TY - JOUR
T1 - Load modulates the alpha and beta oscillatory dynamics serving verbal working memory
AU - Proskovec, Amy L.
AU - Heinrichs-Graham, Elizabeth
AU - Wilson, Tony W.
N1 - Funding Information:
This work was supported by the National Institutes of Health [grants R01 MH103220 and R01 MH116782 ] (TWW) and the National Science Foundation [grant # 1539067 ] (TWW). This work was also supported by a Research Support Fund grant from the Nebraska Health System and the University of Nebraska Medical Center , and a Graduate Research and Creative Activity Award (ALP) from the University of Nebraska at Omaha . The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Funding Information:
This work was supported by the National Institutes of Health [grants R01 MH103220 and R01 MH116782] (TWW) and the National Science Foundation [grant #1539067] (TWW). This work was also supported by a Research Support Fund grant from the Nebraska Health System and the University of Nebraska Medical Center, and a Graduate Research and Creative Activity Award (ALP) from the University of Nebraska at Omaha. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Publisher Copyright:
© 2018 Elsevier Inc.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - A network of predominantly left-lateralized brain regions has been linked to verbal working memory (VWM) performance. However, the impact of memory load on the oscillatory dynamics serving VWM is far less understood. To further investigate this, we had 26 healthy adults perform a high-load (6 letter) and low-load (4 letter) variant of a VWM task while undergoing magnetoencephalography (MEG). MEG data were evaluated in the time-frequency domain and significant oscillatory responses spanning the encoding and maintenance phases were reconstructed using a beamformer. To determine the impact of load on the neural dynamics, the resulting images were examined using paired-samples t-tests and virtual sensor analyses. Our results indicated stronger increases in frontal theta activity in the high- relative to low-load condition during early encoding. Stronger decreases in alpha/beta activity were also observed during encoding in bilateral posterior cortices during the high-load condition, and the strength of these load effects increased as encoding progressed. During maintenance, stronger decreases in alpha activity in the left inferior frontal gyrus, middle temporal gyrus, supramarginal gyrus, and inferior parietal cortices were detected during high- relative to low-load performance, with the strength of these load effects remaining largely static throughout maintenance. Finally, stronger increases in occipital alpha activity were observed during maintenance in the high-load condition, and the strength of these effects grew stronger with time during the first half of maintenance, before dissipating during the latter half of maintenance. Notably, this was the first study to utilize a whole-brain approach to statistically evaluate the temporal dynamics of load-related oscillatory differences during encoding and maintenance processes, and our results highlight the importance of spatial, temporal, and spectral specificity in this regard.
AB - A network of predominantly left-lateralized brain regions has been linked to verbal working memory (VWM) performance. However, the impact of memory load on the oscillatory dynamics serving VWM is far less understood. To further investigate this, we had 26 healthy adults perform a high-load (6 letter) and low-load (4 letter) variant of a VWM task while undergoing magnetoencephalography (MEG). MEG data were evaluated in the time-frequency domain and significant oscillatory responses spanning the encoding and maintenance phases were reconstructed using a beamformer. To determine the impact of load on the neural dynamics, the resulting images were examined using paired-samples t-tests and virtual sensor analyses. Our results indicated stronger increases in frontal theta activity in the high- relative to low-load condition during early encoding. Stronger decreases in alpha/beta activity were also observed during encoding in bilateral posterior cortices during the high-load condition, and the strength of these load effects increased as encoding progressed. During maintenance, stronger decreases in alpha activity in the left inferior frontal gyrus, middle temporal gyrus, supramarginal gyrus, and inferior parietal cortices were detected during high- relative to low-load performance, with the strength of these load effects remaining largely static throughout maintenance. Finally, stronger increases in occipital alpha activity were observed during maintenance in the high-load condition, and the strength of these effects grew stronger with time during the first half of maintenance, before dissipating during the latter half of maintenance. Notably, this was the first study to utilize a whole-brain approach to statistically evaluate the temporal dynamics of load-related oscillatory differences during encoding and maintenance processes, and our results highlight the importance of spatial, temporal, and spectral specificity in this regard.
KW - Encoding
KW - Magnetoencephalography (MEG)
KW - Maintenance
KW - Oscillation
KW - Theta
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U2 - 10.1016/j.neuroimage.2018.09.022
DO - 10.1016/j.neuroimage.2018.09.022
M3 - Article
C2 - 30213775
AN - SCOPUS:85053548391
SN - 1053-8119
VL - 184
SP - 256
EP - 265
JO - NeuroImage
JF - NeuroImage
ER -