Modulations in oscillatory activity with amplitude asymmetry can produce cognitively relevant event-related responses

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Publication year
2010Source
Proceedings of the National Academy of Sciences USA, 107, 2, (2010), pp. 900-905ISSN
Publication type
Article / Letter to editor

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SW OZ DCC BO
SW OZ DCC CO
Journal title
Proceedings of the National Academy of Sciences USA
Volume
vol. 107
Issue
iss. 2
Page start
p. 900
Page end
p. 905
Subject
Action, intention, and motor control; DI-BCB_DCC_Theme 2: Perception, Action and ControlAbstract
Event-related responses and oscillatory activity are typically regarded as manifestations of different neural processes. Recent work has nevertheless revealed a mechanism by which slow event-related responses are created as a direct consequence of modulations in brain oscillations with nonsinusoidal properties. It remains unknown if this mechanism applies to cognitively relevant event-related responses. Here, we investigated whether sustained event-related fields (ERFs) measured during working memory maintenance can be explained by modulations in oscillatory power. In particular, we focused on contralateral delayed activity (CDA) typically observed in working memory tasks in which hemifield specific attention is manipulated. Using magnetoencephalography, we observed sustained posterior ERFs following the presentation of the memory target. These ERFs were systematically lateralized with respect to the hemisphere in which the target was presented. A strikingly similar pattern emerged for modulations in alpha (9–13 Hz) power. The alpha power and ERF lateralization were strongly correlated over subjects. Based on a mechanistic argument pertaining to the nonsinusoidal properties of the alpha activity, we conclude that the ERFs modulated by working memory are likely to be directly produced by the modulations in oscillatory alpha activity. Given that posterior alpha activity typically reflects disengagement, we conclude that the CDA is not attributable to an additive process reflecting memory maintenance per se but, rather, is a consequence of how attentional resources are allocated.
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- Academic publications [232297]
- Electronic publications [115548]
- Faculty of Social Sciences [29102]
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