Persistent Gamma Spiking in Non-Sensory Fast-Spiking Cells Predicts Perceptual Success

Persistent gamma oscillations (30-55Hz) are hypothesized to temporally coordinate stimulus encoding, enabling perception. This prediction poses a conundrum: How can gamma serve as a template when the stimulus itself drives its mediators, presumably perturbing its maintenance? Specifically, fast-spiking interneurons (FS), a key gamma generator, can be highly sensory responsive. Further, the gamma-band local field potential (LFP) shows properties inconsistent with temporal coordination. Combining tetrode recording with controlled psychophysics revealed an FS subtype (γnsFS) that was not sensory responsive, whose inter-spike intervals peaked at gamma, and that fired with higher periodicity than other FS. Successful detection was predicted by increased regularity in γnsFS spiking at gamma, persisting from before to after sensory onset. In contrast, gamma LFP power negatively predicted detection, and was negatively related to gamma band spiking by γnsFS. These results suggest that a distinct interneuron subgroup, not ‘distracted’ by sensory input, mediates perceptually-relevant oscillations independent of LFP.

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

10.1101/803429 ◽

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 ◽

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.

2018 IEEE 18th International Symposium on Computational Intelligence and Informatics (CINTI) ◽

Establishing sleep stages using Delta, Theta and Gamma oscillations from long term Local Field Potential (LFP) recordings in mice

10.1109/cinti.2018.8928237 ◽

2018 ◽

Cited By ~ 1

Author(s):

Laszlo Molnar ◽

Jozsef Domokos ◽

Isabella Ferando ◽

Istvan Mody

Keyword(s):

Local Field ◽

Local Field Potential ◽

Field Potential ◽

Gamma Oscillations ◽

Sleep Stages ◽

Distinct frequency bands in the local field potential are differently tuned to stimulus drift rate

10.1152/jn.00807.2017 ◽

2018 ◽

Vol 120 (2) ◽

pp. 681-692 ◽

Cited By ~ 5

Author(s):

Siddhesh Salelkar ◽

Gowri Manohari Somasekhar ◽

Supratim Ray

Keyword(s):

Local Field ◽

Local Field Potential ◽

Drift Rate ◽

Narrow Band ◽

Field Potential ◽

Gamma Oscillations ◽

Frequency Bands ◽

Wide Range ◽

Distinct Frequency ◽

Local field potential (LFP) recorded with a microelectrode reflects the activity of several neural processes, including afferent synaptic inputs, microcircuit-level computations, and spiking activity. Objectively probing their contribution requires a design that allows dissociation between these potential contributors. Earlier reports have shown that the primate lateral geniculate nucleus (LGN) has a higher temporal frequency (drift rate) cutoff than the primary visual cortex (V1), such that at higher drift rates inputs into V1 from the LGN continue to persist, whereas output ceases, permitting partial dissociation. Using chronic microelectrode arrays, we recorded spikes and LFP from V1 of passively fixating macaques while presenting sinusoidal gratings drifting over a wide range. We further optimized the gratings to produce strong gamma oscillations, since recent studies in rodent V1 have reported LGN-dependent narrow-band gamma oscillations. Consistent with earlier reports, power in higher LFP frequencies (above ~140 Hz) tracked the population firing rate and were tuned to preferred drift rates similar to those for spikes. Significantly, power in the lower (up to ~40 Hz) frequencies increased transiently in the early epoch after stimulus onset, even at high drift rates, and had preferred drift rates higher than for spikes/high gamma. Narrow-band gamma (50–80 Hz) power was not strongly correlated with power in high or low frequencies and had much lower preferred temporal frequencies. Our results demonstrate that distinct frequency bands of the V1 LFP show diverse tuning profiles, which may potentially convey different attributes of the underlying neural activity. NEW & NOTEWORTHY In recent years the local field potential (LFP) has been increasingly studied, but interpreting its rich frequency content has been difficult. We use a stimulus manipulation that generates different tuning profiles for low, gamma, and high frequencies of the LFP, suggesting contributions from potentially different sources. Our results have possible implications for design of better neural prosthesis systems and brain-machine interfacing applications.

Afferent inputs to cortical fast-spiking interneurons organize pyramidal cell network oscillations at high-gamma frequencies (60–200 Hz)

10.1152/jn.00844.2013 ◽

2014 ◽

Vol 112 (11) ◽

pp. 3001-3011 ◽

Cited By ~ 19

Author(s):

Piotr Suffczynski ◽

Nathan E. Crone ◽

Piotr J. Franaszczuk

Keyword(s):

Local Field ◽

Local Field Potential ◽

Field Potential ◽

Pyramidal Cells ◽

Gamma Oscillations ◽

Cortical Activation ◽

Gamma Activity ◽

High Gamma ◽

Fast Spiking ◽

Gamma Frequencies

High-gamma activity, ranging in frequency between ∼60 Hz and 200 Hz, has been observed in local field potential, electrocorticography, EEG and magnetoencephalography signals during cortical activation, in a variety of functional brain systems. The origin of these signals is yet unknown. Using computational modeling, we show that a cortical network model receiving thalamic input generates high-gamma responses comparable to those observed in local field potential recorded in monkey somatosensory cortex during vibrotactile stimulation. These high-gamma oscillations appear to be mediated mostly by an excited population of inhibitory fast-spiking interneurons firing at high-gamma frequencies and pacing excitatory regular-spiking pyramidal cells, which fire at lower rates but in phase with the population rhythm. The physiological correlates of high-gamma activity, in this model of local cortical circuits, appear to be similar to those proposed for hippocampal ripples generated by subsets of interneurons that regulate the discharge of principal cells.

Bimodal RMS distributions for the objective detection of theta (θ) and gamma (γ) brain oscillations during long-term continuous LFP recordings in mice

MACRo 2015 ◽

10.1515/macro-2017-0004 ◽

2017 ◽

Vol 2 (1) ◽

pp. 31-37 ◽

Cited By ~ 2

Author(s):

László Molnár ◽

József Domokos ◽

Isabella Ferando ◽

István Módy

Keyword(s):

Local Field ◽

Local Field Potential ◽

Field Potential ◽

Gamma Oscillations ◽

Bimodal Distribution ◽

Mean Square ◽

Objective Detection ◽

Point Of Intersection ◽

AbstractIn the rodent’s brain the theta (5-12 Hz) and gamma (30-120 Hz) oscillations can be readily detected in local field potential (LFP) recordings, but there is no universal consensus about an objective threshold for their detection.We FIR-filtered the long-term local field potential (LFP) recordings for theta and gamma oscillations. The RMS (root mean square) values of 8 s epochs in 0.5-4 s steps (using corresponding overlaps) were obtained from the filtered recordings. For both theta and gamma oscillations, the histograms showed a bimodal distribution well fitted by two Gaussians. The point of intersection between the two distributions proved to be the most reliable for separating the RMS values belonging to the two Gaussians.

Gamma oscillations in the rat ventral striatum originate in the piriform cortex

10.1101/127126 ◽

2017 ◽

Author(s):

James E. Carmichael ◽

Jimmie M. Gmaz ◽

Matthijs A. A. van der Meer

Keyword(s):

Local Field ◽

Ventral Striatum ◽

Piriform Cortex ◽

Current Source ◽

Field Potential ◽

Gamma Oscillations ◽

Gamma Band ◽

Temporal Organization ◽

Local Circuitry ◽

Gamma Band Oscillations

AbstractLocal field potentials (LFP) recorded from the human and rodent ventral striatum (vStr) exhibit prominent, behaviorally relevant gamma-band oscillations. These oscillations are related to local spiking activity and transiently synchronize with anatomically related areas, suggesting a possible role in organizing vStr activity. However, the origin of vStr gamma is unknown. We recorded vStr gamma oscillations across a 1.4mm2 grid spanned by 64 recording electrodes as rats rested and foraged for rewards, revealing a highly consistent power gradient originating in the adjacent piriform cortex. Phase differences across the vStr were consistently small (<10°) and current source density analysis further confirmed the absence of local sink-source pairs in the vStr. Reversible occlusions of the ipsilateral (but not contralateral) nostril, known to abolish gamma oscillations in the piriform cortex, strongly reduced vStr gamma power and the occurrence of transient gamma-band events. These results imply that local circuitry is not a major contributor to gamma oscillations in the vStr LFP, and that piriform cortex is an important driver of gamma-band oscillations in the vStr and associated limbic areas.Significance StatementThe ventral striatum is an area of anatomical convergence in circuits underlying motivated behavior, but it remains unclear how its inputs from different sources interact. One of the major proposals of how neural circuits may dynamically switch between convergent inputs is through temporal organization reflected in local field potential (LFP) oscillations. Our results show that in the rat, the mechanisms controlling vStr gamma oscillations are primarily located in the in the adjacent piriform cortex, rather than vStr itself. This provides a novel interpretation of previous rodent work on gamma oscillations in the vStr and related circuits, and an important consideration for future work seeking to use oscillations in these areas as biomarkers in rodent models of human behavioral and neurological disorders.

Novel Porous Brain Electrodes for Augmented Local Field Potential Signal Detection

Materials ◽

10.3390/ma12030542 ◽

2019 ◽

Vol 12 (3) ◽

pp. 542 ◽

Cited By ~ 1

Author(s):

Sung Lee ◽

Kyeong-Seok Lee ◽

Saurav Sorcar ◽

Abdul Razzaq ◽

Maan-Gee Lee ◽

...

Keyword(s):

Local Field ◽

Local Field Potential ◽

Brain Activity ◽

Field Potential ◽

Porous Electrodes ◽

Surface Topology ◽

Neural Electrode ◽

Flow Of Information ◽

Potential Signal ◽

Intracerebral local field potential (LFP) measurements are commonly used to monitor brain activity, providing insight into the flow of information across neural networks. Herein we describe synthesis and application of a neural electrode possessing a nano/micro-scale porous surface topology for improved LFP measurement. Compared with conventional brain electrodes, the porous electrodes demonstrate higher measured amplitudes with lower noise levels.

Effect of amplitude correlations on coherence in the local field potential

10.1152/jn.00851.2013 ◽

2014 ◽

Vol 112 (4) ◽

pp. 741-751 ◽

Cited By ~ 28

Author(s):

Ramanujan Srinath ◽

Supratim Ray

Keyword(s):

Local Field ◽

Local Field Potential ◽

Multiple Scales ◽

Field Potential ◽

Interelectrode Distance ◽

Study Phase ◽

Temporal Correlations ◽

Two Factors ◽

The Brain ◽

Neural activity across the brain shows both spatial and temporal correlations at multiple scales, and understanding these correlations is a key step toward understanding cortical processing. Correlation in the local field potential (LFP) recorded from two brain areas is often characterized by computing the coherence, which is generally taken to reflect the degree of phase consistency across trials between two sites. Coherence, however, depends on two factors—phase consistency as well as amplitude covariation across trials—but the spatial structure of amplitude correlations across sites and its contribution to coherence are not well characterized. We recorded LFP from an array of microelectrodes chronically implanted in the primary visual cortex of monkeys and studied correlations in amplitude across electrodes as a function of interelectrode distance. We found that amplitude correlations showed a similar trend as coherence as a function of frequency and interelectrode distance. Importantly, even when phases were completely randomized between two electrodes, amplitude correlations introduced significant coherence. To quantify the contributions of phase consistency and amplitude correlations to coherence, we simulated pairs of sinusoids with varying phase consistency and amplitude correlations. These simulations confirmed that amplitude correlations can significantly bias coherence measurements, resulting in either over- or underestimation of true phase coherence. Our results highlight the importance of accounting for the correlations in amplitude while using coherence to study phase relationships across sites and frequencies.

Pharmacological manipulation of the olfactory bulb modulates beta oscillations: testing model predictions

10.1152/jn.00090.2018 ◽

2018 ◽

Vol 120 (3) ◽

pp. 1090-1106 ◽

Cited By ~ 7

Author(s):

Bolesław L. Osinski ◽

Alex Kim ◽

Wenxi Xiao ◽

Nisarg M. Mehta ◽

Leslie M. Kay

Keyword(s):

Nmda Receptor ◽

Olfactory Bulb ◽

Local Field ◽

Local Field Potential ◽

Field Potential ◽

Gamma Oscillations ◽

Receptor Activation ◽

Beta Oscillations ◽

Pyriform Cortex ◽

Beta Power

The mammalian olfactory bulb (OB) generates gamma (40–100 Hz) and beta (15–30 Hz) local field potential (LFP) oscillations. Gamma oscillations arise at the peak of inhalation supported by dendrodendritic interactions between glutamatergic mitral cells (MCs) and GABAergic granule cells (GCs). Beta oscillations are induced by odorants in learning or odor sensitization paradigms, but their mechanism and function are still poorly understood. When centrifugal OB inputs are blocked, beta oscillations disappear, but gamma oscillations persist. Centrifugal inputs target primarily GABAergic interneurons in the GC layer (GCL) and regulate GC excitability, suggesting a causal link between beta oscillations and GC excitability. Our previous modeling work predicted that convergence of excitatory/inhibitory inputs onto MCs and centrifugal inputs onto GCs increase GC excitability sufficiently to produce beta oscillations primarily through voltage dependent calcium channel-mediated GABA release, independently of NMDA channels. We test some of the predictions of this model by examining the influence of NMDA and muscarinic acetylcholine (ACh) receptors, which affect GC excitability in different ways, on beta oscillations. A few minutes after intrabulbar infusion, scopolamine (muscarinic antagonist) suppressed odor-evoked beta in response to a strong stimulus but increased beta power in response to a weak stimulus, as predicted by our model. Pyriform cortex (PC) beta power was unchanged. Oxotremorine (muscarinic agonist) suppressed all oscillations, likely from overinhibition. APV, an NMDA receptor antagonist, suppressed gamma oscillations selectively (in OB and PC), lending support to the model’s prediction that beta oscillations can be supported independently of NMDA receptors. NEW & NOTEWORTHY Olfactory bulb local field potential beta oscillations appear to be gated by GABAergic granule cell excitability. Reducing excitability with scopolamine reduces beta induced by strong odors but increases beta induced by weak odors. Beta oscillations rely on the same synapse as gamma oscillations but, unlike gamma, can persist in the absence of NMDA receptor activation. Pyriform cortex beta oscillations maintain power when olfactory bulb beta power is low, and the system maintains beta band coherence.