Bridgeman B
Brain Res. 1980 Sep 8;196(2):347-64. doi: 10.1016/0006-8993(80)90400-x.
After measuring metacontrast masking psychophysically in two monkeys, recordings from parafoveal striate cortex of the monkeys were made while they performed a simultaneous brightness discrimination and while they judged the apparent brightness of a stimulus masked by metacontrast. The size and orientation of the stimuli were held constant regardless of receptive field parameters. In both tasks, the single-cell activity immediately following the presentation of flashed discrimination stimuli reflected only stimulus parameters, and was independent of the monkey's behavioral choice. Later activity (up to 400 msec post-stimulus) was significantly greater if the monkey was about to press the correct panel in the discrimination, or if he pressed the unmasked side (with greater apparent brightness but identical intensity) in the masking paradigm. One quarter of the cells showed a change in firing rate during the 250 msec preceding the behavioral response, though the difference in overall firing level between correct and incorrect brightness discrimination trials was diminished in this epoch, and the corresponding firing difference in metacontrast trials was not significant. The temporal pattern of firing also differed between correct and incorrect trials in the pre-response interval. The results suggest an iterative or recurrent coding of visual information, where the same cells participate in early, late, preresponse coding in different ways.
在对两只猴子进行元对比掩蔽的心理物理学测量后，在猴子执行同时亮度辨别任务以及判断被元对比掩蔽的刺激的表观亮度时，对它们的中央凹旁纹状皮层进行了记录。无论感受野参数如何，刺激的大小和方向都保持不变。在这两项任务中，呈现闪光辨别刺激后立即出现的单细胞活动仅反映刺激参数，并且与猴子的行为选择无关。如果猴子即将在辨别任务中按下正确的面板，或者如果它在掩蔽范式中按下未被掩蔽的一侧（具有更高的表观亮度但强度相同），则后期活动（刺激后长达400毫秒）会显著增强。四分之一的细胞在行为反应前的250毫秒内放电率发生了变化，尽管在这个时间段内正确和错误亮度辨别试验之间的总体放电水平差异有所减小，并且元对比试验中的相应放电差异并不显著。在反应前间隔中，正确和错误试验的放电时间模式也有所不同。结果表明视觉信息存在迭代或循环编码，其中相同的细胞以不同方式参与早期、晚期、反应前编码。
