Brain Function Network Of Initiation Of Cross-Modal Working Memory

Cross-modal working memory integrate information from various sensory modalities and it involves the co-activation of different functional brain network. However, the interaction mechanism of the brain networks when the brain initialize the cross-modal working memory remains unclear. In this study, the delayed match-to-sample (DMS) paradigm is used to conduct the audio-audio uni-modal and audio-visual cross-modal working memory task. By inserting the modal-matching task cue in the delay stage, we studied the influence of cross-modal task cue on the working memory task and its brain mechanism, especially the cue-induced change of brain activity and function connections. By analyzing the task’s functional magnetic resonance image (fMRI), we find the cross-modal task cue induced more activities than the uni-modal task cue.in the left thalamus, left superior parietal lobule (1-SPL) and left premotor area. With psycho-physiological interaction (PPI) analysis, We found that after primed by the task cue, significantly increased functional connectivity is found between the fronto-parietal network and the ventral visual pathway in the cross-modal condition than in the uni-modal condition, while significantly decreased functional connectivity is found between the default mode network and the dorsal attention network, visual network and thalamus, and between the salience network and audio areas, and between the dorsal attention network and audio areas. These changes in functional connectivity may be caused by the dynamic modulation and reallocation of cognitive resource among different sensory modalities, and is initialized by the task cue. Especially, the cognitive resource will be less allocated to the visual and attention network in the uni-modal task only requires the coming audio information, and less allocated to the audio system when the coming visual information needs to be attended while the coming audio information needs to be ignored.