Long-range synchronization and local desynchronization of alpha oscillations during visual short-term memory retention in children

Abstract

Local alpha-band synchronization has been associated with both cortical idling and active inhibition. Recent evidence, however, suggests that long-range alpha synchronization increases functional coupling between cortical regions. We demonstrate increased long-range alpha and beta band phase synchronization during short-term memory retention in children 6-10 years of age. Furthermore, whereas alpha-band synchronization between posterior cortex and other regions is increased during retention, local alpha-band synchronization over posterior cortex is reduced. This constitutes a functional dissociation for alpha synchronization across local and long-range cortical scales. We interpret long-range synchronization as reflecting functional integration within a network of frontal and visual cortical regions. Local desynchronization of alpha rhythms over posterior cortex, conversely, likely arises because of increased engagement of visual cortex during retention.

Lifespan age differences in working memory: A two-component framework

“…One of these studies focused on changes in long-range synchronization and local desynchronization of alpha oscillations during visual WM retention in children 6-10 years of age (Doesburg et al, 2010). In accordance with previous observations in adult samples (Doesburg et al, 2009), an increase in long-range synchronization within the frontoposterior network was found, together with a decrease in alpha amplitudes over posterior sensors.…”

Emergence in the central nervous system

“…Specifically, while activations within and between such areas as visual, auditory, and kinesthetic normally occur with gamma frequencies (which can go as high as 250 Hz: e.g., Ojemann et al 2010), the interactions of those areas with, for example, the hippocampus, normally occur at much slower (roughly 5-100 times slower) theta and other, notably beta frequencies (and see Siegel et al 2008;Donner and Siegel 2011, for summaries of this literature). If the coarse maps on the hippocampus need to evoke objects which consist of the unification of (the NCCs of) multi-modal sensations and abstractions (that is, if when we remember something, we remember how it looks, feels, sounds, etc., simultaneously), then if the hypothesis in this paper is correct, we would expect something like within-cortical gamma (or similar)-united activations interacting at theta (or similar) frequencies with withinhippocampal gamma-united maps-which is, in fact, what is found (e.g., Doesburg et al 2005Doesburg et al , 2010. Similarly, if the PFC is in part an ''executive'' which in some manner manipulates concepts, and if those concepts entail neural unifications over multiple sensory areas, then we would 7 In this following section, I will not attempt to explicitly distinguish between neural activations and phenomenal experiences; I have done that above, and one may take it that I am aware that ''neural activations'' and ''sensations'' or ''thoughts'', etc., are at this point no more than correlated, and that when I speak of them I am speaking of their neural correlates-NCCs, since I take it that for a neural activation to be ''phenomenal'' we must be conscious of it (although of course see Block 2008).…”

“…Given that large-scale ENEs are necessary, not so much to generate such unity but to embody it, we would expect to find this dynamic. More recent studies of such large-scale fast interactions include Buzsáki (2010), Buzsáki and Chrobak (1995), Buzsáki and Draguhn (2004), Crone et al (2001, 2011), Del Percio et al (2011), Doesburg et al (2010, Fries (2009), Gollo et al (2010), Miltner et al (1999, ), Pockett and Holmes (2009), Pockett et al (2007, and Singer (2001), to name just a few in addition to the papers cited in previous sections. Canolty also finds long-range coupling in near-gamma (beta) frequencies (Canolty et al 2010, p. 17360) related to behavior.…”

Amplitude modulations and inter-trial phase stability of alpha-oscillations differentially reflect working memory constraints across the lifespan

“…In this study, the presentation of the memory array was followed by a sustained desynchronization of alpha power, which was more pronounced for larger memory load conditions (see also Ciesielski et al, 2010). Doesburg et al (2010) recently investigated local alpha-band synchronization and long-range alpha phase synchronization during short-term memory retention in children. In this study, alpha amplitudes over posterior MEG sensors decreased during the early retention interval.…”

“…In this study, alpha amplitudes over posterior MEG sensors decreased during the early retention interval. Doesburg et al (2010) suggested that this desynchronization reflects the task-dependent activation of the visual cortex. The authors furthermore observed increased alpha band synchronization between posterior sensors and widespread cortical regions, which was interpreted as a mechanism for maintaining memory traces.…”