Saetrevik Bjørn, Hugdahl Kenneth
Department of Biological and Medical Psychology, University of Bergen, Jonas Lies vei 91, N-5009 Bergen, Norway.
Neuropsychologia. 2007 Jan 28;45(2):282-7. doi: 10.1016/j.neuropsychologia.2006.07.005. Epub 2006 Sep 22.
The typical finding in dichotic listening with verbal stimuli is the right ear advantage (REA), indicating a left hemisphere processing superiority, thus making this an effective tool in studying hemispheric asymmetry. It has been shown that the amplitude of the REA can be modulated by instructions to direct attention to left or right side. The current study attempted to modulate the REA by changing the dichotic listening stimulus situation. In Experiment 1, a consonant vowel (CV) syllable prime was presented binaurally briefly before the dichotic stimuli (consisting of two CVs). The prime could be the same as either the left or right ear dichotic stimulus, or it could be a different stimulus. Participants were instructed to report the CV they heard best from the dichotic syllable pair. The traditional REA was found when the prime was different from both dichotic stimuli. When the prime matched the CV in the left half of the subsequent dichotic pair, the REA was increased, while if the prime matched the right half, the REA was reduced. In order to see at which perceptual stage the modulation takes place, in Experiment 2 the prime was visual, presented on a PC screen. The same effect was seen, although the modulation of the REA was weaker. We propose that the memory trace of the prime is a source of interference, and causes cognitive control of attention to inhibit recognition of stimuli similar to recent distractors. Based on previous studies we propose that this inhibition of attention is performed by prefrontal cortical areas. Similarities to the mechanisms involved in negative priming and implications for auditory laterality studies are pointed out.
在使用言语刺激进行双耳分听时的典型发现是右耳优势（REA），这表明左半球处理能力更强，因此使其成为研究半球不对称性的有效工具。研究表明，通过引导注意力指向左侧或右侧的指令，可以调节REA的幅度。当前的研究试图通过改变双耳分听刺激情境来调节REA。在实验1中，在双耳分听刺激（由两个辅音元音（CV）音节组成）之前，短暂地双耳呈现一个辅音元音（CV）音节启动刺激。启动刺激可以与左耳或右耳的双耳分听刺激相同，也可以是不同的刺激。参与者被要求报告他们从双耳音节对中听到的最佳CV。当启动刺激与两个双耳分听刺激都不同时，发现了传统的REA。当启动刺激与后续双耳分听对左半部分的CV匹配时，REA增加，而如果启动刺激与右半部分匹配，则REA降低。为了确定调节发生在哪个感知阶段，在实验2中，启动刺激是视觉的，呈现在电脑屏幕上。虽然REA的调节较弱，但也观察到了相同的效果。我们提出，启动刺激的记忆痕迹是干扰的来源，并导致注意力的认知控制抑制对与近期干扰物相似的刺激的识别。基于先前的研究，我们提出这种注意力抑制是由前额叶皮质区域执行的。指出了与负启动中涉及的机制的相似性以及对听觉偏侧性研究的意义。
