Unimodal and Bimodal Access to Sensory Working Memories by Auditory and Visual Impulses
Unimodal and Bimodal Access to Sensory Working Memories by Auditory and Visual Impulses
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DOI：
10.1523/jneurosci.1194-19.2019
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发表时间：
2019-11
期刊：
影响因子：
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通讯作者：
Michael J. Wolff;G. Kandemir;M. Stokes;Elkan G. Akyürek
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文献类型：
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作者：
Michael J. Wolff;G. Kandemir;M. Stokes;Elkan G. Akyürek
尚不清楚感觉加工区域在多大程度上参与了工作记忆(WM)中感觉信息的维持。到目前为止，以前的研究一直依赖于在相应的感觉皮质中发现神经活动，而忽略了潜在的活动沉默机制，如连接依赖的编码。最近发现，视觉WM维持过程中的视觉刺激通过自下而上的神经反应揭示了WM依赖的变化。在这里，我们测试这种冲动反应是否具有独特的视觉和感官特性。受试者(男女)完成视觉和听觉WM任务，同时记录脑电。在维持期，WM网络受到固定和任务中立的听觉和视觉刺激的连续干扰。我们发现，在维持纯音的过程中出现的中性听觉脉冲刺激导致了WM依赖的神经反应，这为先前报道的视觉WM发现的听觉对应提供了证据。有趣的是，视觉刺激还导致听觉WM依赖的脉冲反应，这意味着视觉皮质直接或间接地参与了听觉信息的维持，成为通向其他地方的神经听觉WM表征的途径。相比之下，在视觉WM维持期间，只有对视觉刺激的冲动反应是特定于内容的，这表明视觉信息被维持在感觉特定的神经网络中，与听觉处理区域分开。重要性陈述工作记忆是智能、适应性行为的重要组成部分。我们对支持它的神经机制的理解最近发生了转变：工作记忆可能依赖于神经元连接性的瞬时变化，而不是依赖于一系列不间断的神经活动，而这种变化可以在活动-沉默的大脑状态下有效地维持。以前的研究使用视觉冲动刺激来扰乱记忆网络，已经发现这种沉默状态与视觉工作记忆中线方向的保持有关。在这里，我们展示了听觉工作记忆类似地保留听觉信息。我们还在视觉工作记忆中观察到了感觉特有的脉冲反应，而听觉记忆对视觉和听觉脉冲的反应都是双峰的，这可能反映了工作记忆的视觉优势。
It is unclear to what extent sensory processing areas are involved in the maintenance of sensory information in working memory (WM). Previous studies have thus far relied on finding neural activity in the corresponding sensory cortices, neglecting potential activity-silent mechanisms, such as connectivity-dependent encoding. It has recently been found that visual stimulation during visual WM maintenance reveals WM-dependent changes through a bottom-up neural response. Here, we test whether this impulse response is uniquely visual and sensory-specific. Human participants (both sexes) completed visual and auditory WM tasks while electroencephalography was recorded. During the maintenance period, the WM network was perturbed serially with fixed and task-neutral auditory and visual stimuli. We show that a neutral auditory impulse-stimulus presented during the maintenance of a pure tone resulted in a WM-dependent neural response, providing evidence for the auditory counterpart to the visual WM findings reported previously. Interestingly, visual stimulation also resulted in an auditory WM-dependent impulse response, implicating the visual cortex in the maintenance of auditory information, either directly or indirectly, as a pathway to the neural auditory WM representations elsewhere. In contrast, during visual WM maintenance, only the impulse response to visual stimulation was content-specific, suggesting that visual information is maintained in a sensory-specific neural network, separated from auditory processing areas. SIGNIFICANCE STATEMENT Working memory is a crucial component of intelligent, adaptive behavior. Our understanding of the neural mechanisms that support it has recently shifted: rather than being dependent on an unbroken chain of neural activity, working memory may rely on transient changes in neuronal connectivity, which can be maintained efficiently in activity-silent brain states. Previous work using a visual impulse stimulus to perturb the memory network has implicated such silent states in the retention of line orientations in visual working memory. Here, we show that auditory working memory similarly retains auditory information. We also observed a sensory-specific impulse response in visual working memory, while auditory memory responded bimodally to both visual and auditory impulses, possibly reflecting visual dominance of working memory.