Ultrasonic thalamic stimulation modulates neural activity of thalamus and motor cortex in the mouse

Abstract Objective. Previous studies have demonstrated that ultrasound thalamic stimulation (UTS) can treat disorders of consciousness. However, it is still unclear how UTS modulates neural activity in the thalamus and cortex. Approach. In this study, we performed UTS in mice and recorded the neural activities including spike and local field potential (LFP) of the thalamus and motor cortex. We analyzed the firing rate of spikes and the power spectrum of LFPs and evaluated the coupling relationship between LFPs from the thalamus and motor cortex with Granger causality. Main results. Our results clearly indicate that UTS can directly induce neural activity in the thalamus and indirectly induce neural activity in the motor cortex. We also found that there is a strong connection relationship of neural activity between thalamus and motor cortex under UTS. Significance. These results demonstrate that UTS can modulate the neural activity of the thalamus and motor cortex in mice. It has the potential to provide guidance for the ultrasound treatment of thalamus-related diseases.

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Chronic Stability of Single-Channel Neurophysiological Correlates of Gross and Fine Reaching Movements in the Rat

10.1101/674101 ◽

2019 ◽

Author(s):

David T. Bundy ◽

David J Guggenmos ◽

Maxwell D Murphy ◽

Randolph J. Nudo

Keyword(s):

Motor Cortex ◽

Local Field ◽

Neural Activity ◽

Local Field Potential ◽

Primary Motor Cortex ◽

Spectral Power ◽

Premotor Cortex ◽

Field Potential ◽

Motor Recovery ◽

Reaching Movements

AbstractFollowing injury to motor cortex, reorganization occurs throughout spared brain regions and is thought to underlie motor recovery. Unfortunately, the standard neurophysiological and neuroanatomical measures of post-lesion plasticity are only indirectly related to observed changes in motor execution. While substantial task-related neural activity has been observed during motor tasks in rodent primary motor cortex and premotor cortex, the long-term stability of these responses in healthy rats is uncertain, limiting the interpretability of longitudinal changes in the specific patterns of neural activity during motor recovery following injury. This study examined the stability of task-related neural activity associated with execution of reaching movements in healthy rodents. Rats were trained to perform a novel reaching task combining a ‘gross’ lever press and a ‘fine’ pellet retrieval. In each animal, two chronic microelectrode arrays were implanted in motor cortex spanning the caudal forelimb area (rodent primary motor cortex) and the rostral forelimb area (rodent premotor cortex). We recorded multiunit spiking and local field potential activity from 10 days to 7-10 weeks post-implantation to characterize the patterns of neural activity observed during each task component and analyzed the consistency of channel-specific task-related neural activity. Task-related changes in neural activity were observed on the majority of channels. While the task-related changes in multi-unit spiking and local field potential spectral power were consistent over several weeks, spectral power changes were more stable, despite the trade-off of decreased spatial and temporal resolution. These results show that rodent primary and premotor cortex are both involved in reaching movements with stable patterns of task-related activity across time, establishing the relevance of the rodent for future studies designed to examine changes in task-related neural activity during recovery from focal cortical lesions.

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Enhanced hippocampal theta rhythmicity and emergence of eta oscillation in virtual reality

10.1101/2020.06.29.178186 ◽

2020 ◽

Author(s):

Karen Safaryan ◽

Mayank R. Mehta

Keyword(s):

Virtual Reality ◽

Neural Activity ◽

Pyramidal Neurons ◽

Cell Layer ◽

Field Potential ◽

Theta Oscillations ◽

Spatial Coding ◽

Slow Oscillations ◽

Hippocampal Theta ◽

Local Field Potential Lfp

AbstractHippocampal theta oscillations in rodents profoundly impact neural activity, spatial coding, and synaptic plasticity and learning. What are the sensory mechanisms governing slow oscillations? We hypothesized that the nature of multisensory inputs is a crucial factor in hippocampal rhythmogenesis. We compared the rat hippocampal slow oscillations in the multisensory-rich real world (RW) and in a body-fixed, visual virtual reality (VR). The amplitude and rhythmicity of the hippocampal ~8 Hz theta were enhanced in VR compared to RW. This was accompanied by the emergence of a ~4 Hz oscillation, termed the eta rhythm, evident in the local field potential (LFP) in VR, but not in RW. Similar to theta, eta band amplitude increased with running speed in VR, but not in RW. However, contrary to theta, eta amplitude was highest in the CA1 cell layer, implicating intra-CA1 mechanisms. Consistently, putative CA1 interneurons, but not pyramidal neurons, showed substantially more eta modulation in VR than in RW. These results elucidate the multisensory mechanisms of hippocampal rhythms and the surprising effects of VR on enhancing these rhythms, which has not been achieved pharmacologically and has significant broader implications for VR use in humans.One Sentence SummaryNavigation in virtual reality greatly enhances hippocampal 8Hz theta rhythmicity, and generates a novel, ~4Hz eta rhythm that is localized in the CA1 cell layer and influences interneurons more than pyramidal neurons.

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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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Less efficacy of valproic acid monotherapy may be caused by neural excitatory rebound in seizures

10.1101/2021.11.02.21265719 ◽

2021 ◽

Author(s):

Xiang Zou ◽

Zilu Zhu ◽

Yu Guo ◽

Hongmiao Zhang ◽

Yuchen Liu ◽

...

Keyword(s):

Valproic Acid ◽

Neural Activity ◽

Field Potential ◽

Multiple Wave ◽

Focal Seizures ◽

Power Shift ◽

Power Spectral ◽

Inhibitory Power ◽

Local Field Potential Lfp ◽

Spike Firing

Valproic acid (VPA) represents one of the most efficient antiepileptic drugs (AEDs) with either general or focal seizures, but a certain percentage of patients are not recovered or even worse, the mechanism under this phenomenon remains unclear. Here, we retrospectively reviewed 16 patients who received awake craniotomy surgery. Intro-operative high density electrocorticogram (ECoG) was used to record the local field potential (LFP) response to VPA treatment. We found the less efficacy of VPA monotherapy was associated with ECoG spectrum power shift from higher to lower frequency after VPA injection, together with increased synchronization of the LFP. Furthermore, we established the computational model to testify the hypothesis that the ineffectivity of VPA may be caused by excitatory dynamic rebound during the inhibitory power increasing. In addition to test the hypothesis, we employed the mice with Kanic Acid (KA)-induced epileptic model to confirm that it would be inhibited by VPA on behavior and neural activity. Also, the neural activity shows significant rebound on spike firing. Then we discovered that the LFP would increase the power spectral density in multiple wave bands after the VPA delivers. These findings suggest that less efficacy of valproic acid monotherapy in focal seizures may be caused by neural excitatory rebound which mediated by elevated inhibitory power.

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Network Amplification of Local Fluctuations Causes High Spike Rate Variability, Fractal Firing Patterns and Oscillatory Local Field Potentials

Neural Computation ◽

10.1162/neco.1994.6.5.795 ◽

1994 ◽

Vol 6 (5) ◽

pp. 795-836 ◽

Cited By ~ 57

Author(s):

Marius Usher ◽

Martin Stemmler ◽

Christof Koch ◽

Zeev Olami

Keyword(s):

Power Spectrum ◽

Local Field ◽

Neural Activity ◽

Cortical Neurons ◽

Interspike Interval ◽

Field Potential ◽

External Source ◽

Recurrent Network ◽

Stochastic Input ◽

Behaving Monkeys

We investigate a model for neural activity in a two-dimensional sheet of leaky integrate-and-fire neurons with feedback connectivity consisting of local excitation and surround inhibition. Each neuron receives stochastic input from an external source, independent in space and time. As recently suggested by Softky and Koch (1992, 1993), independent stochastic input alone cannot explain the high interspike interval variability exhibited by cortical neurons in behaving monkeys. We show that high variability can be obtained due to the amplification of correlated fluctuations in a recurrent network. Furthermore, the cross-correlation functions have a dual structure, with a sharp peak on top of a much broader hill. This is due to the inhibitory and excitatory feedback connections, which cause “hotspots” of neural activity to form within the network. These localized patterns of excitation appear as clusters or stripes that coalesce, disintegrate, or fluctuate in size while simultaneously moving in a random walk constrained by the interaction with other clusters. The synaptic current impinging upon a single neuron shows large fluctuations at many time scales, leading to a large coefficient of variation (CV) for the interspike interval statistics. The power spectrum associated with single units shows a 1/f decay for small frequencies and is flat at higher frequencies, while the power spectrum of the spiking activity averaged over many cells—equivalent to the local field potential—shows no 1/f decay but a prominent peak around 40 Hz, in agreement with data recorded from cat and monkey cortex (Gray et al. 1990; Eckhorn et al. 1993). Firing rates exhibit self-similarity between 20 and 800 msec, resulting in 1/f-like noise, consistent with the fractal nature of neural spike trains (Teich 1992).

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Synaptic proliferation in the motor cortex of adult cats after long-term thalamic stimulation

Journal of Neurophysiology ◽

10.1152/jn.1992.68.1.295 ◽

1992 ◽

Vol 68 (1) ◽

pp. 295-308 ◽

Cited By ~ 59

Author(s):

A. Keller ◽

K. Arissian ◽

H. Asanuma

Keyword(s):

Motor Cortex ◽

Dendritic Spines ◽

Neural Activity ◽

Structural Changes ◽

Primary Motor Cortex ◽

Information Storage ◽

Numerical Density ◽

Thalamic Stimulation ◽

Adult Cats

1. One of the hypotheses for information storage in the CNS postulates the induction of structural changes in synaptic circuits. This postulate predicts that behavioral experiences produce changes in neural activity that subsequently induce synaptogenesis in the mature CNS. Available data indicate that the establishment of engrams for novel motor acts may involve alterations of synaptic interactions within the primary motor cortex. The present study examines the hypothesis that patterns of synaptic circuitry and of synaptic activation are rearranged after enhanced neural activity in pathways projecting to the motor cortex. 2. Electrodes implanted in the ventroposterolateral (VPL) nucleus of the thalamus were used for long-term stimulation (20 microA, 4 days) of afferents to the motor cortex in freely behaving, adult cats. This stimulation primarily affected corticocortical inputs from the somatosensory cortex (area 2) to area 4 gamma of the motor cortex. Electron microscopy and stereological procedures were used to compare the numerical density (Nv) of various types of synapses in layers II/III of the stimulated (experimental) motor cortex with the Nv of the corresponding synapses in the contralateral (control) hemisphere. 3. Long-term stimulation produced a significant increase (25.6%) in synaptic Nv in experimental motor cortex. This increase was due primarily to an increase in the Nv of asymmetrical synapses with dendritic spines. The numbers of symmetrical synapses, and of asymmetrical synapses with dendritic shafts, were not affected by long-term stimulation. 4. Synaptic active zones [calculated by measuring the lengths of postsynaptic densities (PSDs)] were significantly longer in experimental motor cortex. Lengthening of PSDs occurred selectively in asymmetrical synapses with dendritic shafts (28% increase). 5. The Nv of synapses having perforations in their PSDs (perforated synapses) was significantly higher in experimental hemispheres. Also increased was the incidence of synapse-associated polyribosomes, which are most commonly found at the base of dendritic spines. An increase in the number of perforated synapses and of polyribosomes are both morphological hallmarks of synaptogenesis. 6. The percentages of synapses having different curvatures (i.e., presynaptically concave, convex, or flat) were similar in experimental and in control motor cortex.(ABSTRACT TRUNCATED AT 400 WORDS)

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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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nNOS-expressing interneurons control basal and behaviorally evoked arterial dilation in somatosensory cortex of mice

eLife ◽

10.7554/elife.60533 ◽

2020 ◽

Vol 9 ◽

Cited By ~ 1

Author(s):

Christina T Echagarruga ◽

Kyle W Gheres ◽

Jordan N Norwood ◽

Patrick J Drew

Keyword(s):

Neural Activity ◽

Cerebral Arteries ◽

Field Potential ◽

Neuron Activity ◽

Arterial Diameter ◽

Cellular Mechanisms ◽

Basal Diameter ◽

Arterial Dilation ◽

Oxide Synthase ◽

Local Field Potential Lfp

Cortical neural activity is coupled to local arterial diameter and blood flow. However, which neurons control the dynamics of cerebral arteries is not well understood. We dissected the cellular mechanisms controlling the basal diameter and evoked dilation in cortical arteries in awake, head-fixed mice. Locomotion drove robust arterial dilation, increases in gamma band power in the local field potential (LFP), and increases calcium signals in pyramidal and neuronal nitric oxide synthase (nNOS)-expressing neurons. Chemogenetic or pharmocological modulation of overall neural activity up or down caused corresponding increases or decreases in basal arterial diameter. Modulation of pyramidal neuron activity alone had little effect on basal or evoked arterial dilation, despite pronounced changes in the LFP. Modulation of the activity of nNOS-expressing neurons drove changes in the basal and evoked arterial diameter without corresponding changes in population neural activity.

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Effects of transcranial static magnetic stimulation over the primary motor cortex on local and network spontaneous electroencephalogram oscillations

Scientific Reports ◽

10.1038/s41598-021-87746-2 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sumiya Shibata ◽

Tatsunori Watanabe ◽

Yoshihiro Yukawa ◽

Masatoshi Minakuchi ◽

Ryota Shimomura ◽

...

Keyword(s):

Motor Cortex ◽

Power Spectrum ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Cortical Excitability ◽

Controlled Study ◽

Functional Coupling ◽

Phase Lag ◽

Theta Band ◽

Double Blind

AbstractTranscranial static magnetic stimulation (tSMS) is a novel non-invasive brain stimulation technique that reduces cortical excitability at the stimulation site. We investigated the effects of tSMS over the left primary motor cortex (M1) for 20 min on the local electroencephalogram (EEG) power spectrum and interregional EEG coupling. Twelve right-handed healthy subjects participated in this crossover, double-blind, sham-controlled study. Resting-state EEG data were recorded for 3 min before the intervention and 17 min after the beginning of the intervention. The power spectrum at the left central electrode (C3) and the weighted phase lag index (wPLI) between C3 and the other electrodes was calculated for theta (4–8 Hz), alpha (8–12 Hz), and beta (12–30 Hz) frequencies. The tSMS significantly increased theta power at C3 and the functional coupling in the theta band between C3 and the parietal midline electrodes. The tSMS over the left M1 for 20 min exhibited modulatory effects on local cortical activity and interregional functional coupling in the theta band. The neural oscillations in the theta band may have an important role in the neurophysiological effects induced by tSMS over the frontal cortex.

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