Coding of digit displacement by cell spiking and network oscillations in the monkey sensorimotor cortex

β-Band oscillations occur in motor and somatosensory cortices and muscle activity. Oscillations appear most strongly after movements, suggesting that they may represent or probe the limb's final sensory state. We tested this idea by training two macaque monkeys to perform a finger flexion to one of four displacements, which was then held for 2 s without visual feedback of absolute displacement. Local field potential (LFP) and single unit spiking were recorded from the rostral and caudal primary motor cortex and parietal areas 3a, 3b, 2, and 5. Information theoretic analysis determined how well unit firing rate or the power of LFP oscillations coded finger displacement. All areas encoded significant information about finger displacement after the movement into target, both in β-band (∼20 Hz) oscillatory activity and unit firing rate. On average, the information carried by unit firing was greater (0.07 bits) and peaked earlier (0.73 s after peak velocity) than that by LFP β-oscillations (0.05 bits and 0.95 s). However, there was considerable heterogeneity among units: some cells did not encode maximal information until midway through the holding phase. In 30% of cells, information in rate lagged information in LFP oscillations recorded at the same site. Finger displacement may be represented in the cortex in multiple ways. Coding the digit configuration immediately after a movement probably relies on nonoscillatory feedback, or efference copy. With increasing delay after movement cessation, oscillatory processing may also play a part.

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State-based decoding of hand and finger kinematics using neuronal ensemble and LFP activity during dexterous reach-to-grasp movements

Journal of Neurophysiology ◽

10.1152/jn.01038.2011 ◽

2013 ◽

Vol 109 (12) ◽

pp. 3067-3081 ◽

Cited By ~ 54

Author(s):

Vikram Aggarwal ◽

Mohsen Mollazadeh ◽

Adam G. Davidson ◽

Marc H. Schieber ◽

Nitish V. Thakor

Keyword(s):

Upper Limb ◽

Primary Motor Cortex ◽

Mean Squared Error ◽

Field Potential ◽

Reach To Grasp ◽

Dexterous Manipulation ◽

Neuronal Ensemble ◽

Limb Kinematics ◽

Behavioral States ◽

Local Field Potential Lfp

The performance of brain-machine interfaces (BMIs) that continuously control upper limb neuroprostheses may benefit from distinguishing periods of posture and movement so as to prevent inappropriate movement of the prosthesis. Few studies, however, have investigated how decoding behavioral states and detecting the transitions between posture and movement could be used autonomously to trigger a kinematic decoder. We recorded simultaneous neuronal ensemble and local field potential (LFP) activity from microelectrode arrays in primary motor cortex (M1) and dorsal (PMd) and ventral (PMv) premotor areas of two male rhesus monkeys performing a center-out reach-and-grasp task, while upper limb kinematics were tracked with a motion capture system with markers on the dorsal aspect of the forearm, hand, and fingers. A state decoder was trained to distinguish four behavioral states (baseline, reaction, movement, hold), while a kinematic decoder was trained to continuously decode hand end point position and 18 joint angles of the wrist and fingers. LFP amplitude most accurately predicted transition into the reaction (62%) and movement (73%) states, while spikes most accurately decoded arm, hand, and finger kinematics during movement. Using an LFP-based state decoder to trigger a spike-based kinematic decoder [ r = 0.72, root mean squared error (RMSE) = 0.15] significantly improved decoding of reach-to-grasp movements from baseline to final hold, compared with either a spike-based state decoder combined with a spike-based kinematic decoder ( r = 0.70, RMSE = 0.17) or a spike-based kinematic decoder alone ( r = 0.67, RMSE = 0.17). Combining LFP-based state decoding with spike-based kinematic decoding may be a valuable step toward the realization of BMI control of a multifingered neuroprosthesis performing dexterous manipulation.

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Discrete ripples reflect a spectrum of synchronous spiking activity in human association cortex

10.1101/2021.03.14.435276 ◽

2021 ◽

Author(s):

Ai Phuong S. Tong ◽

Alex P. Vaz ◽

John H. Wittig ◽

Sara K. Inati ◽

Kareem A. Zaghloul

Keyword(s):

Temporal Cortex ◽

Field Potential ◽

Human Memory ◽

Oscillatory Activity ◽

Association Cortex ◽

Memory Processing ◽

Dynamic Coordination ◽

Macro Scale ◽

Human Association ◽

Local Field Potential Lfp

AbstractDirect brain recordings have provided important insights into how persistent oscillatory activity support human memory retrieval, but the extent to which transient fluctuations in intracranial EEG (iEEG) captures the dynamic coordination of underlying neurons involved in memory processing remains unclear. Here, we simultaneously record iEEG, local field potential (LFP), and single unit activity in the human temporal cortex. We demonstrate that cortical ripples contribute to broadband high frequency activity and exhibit a spectrum of amplitudes and durations related to the amount of underlying neuronal spiking. Ripples in the macro-scale iEEG are related to the number and synchrony of ripples in the micro-scale LFP, which in turn are related to the synchrony of neuronal spiking. Our data suggest that neural activity in the human cortex is organized into dynamic, discrete packets of information.

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Is there an Intrinsic Relationship between LFP Beta Oscillation Amplitude and Firing Rate of Individual Neurons in Macaque Motor Cortex?

Cerebral Cortex Communications ◽

10.1093/texcom/tgaa017 ◽

2020 ◽

Vol 1 (1) ◽

Author(s):

Joachim Confais ◽

Nicole Malfait ◽

Thomas Brochier ◽

Alexa Riehle ◽

Bjørg Elisabeth Kilavik

Keyword(s):

Motor Cortex ◽

Firing Rate ◽

Oscillation Amplitude ◽

Field Potential ◽

Control Analysis ◽

Single Trial ◽

Beta Oscillations ◽

Visuomotor Behavior ◽

Local Field Potential Lfp ◽

Beta Oscillation

Abstract The properties of motor cortical local field potential (LFP) beta oscillations have been extensively studied. Their relationship to the local neuronal spiking activity was also addressed. Yet, whether there is an intrinsic relationship between the amplitude of beta oscillations and the firing rate of individual neurons remains controversial. Some studies suggest a mapping of spike rate onto beta amplitude, while others find no systematic relationship. To help resolve this controversy, we quantified in macaque motor cortex the correlation between beta amplitude and neuronal spike count during visuomotor behavior. First, in an analysis termed “task-related correlation”, single-trial data obtained across all trial epochs were included. These correlations were significant in up to 32% of cases and often strong. However, a trial-shuffling control analysis recombining beta amplitudes and spike counts from different trials revealed these task-related correlations to reflect systematic, yet independent, modulations of the 2 signals with the task. Second, in an analysis termed “trial-by-trial correlation”, only data from fixed trial epochs were included, and correlations were calculated across trials. Trial-by-trial correlations were weak and rarely significant. We conclude that there is no intrinsic relationship between the firing rate of individual neurons and LFP beta oscillation amplitude in macaque motor cortex.

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Lack of mutant huntingtin in cortical efferents improves behavioral inflexibility and corticostriatal dynamics in Huntington’s disease mice

Journal of Neurophysiology ◽

10.1152/jn.00777.2018 ◽

2019 ◽

Vol 122 (6) ◽

pp. 2621-2629

Author(s):

Ana María Estrada-Sánchez ◽

Courtney L. Blake ◽

Scott J. Barton ◽

Andrew G. Howe ◽

George V. Rebec

Keyword(s):

Motor Cortex ◽

Huntington's Disease ◽

Huntington’S Disease ◽

Local Field ◽

Local Field Potential ◽

Primary Motor Cortex ◽

Field Potential ◽

Full Length ◽

Mutant Huntingtin ◽

Local Field Potential Lfp

Abnormal communication between cerebral cortex and striatum plays a major role in the motor symptoms of Huntington’s disease (HD), a neurodegenerative disorder caused by a mutation of the huntingtin gene ( mHTT). Because cortex is the main driver of striatal processing, we recorded local field potential (LFP) activity simultaneously in primary motor cortex (M1) and dorsal striatum (DS) in BACHD mice, a full-length HD gene model, and in a conditional BACHD/Emx-1 Cre (BE) model in which mHTT is suppressed in cortical efferents, while mice freely explored a plus-shaped maze beginning at 20 wk of age. Relative to wild-type (WT) controls, BACHD mice were just as active across >40 wk of testing but became progressively less likely to turn into a perpendicular arm as they approached the choice point of the maze, a sign of HD motor inflexibility. BE mice, in contrast, turned as freely as WT throughout testing. Although BE mice did not exactly match WT in LFP activity, the reduction in alpha (8–13 Hz), beta (13–30 Hz), and low-gamma (30–50 Hz) power that occurred in M1 of turning-impaired BACHD mice was reversed. No reversal occurred in DS. In fact, BE mice showed further reductions in DS theta (4–8 Hz), beta, and low-gamma power relative to the BACHD model. Coherence analysis indicated a dysregulation of corticostriatal information flow in both BACHD and BE mice. Collectively, our results suggest that mHTT in cortical outputs drives the dysregulation of select cortical frequencies that accompany the loss of behavioral flexibility in HD. NEW & NOTEWORTHY BACHD mice, a full-length genetic model of Huntington’s disease (HD), express aberrant local field potential (LFP) activity in primary motor cortex (M1) along with decreased probability of turning into a perpendicular arm of a plus-shaped maze, a motor inflexibility phenotype. Suppression of the mutant huntingtin gene in cortical output neurons prevents decline in turning and improves alpha, beta, and low-gamma activity in M1. Our results implicate cortical networks in the search for therapeutic strategies to alleviate HD motor signs.

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Local differences in neuronal activation level decorrelate spatially coherent global fluctuations in gamma rhythms

10.1101/150532 ◽

2017 ◽

Author(s):

Kaushik J. Lakshminarasimhan ◽

Nikos K. Logothetis ◽

Georgios A. Keliris

Keyword(s):

Firing Rate ◽

Field Potential ◽

Statistical Technique ◽

Rate Code ◽

Firing Rates ◽

Activation Level ◽

Gamma Rhythms ◽

Global Fluctuations ◽

Neuronal Coherence ◽

Local Field Potential Lfp

AbstractNeuronal coherence is thought to constitute a unique substrate for information transmission distinct from firing rate. However, since the spatial scale of extracellular oscillations typically exceeds that of firing rates, it is unclear whether coherence complements or compromises the rate code. We examined responses in the macaque primary visual cortex and found that fluctuations in gamma-band (~40Hz) neuronal coherence correlated more with firing rate than oscillations in the local-field-potential (LFP). Although the spatial extent of LFP rhythms was broader, that of neuronal coherence was indistinguishable from firing rates. To identify the mechanism, we developed a statistical technique to isolate the rhythmic component of the spiking process and found that above results are explained by an activation-dependent increase in neuronal sensitivity to gamma-rhythmic input. Such adaptive changes in sensitivity to rhythmic inputs might constitute a fundamental homeostatic mechanism that prevents globally coherent inputs from undermining spatial resolution of the neural code.

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Neuronal Activity of Mitral-Tufted Cells in Awake Rats During Passive and Active Odorant Stimulation

Journal of Neurophysiology ◽

10.1152/jn.00095.2008 ◽

2008 ◽

Vol 100 (1) ◽

pp. 422-430 ◽

Cited By ~ 28

Author(s):

Romulo A. Fuentes ◽

Marcelo I. Aguilar ◽

María L. Aylwin ◽

Pedro E. Maldonado

Keyword(s):

Firing Rate ◽

Strong Dependence ◽

Field Potential ◽

Temporal Patterns ◽

Neuronal Population ◽

Oscillatory Activity ◽

Population Activity ◽

Oscillatory Power ◽

Rhythmic Discharge ◽

Excitatory Responses

Odorants induce specific modulation of mitral/tufted (MT) cells' firing rate in the mammalian olfactory bulb (OB), inducing temporal patterns of neuronal discharge embedded in an oscillatory local field potential (LFP). While most studies have examined anesthetized animals, little is known about the firing rate and temporal patterns of OB single units and population activity in awake behaving mammals. We examined the firing rate and oscillatory activity of MT cells and LFP signals in behaving rats during two olfactory tasks: passive exposure (PE) and two-alternative (TA) choice discrimination. MT inhibitory responses are predominant in the TA task (76.5%), whereas MT excitatory responses predominate in the PE task (59.2%). Rhythmic discharge in the 12- to 100-Hz range was found in 79.0 and 68.9% of MT cells during PE and TA tasks, respectively. Most odorants presented in PE task increase rhythmic discharges at frequencies >50 Hz, whereas in TA, one of four odorants produced a modest increment <40 Hz. LFP oscillations were clearly modulated by odorants during the TA task, increasing their oscillatory power at frequencies centered at 20 Hz and decreasing power at frequencies >50 Hz. Our results indicate that firing rate responses of MT cells in awake animals are behaviorally modulated with inhibition being a prominent feature of this modulation. The occurrence of oscillatory patterns in single- and multiunitary discharge is also related to stimulation and behavioral context, while the oscillatory patterns of the neuronal population showed a strong dependence on odorant stimulation.

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Is there an intrinsic relationship between LFP beta oscillation amplitude and firing rate of individual neurons in monkey motor cortex?

10.1101/586727 ◽

2019 ◽

Cited By ~ 1

Author(s):

Joachim Confais ◽

Nicole Malfait ◽

Thomas Brochier ◽

Alexa Riehle ◽

Bjørg Elisabeth Kilavik

Keyword(s):

Motor Cortex ◽

Firing Rate ◽

Oscillation Amplitude ◽

Field Potential ◽

Spike Rate ◽

Behavioral Task ◽

Beta Oscillations ◽

Macaque Monkeys ◽

Local Field Potential Lfp ◽

Beta Oscillation

ABSTRACTIt is a long-standing controversial issue whether an intrinsic relationship between the local field potential (LFP) beta oscillation amplitude and the spike rate of individual neurons in the motor cortex exists. Beta oscillations are prominent in motor cortical LFPs, and their relationship to the local neuronal spiking activity has been extensively studied. Many studies demonstrated that the spikes of individual neurons lock to the phase of LFP beta oscillations. However, the results concerning whether there is also an intrinsic relationship between the amplitude of LFP beta oscillations and the firing rate of individual neurons are contradictory. Some studies suggest a systematic mapping of spike rates onto LFP beta amplitude, and others find no systematic relationship. To resolve this controversy, we correlated the amplitude of LFP beta oscillations recorded in motor cortex of two male macaque monkeys with spike counts of individual neurons during visuomotor behavior, in two different manners. First, in an analysis termed task-related correlation, data obtained across all behavioral task epochs was included. These task-related correlations were frequently significant, and in majority of negative sign. Second, in an analysis termed trial-by-trial correlation, only data from a fixed pre-cue task epoch was included, and correlations were calculated across trials. Such trial-by-trial correlations were weak and rarely significant. We conclude that there is no intrinsic relationship between the firing rate of individual neurons and LFP beta oscillation amplitude in macaque motor cortex, beyond each of these signals being modulated by external factors such as the behavioral task.SIGNIFICANCE STATEMENTWe addressed the long-standing controversial issue of whether there is an intrinsic relationship between the local field potential (LFP) beta oscillation amplitude and the spike rate of individual neurons in the motor cortex. In two complementary analyses of data from macaque monkeys, we first demonstrate that the unfolding behavioral task strongly affects both the LFP beta amplitude and the neuronal spike rate, creating task-related correlations between the two signals. However, when limiting the influence of the task, by restricting our analysis to a fixed task epoch, correlations between the two signals were largely eliminated. We conclude that there is no intrinsic relationship between the firing rate of individual neurons and LFP beta oscillation amplitude in motor cortex.

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Psychosocial Crowding Stress-Induced Changes in Synaptic Transmission and Glutamate Receptor Expression in the Rat Frontal Cortex

Biomolecules ◽

10.3390/biom11020294 ◽

2021 ◽

Vol 11 (2) ◽

pp. 294

Author(s):

Agnieszka Zelek-Molik ◽

Bartosz Bobula ◽

Anna Gądek-Michalska ◽

Katarzyna Chorązka ◽

Adam Bielawski ◽

...

Keyword(s):

Frontal Cortex ◽

Primary Motor Cortex ◽

Interleukin 1 ◽

Field Potential ◽

Long Term Potentiation ◽

Plasma Corticosterone ◽

Receptor Expression ◽

Synaptic Activity ◽

Common Mechanism ◽

Crowding Stress

This study demonstrates how exposure to psychosocial crowding stress (CS) for 3, 7, and 14 days affects glutamate synapse functioning and signal transduction in the frontal cortex (FC) of rats. CS effects on synaptic activity were evaluated in FC slices of the primary motor cortex (M1) by measuring field potential (FP) amplitude, paired-pulse ratio (PPR), and long-term potentiation (LTP). Protein expression of GluA1, GluN2B mGluR1a/5, VGLUT1, and VGLUT2 was assessed in FC by western blot. The body’s response to CS was evaluated by measuring body weight and the plasma level of plasma corticosterone (CORT), adrenocorticotropic hormone (ACTH), and interleukin 1 beta (IL1B). CS 3 14d increased FP and attenuated LTP in M1, while PPR was augmented in CS 14d. The expression of GluA1, GluN2B, and mGluR1a/5 was up-regulated in CS 3d and downregulated in CS 14d. VGLUTs expression tended to increase in CS 7d. The failure to blunt the effects of chronic CS on FP and LTP in M1 suggests the impairment of habituation mechanisms by psychosocial stressors. PPR augmented by chronic CS with increased VGLUTs level in the CS 7d indicates that prolonged CS exposure changed presynaptic signaling within the FC. The CS bidirectional profile of changes in glutamate receptors’ expression seems to be a common mechanism evoked by stress in the FC.

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Corticospinal Tract Microstructure Correlates With Beta Oscillatory Activity in the Primary Motor Cortex After Stroke

Stroke ◽

10.1161/strokeaha.121.034344 ◽

2021 ◽

Author(s):

Robert Schulz ◽

Marlene Bönstrup ◽

Stephanie Guder ◽

Jingchun Liu ◽

Benedikt Frey ◽

...

Keyword(s):

Motor Cortex ◽

Fractional Anisotropy ◽

Primary Motor Cortex ◽

Supplementary Motor Area ◽

Premotor Cortex ◽

Motor Impairment ◽

Motor Area ◽

Oscillatory Activity ◽

Premotor Area ◽

Beta Power

Background and Purpose: Cortical beta oscillations are reported to serve as robust measures of the integrity of the human motor system. Their alterations after stroke, such as reduced movement-related beta desynchronization in the primary motor cortex, have been repeatedly related to the level of impairment. However, there is only little data whether such measures of brain function might directly relate to structural brain changes after stroke. Methods: This multimodal study investigated 18 well-recovered patients with stroke (mean age 65 years, 12 males) by means of task-related EEG and diffusion-weighted structural MRI 3 months after stroke. Beta power at rest and movement-related beta desynchronization was assessed in 3 key motor areas of the ipsilesional hemisphere that are the primary motor cortex (M1), the ventral premotor area and the supplementary motor area. Template trajectories of corticospinal tracts (CST) originating from M1, premotor cortex, and supplementary motor area were used to quantify the microstructural state of CST subcomponents. Linear mixed-effects analyses were used to relate tract-related mean fractional anisotropy to EEG measures. Results: In the present cohort, we detected statistically significant reductions in ipsilesional CST fractional anisotropy but no alterations in EEG measures when compared with healthy controls. However, in patients with stroke, there was a significant association between both beta power at rest ( P =0.002) and movement-related beta desynchronization ( P =0.003) in M1 and fractional anisotropy of the CST specifically originating from M1. Similar structure-function relationships were neither evident for ventral premotor area and supplementary motor area, particularly with respect to their CST subcomponents originating from premotor cortex and supplementary motor area, in patients with stroke nor in controls. Conclusions: These data suggest there might be a link connecting microstructure of the CST originating from M1 pyramidal neurons and beta oscillatory activity, measures which have already been related to motor impairment in patients with stroke by previous reports.

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Coherent network oscillations by olfactory interneurons: modulation by endogenous amines

Journal of Neurophysiology ◽

10.1152/jn.1993.69.6.1930 ◽

1993 ◽

Vol 69 (6) ◽

pp. 1930-1939 ◽

Cited By ~ 36

Author(s):

A. Gelperin ◽

L. D. Rhines ◽

J. Flores ◽

D. W. Tank

Keyword(s):

Second Messengers ◽

Field Potential ◽

Learning Ability ◽

Odor Recognition ◽

Axonal Projections ◽

Odor Learning ◽

Olfactory Systems ◽

Olfactory Interneurons ◽

Limax Maximus ◽

Local Field Potential Lfp

1. The procerebral (PC) lobe of the terrestrial mollusk Limax maximus contains a highly interconnected network of local olfactory interneurons that receives direct axonal projections from the two pairs of noses. This olfactory processing network generates a 0.7-Hz oscillation in its local field potential (LFP) that is coherent throughout the network. The oscillating LFP is modulated by natural odorants applied to the neuroepithelium of the superior nose. 2. Two amines known to be present in the PC lobe, dopamine and serotonin, increase the frequency of the PC lobe oscillation and alter its waveform. 3. Glutamate, another putative neurotransmitter known to be present in the lobe, suppresses the PC lobe oscillation by a quisqualate-type receptor and appears to be used by one of the two classes of neurons in the PC lobe to generate the basic LFP oscillation. 4. The known activation of second messengers in Limax PC lobe by dopamine and serotonin together with their effects on the oscillatory rhythm suggest the hypothesis that these amines augment mechanisms mediating synaptic plasticity in the olfactory network, similar to hypothesized effects of amines in vertebrate olfactory systems. 5. The use of a distributed network of interneurons showing coherent oscillations may relate to the highly developed odor recognition and odor learning ability of Limax.

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