with its major axis oriented either parallel or orthogonal to the visual streak. These cells preferred light stimuli oriented along the major axis of the center receptive field. However, whereas the excitatory response of these cells was reduced when a stimulus was rotated from the preferred orientation, there was no corresponding hyperpolarization. No null inhibition was detected even after modulation of the membrane potential with extrinsic current.5. Although orientation-biased amacrine cells were morphologically heterogeneous, they all displayed dendritic arbors that were markedly elongated along an axis corresponding to their physiological preferred orientation. Thus it appears that the elongated dendritic fields of these cells may provide for the anisotropy of their center receptive fields and, in turn, their orientation sensitivity.6. Orientation-selective amacrine cells formed a rather homogeneous morphological group of cells. These neurons displayed large, radially symmetric dendritic arbors with diameters averaging 1,100 mu m. There were no asymmetries in their dendritic fields and thus no clear structural basis for their orientation selectivity.7. In contrast, orientation-selective ganglion cells displayed diverse soma-dendritic architecture and thus could not be placed into a single morphological class. Although some cells showed asymmetric dendritic arbors, there was no clear correspondence between their structure and orientation selectivity.