Multisensory information facilitates reaction speed by enlarging activity difference between superior colliculus hemispheres in rats.
Multisensory information facilitates reaction speed by enlarging activity difference between superior colliculus hemispheres in rats.
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DOI：
10.1371/journal.pone.0025283
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发表时间：
2011
期刊：
影响因子：
3.7
通讯作者：
Yamamori T
中科院分区：
文献类型：
--
作者：
Hirokawa J;Sadakane O;Sakata S;Bosch M;Sakurai Y;Yamamori T
动物对多感官刺激的行为反应比对单感官刺激的反应快。上级丘（SC），它接受来自不同感觉模态的多种输入，被认为是参与运动反应的启动。然而，多感官信息促进运动反应的机制尚未被理解。在这里，我们表明，多感官信息调节SC神经元之间的竞争，以引起更快的反应。我们进行了多单元记录从SC的大鼠执行两个替代的空间歧视任务，使用听觉和/或视觉刺激。我们发现，一个大的SC神经元的人口显示出方向选择性活动之前，运动在响应的刺激，无论刺激方式。逐试相关分析表明，在逆运动时，许多SC神经元的运动前活动随反应速度的加快而增加，而在同运动时，另一群SC神经元的运动前活动随反应速度的加快而减少。当视觉和听觉刺激同时呈现时，用于逆向运动的神经元群体的运动前活动被增强，而用于同向运动的另一神经元群体的运动前活动被抑制。使用蝇蕈醇单侧失活SC延长了反向运动的反应时间，但缩短了同向运动的反应时间。这些发现表明，SC半球之间的活动差异调节运动反应的反应速度，和多感官信息扩大的活动差异，导致更快的反应。
Animals can make faster behavioral responses to multisensory stimuli than to unisensory stimuli. The superior colliculus (SC), which receives multiple inputs from different sensory modalities, is considered to be involved in the initiation of motor responses. However, the mechanism by which multisensory information facilitates motor responses is not yet understood. Here, we demonstrate that multisensory information modulates competition among SC neurons to elicit faster responses. We conducted multiunit recordings from the SC of rats performing a two-alternative spatial discrimination task using auditory and/or visual stimuli. We found that a large population of SC neurons showed direction-selective activity before the onset of movement in response to the stimuli irrespective of stimulation modality. Trial-by-trial correlation analysis showed that the premovement activity of many SC neurons increased with faster reaction speed for the contraversive movement, whereas the premovement activity of another population of neurons decreased with faster reaction speed for the ipsiversive movement. When visual and auditory stimuli were presented simultaneously, the premovement activity of a population of neurons for the contraversive movement was enhanced, whereas the premovement activity of another population of neurons for the ipsiversive movement was depressed. Unilateral inactivation of SC using muscimol prolonged reaction times of contraversive movements, but it shortened those of ipsiversive movements. These findings suggest that the difference in activity between the SC hemispheres regulates the reaction speed of motor responses, and multisensory information enlarges the activity difference resulting in faster responses.