TY  - JOUR
AU  - Hindriks, R.
AU  - Micheli, C.
AU  - Bosman Vittini, C.A.
AU  - Oostenveld, R.
AU  - Lewis, C.M.
AU  - Mantini, D.
AU  - Fries, P.
AU  - Deco, G.
PY  - 2018
UR  - https://hdl.handle.net/2066/194030
AB  - The discovery of hemodynamic (BOLD-fMRI) resting-state networks (RSNs) has brought about a fundamental shift in our thinking about the role of intrinsic brain activity. The electrophysiological underpinnings of RSNs remain largely elusive and it has been shown only recently that electric cortical rhythms are organized into the same RSNs as hemodynamic signals. Most electrophysiological studies into RSNs use magnetoencephalography (MEG) or scalp electroencephalography (EEG), which limits the spatial resolution with which electrophysiological RSNs can be observed. Due to their close proximity to the cortical surface, electrocorticographic (ECoG) recordings can potentially provide a more detailed picture of the functional organization of resting-state cortical rhythms, albeit at the expense of spatial coverage. In this study we propose using source-space spatial independent component analysis (spatial ICA) for identifying generators of resting-state cortical rhythms as recorded with ECoG and for reconstructing their functional connectivity. Network structure is assessed by two kinds of connectivity measures: instantaneous correlations between band-limited amplitude envelopes and oscillatory phase-locking. By simulating rhythmic cortical generators, we find that the reconstruction of oscillatory phase-locking is more challenging than that of amplitude correlations, particularly for low signal-to-noise levels. Specifically, phase-lags can both be over- and underestimated, which troubles the interpretation of lag-based connectivity measures. We illustrate the methodology on somatosensory beta rhythms recorded from a macaque monkey using ECoG. The methodology decomposes the resting-state sensorimotor network into three cortical generators, distributed across primary somatosensory and primary and higher-order motor areas. The generators display significant and reproducible amplitude correlations and phase-locking values with non-zero lags. Our findings illustrate the level of spatial detail attainable with source-projected ECoG and motivates wider use of the methodology for studying resting-state as well as event-related cortical dynamics in macaque and human.
TI  - Source-reconstruction of the sensorimotor network from resting-state macaque electrocorticography
EP  - 358
SN  - 1053-8119
SP  - 347
JF  - NeuroImage
VL  - vol. 181
PS  - 12 p.
DO  - https://doi.org/10.1016/j.neuroimage.2018.06.010
ER  - 
TY  - JOUR
AU  - de Pesters, A.
AU  - Coon, W.G.
AU  - Brunner, P.
AU  - Gunduz, A.
AU  - Ritaccio, A.L.
AU  - Brunet, N.M.
AU  - Weerd, P. de
AU  - Roberts, M.J.
AU  - Oostenveld, R.
AU  - Fries, P.
AU  - Schalk, G.
PY  - 2016
UR  - https://hdl.handle.net/2066/162022
TI  - Alpha power indexes task-related networks on large and small scales: A multimodal ECoG study in humans and a non-human primate
EP  - 131
SN  - 1053-8119
SP  - 122
JF  - NeuroImage
VL  - vol. 134
DO  - https://doi.org/10.1016/j.neuroimage.2016.03.074
ER  - 
TY  - JOUR
AU  - Larson-Prior, L.J.
AU  - Oostenveld, R.
AU  - Della Penna, S.
AU  - Michalareas, G.
AU  - Prior, F.
AU  - Babajani-Feremi, A.
AU  - Schoffelen, J.M.
AU  - Marzetti, L.
AU  - De Pasquale, F.
AU  - Di Pompeo, F.
AU  - Stout, J.
AU  - Woolrich, M.
AU  - Luo, Q.
AU  - Bucholz, R.D.
AU  - Fries, P.
AU  - Pizzella, V.
AU  - Romani, G.L.
AU  - Corbetta, M.
AU  - Snyder, A.Z.
PY  - 2013
UR  - https://hdl.handle.net/2066/218374
AB  - The Human Connectome Project (HCP) seeks to map the structural and functional connections between network elements in the human brain. Magnetoencephalography (MEG) provides a temporally rich source of information on brain network dynamics and represents one source of functional connectivity data to be provided by the HCP. High quality MEG data will be collected from 50 twin pairs both in the resting state and during performance of motor, working memory and language tasks. These data will be available to the general community. Additionally, using the cortical parcellation scheme common to all imaging modalities, the HCP will provide processing pipelines for calculating connection matrices as a function of time and frequency. Together with structural and functional data generated using magnetic resonance imaging methods, these data represent a unique opportunity to investigate brain network connectivity in a large cohort of normal adult human subjects. The analysis pipeline software and the dynamic connectivity matrices that it generates will all be made freely available to the research community.
TI  - Adding dynamics to the Human Connectome Project with MEG
EP  - 201
SN  - 1053-8119
SP  - 190
JF  - NeuroImage
VL  - vol. 80
PS  - 12 p.
DO  - https://doi.org/10.1016/j.neuroimage.2013.05.056
ER  - 
TY  - JOUR
AU  - Lange, J.
AU  - Oostenveld, R.
AU  - Fries, P.
PY  - 2011
UR  - https://hdl.handle.net/2066/92181
TI  - Perception of the touch-induced visual double-flash illusion correlates with changes of rhythmic neuronal activity in human visual and somatosensory areas.
EP  - 1405
SN  - 1053-8119
IS  - iss. 2
SP  - 1395
JF  - NeuroImage
VL  - vol. 54
PS  - 11 p.
DO  - https://doi.org/10.1016/j.neuroimage.2010.09.031
ER  - 
TY  - JOUR
AU  - Hoogenboom, N.
AU  - Schoffelen, J.M.
AU  - Oostenveld, R.
AU  - Fries, P.
PY  - 2010
UR  - https://hdl.handle.net/2066/83679
AB  - Groups of activated neurons typically synchronize in the gamma-frequency band (30-100 Hz), and gamma-band synchronization has been implicated in numerous cognitive functions. Those functions are ultimately expressed as behavior and therefore, functional gamma-band synchronization should be directly related to behavior. We recorded the magnetoencephalogram in human subjects and used a visual stimulus to induce occipital gamma-band activity. We found that the strength of this gamma-band activity at a given moment predicted the speed with which the subject was able to report a change in the stimulus. This predictive effect was restricted in time, frequency and space: It started only around 200 ms before the behaviorally relevant stimulus change, was present only between 50 and 80 Hz, and was significant only in bilateral middle occipital gyrus, while the peak of overall visually induced gamma-band activity was found in the calcarine sulcus. These results suggest that visually induced gamma-band activity is functionally relevant for the efficient transmission of stimulus change information to brain regions issuing the corresponding motor response.
TI  - Visually induced gamma-band activity predicts speed of change detection in humans
EP  - 1167
SN  - 1053-8119
IS  - iss. 3
SP  - 1162
JF  - NeuroImage
VL  - vol. 51
PS  - 6 p.
DO  - https://doi.org/10.1016/j.neuroimage.2010.03.041
ER  - 
TY  - JOUR
AU  - Schoffelen, J.M.
AU  - Oostenveld, R.
AU  - Fries, P.
PY  - 2008
UR  - https://hdl.handle.net/2066/69869
AB  - Rhythmic synchronization likely subserves interactions among neuronal groups. One of the best studied rhythmic synchronization phenomena in the human nervous system is the beta-band (15–30 Hz) synchronization in the motor system. In this study, we imaged structures across the human brain that are synchronized to the motor system’s beta rhythm. We recorded whole-head magnetoencephalograms (MEG) and electromyograms (EMG) of left/right extensor carpi radialis muscle during left/right wrist extension. We analyzed coherence, on the one hand between the EMG and neuronal sources in the brain, and on the other hand between different brain sources, using a spatial filtering approach. Cortico-muscular coherence analysis revealed a spatial maximum of coherence to the muscle in motor cortex contralateral to the muscle in accordance with earlier findings. Moreover, by applying a two-dipole source model, we unveiled significantly coherent clusters of voxels in the ipsilateral cerebellar hemisphere and ipsilateral cerebral motor regions. The spatial pattern of coherence to the right and left arm EMG was roughly mirror reversed across the midline, in agreement with known physiology. Subsequently, we analyzed the brain-wide pattern of beta-band coherence to the motor cortex contralateral to the contracting muscle. This analysis did not reveal any convincing pattern. Because the prior cortico-muscular analysis had demonstrated the expected pattern in our data, this negative finding demonstrates a current limitation of the applied method for cortico-cortical coherence analysis. We conclude that during an isometric muscle contraction, several distributed brain regions form a brain-wide beta-band network for motor control.
TI  - Imaging the human motor system's beta-band synchronization during isometric contraction
EP  - 447
SN  - 1053-8119
IS  - iss. 2
SP  - 437
JF  - NeuroImage
VL  - vol. 41
PS  - 11 p.
DO  - https://doi.org/10.1016/j.neuroimage.2008.01.045
ER  - 
TY  - JOUR
AU  - Hoogenboom, N.
AU  - Schoffelen, J.M.
AU  - Oostenveld, R.
AU  - Parkes, L.M.
AU  - Fries, P.
PY  - 2006
UR  - https://hdl.handle.net/2066/218389
AB  - Neuronal gamma-band (30-100 Hz) synchronization subserves fundamental functions in neuronal processing. However, different experimental approaches differ widely in their success in finding gamma-band activity. We aimed at linking animal and human studies of gamma-band activity and at preparing optimized methods for an in-depth investigation of the mechanisms and functions of gamma-band activity and gamma-band coherence in humans. In the first step described here, we maximized the signal-to-noise ratio with which we can observe visually induced gamma-band activity in human magnetoencephalographic recordings. We used a stimulus and task design that evoked strong gamma-band activity in animals and combined it with multi-taper methods for spectral analysis and adaptive spatial filtering for source analysis. With this approach, we found human visual gamma-band activity very reliably across subjects and across multiple recording sessions of a given subject. While increases in gamma-band activity are typically accompanied by decreases in alpha- and beta-band activity, the gamma-band enhancement was often the spectral component with the highest signal-to-noise ratio. Furthermore, some subjects demonstrated two clearly separate visually induced gamma bands, one around 40 Hz and another between 70 and 80 Hz. Gamma-band activity was sustained for the entire stimulation period, which was up to 3 s. The sources of gamma-band activity were in the calcarine sulcus in all subjects. The results localize human visual gamma-band activity in frequency, time and space and the described methods allow its forth er investigation with great sensitivity.
TI  - Localizing human visual gamma-band activity in frequency, time and space
EP  - 773
SN  - 1053-8119
IS  - iss. 3
SP  - 764
JF  - NeuroImage
VL  - vol. 29
PS  - 10 p.
DO  - https://doi.org/10.1016/j.neuroimage.2005.08.043
ER  -