Oscillatory activity during maintenance of spatial and temporal information in working memory

Abstract

Working Memory (WM) processes help keep information in an active state so it can be used to guide future behavior. Although numerous studies have investigated brain activity associated with spatial WM in humans and monkeys, little research has focused on the neural mechanisms of WM for temporal order information, and how processing of temporal and spatial information might differ. Available evidence indicates that similar frontoparietal regions are recruited during temporal and spatial WM, although there are data suggesting that they are distinct processes. The mechanisms that allow for differential maintenance of these two types of information are unclear. One possibility is that neural oscillations may differentially contribute to temporal and spatial WM. In the present study, we used scalp electroencephalography (EEG) to compare patterns of oscillatory activity during maintenance of spatial and temporal information in WM. Time-frequency analysis of EEG data revealed enhanced left frontal theta (5–8 Hz), enhanced posterior alpha (9–12 Hz), and enhanced left posterior beta (14–28 Hz) power during the delay period of correct temporal order trials compared to correct spatial trials. In contrast, gamma (30–50 Hz) power at right lateral frontal sites was increased during the delay period of spatial WM trials, as compared to temporal WM trials. The present results are consistent with the idea that neural oscillatory patterns provide distinct mechanisms for the maintenance of temporal and spatial information in WM. Specifically, theta oscillations are most critical for the maintenance of temporal information in WM. Possible roles of higher frequency oscillations in temporal and spatial memory are also discussed.

Parallax-sensitive remapping of visual space in occipito-parietal alpha-band activity during whole-body motion

“…Low-frequency oscillations, such as the alpha band (8 -12 Hz) and the theta band (5-8 Hz), have been implicated in working memory processes (Jensen et al 2002;Raghavachari et al 2006;Sauseng et al 2009). Whereas theta band oscillations seem to be involved in sequential processing (Hsieh et al 2011;Roberts et al 2013;VanRullen 2013), the alpha band seems to be more specific for (visuo)spatial memory tasks (Fries et al 2001;Roux and Uhlhaas 2014;Sauseng et al 2005), which is consistent with the present observations.…”

Decreased theta power at encoding and cognitive mapping deficits in elderly individuals during a spatial memory task

“…In elderly individuals however, encoding was associated with beta activity in the left frontal and left parietal cortices. Frontal theta activity and parietal alpha activity observed in our young subjects have previously been observed during maintenance in working memory and were both found to increase with memory load ,Jensen and Tesche, 2002,Klimesch, 1999,Klimesch, et al, 2007,Pesonen, et al, 2006,Roberts, et al, 2013,Schack and Klimesch, 2002. Whereas theta oscillations seem to reflect active maintenance of information in working memory (Freunberger, et al, 2011,Klimesch, et al, 2008 and may induce long term potentiation (Freunberger, et al, 2011,Greenstein, et al, 1988,Huerta and Lisman, 1995, alpha activity may rather contribute indirectly to working memory performances by the filtering of irrelevant information and predicting interference due to conflicting stimuli (Freunberger, et al, 2011,Klimesch, 1999,Klimesch, et al, 2007,Sauseng, et al, 2009.…”

Frontal–posterior theta oscillations reflect memory retrieval during sentence comprehension

“…A C C E P T E D ACCEPTED MANUSCRIPT 4 In support, theta-power increases have been reported for the retention of ordered items in spatial (Roberts, Hsieh, & Ranganath, 2013) and visual working memory (Hsieh, Ekstrom, & Ranganath, 2011). The suggested frontal generators of such effects (Ishii et al, 1999;Tsujimoto, Shimazu, & Isomura, 2006) are in line with positron-emission-tomography (PET) and functional-magnetic-resonance-imaging (fMRI) data (Amiez & Petrides, 2007;Clark et al, 2000;D'Esposito, Postle, Ballard, & Lease, 1999;Gerton et al, 2004).…”