scholarly journals Identified Cellular Correlates of Neocortical Ripple and High-Gamma Oscillations during Spindles of Natural Sleep

Neuron ◽  
2016 ◽  
Vol 92 (4) ◽  
pp. 916-928 ◽  
Author(s):  
Robert G. Averkin ◽  
Viktor Szemenyei ◽  
Sándor Bordé ◽  
Gábor Tamás
Keyword(s):  
Gamma Oscillations ◽  
Natural Sleep ◽  
High Gamma

scholarly journals Superimposed gratings induce diverse response patterns of gamma oscillations in primary visual cortex

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Bin Wang ◽  
Chuanliang Han ◽  
Tian Wang ◽  
Weifeng Dai ◽  
Yang Li ◽  
...  
Keyword(s):  
Visual Cortex ◽  
Primary Visual Cortex ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Neural Mechanisms ◽  
Model Parameters ◽  
Response Patterns ◽  
Region Difference ◽  
High Gamma ◽  
Spiking Activity

AbstractStimulus-dependence of gamma oscillations (GAMMA, 30–90 Hz) has not been fully understood, but it is important for revealing neural mechanisms and functions of GAMMA. Here, we recorded spiking activity (MUA) and the local field potential (LFP), driven by a variety of plaids (generated by two superimposed gratings orthogonal to each other and with different contrast combinations), in the primary visual cortex of anesthetized cats. We found two distinct narrow-band GAMMAs in the LFPs and a variety of response patterns to plaids. Similar to MUA, most response patterns showed that the second grating suppressed GAMMAs driven by the first one. However, there is only a weak site-by-site correlation between cross-orientation interactions in GAMMAs and those in MUAs. We developed a normalization model that could unify the response patterns of both GAMMAs and MUAs. Interestingly, compared with MUAs, the GAMMAs demonstrated a wider range of model parameters and more diverse response patterns to plaids. Further analysis revealed that normalization parameters for high GAMMA, but not those for low GAMMA, were significantly correlated with the discrepancy of spatial frequency between stimulus and sites’ preferences. Consistent with these findings, normalization parameters and diversity of high GAMMA exhibited a clear transition trend and region difference between area 17 to 18. Our results show that GAMMAs are also regulated in the form of normalization, but that the neural mechanisms for these normalizations might differ from those of spiking activity. Normalizations in different brain signals could be due to interactions of excitation and inhibitions at multiple stages in the visual system.

Visual Grouping and the Focusing of Attention Induce Gamma-band Oscillations at Different Frequencies in Human Magnetoencephalogram Signals

2006 ◽  
Vol 18 (11) ◽  
pp. 1850-1862 ◽  
Author(s):  
Juan R. Vidal ◽  
Maximilien Chaumon ◽  
J. Kevin O'Regan ◽  
Catherine Tallon-Baudry
Keyword(s):  
Short Term Memory ◽  
Implementation Process ◽  
Visual Display ◽  
Gamma Oscillations ◽  
Gamma Band ◽  
Visual Grouping ◽  
Gamma Range ◽  
High Gamma ◽  
The One ◽  
Attentional Filter

Neural oscillatory synchrony could implement grouping processes, act as an attentional filter, or foster the storage of information in short-term memory. Do these findings indicate that oscillatory synchrony is an unspecific epiphenomenon occurring in any demanding task, or that oscillatory synchrony is a fundamental mechanism involved whenever neural cooperation is requested? If the latter hypothesis is true, then oscillatory synchrony should be specific, with distinct visual processes eliciting different types of oscillations. We recorded magnetoencephalogram (MEG) signals while manipulating the grouping properties of a visual display on the one hand, and the focusing of attention to memorize part of this display on the other hand. Grouping-related gamma oscillations were present in all conditions but modulated by the grouping properties of the stimulus (one or two groups) in the high gamma-band (70–120 Hz) at central occipital locations. Attention-related gamma oscillations appeared as an additional component whenever attentional focusing was requested in the low gamma-band (44–66 Hz) at parietal locations. Our results thus reveal the existence of a functional specialization in the gamma range, with grouping-related oscillations showing up at higher frequencies than attention-related oscillations. The pattern of oscillatory synchrony is thus specific of the visual process it is associated with. Our results further suggest that both grouping processes and focused attention rely on a common implementation process, namely, gamma-band oscillatory synchrony, a finding that could account for the fact that coherent percepts are more likely to catch attention than incoherent ones.

scholarly journals Comparison of tuning properties of gamma and high-gamma power in local field potential (LFP) versus electrocorticogram (ECoG) in visual cortex

2019 ◽  
Author(s):  
Agrita Dubey ◽  
Supratim Ray
Keyword(s):  
Visual Cortex ◽  
Local Field ◽  
Local Field Potential ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Orientation Contrast ◽  
High Gamma ◽  
Gamma Power ◽  
Electrocorticogram Ecog ◽  
Local Field Potential Lfp

AbstractElectrocorticogram (ECoG), obtained from macroelectrodes placed on the cortex, is typically used in drug-resistant epilepsy patients, and is increasingly being used to study cognition in humans. These studies often use power in gamma (30-70 Hz) or high-gamma (>80 Hz) ranges to make inferences about neural processing. However, while the stimulus tuning properties of gamma/high-gamma power have been well characterized in local field potential (LFP; obtained from microelectrodes), analogous characterization has not been done for ECoG. Using a hybrid array containing both micro and ECoG electrodes implanted in the primary visual cortex of two female macaques, we compared the stimulus tuning preferences of gamma/high-gamma power in LFP versus ECoG and found them to be surprisingly similar. High-gamma power, thought to index the average firing rate around the electrode, was highest for the smallest stimulus (0.3° radius), and decreased with increasing size in both LFP and ECoG, suggesting local origins of both signals. Further, gamma oscillations were similarly tuned in LFP and ECoG to stimulus orientation, contrast and spatial frequency. This tuning was significantly weaker in electroencephalogram (EEG), suggesting that ECoG is more like LFP than EEG. Overall, our results validate the use of ECoG in clinical and basic cognitive research.

scholarly journals High-gamma activity in the human hippocampus during inter-trial rest periods of a virtual navigation task

2018 ◽  
Author(s):  
Yi Pu ◽  
Brian R. Cornwell ◽  
Douglas Cheyne ◽  
Blake W. Johnson
Keyword(s):  
Gamma Oscillations ◽  
Gamma Activity ◽  
Training Set ◽  
Virtual Navigation ◽  
Navigation Task ◽  
Theta Power ◽  
Rest Periods ◽  
Synthetic Aperture Magnetometry ◽  
High Gamma ◽  
Gamma Power

AbstractIn rodents, hippocampal cell assemblies formed during learning of a navigation task are observed to re-emerge during resting (offline) periods, accompanied by high-frequency oscillations (HFOs). This phenomenon is believed to reflect mechanisms for strengthening newly-formed memory traces. Using magnetoencephalography recordings and a beamforming source location algorithm (synthetic aperture magnetometry), we investigated high-gamma (80 – 140 Hz) oscillations in the hippocampal region in 18 human participants during inter-trial rest periods in a virtual navigation task. We found right hippocampal gamma oscillations mirrored the pattern of theta power in the same region during navigation, varying as a function of environmental novelty. Gamma power during inter-trial rest periods was positively correlated with theta power during navigation in the first training set when the environment was new and predicted faster learning in the subsequent training set two where the environment became familiar. These findings provide evidence for human hippocampal reactivation accompanied by high-gamma activities immediately after learning and establish a link between hippocampal high-gamma activities and memory consolidation.

scholarly journals Synchronous spiking associated with high gamma oscillations in prefrontal cortex exerts top-down control over a 5Hz-rhythmic modulation of spiking in locus coeruleus

2020 ◽  
Author(s):  
Nelson K. Totah ◽  
Nikos K. Logothetis ◽  
Oxana Eschenko
Keyword(s):  
Prefrontal Cortex ◽  
Locus Coeruleus ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Neuronal Population ◽  
Excitatory Input ◽  
Top Down ◽  
Population Activity ◽  
Oscillation Analysis ◽  
High Gamma

AbstractThe brainstem noradrenergic locus coeruleus (LC) is reciprocally connected with the prefrontal cortex (PFC). Strong coupling between LC spiking and depolarizing phase of slow (1 – 2 Hz) waves in the PFC field potentials during sleep and anesthesia suggests that the LC drives cortical state transition. Reciprocal LC-PFC connectivity should also allow interactions in the opposing (top-down) direction, but prior work has only studied prefrontal control over LC activity using direct electrical (or optogenetic) stimulation paradigms. Here, we describe the physiological characteristics of naturally occurring top-down prefrontal-coerulear interactions. Specifically, we recorded LC multi-unit activity (MUA) simultaneously with PFC single unit and local field potential (LFP) activity in urethane-anesthetized rats. We observed cross-regional coupling between the phase of ~5 Hz oscillations in LC population spike rate and the power of PFC LFP oscillations within the high Gamma (hGamma) range (60 – 200 Hz). Specifically, transient increases in PFC hGamma power preceded peaks in the ~5 Hz LC-MUA oscillation. Analysis of cross-regional transfer entropy demonstrated that the PFC hGamma transients were predictive of a transient increase in LC-MUA. A ~29 msec delay between these signals was consistent with the conduction velocity from the PFC to the LC. Finally, we showed that PFC hGamma transients are associated with synchronized spiking of a subset (27%) of PFC single units. Our data suggest that, PFC hGamma transients may indicate the timing of the top-down excitatory input to LC, at least under conditions when LC neuronal population activity fluctuates rhythmically at ~5 Hz. Synchronized PFC neuronal spiking that occurs during hGamma transients may provide a previously unknown mode of top-down control over the LC.

Opposite effects of lateralised transcranial alpha versus gamma stimulation on spatial attention

2017 ◽  
Author(s):  
Malte Wöstmann ◽  
Johannes Vosskuhl ◽  
Jonas Obleser ◽  
Christoph S. Herrmann
Keyword(s):  
Spatial Attention ◽  
Gamma Oscillations ◽  
Proof Of Concept ◽  
Functional Roles ◽  
Dichotic Listening Task ◽  
High Gamma ◽  
Transcranial Alternating Current Stimulation ◽  
Human Participants ◽  
Listening Task ◽  
Selection Of

AbstractSpatial attention relatively increases the power of neural 10-Hz alpha oscillations in the hemisphere ipsilateral to attention. The functional roles of lateralised oscillations for attention are unclear. Here, 20 human participants performed a dichotic listening task under continuous transcranial alternating current stimulation (tACS) at alpha (10 Hz, vs sham) or gamma (47 Hz, vs sham) frequency, targeting left temporo-parietal cortex. Participants attended to four spoken numbers presented to one ear, while ignoring numbers on the other ear. As predicted, we found that alpha-tACS contralateral to the attended ear decreased recall of attended targets. Notably, gamma-tACS reversed the effect. Results provide a proof of concept that externally amplified oscillations can enhance spatial attention and facilitate attentional selection of speech. Furthermore, opposite effects of alpha versus gamma oscillations support the view that, across modalities, states of high alpha are incommensurate with active neural processing as reflected by states of high gamma.

High-gamma oscillations in the motor cortex during visuo-motor coordination: A tACS interferential study

2017 ◽  
Vol 131 ◽  
pp. 47-54 ◽  
Author(s):  
E. Santarnecchi ◽  
A. Biasella ◽  
E. Tatti ◽  
A. Rossi ◽  
D. Prattichizzo ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor Coordination ◽  
Gamma Oscillations ◽  
High Gamma

High-gamma oscillations as neurocorrelates of ADHD: A MEG crossover placebo-controlled study

2021 ◽  
Vol 137 ◽  
pp. 186-193
Author(s):  
Yair Dor-Ziderman ◽  
Maor Zeev-Wolf ◽  
Efrat Hirsch Klein ◽  
Dor Bar-Oz ◽  
Uriel Nitzan ◽  
...  
Keyword(s):  
Gamma Oscillations ◽  
Controlled Study ◽  
High Gamma

scholarly journals High‐gamma oscillations precede visual steady‐state responses: A human electrocorticography study

2020 ◽  
Vol 41 (18) ◽  
pp. 5341-5355
Author(s):  
Benjamin Wittevrongel ◽  
Elvira Khachatryan ◽  
Evelien Carrette ◽  
Paul Boon ◽  
Alfred Meurs ◽  
...  
Keyword(s):  
Steady State ◽  
Gamma Oscillations ◽  
High Gamma ◽  
Steady State Responses ◽  
State Responses

scholarly journals Low- and high-gamma oscillations deviate in opposite directions from zero-phase synchrony in the limbic corticostriatal loop

2016 ◽  
Vol 116 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Julien Catanese ◽  
J. Eric Carmichael ◽  
Matthijs A. A. van der Meer
Keyword(s):  
Neural Activity ◽  
Field Potential ◽  
Gamma Oscillations ◽  
Time Lags ◽  
Phase Synchrony ◽  
Behavioral Differences ◽  
High Gamma ◽  
Tightly Coupled ◽  
Flow Of Information ◽  
Zero Phase

The loop structure of cortico-striatal anatomy in principle enables both descending (cortico-striatal) and ascending (striato-cortical) influences, but the factors that regulate the flow of information in these loops are not known. We report that low- and high-gamma oscillations (∼50 and ∼80 Hz, respectively) in the local field potential of freely moving rats are highly synchronous between the infralimbic region of the medial prefrontal cortex (mPFC) and the ventral striatum (vStr). Strikingly, high-gamma oscillations in mPFC preceded those in vStr, whereas low-gamma oscillations in mPFC lagged those in vStr, with short (∼1 ms) time lags. These systematic deviations from zero-phase synchrony were consistent across measures based on amplitude cross-correlation and phase slopes and were robustly maintained between behavioral states and different individual subjects. Furthermore, low- and high-gamma oscillations were associated with distinct ensemble spiking patterns in vStr, even when controlling for overt behavioral differences and slow changes in neural activity. These results imply that neural activity in vStr and mPFC is tightly coupled at the gamma timescale and raise the intriguing possibility that frequency-specific deviations from this coupling may signal transient leader-follower switches.

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