Parametric Alpha- and Beta-Band Signatures of Supramodal Numerosity Information in Human Working Memory
Parametric Alpha- and Beta-Band Signatures of Supramodal Numerosity Information in Human Working Memory
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DOI：
10.1523/jneurosci.4580-13.2014
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发表时间：
2014-03
期刊：
影响因子：
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通讯作者：
B. Spitzer;S. Fleck;F. Blankenburg
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文献类型：
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作者：
B. Spitzer;S. Fleck;F. Blankenburg
数量可以通过模拟估计来评估，类似于连续的量值，或者通过对集合中的单个项目进行离散量化。虽然这两个过程在多大程度上依赖于共同的神经机制仍然存在争议，但最近对感觉工作记忆（WM）的研究已经确定了连续幅度信息的振荡特征，即前额叶上β活动（20-30 Hz）的定量调制。在这里，我们研究了这种参数振荡WM活动也可能反映离散项目的数量的抽象评估。我们记录EEG，而参与者（n = 24）处理的刺激脉冲的数量在视觉，听觉或触觉的方式，在其他相同的实验条件下。行为反应曲线显示不同程度的模拟估计和离散化量化的不同方式。在WM的持续加工过程中，后部α振荡（8-13 Hz）的幅度反映了与维持较大的离散项目集相关的记忆负荷增加。相比之下，右前额叶上β（20-30 Hz）的早期数字依赖性调制具体反映了数字通过模拟估计评估的程度，包括呈现方式之间和呈现方式内。总之，模拟近似，但不是离散表示的数字信息表现出类似于一个连续的感觉幅度的参数振荡签名。结果表明，分离振荡机制的抽象数字集成，在超模态处理阶段，在人类WM。
Numerosity can be assessed by analog estimation, similar to a continuous magnitude, or by discrete quantification of the individual items in a set. While the extent to which these two processes rely on common neural mechanisms remains debated, recent studies of sensory working memory (WM) have identified an oscillatory signature of continuous magnitude information, in terms of quantitative modulations of prefrontal upper beta activity (20–30 Hz). Here, we examined how such parametric oscillatory WM activity may also reflect the abstract assessment of the numerosity of discrete items. We recorded EEG while participants (n = 24) processed the number of stimulus pulses presented in the visual, auditory, or tactile modality, under otherwise identical experimental conditions. Behavioral response profiles showed varying degrees of analog estimation and of discretized quantification in the different modalities. During sustained processing in WM, the amplitude of posterior alpha oscillations (8–13 Hz) reflected the increased memory load associated with maintaining larger sets of discrete items. In contrast, earlier numerosity-dependent modulations of right prefrontal upper beta (20–30 Hz) specifically reflected the extent to which numerosity was assessed by analog estimation, both between and within presentation modalities. Together, the analog approximation—but not the discretized representation—of numerosity information exhibited a parametric oscillatory signature akin to a continuous sensory magnitude. The results suggest dissociable oscillatory mechanisms of abstract numerosity integration, at a supramodal processing stage in human WM.