Galbraith G C, Doan B Q
University of California, Los Angeles, School of Medicine, USA.
Int J Psychophysiol. 1995 Apr;19(3):203-14. doi: 10.1016/0167-8760(95)00008-g.
Reaction time (RT), discrimination sensitivity (d'), and the brainstem frequency-following response (FFR) were recorded in 32 subjects performing a selective attention task. Auditory stimuli were a 400 Hz pure tone and a complex "missing fundamental" (MF) presented dichotically to separate ears (channels). In two tasks, infrequent target stimuli were either of lower intensity or greater duration than standard stimuli. Behavioral results showed consistently better performance (faster RTs and higher d' scores) in the duration task, and better overall detection of MF targets. FFR attention effects were evidenced by differing amplitudes in attend and ignore conditions. Amplitudes in the attended channel were larger to MF stimuli in both tasks, and to the tone stimulus in the duration task. Responses to tone in the intensity task, however, were lowest when the channel was attended, perhaps reflecting some property of greater task difficulty. The demonstration of FFR amplitude differences between attended and ignored channels suggests that selective attention can modify brainstem evoked responses in humans.
对32名执行选择性注意任务的受试者记录了反应时间（RT）、辨别灵敏度（d'）和脑干频率跟随反应（FFR）。听觉刺激为400赫兹纯音和复杂的“缺基音”（MF），分别通过双耳（声道）呈现。在两项任务中，罕见的目标刺激强度低于或持续时间长于标准刺激。行为结果显示，在持续时间任务中表现始终更好（反应时间更快，d'分数更高），并且对MF目标的总体检测更好。FFR的注意效应通过在注意和忽略条件下不同的振幅得以证明。在两项任务中，被注意声道中对MF刺激的振幅更大，在持续时间任务中对纯音刺激的振幅也更大。然而，在强度任务中，当声道被注意时，对纯音的反应最低，这可能反映了更大任务难度的某些特性。被注意和被忽略声道之间FFR振幅差异的证明表明，选择性注意可以改变人类的脑干诱发反应。
