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Working memory and neural oscillations: alpha–gamma versus theta–gamma codes for distinct WM information?

2013; Elsevier BV; Volume: 18; Issue: 1 Linguagem: Inglês

10.1016/j.tics.2013.10.010

1879-307X

Frédéric Roux, Peter J. Uhlhaas,

EEG and Brain-Computer Interfaces

•We outline a framework for assigning distinct roles of theta/alpha/gamma-band oscillations to different WM-processes. •Gamma-band oscillations are actively involved in WM-maintenance. •Alpha-band activity underlies the inhibition of task-irrelevant activity. •Theta-band oscillations underlie the temporal organization of WM items. •Through cross-frequency coupling, alpha–gamma versus theta–gamma codes provide distinct mechanisms for different WM information. Neural oscillations at different frequencies have recently been related to a wide range of basic and higher cognitive processes. One possible role of oscillatory activity is to assure the maintenance of information in working memory (WM). Here we review the possibility that rhythmic activity at theta, alpha, and gamma frequencies serve distinct functional roles during WM maintenance. Specifically, we propose that gamma-band oscillations are generically involved in the maintenance of WM information. By contrast, alpha-band activity reflects the active inhibition of task-irrelevant information, whereas theta-band oscillations underlie the organization of sequentially ordered WM items. Finally, we address the role of cross-frequency coupling (CFC) in enabling alpha–gamma and theta–gamma codes for distinct WM information. Neural oscillations at different frequencies have recently been related to a wide range of basic and higher cognitive processes. One possible role of oscillatory activity is to assure the maintenance of information in working memory (WM). Here we review the possibility that rhythmic activity at theta, alpha, and gamma frequencies serve distinct functional roles during WM maintenance. Specifically, we propose that gamma-band oscillations are generically involved in the maintenance of WM information. By contrast, alpha-band activity reflects the active inhibition of task-irrelevant information, whereas theta-band oscillations underlie the organization of sequentially ordered WM items. Finally, we address the role of cross-frequency coupling (CFC) in enabling alpha–gamma and theta–gamma codes for distinct WM information. measurement of electrical brain signals using electrodes that are implanted subdurally on the surface of the brain. non-invasive methods for studying brain function that reflect the electrical activity of neuronal populations with millisecond temporal resolution. electric potential in the extracellular space around neurons. LFP is a widely available signal in many recording configurations, ranging from single-electrode recordings to multi-electrode arrays. synchronizations between widely separated brain regions (> 2 cm) as reflected, for example, in phase synchrony. prominent feature of spontaneous and task-related brain activity that occur at the level of single units, local field potentials (LFPs), and EEG/MEG recordings. The traditional view is that neuronal oscillations reflect inhibition-based fluctuations of neuronal activity that emerge from the synchronous activation of large neuronal ensembles. way of quantifying the difference between two oscillations according to some feature (peak or trough) of one of the oscillation with respect to the other. reflects the amplitude of neural oscillations computed through a time–frequency transformation (TFT).