Rockstroh B, Müller M, Heinz A, Wagner M, Berg P, Elbert T
Fachgruppe Psychologie, Universität Konstanz, Germany.
Biol Psychol. 1996 Mar 8;43(1):41-55. doi: 10.1016/0301-0511(95)05175-9.
The modulation of auditory input processing in relation to slow event-related potentials was examined in two studies. A steady-state response (SSR) was evoked by a stimulus train delivered at 40 Hz. Slow potentials were elicited by an oddball task implemented as changes in the pitch of single stimuli within this 40-Hz train. In study 1, subjects responded to rare targets by means of a button press. In study 2, subjects responded to targets by means of a motor response in one session and by silent counting in another session. In both studies, the oddball task elicited a P300 to targets. SSR amplitude was reduced 100 ms following each stimulus, while a second amplitude reduction around 350-400 ms was discovered following targets, in particular, following a button press. Parallel to SSR amplitude reductions, the latencies between stimulus and subsequent SSR peak were reduced. Results indicate that processing of oddball stimuli and motor responding alters 'automatic' auditory processing at the level of the primary auditory cortex; the second SSR amplitude reduction which develops in parallel to P300 might support the hypothesis that slow positive potentials indicate widespread (disfacilitation) inhibition of cortical neural excitability.
两项研究考察了与慢事件相关电位有关的听觉输入处理的调制情况。通过以40赫兹传递的刺激序列诱发稳态反应（SSR）。通过将40赫兹序列中单个刺激的音高变化作为异常刺激任务来诱发慢电位。在研究1中，受试者通过按键对罕见目标做出反应。在研究2中，受试者在一个实验环节中通过运动反应对目标做出反应，而在另一个实验环节中通过默读计数做出反应。在两项研究中，异常刺激任务都诱发了对目标的P300。每次刺激后100毫秒时SSR振幅降低，而在目标之后，特别是在按键之后，在350 - 400毫秒左右发现了第二次振幅降低。与SSR振幅降低并行，刺激与随后的SSR峰值之间的潜伏期缩短。结果表明，异常刺激的处理和运动反应在初级听觉皮层水平上改变了“自动”听觉处理；与P300并行出现的第二次SSR振幅降低可能支持这样的假设，即慢正电位表明皮质神经兴奋性存在广泛的（去易化）抑制。
