Center for Studies of Psychological Application and School of Psychology, South China Normal University, Guangzhou 510631, PR China.
Epilepsy Center, Shanghai Deji Hospital, No. 378 Gulang Road, Putuo District, Shanghai 200331, PR China.
Cortex. 2018 Sep;106:47-64. doi: 10.1016/j.cortex.2018.05.003. Epub 2018 May 16.
Practice and experiences gradually shape the central nervous system, from the synaptic level to large-scale neural networks. In natural multisensory environment, even when inundated by streams of information from multiple sensory modalities, our brain does not give equal weight to different modalities. Rather, visual information more frequently receives preferential processing and eventually dominates consciousness and behavior, i.e., visual dominance. It remains unknown, however, the supra-modal and modality-specific practice effect during cross-modal selective attention, and moreover whether the practice effect shows similar modality preferences as the visual dominance effect in the multisensory environment. To answer the above two questions, we adopted a cross-modal selective attention paradigm in conjunction with the hybrid fMRI design. Behaviorally, visual performance significantly improved while auditory performance remained constant with practice, indicating that visual attention more flexibly adapted behavior with practice than auditory attention. At the neural level, the practice effect was associated with decreasing neural activity in the frontoparietal executive network and increasing activity in the default mode network, which occurred independently of the modality attended, i.e., the supra-modal mechanisms. On the other hand, functional decoupling between the auditory and the visual system was observed with the progress of practice, which varied as a function of the modality attended. The auditory system was functionally decoupled with both the dorsal and ventral visual stream during auditory attention while was decoupled only with the ventral visual stream during visual attention. To efficiently suppress the irrelevant visual information with practice, auditory attention needs to additionally decouple the auditory system from the dorsal visual stream. The modality-specific mechanisms, together with the behavioral effect, thus support the visual dominance model in terms of the practice effect during cross-modal selective attention.
实践和经验逐渐塑造了中枢神经系统，从突触水平到大规模神经网络。在自然的多感觉环境中，即使被来自多个感觉模态的信息流淹没，我们的大脑也不会对不同模态一视同仁。相反，视觉信息更频繁地受到优先处理，最终主导意识和行为，即视觉优势。然而，在跨感觉选择性注意中，超模态和模态特异性的实践效应尚不清楚，而且实践效应是否表现出与多感觉环境中视觉优势效应相似的模态偏好。为了回答上述两个问题，我们采用了跨感觉选择性注意范式，并结合混合 fMRI 设计。行为上，随着练习的进行，视觉表现显著提高，而听觉表现保持不变，表明与听觉注意相比，视觉注意更灵活地适应行为。在神经水平上，实践效应与额顶执行网络中的神经活动减少和默认模式网络中的活动增加有关，而与注意的模态无关，即超模态机制。另一方面，随着练习的进展，观察到听觉和视觉系统之间的功能解耦，其变化取决于注意的模态。在听觉注意时，听觉系统与背侧和腹侧视觉流都解耦，而在视觉注意时，听觉系统仅与腹侧视觉流解耦。为了随着练习有效地抑制无关的视觉信息，听觉注意需要将听觉系统与背侧视觉流进一步解耦。因此，模态特异性机制与行为效应一起，支持跨感觉选择性注意中实践效应的视觉优势模型。
