Dyson Benjamin J, Alain Claude
Department of Psychology, University of Sussex, Falmer, Brighton, BN1 9QH, UK.
Brain Res. 2008 Jan 16;1189:135-44. doi: 10.1016/j.brainres.2007.10.093. Epub 2007 Nov 12.
The effects of local and global context on concurrent sound segregation were examined using a mistuned harmonic paradigm. Presented with the same sounds over three conditions, participants were asked to either categorise the incoming complex according to pitch or harmonicity (active listening) or watch a muted subtitled movie of their choice (passive listening). Global context was defined according to task instruction, while local context was defined relative to the repetition or change of harmonicity across trials. An interaction between global and local context in both behavioural and event-related potential measures was found, with participants showing sensitivity to change and repetition in harmonicity when it was task-relevant, in addition to enhanced P3 amplitude for cases where a tuned stimulus changed into a mistuned stimulus over consecutive trials. The data are discussed in terms of current models of concurrent sound perception and how top-down processes might influence these mechanisms.
使用失谐谐波范式研究了局部和全局背景对同时进行的声音分离的影响。在三种条件下呈现相同的声音，要求参与者要么根据音高或和声对传入的复合体进行分类（主动聆听），要么观看他们选择的静音字幕电影（被动聆听）。全局背景根据任务指令定义，而局部背景相对于试验中谐波的重复或变化定义。在行为和事件相关电位测量中均发现了全局和局部背景之间的相互作用，参与者在谐波与任务相关时对谐波的变化和重复表现出敏感性，此外，对于在连续试验中调谐刺激变为失谐刺激的情况，P3波幅增强。根据当前的同时声音感知模型以及自上而下的过程可能如何影响这些机制对数据进行了讨论。
