Bell A H, Corneil B D, Munoz D P, Meredith M A
Centre for Neuroscience Studies, Department of Physiology, Queen's University, Kingston, Ontario, Canada K7L 3 N6.
Eur J Neurosci. 2003 Nov;18(10):2867-73. doi: 10.1111/j.1460-9568.2003.02976.x.
Neurons in the intermediate and deep layers of the superior colliculus (SC) often exhibit sensory-related activity in addition to discharging for saccadic eye movements. These two patterns of activity can combine so that modifications of the sensory response can lead to changes in orienting behaviour. Can behavioural factors, however, influence sensory activity? In this study of rhesus monkeys, we isolate one behavioural factor, the state of visual fixation, and examine its influences on sensory processing and multisensory integration in the primate SC. Two interleaved fixation conditions were used: a FIX condition requiring exogenous fixation of a visible fixation point; and a FIX-BLINK condition, requiring endogenous fixation in the absence of a visible fixation point. Neurons of the SC were influenced by fixation state, exhibiting both lower levels of sensory activity and reduced multisensory interactions when fixation was exogenously engaged on a visible fixation point. These results are consistent with active visual fixation suppressing responses to extraneous stimuli, and thus demonstrate that sensory processing and multisensory responses in the SC are not dependent solely on the physical properties of the sensory environment, but are also dynamically influenced by the behavioural state of the animal.
上丘（SC）中层和深层的神经元除了在眼球扫视运动时放电外，通常还表现出与感觉相关的活动。这两种活动模式可以结合起来，使得感觉反应的改变能够导致定向行为的变化。然而，行为因素会影响感觉活动吗？在这项针对恒河猴的研究中，我们分离出一个行为因素，即视觉注视状态，并研究其对灵长类动物上丘感觉处理和多感觉整合的影响。我们使用了两种交错的注视条件：一种是FIX条件，要求对外在可见的注视点进行外源性注视；另一种是FIX - BLINK条件，要求在没有可见注视点的情况下进行内源性注视。上丘的神经元受到注视状态的影响，当外源性地注视一个可见的注视点时，它们表现出较低水平的感觉活动以及减少的多感觉相互作用。这些结果与主动视觉注视抑制对外界刺激的反应相一致，因此表明上丘中的感觉处理和多感觉反应不仅仅取决于感觉环境的物理特性，还受到动物行为状态的动态影响。
