Tsunoda Yoshiaki, Kakei Shinji
Department of Behavioral Physiology, Tokyo Metropolitan Institute for Neuroscience, 2-6 Musashi-dai, Fuchu, Tokyo 183-8526, Japan.
Neurosci Lett. 2008 Mar 12;433(2):152-7. doi: 10.1016/j.neulet.2007.12.063. Epub 2008 Jan 10.
Anticipating the timing of behaviorally relevant events is crucial for organizing movement. The time to initiate actions based on events (i.e., reaction time (RT)) is a useful measure to quantify states of anticipation. Few studies have examined how anticipation affects the timing of limb movements. We addressed this question behaviorally with two macaque monkeys performing delayed wrist movement tasks. The interval between target onset and go signal (i.e., foreperiod) varied randomly from 1 to 2 s. The probability that the go signal was about to occur (i.e., hazard rate) increased as the foreperiod increased. The kinematics of wrist movements was not influenced by foreperiod duration. Analyzing RT data with the LATER model indicated that RT distributions swiveled on reciprobit plots as foreperiods increased, suggesting that changes in RT distributions were due to changes in anticipation. RT was inversely related to hazard rate. To better understand the general implications of anticipatory states, we introduced an additional rectangular foreperiod distribution that ranged from 0.9 to 1.5 s. For that distribution, the hazard rate peaks were higher than those of the 1-2 s distribution. Changes in RT were clearly explained by quantitative differences in hazard rate. The decrease in RT in the 0.9-1.5 s foreperiod distribution was greater than that in the 1-2 s foreperiod. Thus, monkeys learned the temporal structure of foreperiod distributions and anticipated the onset of the go signal, based on hazard rates.
预测与行为相关事件的时间对于组织运动至关重要。基于事件启动行动的时间(即反应时间(RT))是量化预期状态的一个有用指标。很少有研究探讨预期如何影响肢体运动的时间安排。我们通过让两只猕猴执行延迟腕部运动任务,从行为学角度解决了这个问题。目标出现与开始信号之间的间隔(即前周期)在1到2秒之间随机变化。开始信号即将出现的概率(即危险率)随着前周期的增加而增加。腕部运动的运动学不受前周期持续时间的影响。用LATER模型分析反应时间数据表明,随着前周期增加,反应时间分布在倒数概率图上发生旋转,这表明反应时间分布的变化是由于预期的变化。反应时间与危险率呈负相关。为了更好地理解预期状态的一般含义,我们引入了一个额外的矩形前周期分布,范围从0.9到1.5秒。对于该分布,危险率峰值高于1 - 2秒分布的峰值。反应时间的变化可以通过危险率的定量差异得到清晰解释。在0.9 - 1.5秒前周期分布中反应时间的减少大于在1 - 2秒前周期分布中的减少。因此,猴子学会了前周期分布的时间结构,并根据危险率预测开始信号的出现。