Lehnert Günther, Zimmer Hubert D
Brain and Cognition Unit, Department of Psychology, Saarland University, PO Box 151 150, 66041 Saarbrücken, Germany.
Brain Res. 2008 Sep 16;1230:158-67. doi: 10.1016/j.brainres.2008.07.005. Epub 2008 Jul 9.
We compared spatial short-term memory for visual and auditory stimuli in an event-related slow potentials study. Subjects encoded object locations of either four or six sequentially presented auditory or visual stimuli and maintained them during a retention period of 6 s. Slow potentials recorded during encoding were modulated by the modality of the stimuli. Stimulus related activity was stronger for auditory items at frontal and for visual items at posterior sites. At frontal electrodes, negative potentials incrementally increased with the sequential presentation of visual items, whereas a strong transient component occurred during encoding of each auditory item without the cumulative increment. During maintenance, frontal slow potentials were affected by modality and memory load according to task difficulty. In contrast, at posterior recording sites, slow potential activity was only modulated by memory load independent of modality. We interpret the frontal effects as correlates of different encoding strategies and the posterior effects as a correlate of common coding of visual and auditory object locations.
在一项事件相关慢电位研究中，我们比较了视觉和听觉刺激的空间短期记忆。受试者对四个或六个依次呈现的听觉或视觉刺激的物体位置进行编码，并在6秒的保持期内维持这些位置信息。编码过程中记录的慢电位受刺激模态的调节。额叶部位的听觉项目和后部部位的视觉项目的刺激相关活动更强。在额叶电极处，随着视觉项目的依次呈现，负电位逐渐增加，而在每个听觉项目编码期间会出现一个强烈的瞬态成分，没有累积增加。在维持阶段，额叶慢电位根据任务难度受模态和记忆负荷的影响。相比之下，在后部记录部位，慢电位活动仅受记忆负荷调节，与模态无关。我们将额叶效应解释为不同编码策略的相关因素，将后部效应解释为视觉和听觉物体位置共同编码的相关因素。
