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Coherent oscillatory networks supporting short-term memory retention
- Source :
-
Brain Research . Jan2009, Vol. 1247, p126-132. 7p. - Publication Year :
- 2009
-
Abstract
- Abstract: Accumulating evidence suggests that top-down processes, reflected by frontal-midline theta-band (4–8 Hz) electroencephalogram (EEG) oscillations, strengthen the activation of a memory set during short-term memory (STM) retention. In addition, the amplitude of posterior alpha-band (8–13 Hz) oscillations during STM retention is thought to reflect a mechanism that protects fragile STM activations from interference by gating bottom-up sensory inputs. The present study addressed two important questions about these phenomena. First, why have previous studies not consistently found memory set-size effects on frontal-midline theta? Second, how does posterior alpha participate in STM retention? To answer these questions, large-scale network connectivity during STM retention was examined by computing EEG wavelet coherence during the retention period of a modified Sternberg task using visually-presented letters as stimuli. The results showed (a) increasing theta-band coherence between frontal-midline and left temporal-parietal sites with increasing memory load, and (b) increasing alpha-band coherence between midline parietal and left temporal/parietal sites with increasing memory load. These findings support the view that theta-band coherence, rather than amplitude, is the key factor in selective top-down strengthening of the memory set and demonstrate that posterior alpha-band oscillations associated with sensory gating are involved in STM retention by participating in the STM network. [Copyright &y& Elsevier]
Details
- Language :
- English
- ISSN :
- 00068993
- Volume :
- 1247
- Database :
- Academic Search Index
- Journal :
- Brain Research
- Publication Type :
- Academic Journal
- Accession number :
- 36003714
- Full Text :
- https://doi.org/10.1016/j.brainres.2008.09.095