High-gamma band activity of primary hand cortical areas: A sensorimotor feedback efficiency index

AbstractFunctional magnetic resonance imaging (fMRI) is among the foremost methods for mapping human brain function but provides only an indirect measure of underlying neural activity. Recent findings suggest that the neurophysiological correlates of the fMRI blood-oxygen-level-dependent (BOLD) signal might be regionally specific. We examined the neurophysiological correlates of the fMRI BOLD signal in the hippocampus and neocortex, where differences in neural architecture might result in a different relationship between the respective signals. Fifteen human neurosurgical patients (10 female, 5 male) implanted with depth electrodes performed a verbal free recall task while electrophysiological activity was recorded simultaneously from hippocampal and neocortical sites. The same patients subsequently performed a similar version of the task during a later fMRI session. Subsequent memory effects (SMEs) were computed for both imaging modalities as patterns of encoding-related brain activity predictive of later free recall. Linear mixed-effects modelling revealed that the relationship between BOLD and gamma-band SMEs was moderated by the lobar location of the recording site. BOLD and high gamma (70-150 Hz) SMEs positively covaried across much of the neocortex. This relationship was reversed in the hippocampus, where a negative correlation between BOLD and high gamma SMEs was evident. We also observed a negative relationship between BOLD and low gamma (30-70 Hz) SMEs in the medial temporal lobe more broadly. These results suggest that the neurophysiological correlates of the BOLD signal in the hippocampus differ from those observed in the neocortex.Significance StatementThe blood-oxygen-level-dependent (BOLD) signal forms the basis of fMRI but provides only an indirect measure of neural activity. Task-related modulation of BOLD signals are typically equated with changes in gamma-band activity; however, relevant empirical evidence comes largely from the neocortex. We examined neurophysiological correlates of the BOLD signal in the hippocampus, where the differing neural architecture might result in a different relationship between the respective signals. We identified a positive relationship between encoding-related changes in BOLD and gamma-band activity in frontal, temporal, and parietal cortex. This effect was reversed in the hippocampus, where BOLD and gamma-band effects negatively covaried. These results suggest regional variability in the transfer function between neural activity and the BOLD signal in the hippocampus and neocortex.

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Non-invasive detection of high gamma band activity during motor imagery

Frontiers in Human Neuroscience ◽

10.3389/fnhum.2014.00817 ◽

2014 ◽

Vol 8 ◽

Cited By ~ 15

Author(s):

Melissa M. Smith ◽

Kurt E. Weaver ◽

Thomas J. Grabowski ◽

Rajesh P. N. Rao ◽

Felix Darvas

Keyword(s):

Motor Imagery ◽

Gamma Band ◽

Non Invasive ◽

High Gamma ◽

Gamma Band Activity ◽

Band Activity

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High gamma band activity in noninvasively measured EEG preceding anti-saccade initiation

2014 IEEE International Symposium on Medical Measurements and Applications (MeMeA) ◽

10.1109/memea.2014.6860091 ◽

2014 ◽

Author(s):

Masayoshi Furukawa ◽

Shigeo Wada ◽

Akinori Ueno ◽

Abraham Akinin ◽

Gert Cauwenberghs

Keyword(s):

Gamma Band ◽

High Gamma ◽

Gamma Band Activity ◽

Band Activity

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Resting-state gamma-band power alterations in schizophrenia reveal E/I-balance abnormalities across illness-stages

eLife ◽

10.7554/elife.37799 ◽

2018 ◽

Vol 7 ◽

Cited By ~ 22

Author(s):

Tineke Grent-'t-Jong ◽

Joachim Gross ◽

Jozien Goense ◽

Michael Wibral ◽

Ruchika Gajwani ◽

...

Keyword(s):

Resting State ◽

Clinical Symptoms ◽

Spectral Power ◽

Gamma Band ◽

Psychotic Symptoms ◽

First Episode ◽

Band Power ◽

High Gamma ◽

Gamma Band Activity ◽

Band Activity

We examined alterations in E/I-balance in schizophrenia (ScZ) through measurements of resting-state gamma-band activity in participants meeting clinical high-risk (CHR) criteria (n = 88), 21 first episode (FEP) patients and 34 chronic ScZ-patients. Furthermore, MRS-data were obtained in CHR-participants and matched controls. Magnetoencephalographic (MEG) resting-state activity was examined at source level and MEG-data were correlated with neuropsychological scores and clinical symptoms. CHR-participants were characterized by increased 64–90 Hz power. In contrast, FEP- and ScZ-patients showed aberrant spectral power at both low- and high gamma-band frequencies. MRS-data showed a shift in E/I-balance toward increased excitation in CHR-participants, which correlated with increased occipital gamma-band power. Finally, neuropsychological deficits and clinical symptoms in FEP and ScZ-patients were correlated with reduced gamma band-activity, while elevated psychotic symptoms in the CHR group showed the opposite relationship. The current study suggests that resting-state gamma-band power and altered Glx/GABA ratio indicate changes in E/I-balance parameters across illness stages in ScZ.

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Painful cutaneous laser stimuli induce event-related gamma-band activity in the lateral thalamus of humans

Journal of Neurophysiology ◽

10.1152/jn.00778.2014 ◽

2015 ◽

Vol 113 (5) ◽

pp. 1564-1573 ◽

Cited By ~ 8

Author(s):

J. H. Kim ◽

J. H. Chien ◽

C. C. Liu ◽

F. A. Lenz

Keyword(s):

Experimental Pain ◽

Gamma Band ◽

Beta Band ◽

Gamma Activation ◽

High Gamma ◽

Gamma Band Activity ◽

Cross Frequency Coupling ◽

Induce Event ◽

Band Activity ◽

Deep Brain

Although the thalamus is an important module in “pain networks,” there are few studies of the effect of experimental pain upon thalamic oscillations. We have now examined the hypothesis that, during a series of painful cutaneous laser stimuli, thalamic signals will show stimulus-related gamma-band spectral activity, which is modulated by attention to vs. distraction from the painful stimulus. When the series of laser stimuli was presented, attention was focused by counting the laser stimuli (count laser task), while distraction was produced by counting backward (count back plus laser task). We have studied the effect of a cutaneous laser on thalamic local field potentials and EEG activity during awake procedures (deep brain stimulation implants) for the treatment of essential tremor. At different delays after the stimulus, three low gamma- (30–50 Hz) and two high gamma-band (70–90 Hz) activations were observed during the two tasks. Greater high-gamma activation was found during the count laser task for the earlier window, while greater high-gamma activation was found during the count back plus laser task for the later window. Thalamic signals were coherent with EEG signals in the beta band, which indicated significant synchrony. Thalamic cross-frequency coupling analysis indicated that the phase of the lower frequency activity (theta to beta) modulated the amplitude of the higher frequency activity (low and high gamma) more strongly during the count laser task than during the count back plus laser task. This modulation might result in multiplexed signals each encoding a different aspect of pain.

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Stimulus-induced Gamma Power Predicts the Amplitude of the Subsequent Visual Evoked Response

10.1101/388587 ◽

2018 ◽

Author(s):

Mats W.J. van Es ◽

Jan-Mathijs Schoffelen

Keyword(s):

Gamma Band ◽

Evoked Response ◽

Pattern Reversal ◽

Visual Evoked Response ◽

Cortical Areas ◽

Gamma Power ◽

Visual Cortical ◽

Gamma Band Activity ◽

Band Activity ◽

Visual Evoked

AbstractThe efficiency of neuronal information transfer in activated brain networks may affect behavioral performance. Gamma-band synchronization has been proposed to be a mechanism that facilitates neuronal processing of behaviorally relevant stimuli. In line with this, it has been shown that strong gamma-band activity in visual cortical areas leads to faster responses to a visual go cue. We investigated whether there are directly observable consequences of trial-by-trial fluctuations in non-invasively observed gamma-band activity on the neuronal response. Specifically, we hypothesizedthat the amplitude of the visual evoked response to a go cue can be predicted by gamma power in the visual system, in the window preceding the evoked response. Thirty-three human subjects (22 female) performed a visual speeded response task while their magnetoencephalogram (MEG) was recorded. The participants had to respond to a pattern reversal of a concentric moving grating. We estimated single trial stimulus-induced visual cortical gamma power, and correlated this with the estimated single trial amplitude of the most prominent event-related field (ERF) peak within the first 100 ms after the pattern reversal. In parieto-occipital cortical areas, the amplitude of the ERF correlated positively with gamma power, and correlated negatively with reaction times. No effects were observed for the alpha and beta frequency bands, despite clear stimulus onset induced modulation at those frequencies. These results support a mechanistic model, in which gamma-band synchronization enhances the neuronal gain to relevant visual input, thus leading to more efficient downstream processing and to faster responses.Significance statementGamma-band activity has been associated with many cognitive functions and improved behavioral performance. For example, high amplitude gamma-band activity in visual cortical areas before a go cue leads to faster reaction times. However, it remains unclear through which neural mechanism(s) gamma-band activity eventually affects behavior. We tested whether the strength of induced gamma-band activity affects evoked activity elicited by a subsequent visual stimulus. We found enhanced amplitudes of early visual evoked activity, and faster responses with higher gamma power. This suggests that gamma-band activity affects the neuronal gain to new sensory input, and thus these results bridge the gap between gamma power and behavior, and support the putative role of gamma-band activity in the efficiency of cortical processing.

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