Berti Stefan, Roeber Urte
Department for Psychology, Johannes Gutenberg-University Mainz, Wallstraße 3, 55099 Mainz, Germany.
Disciplin of Psychology, School of Health and Human Sciences, Southern Cross University, Hogbin Drive, Coffs Harbour, NSW 2450, Australia ; Institute for Psychology, University of Leipzig, Seeburgstraße 14-20, 04103 Leipzig, Germany ; Biomedical Science, School of Medical Sciences, The University of Sydney, P.O. Box 170, Lidcombe, NSW 1825, Australia.
Neurosci J. 2013;2013:172614. doi: 10.1155/2013/172614. Epub 2013 May 12.
Encoding and maintenance of information in visual working memory in an S1-S2 task with a 1500 ms retention phase were investigated by means of event-related brain potentials (ERPs). Participants were asked to decide whether two visual stimuli were physically identical (identity comparison (IC) task) or belonged to the same set or category of equivalent patterns (category comparison (CC) task). The stimuli differ with regard to two features. (1) Each pattern can belong to a set of either four (ESS 4) or eight (ESS 8) equivalent patterns, mirroring differences in the complexity with regard to the representational structure of each pattern (i.e., equivalence set size (ESS)). (2) The set of patterns differ with regard to the rated complexity. Memory performance obtained the effects of the task instructions (IC versus CC) and the ESS (ESS 4 versus ESS 8) but not of the rated complexity. ERPs in the retention interval reveal that the stimulus-related factors (subjective complexity and ESS) affect the encoding of the stimuli as mirrored by the pronounced P3b amplitude in ESS 8 compared to ESS 4 patterns. Importantly, these effects are independent of task instructions. The pattern of results suggests an automatic processing of the ESS in the encoding phase.
通过事件相关脑电位（ERP）研究了在具有1500毫秒保持期的S1-S2任务中视觉工作记忆中信息的编码和维持。要求参与者判断两个视觉刺激在物理上是否相同（同一性比较（IC）任务），或者是否属于同一组或等价模式的同一类别（类别比较（CC）任务）。刺激在两个特征方面有所不同。（1）每个模式可以属于一组四个（ESS 4）或八个（ESS 8）等价模式，反映了每个模式的表征结构在复杂性方面的差异（即等价集大小（ESS））。（2）模式集在额定复杂性方面有所不同。记忆表现受到任务指令（IC与CC）和ESS（ESS 4与ESS 8）的影响，但不受额定复杂性的影响。保持间隔期的ERP显示，刺激相关因素（主观复杂性和ESS）会影响刺激的编码，如与ESS 4模式相比，ESS 8中明显的P3b振幅所反映的那样。重要的是，这些影响与任务指令无关。结果模式表明在编码阶段对ESS进行了自动处理。
