Moore Tirin, Armstrong Katherine M
Department of Psychology, Princeton University, Princeton, New Jersey 08544, USA.
Nature. 2003 Jan 23;421(6921):370-3. doi: 10.1038/nature01341.
Several decades of psychophysical and neurophysiological studies have established that visual signals are enhanced at the locus of attention. What remains a mystery is the mechanism that initiates biases in the strength of visual representations. Recent evidence argues that, during spatial attention, these biases reflect nascent saccadic eye movement commands. We examined the functional interaction of saccade preparation and visual coding by electrically stimulating sites within the frontal eye fields (FEF) and measuring its effect on the activity of neurons in extrastriate visual cortex. Here we show that visual responses in area V4 could be enhanced after brief stimulation of retinotopically corresponding sites within the FEF using currents below that needed to evoke saccades. The magnitude of the enhancement depended on the effectiveness of receptive field stimuli as well as on the presence of competing stimuli outside the receptive field. Stimulation of non-corresponding FEF representations could suppress V4 responses. The results suggest that the gain of visual signals is modified according to the strength of spatially corresponding eye movement commands.
几十年的心理物理学和神经生理学研究已经证实，视觉信号在注意力集中的位置会得到增强。然而，启动视觉表征强度偏差的机制仍然是个谜。最近的证据表明，在空间注意力过程中，这些偏差反映了初现的扫视眼动指令。我们通过电刺激额叶眼区（FEF）内的位点并测量其对纹外视觉皮层神经元活动的影响，研究了扫视准备与视觉编码的功能相互作用。在此我们表明，使用低于诱发扫视所需的电流短暂刺激FEF内视网膜拓扑对应位点后，V4区的视觉反应会增强。增强的幅度取决于感受野刺激的有效性以及感受野之外竞争性刺激的存在。刺激非对应FEF表征可抑制V4反应。结果表明，视觉信号的增益会根据空间对应眼动指令的强度进行调整。
