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

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.

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

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.

scholarly journals Learning Task-Related Activities From Independent Local-Field-Potential Components Across Motor Cortex Layers

2018 ◽  
Vol 12 ◽  
Author(s):  
Gonzalo Martín-Vázquez ◽  
Toshitake Asabuki ◽  
Yoshikazu Isomura ◽  
Tomoki Fukai
Keyword(s):  
Motor Cortex ◽  
Local Field ◽  
Local Field Potential ◽  
Field Potential ◽  
Learning Task

Abstract 25: Periinfarct Rewiring Supports Recovery After Primary Motor Cortex Stroke

Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Mitsouko van Assche ◽  
Elisabeth Dirren ◽  
Alexia Bourgeois ◽  
Andreas Kleinschmidt ◽  
Jonas Richiardi ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Spatial Scales ◽  
Premotor Cortex ◽  
Brain Regions ◽  
Relative Increase ◽  
Motor Recovery ◽  
The Core ◽  
Hand Dexterity ◽  
Motor Network

Background and Purpose: After stroke restricted to the primary motor cortex (M1), it is uncertain whether network reorganization associated with motor recovery involves the periinfarct or more remote brain regions. In humans, the challenge is to recruit patients with similar lesions in size and location. Methods: We studied 16 patients with focal M1 stroke and hand paresis. Motor function and resting-state MRI functional connectivity (FC) were studied at three time points: acute (<10 days), early subacute (3 weeks), and late subacute (3 months). FC correlates of motor recovery were investigated at three spatial scales, i) ipsilesional non-infarcted M1, ii) core motor network (including M1, premotor cortex (PMC), supplementary motor area (SMA), and primary somatosensory cortex), and iii) extended motor network including all regions structurally connected to the upper limb representation of M1. Results: Hand dexterity was impaired only in the acute phase ( P =0.036). At a small spatial scale, improved dexterity was associated with increased FC involving mainly the ipsilesional non-infarcted M1 and contralesional motor regions (cM1: rho=0.732; P =0.004; cPMC: rho=0.837, P <0.001; cSMA: rho=0.736; P =0.004). At a larger scale, motor recovery correlated with the relative increase in total FC strength in the core motor network compared to the extended motor network (rho=0.71; P =0.006). Conclusions: FC changes associated with motor improvement involve the perilesional M1 and do not extend beyond the core motor network. The ipsilesional non-infarcted M1 and core motor regions could hence be primary targets for future restorative therapies.

Population encoding of spatial frequency, orientation, and color in macaque V1

1994 ◽  
Vol 72 (5) ◽  
pp. 2151-2166 ◽  
Author(s):  
J. D. Victor ◽  
K. Purpura ◽  
E. Katz ◽  
B. Mao
Keyword(s):  
Spatial Frequency ◽  
Local Field ◽  
Neural Activity ◽  
Local Field Potential ◽  
Field Potential ◽  
Orientation Tuning ◽  
Information Rate ◽  
Response Dynamics ◽  
Spatial Tuning ◽  
Band Limited

1. We recorded local field potentials in the parafoveal representation in the primary visual cortex of anesthetized and paralyzed macaque monkeys with a multicontact electrode that provided for sampling of neural activity at 16 sites along a vertical penetration. Differential recordings at adjacent contacts were transformed into an estimate of current source density (CSD), to provide a measure of local neural activity. 2. We used m-sequence stimuli to map the region of visual space that provided input to the recording site. The local field potential recorded in macaque V1 has a population receptive field (PRF) size of approximately 2 deg2. 3. We assessed spatial tuning by the responses to two-dimensional Gaussian noise, spatially filtered to retain power only within one octave. Responses to achromatic band-limited noise stimuli revealed a prominent band-pass spatial tuning in the upper layers, but a more low-pass spatial tuning in lower layers. 4. We assessed orientation tuning by the responses to band-limited noise whose spectrum was further restricted to lie within 45 degrees wedges. The local field potential showed evidence of orientation tuning at most sites. Orientation tuning in upper and lower layers was manifest by systematic variations not only in response size but also in response dynamics. 5. We assessed chromatic tuning by the responses to isotropic band-limited noise modulated in a variety of directions in tristimulus space. Some lower-layer locations showed a nulling of response under near-isoluminant conditions. However, response dynamics in upper and lower layers depended not only on luminance contrast, but also on chromatic inputs. 6. Responses to near-isoluminant stimuli and to low-contrast luminance modulation were shifted to lower spatial frequencies. 7. We determined the extent to which various temporal frequencies in the response conveyed information concerning spatial frequency, orientation, and color under the steady-state conditions used in these studies. In each case, information is distributed in the response dynamics across a broad temporal frequency range, beginning at 4 Hz (the lowest frequency used). For spatial frequency the information rate remains significant up to at least 25 Hz. For orientation tuning and chromatic tuning, the information rate is lower overall and remains significant up to 13 Hz. In contrast, for texture discrimination, information is shifted to lower temporal frequencies.

scholarly journals Microstimulation of dorsal premotor and primary motor cortex delays the volitional commitment to an action choice

2020 ◽  
Vol 123 (3) ◽  
pp. 927-935
Author(s):  
David Thura ◽  
Paul Cisek
Keyword(s):  
Motor Cortex ◽  
Neural Activity ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Neural Substrates ◽  
Daily Basis ◽  
Decision Task ◽  
Movement Initiation ◽  
Deliberation Process ◽  
The Moment

Humans and other animals are faced with decisions about actions on a daily basis. These typically include a period of deliberation that ends with the commitment to a choice, which then leads to the overt expression of that choice through action. Previous studies with monkeys have demonstrated that neural activity in sensorimotor areas correlates with the deliberation process and reflects the moment of commitment before movement initiation, but the causal roles of these regions are challenging to establish. Here, we tested whether dorsal premotor (PMd) and primary motor cortex (M1) are causally involved in the volitional commitment to a reaching choice. We found that brief subthreshold microstimulation in PMd or M1 delayed commitment to an action but not the initiation of the action itself. Importantly, microstimulation only had a significant effect when it was delivered close to and before commitment time. These results are consistent with the proposal that PMd and M1 participate in the commitment process, which occurs when a critical firing rate difference is reached between cells voting for the selected option and those voting for the competing one. NEW & NOTEWORTHY The neural substrates of decisions between actions are typically investigated by correlating neural activity and subjects’ decision behavior, but this does not establish causality. In a reaching decision task, we demonstrate that subthreshold microstimulation of the monkey dorsal premotor cortex or primary motor cortex delays the deliberation duration if applied shortly before choice commitment. This result suggests a causal role of the sensorimotor cortex in the determination of decisions between actions.

scholarly journals Cyclic, condition-independent activity in primary motor cortex predicts corrective movement behavior

2018 ◽  
Author(s):  
Adam G. Rouse ◽  
Marc H. Schieber ◽  
Sridevi V. Sarma
Keyword(s):  
Motor Cortex ◽  
Neural Activity ◽  
Time Course ◽  
Primary Motor Cortex ◽  
Reaching Movements ◽  
Movement Behavior ◽  
Cyclic Activity ◽  
Cyclic Condition ◽  
Neuron Populations ◽  
Optimizing Control

AbstractReaching movements have previously been observed to have large condition-independent neural activity and cyclic neural dynamics. A new precision center-out task was used to test whether cyclic neural activity in the primary motor cortex (M1) occurred not only during initial reaching movements but also during subsequent corrective movements. Corrective movements were observed to be discrete with a time course and bell-shaped speed profile similar to the initial movements. Cyclic trajectories identified in the condition-independent neural activity were similar for initial and corrective submovements. The phase of the cyclic condition-independent neural activity predicted when peak movement speeds occurred, even when the subject made multiple corrective movements. Rather than being controlled as continuations of the initial reach, a discrete cycle of motor cortex activity encodes each corrective submovement.Significance StatementDuring a precision center-out task, initial and subsequent corrective movements occur as discrete submovements with bell-shaped speed profiles. A cycle of condition-independent activity in primary motor cortex neuron populations corresponds to each submovement whether initial or corrective, such that the phase of this cyclic activity predicts the time of peak speed. These submovements accompanied by cyclic neural activity offer important clues into how the we successfully execute precise, corrective reaching movements and may have implications for optimizing control of brain-computer interfaces.

Sign in / Sign up

Export Citation Format

Share Document