Cohen Yale E, Cohen Ian S, Gifford Gordon W
Department of Psychological and Brain Sciences, Dartmouth College, Hanover, NH 03755, USA.
Cereb Cortex. 2004 Dec;14(12):1287-301. doi: 10.1093/cercor/bhh090. Epub 2004 May 27.
The lateral intraparietal area (area LIP) contains a multimodal representation of extra-personal space. To further examine this representation, we trained rhesus monkeys on the predictive-cueing task. During this task, monkeys shifted their gaze to a visual target whose location was predicted by the location of an auditory or visual cue. We found that, when the sensory cue was at the same location as the visual target, the monkeys' mean saccadic latency was faster than when the sensory cue and the visual target were at different locations. This difference in mean saccadic latency was the same for both auditory cues and visual cues. Despite the fact that the monkeys used auditory and visual cues in a similar fashion, LIP neurons responded more to visual cues than to auditory cues. This modality-dependent activity was also seen during auditory and visual memory-guided saccades but to a significantly greater extent than during the predictive-cueing task. Additionally, we found that the firing rate of LIP neurons was inversely correlated with saccadic latency. This study indicates further that modality-dependent differences in LIP activity do not simply reflect differences in sensory processing but also reflect the cognitive and behavioral requirements of a task.
顶叶内侧面区域（LIP区）包含对身外空间的多模态表征。为了进一步研究这种表征，我们让恒河猴接受预测性线索任务训练。在这个任务中，猴子将目光转向一个视觉目标，该目标的位置由听觉或视觉线索的位置预测。我们发现，当感觉线索与视觉目标位于同一位置时，猴子的平均扫视潜伏期比感觉线索和视觉目标位于不同位置时更快。这种平均扫视潜伏期的差异在听觉线索和视觉线索中都是相同的。尽管猴子以类似的方式使用听觉和视觉线索，但LIP神经元对视觉线索的反应比对听觉线索的反应更强烈。这种依赖于模态的活动在听觉和视觉记忆引导的扫视过程中也能看到，但程度比预测性线索任务中要大得多。此外，我们发现LIP神经元的放电频率与扫视潜伏期呈负相关。这项研究进一步表明，LIP活动中依赖于模态的差异不仅简单地反映了感觉处理的差异，还反映了任务的认知和行为要求。
