Division of Cognitive Psychology and Neuropsychology, Institute of Behavioural Sciences, University of Helsinki, Finland.
Brain Res. 2013 Feb 16;1496:55-69. doi: 10.1016/j.brainres.2012.12.013. Epub 2012 Dec 19.
We used functional magnetic resonance imaging to measure human brain activity during tasks demanding selective attention to auditory or visual stimuli delivered in concurrent streams. Auditory stimuli were syllables spoken by different voices and occurring in central or peripheral space. Visual stimuli were centrally or more peripherally presented letters in darker or lighter fonts. The participants performed a phonological, spatial or "simple" (speaker-gender or font-shade) discrimination task in either modality. Within each modality, we expected a clear distinction between brain activations related to nonspatial and spatial processing, as reported in previous studies. However, within each modality, different tasks activated largely overlapping areas in modality-specific (auditory and visual) cortices, as well as in the parietal and frontal brain regions. These overlaps may be due to effects of attention common for all three tasks within each modality or interaction of processing task-relevant features and varying task-irrelevant features in the attended-modality stimuli. Nevertheless, brain activations caused by auditory and visual phonological tasks overlapped in the left mid-lateral prefrontal cortex, while those caused by the auditory and visual spatial tasks overlapped in the inferior parietal cortex. These overlapping activations reveal areas of multimodal phonological and spatial processing. There was also some evidence for intermodal attention-related interaction. Most importantly, activity in the superior temporal sulcus elicited by unattended speech sounds was attenuated during the visual phonological task in comparison with the other visual tasks. This effect might be related to suppression of processing irrelevant speech presumably distracting the phonological task involving the letters.
我们使用功能磁共振成像来测量人类大脑在需要选择性注意同时呈现的听觉或视觉刺激的任务中的活动。听觉刺激是由不同声音说出的音节，出现在中央或外围空间。视觉刺激是中央或更外围呈现的字母，字体较暗或较亮。参与者在任一种模式下执行语音、空间或“简单”（说话者性别或字体阴影）辨别任务。在每种模式中，我们预计与非空间和空间处理相关的大脑激活之间会有明显区别，正如之前的研究报告的那样。然而，在每种模式中，不同的任务在特定于模式的（听觉和视觉）皮质中以及顶叶和额叶大脑区域中激活了大量重叠的区域，这些重叠可能是由于每种模式中所有三个任务的注意力共同作用，或者是处理与任务相关的特征以及注意力刺激中变化的与任务无关的特征之间的相互作用。尽管如此，听觉和视觉语音任务引起的大脑激活在左中侧前额叶皮质中重叠，而听觉和视觉空间任务引起的大脑激活在顶下皮质中重叠。这些重叠的激活揭示了多模态语音和空间处理的区域。也有一些证据表明存在跨模态注意力相关的相互作用。最重要的是，与未被注意的语音声音相关的颞上回的活动在视觉语音任务中与其他视觉任务相比减弱了。这种效应可能与处理无关的语音的抑制有关，这些语音可能会分散涉及字母的语音任务。
