Tootell R B, Hamilton S L, Silverman M S, Switkes E
Department of Psychology, University of California, Berkeley 94720.
J Neurosci. 1988 May;8(5):1500-30. doi: 10.1523/JNEUROSCI.08-05-01500.1988.
A series of experiments was carried out using 14C-2-deoxy-d-glucose (DG) in order to examine the functional architecture of macaque striate (primary visual) cortex. This paper describes the results of experiments on uptake during various baseline (or reference) conditions of visual stimulation (described below), and on differences in the functional architecture following monocular versus binocular viewing conditions. In binocular "baseline" experiments, monkeys were stimulated either (1) in the dark, (2) with a diffuse gray screen, or (3) with a very general visual stimulus composed of gratings of varied orientation and spatial frequency. In all of these conditions, DG uptake was found to be topographically uniform within all layers of parafoveal striate cortex. In monocular experiments that were otherwise similar, uptake was topographically uniform within the full extent of the eye dominance strip, in all layers. Certain other visual stimuli produce high uptake in the blobs, and still another set of visual stimuli (including high-spatial-frequency gratings) produce highest uptake between the blobs at parafoveal eccentricities, even in an unanesthetized, unparalyzed monkey. Eye movements per se had no obvious effect on striate DG uptake. Endogenous uptake in the blobs (relative to that in the interblobs) appears higher in the squirrel monkey than in the macaque. The pattern of DG uptake produced by binocular viewing was found to deviate in a number of ways from that expected by linearly summing the component monocular DG patterns. One of the most interesting deviations was an enhancement of the representation of visual field borders between stimuli differing from each other in texture, orientation, direction, etc. This "border enhancement" was confined to striate layers 1-3 (not appearing in any of the striate input layers), and it only appeared following binocular, but not monocular, viewing conditions. The border enhancement may be related to a suppression of DG uptake that occurs during binocular viewing conditions in layers 2 + 3 (and perhaps layers 1 and 4B), but not in layers 4Ca, 4Cb, 5 or 6. Another major class of binocular interaction was a spread of neural activity into the "unstimulated" ocular dominance strips following monocular stimulation. Such an effect was prominent in striate layer 4Ca, but it did not occur in layer 4Cb. This "binocular" spread of DG uptake into the inappropriate eye dominance strip in 4Ca may be related to the appearance of orientation tuning and orientation columns in that layer. No DG effects were seen that depended on the absolute disparity of visual stimuli in macaque striate cortex.
为了研究猕猴纹状（初级视）皮层的功能结构，进行了一系列使用¹⁴C - 2 - 脱氧 - D - 葡萄糖（DG）的实验。本文描述了在各种视觉刺激的基线（或参考）条件下摄取实验的结果，以及单眼与双眼观察条件下功能结构的差异。在双眼“基线”实验中，猴子分别在以下条件下受到刺激：（1）在黑暗中；（2）使用漫射灰屏；（3）使用由不同方向和空间频率的光栅组成的非常一般的视觉刺激。在所有这些条件下，发现DG摄取在中央凹旁纹状皮层的所有层内呈地形学上的均匀分布。在其他方面类似的单眼实验中，摄取在眼优势带的整个范围内的所有层中呈地形学上的均匀分布。某些其他视觉刺激在斑点中产生高摄取，而另一组视觉刺激（包括高空间频率光栅）即使在未麻醉、未麻痹的猴子中，在中央凹偏心度处的斑点之间产生最高摄取。眼动本身对纹状DG摄取没有明显影响。松鼠猴斑点中的内源性摄取（相对于斑间区域）似乎比猕猴中的更高。发现双眼观察产生的DG摄取模式在许多方面偏离了通过线性叠加单眼DG模式所预期的模式。最有趣的偏差之一是在纹理、方向、方向等方面彼此不同的刺激之间的视野边界的表征增强。这种“边界增强”局限于纹状层1 - 3（在任何纹状输入层中均未出现），并且仅在双眼而非单眼观察条件下出现。边界增强可能与在双眼观察条件下在2 + 3层（也许还有1层和4B层）中发生的DG摄取抑制有关，但在4Ca、4Cb、5或6层中不发生。另一类主要的双眼相互作用是单眼刺激后神经活动扩散到“未受刺激”的眼优势带。这种效应在纹状层4Ca中很明显，但在4Cb层中不发生。这种DG摄取在4Ca中向不适当的眼优势带的“双眼”扩散可能与该层中方向调谐和方向柱的出现有关。在猕猴纹状皮层中未观察到依赖于视觉刺激绝对视差的DG效应。
