Reynolds John H, Chelazzi Leonardo
Systems Neurobiology Laboratory, Salk Institute for Biological Studies, La Jolla, California 92037-1099, USA.
Annu Rev Neurosci. 2004;27:611-47. doi: 10.1146/annurev.neuro.26.041002.131039.
Single-unit recording studies in the macaque have carefully documented the modulatory effects of attention on the response properties of visual cortical neurons. Attention produces qualitatively different effects on firing rate, depending on whether a stimulus appears alone or accompanied by distracters. Studies of contrast gain control in anesthetized mammals have found parallel patterns of results when the luminance contrast of a stimulus increases. This finding suggests that attention has co-opted the circuits that mediate contrast gain control and that it operates by increasing the effective contrast of the attended stimulus. Consistent with this idea, microstimulation of the frontal eye fields, one of several areas that control the allocation of spatial attention, induces spatially local increases in sensitivity both at the behavioral level and among neurons in area V4, where endogenously generated attention increases contrast sensitivity. Studies in the slice have begun to explain how modulatory signals might cause such increases in sensitivity.
对猕猴的单神经元记录研究已经仔细记录了注意力对视觉皮层神经元反应特性的调节作用。根据刺激是单独出现还是伴有干扰物，注意力对 firing rate 产生质的不同影响。对麻醉哺乳动物的对比度增益控制研究发现，当刺激的亮度对比度增加时，会出现类似的结果模式。这一发现表明，注意力已经利用了介导对比度增益控制的回路，并且它通过增加被关注刺激的有效对比度来发挥作用。与这一观点一致的是，对额叶眼区（控制空间注意力分配的几个区域之一）进行微刺激，在行为水平和 V4 区的神经元中都会引起空间局部的敏感度增加，内源性产生的注意力在 V4 区会增加对比度敏感度。切片研究已经开始解释调节信号可能如何导致这种敏感度增加。
