COMPARISON OF THE RESPONSES TO MOVING TEXTURE PATTERNS OF SIMPLE AND COMPLEX CELLS IN THE CATS AREA-17
COMPARISON OF THE RESPONSES TO MOVING TEXTURE PATTERNS OF SIMPLE AND COMPLEX CELLS IN THE CATS AREA-17
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DOI：
10.1152/jn.1995.74.3.1271
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发表时间：
1995-09-01
影响因子：
2.5
通讯作者：
MINVILLE, K
中科院分区：
文献类型：
--
作者：
CASANOVA, C;SAVARD, T;MINVILLE, K
1. 复杂（C）细胞是否是猫初级视觉皮层中唯一真正的纹理敏感单元仍然存在争议。鉴于纹状皮层中假定只有一类细胞对视觉噪声敏感的强烈生理意义，我们重新研究了这个问题。对简单(S)细胞和C细胞对噪声的敏感性进行定量研究和比较，以便清楚地记录纹状皮层细胞对视觉噪声的反应特性，并确定是否可以根据这些特定特性明确地将S细胞与C细胞分开。2．使用所有相关刺激来刺激感受野，即漂移的正弦波光栅、256 x 256 元素的电子生成噪声模式（暗元素和亮元素的比例为 1:1）以及闪烁和移动条（亮和暗）。 3． 85 个 S 细胞中共有 60 个 (70.6%) 和 101 个 C 细胞中共有 90 个 (81.8%) 对视觉噪声的运动做出了反应。大多数 C 细胞的反应是持续的，即在整个刺激过程中，它们的放电率保持在恒定水平。另一方面，大多数 S 细胞的反应以多次放电爆发为特征。平均而言，光栅的最佳发射率高于噪声的最佳发射率。4．对于几乎所有细胞来说，对噪声的反应随着运动方向的变化而变化。 S 细胞和 C 细胞的平均方向带宽分别为 43 +/- 24 度和 48 +/- 23 度（平均值 +/- SD）。在两组中，神经元对噪声方向的调整比光栅更广泛（t 检验，P < 0.001）。我们很少观察到噪声的双峰调谐曲线，每个峰值位于方向曲线的两侧。如果人们不在空间域（如点图案）而是在频域（即包含所有空间频率和方向的图案）中考虑纹理刺激，则可以预期这些结果。5。一般来说，无论是受到漂移噪声还是光栅的刺激，S细胞和C细胞的方向指数都相似。与光栅相比，S 细胞对噪声具有更强的方向选择性倾向。6．对于所有测试的 S 和 C 细胞，对噪声的响应随着漂移速度的变化而变化。 S 细胞和 C 细胞的平均最佳速度分别为 12.9 度/秒和 10.2 度/秒（t 检验，P > 0.05）。大多数单元是带通的，S 单元和 C 单元的平均带宽分别为 2.2 和 2.7 倍频程。扩大图案元素的尺寸会增加两个细胞组的响应幅度和带宽。7．纹理敏感单元分布在所有层中。对质地敏感的 C 细胞通常位于颗粒下层。 S细胞的层流分布与噪声反应性之间没有明确的关系。8．我们的研究表明，除了响应曲线和强度外，S 细胞和 C 细胞的响应特性在噪声敏感性方面没有显着差异。这些数据表明，视觉噪声无法将 S 细胞与 C 细胞清楚地分开。此外，他们也不支持 C 细胞接收不由 S 细胞介导的输入的观点。
1. Whether complex (C) cells are the only truly texture-sensitive units in the cat's primary visual cortex remains controversial. in view of the strong physiological significance of having putatively only one class of cells sensitive to visual noise in the striate cortex, we reinvestigated this issue. Sensitivities of simple(S) and C cells to noise were quantitatively studied and compared in order to clearly document the response properties of cells in the striate cortex to visual noise and to establish whether one can unequivocally segregate S from C cells on the basis of those specific properties.2. Receptive fields were stimulated with all relevant stimuli, i.e., drifting sine-wave gratings, electronically generated noise pattern of 256 x 256 elements (ratio 1:1 of dark and light elements), and flashing and moving bars (both bright and dark).3. A total of 60 S cells out of 85 (70.6%) and 90 C cells out of 101 (81.8%) responded to the motion of visual noise. Responses of most C cells were sustained, i.e., their discharge rate was maintained at a constant level throughout presentation of the stimulus. On the other hand, responses of the majority of S cells were characterized by several bursts of discharges. On average, optimal firing rates were greater for gratings than for noise.4. For practically all cells, responses to noise varied as a function of direction of motion. The mean direction bandwidths were, respectively, 43 +/- 24 degrees and 48 +/- 23 degrees (mean +/- SD) for S and C cells. In both groups, neurons were more broadly tuned for the direction of noise than that of gratings (t-test, P < 0.001). We rarely observed bimodal tuning curves for noise, with each peak lying on either side of the orientation curve. These results could be expected if one considers texture stimuli not in the space domain (as dot patterns) but in the frequency domain, i.e., patterns containing all spatial frequencies and orientations.5. In general, the direction indexes of S and C cells were similar whether they were stimulated by drifting noise or gratings. S cells had a slight tendency to be more direction selective for noise than for gratings.6. For all S and C cells tested, responses to noise varied as a function of drift velocity. The mean optimal velocity was 12.9 and 10.2 degrees/s for S and C cells, respectively (t-test, P > 0.05). Most cells were band-pass with mean bandwidths of 2.2 and 2.7 octaves for S and C cells, respectively. Enlarging the size of pattern elements yielded an increase in response amplitude and bandwidth in both cell groups.7. Texture-sensitive units were distributed in all layers. Strong texture-sensitive C cells were generally located in the infragranular layers. There was no clear relationship between laminar distribution and noise responsiveness for S cells.8. Our study shows that, except for response profile and strength, there were no significant differences between response properties of S and C cells with respect to their noise sensitivity. These data suggest that visual noise does not allow one to clearly segregate S from C cells. Also, they do not support the notion that C cells receive inputs not mediated by S cells.