Casanova C, Savard T
Department of Surgery-Ophthalmology, University of Sherbrooke, Quebec, Canada.
Neuroscience. 1996 Jan;70(2):439-47. doi: 10.1016/0306-4522(95)00359-2.
We have studied the response properties of cells in the lateral part of the lateral posterior nucleus or striate-recipient zone (LPl) of the lateral posterior nucleus-pulvinar complex to the motion of textured patterns [visual noise]. Our purpose was to determine basic noise response characteristics and to compare these properties to that of cells in area 17 known to project to the LPl. Practically all LPl cells (87%) responded to the motion of visual noise. The evoked discharges were either sustained or characterized by several bursts. On average, as found in cortex, LPl neurons were more broadly tuned for the direction of noise than that of gratings (bandwidths of 49 and 36 degrees, respectively; t-test, P < 0.005). Noise tuning function in LPl was comparable to that found in cortex (mean of 48 degrees). One third of the LPl units did not exhibit any preferences for drift direction of noise. Such cells were virtually not encountered in the striate cortex. This group of LPl cells was generally not tuned for grating direction. For practically all LPl cells, responses to noise varied as a function of drift velocity. The mean optimal velocity was 27.5 degrees/s with mean bandwidth of 2.5 octaves. LPl cells were sensitive to a broader range of velocities than complex cells in area 17. The results of the present study showed that visual noise is an appropriate stimulus for studying motion sensitivity of cells in the LPl. It also revealed that the noise response properties, such as direction and velocity tuning functions, are very similar to those reported in the striate cortex. The exact contribution of area 17 in the visual noise responsiveness of LPl cells remains to be determined. This study provides additional evidence that the lateral posterior nucleus-pulvinar complex may be involved in many aspects of visual processing.
我们研究了外侧后核-丘脑枕复合体的外侧后核的外侧部分或纹状接受区（LPl）中的细胞对纹理图案（视觉噪声）运动的反应特性。我们的目的是确定基本的噪声反应特征，并将这些特性与已知投射到LPl的17区细胞的特性进行比较。实际上，所有LPl细胞（87%）都对视觉噪声的运动有反应。诱发放电要么持续，要么以几次爆发为特征。平均而言，正如在皮层中发现的那样，LPl神经元对噪声方向的调谐比光栅更宽泛（带宽分别为49度和36度；t检验，P<0.005）。LPl中的噪声调谐函数与在皮层中发现的相当（平均为48度）。三分之一的LPl单位对噪声的漂移方向没有任何偏好。在纹状皮层中几乎没有遇到这样的细胞。这组LPl细胞通常对光栅方向没有调谐。对于几乎所有LPl细胞，对噪声的反应随漂移速度而变化。平均最佳速度为27.5度/秒，平均带宽为2.5倍频程。LPl细胞比17区的复杂细胞对更广泛的速度范围敏感。本研究结果表明，视觉噪声是研究LPl中细胞运动敏感性的合适刺激。它还表明，噪声反应特性，如方向和速度调谐函数，与纹状皮层中报道的非常相似。17区在LPl细胞视觉噪声反应性中的确切作用仍有待确定。这项研究提供了额外的证据，表明外侧后核-丘脑枕复合体可能参与视觉处理的许多方面。
