Winkowski Daniel E, Knudsen Eric I
Stanford University Medical Center, Neurobiology Department, Stanford, California 94305-5125, USA.
J Neurosci. 2007 Nov 28;27(48):13279-91. doi: 10.1523/JNEUROSCI.3937-07.2007.
We studied the effects of electrically microstimulating a gaze-control area in the owl's forebrain, the arcopallial gaze fields (AGFs), on the responsiveness of neurons in the optic tectum (OT) to visual and auditory stimuli. Microstimulation of the AGF enhanced the visual and auditory responsiveness and stimulus discriminability of OT neurons representing the same location in space as that represented at the microstimulation site in the AGF. At such OT sites, AGF microstimulation also sharpened auditory receptive fields and shifted them toward the location represented at the AGF stimulation site. At the same time, AGF microstimulation suppressed the responsiveness of OT neurons that represented visual or auditory stimuli at other locations in space. The top-down influences of this forebrain gaze-control area on sensory responsiveness in the owl OT are strikingly similar to the space-specific regulation of visual responsiveness in the monkey visual cortex produced by voluntary attention as well as by microstimulation of the frontal eye fields. This experimental approach provides a means for discovering mechanisms that underlie the top-down regulation of sensory responses.
我们研究了电微刺激猫头鹰前脑的一个注视控制区域——弧状皮质注视区（AGF），对中脑顶盖（OT）神经元对视觉和听觉刺激的反应性的影响。对AGF的微刺激增强了OT神经元的视觉和听觉反应性以及刺激辨别能力，这些OT神经元所代表的空间位置与AGF微刺激部位所代表的空间位置相同。在这些OT部位，AGF微刺激还锐化了听觉感受野，并将它们向AGF刺激部位所代表的位置移动。与此同时，AGF微刺激抑制了OT神经元对空间中其他位置的视觉或听觉刺激的反应性。这个前脑注视控制区域对猫头鹰OT感觉反应性的自上而下的影响，与自愿注意力以及额叶眼区微刺激所产生的对猴子视觉皮层视觉反应性的空间特异性调节惊人地相似。这种实验方法为发现感觉反应自上而下调节的潜在机制提供了一种手段。
