Gene expression changes of interconnected spared cortical neurons 7 days after ischemic infarct of the primary motor cortex in the rat

1. The previous paper has described in detail the input and output features of single neurons located at sites within primate face motor cortex from which intracortical microstimulation (ICMS, less than or equal to 20 microA) evoked tongue movements at the lowest threshold ("tongue-MI" sites); for comparative purposes, we also reported on the input and output features of a smaller number of neurons recorded at sites from which ICMS could evoke jaw movements ("jaw-MI" sites), facial movements ("face-MI" sites), or, at a few sites, tongue movements and, at the same threshold intensity, either a jaw movement or a facial movement. 2. Our findings of an extensive and diverse representation of sites within face motor cortex of monkeys for the generation of elemental components of tongue movement, and the relatively few sites from which jaw-closing movements could be evoked, were consistent with our recent observations that reversible, cooling-induced inactivation of the face motor cortex severely impaired the performance by monkeys of a tongue-protrusion task but had only relatively minor effects on the performance of a biting task. In an attempt to establish a neuronal correlate for these different behavioral relations, the present study has documented the task-related activities of those single neurons that were characterized in the previous paper in terms of afferent input and ICMS-defined output features. 3. Each task required the development and maintenance by each monkey of a fixed force level for a minimum period of time to obtain a fruit-juice reward. During one or both of these tasks, we characterized the activities of 231 single face motor cortical neurons that were located at the above-mentioned ICMS-defined sites. Neurons were said to be related to a particular task if they showed statistically significant differences in firing rates during the task in comparison with a control pretrial period (PTP). 4. In tongue-MI, there was a significantly higher proportion of neurons (63% of 156 neurons tested) that were related to the tongue-protrusion task than to the biting task (15% of 65). However, in jaw-MI the proportion of neurons that were biting task-related (63% of 19) was significantly higher than the proportion related to the tongue-protrusion task (11% of 9); the proportion of biting task-related neurons at ICMS-defined jaw-closing sites was also higher than that at jaw-opening sites.(ABSTRACT TRUNCATED AT 400 WORDS)

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Effects of Forced Use on the Ventral Premotor Cortex Distal Forelimb Representation After Ischemic Infarct in Primary Motor Cortex

PM&R ◽

10.1016/j.pmrj.2016.07.038 ◽

2016 ◽

Vol 8 (9) ◽

pp. S158 ◽

Cited By ~ 1

Author(s):

Shawn B. Frost ◽

Daofen Chen ◽

Scott Barbay ◽

Kathleen M. Friel ◽

Erik J. Plautz ◽

...

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Premotor Cortex ◽

Ventral Premotor Cortex ◽

Ischemic Infarct

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Cellular Mechanisms Preventing Sustained Activation of Cortex During Subcortical High-Frequency Stimulation

Journal of Neurophysiology ◽

10.1152/jn.00105.2006 ◽

2006 ◽

Vol 96 (2) ◽

pp. 613-621 ◽

Cited By ~ 58

Author(s):

Karl J. Iremonger ◽

Trent R. Anderson ◽

Bin Hu ◽

Zelma H. T. Kiss

Keyword(s):

Motor Cortex ◽

High Frequency ◽

Cortical Neurons ◽

Primary Motor Cortex ◽

Brain Slices ◽

Subcortical White Matter ◽

High Frequency Stimulation ◽

Cellular Mechanisms ◽

Ventral Thalamus ◽

Frequency Stimulation

Axonal excitation has been proposed as a key mechanism in therapeutic brain stimulation. In this study we examined how high-frequency stimulation (HFS) of subcortical white matter tracts projecting to motor cortex affects downstream postsynaptic responses in cortical neurons. Whole cell recordings were performed in the primary motor cortex (M1) and ventral thalamus of rat brain slices. In M1, neurons showed only an initial depolarization in response to HFS, after which the membrane potential returned to prestimulation levels. The prolonged suppression of excitation during stimulation was neither associated with GABAergic inhibition nor complete action potential failure in stimulated axons. Instead we found that HFS caused a depression of excitatory synaptic currents in postsynaptic neurons that was specific to the stimulated subcortical input. These data are consistent with the hypothesis that axonal HFS produces a functional deafferentation of postsynaptic targets likely from depletion of neurotransmitter.

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Transcranial direct current stimulation effects on I-wave activity in humans

Journal of Neurophysiology ◽

10.1152/jn.00617.2010 ◽

2011 ◽

Vol 105 (6) ◽

pp. 2802-2810 ◽

Cited By ~ 40

Author(s):

Nicolas Lang ◽

Michael A. Nitsche ◽

Michele Dileone ◽

Paolo Mazzone ◽

Javier De Andrés-Arés ◽

...

Keyword(s):

Motor Cortex ◽

Direct Current ◽

Transcranial Direct Current Stimulation ◽

Cortical Neurons ◽

Primary Motor Cortex ◽

Motor Evoked Potential ◽

Anodal Tdcs ◽

Direct Current Stimulation ◽

Cathodal Tdcs ◽

Motor Cortex Excitability

Transcranial direct current stimulation (tDCS) of the human cerebral cortex modulates cortical excitability noninvasively in a polarity-specific manner: anodal tDCS leads to lasting facilitation and cathodal tDCS to inhibition of motor cortex excitability. To further elucidate the underlying physiological mechanisms, we recorded corticospinal volleys evoked by single-pulse transcranial magnetic stimulation of the primary motor cortex before and after a 5-min period of anodal or cathodal tDCS in eight conscious patients who had electrodes implanted in the cervical epidural space for the control of pain. The effects of anodal tDCS were evaluated in six subjects and the effects of cathodal tDCS in five subjects. Three subjects were studied with both polarities. Anodal tDCS increased the excitability of cortical circuits generating I waves in the corticospinal system, including the earliest wave (I1 wave), whereas cathodal tDCS suppressed later I waves. The motor evoked potential (MEP) amplitude changes immediately following tDCS periods were in agreement with the effects produced on intracortical circuitry. The results deliver additional evidence that tDCS changes the excitability of cortical neurons.

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Temporal course of gene expression during motor memory formation in primary motor cortex of rats

Neurobiology of Learning and Memory ◽

10.1016/j.nlm.2016.09.018 ◽

2016 ◽

Vol 136 ◽

pp. 105-115 ◽

Cited By ~ 6

Author(s):

B. Hertler ◽

M.M. Buitrago ◽

A.R. Luft ◽

J.A. Hosp

Keyword(s):

Gene Expression ◽

Motor Cortex ◽

Primary Motor Cortex ◽

Memory Formation ◽

Motor Memory ◽

Temporal Course

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Reorganization of movement representations in primary motor cortex following focal ischemic infarcts in adult squirrel monkeys

Journal of Neurophysiology ◽

10.1152/jn.1996.75.5.2144 ◽

1996 ◽

Vol 75 (5) ◽

pp. 2144-2149 ◽

Cited By ~ 493

Author(s):

R. J. Nudo ◽

G. W. Milliken

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Squirrel Monkeys ◽

Intracortical Microstimulation ◽

Functional Reorganization ◽

Cortex Area ◽

Ischemic Infarct ◽

Contralateral Hand ◽

Forelimb Movement ◽

Cortical Regions

1. Intracortical microstimulation (ICMS) techniques were used to derive detailed maps of distal forelimb movement representations in primary motor cortex (area 4) of adult squirrel monkeys before and a few months after a focal ischemic infarct. 2. Infarcts caused a marked but transient deficit in use of the contralateral hand, as evidenced by increased use of the ipsilateral hand, and reduced performance on a task requiring skilled digit use. 3. Infarcts resulted in a widespread reduction in the areal extent of digit representations adjacent to the lesion, and apparent increases in adjacent proximal representations. 4. We conclude that substantial functional reorganization occurs in primary motor cortex of adult primates following a focal ischemic infarct, but at least in the absence of postinfarct training, the movements formerly represented in the infarcted zone do not reappear in adjacent cortical regions.

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Forelimb movements evoked by optogenetic stimulation of the macaque motor cortex

10.1101/2019.12.13.876219 ◽

2019 ◽

Author(s):

Hidenori Watanabe ◽

Hiromi Sano ◽

Satomi Chiken ◽

Kenta Kobayashi ◽

Yuko Fukata ◽

...

Keyword(s):

Motor Cortex ◽

Cortical Neurons ◽

Primary Motor Cortex ◽

Viral Vector ◽

Single Pulse ◽

Brain Functions ◽

Optogenetic Stimulation ◽

Indispensable Tool ◽

Cag Promoter ◽

Forelimb Movements

AbstractOptogenetics has become an indispensable tool for investigating brain functions. Although non-human primates are particularly useful models for understanding the functions and dysfunctions of the human brain, application of optogenetics to non-human primates is still limited. In the present study, we generated an effective adeno-associated viral vector serotype DJ to express channelrhodopsin-2 (ChR2) under the control of a strong ubiquitous CAG promoter and injected into the somatotopically identified forelimb region of the primary motor cortex in macaque monkeys. ChR2 was strongly expressed around the injection sites, and optogenetic intracortical microstimulation (oICMS) through a homemade optrode induced prominent cortical activity: Even single-pulse, short duration oICMS evoked long-lasting repetitive firings of cortical neurons. In addition, oICMS elicited distinct forelimb movements and muscle activity, which were comparable to those elicited by conventional electrical ICMS. The present study removed obstacles to optogenetic manipulation of neuronal activity and behaviors in non-human primates.

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Task Related Neural Activity Following Primary Motor Cortical Ischemic Injury in Rats

10.1101/2020.06.11.146266 ◽

2020 ◽

Author(s):

Andrea R. Pack ◽

Max D. Murphy ◽

Scott Barbay ◽

Randolph J. Nudo ◽

David J. Guggenmos

Keyword(s):

Motor Cortex ◽

Functional Recovery ◽

Neural Activity ◽

Primary Motor Cortex ◽

Ischemic Injury ◽

Motor Recovery ◽

Control Group ◽

Cortical Motor ◽

Ischemic Infarct ◽

Motor Areas

ABSTRACTAcquired injuries to primary motor cortex (M1) contribute to motor impairment and disability. Functional recovery is predicated on the reorganization of spared areas, which has been demonstrated through cortical motor map representations and neuroanatomical projection and termination patterns. The purpose of this study was to understand how neurophysiological outputs of spared motor areas relate to motor recovery of a skilled reach task following an ischemic infarct to M1. We examined changes in single unit activity within ipsilesional pre-motor (PM) and contralesional M1 cortices of rats during a behavioral task after a unilateral ischemic injury to ipsilesional M1. The data show a shift in neuronal firing patterns in the contralateral PM and ipsilateral M1 during behavioral recovery in lesion rats compared to a non-lesion control group, suggesting that spike-timing properties are altered in specific phases of the task, and that this altered activity may support spontaneous restoration of motor behavior.SIGNIFICANCE STATEMENTFollowing ischemic stroke to primary motor cortex (M1), motor recovery is associated with reorganization of spared cortical motor areas in injured and spared hemispheres. Currently, it is unclear how cortical plasticity within spared motor areas relates to motor recovery. This study examines how task-related neural activity within spared motor areas in rats correlates with motor restoration of a skilled reach task following an ischemic infarct to M1. The data suggest contralateral pre-motor and ipsilateral M1 alter their neural response profiles with respect to the timing of a motor task during recovery. To our knowledge, this is the first demonstration of a compensatory single-spike neurophysiological mechanism that may explain how remote, spared cortical areas contribute to functional recovery after M1 injury.

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Synchronization of Neuronal Activity in the Human Primary Motor Cortex by Transcranial Magnetic Stimulation: An EEG Study

Journal of Neurophysiology ◽

10.1152/jn.2001.86.4.1983 ◽

2001 ◽

Vol 86 (4) ◽

pp. 1983-1990 ◽

Cited By ~ 229

Author(s):

T. Paus ◽

P. K. Sipila ◽

A. P. Strafella

Keyword(s):

Transcranial Magnetic Stimulation ◽

Motor Cortex ◽

Cortical Neurons ◽

Magnetic Stimulation ◽

Primary Motor Cortex ◽

Temporal Dynamics ◽

Single Pulse ◽

Cortical Oscillations ◽

Cortical Rhythms ◽

Oscillatory Response

Using multichannel electroencephalography (EEG), we investigated temporal dynamics of the cortical response to transcranial magnetic stimulation (TMS). TMS was applied over the left primary motor cortex (M1) of healthy volunteers, intermixing single suprathreshold pulses with pairs of sub- and suprathreshold pulses and simultaneously recording EEG from 60 scalp electrodes. Averaging of EEG data time locked to the onset of TMS pulses yielded a waveform consisting of a positive peak (30 ms after the pulse P30), followed by two negative peaks [at 45 (N45) and 100 ms]. Peak-to-peak amplitude of the P30–N45 waveform was high, ranging from 12 to 70 μV; in most subjects, the N45 potential could be identified in single EEG traces. Spectral analysis revealed that single-pulse TMS induced a brief period of synchronized activity in the beta range (15–30 Hz) in the vicinity of the stimulation site; again, this oscillatory response was apparent not only in the EEG averages but also in single traces. Both the N45 and the oscillatory response were lower in amplitude in the 12-ms (but not 3-ms) paired-pulse trials, compared with the single-pulse trials. These findings are consistent with the possibility that TMS applied to M1 induces transient synchronization of spontaneous activity of cortical neurons within the 15- to 30-Hz frequency range. As such, they corroborate previous studies of cortical oscillations in the motor cortex and point to the potential of the combined TMS/EEG approach for further investigations of cortical rhythms in the human brain.

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A Model of Reaching Dynamics in Primary Motor Cortex

Journal of Cognitive Neuroscience ◽

10.1162/089892998563761 ◽

1998 ◽

Vol 10 (1) ◽

pp. 35-45 ◽

Cited By ~ 13

Author(s):

Sohie Lee Moody ◽

David Zipser

Keyword(s):

Neural Network ◽

Motor Cortex ◽

Recurrent Neural Network ◽

Cortical Neurons ◽

Primary Motor Cortex ◽

Voluntary Movements ◽

Reaching Movement ◽

Time Constants ◽

Movement Representation ◽

The Individual

Features of virtually all voluntary movements are represented in the primary motor cortex. The movements can be ongoing, imminent, delayed, or imagined. Our goal was to investigate the dynamics of movement representation in the motor cortex. To do this we trained a fully recurrent neural network to continually output the direction and magnitude of movements required to reach randomly changing targets. Model neurons developed preferred directions and other properties similar to real motor cortical neurons. The key finding is that when the target for a reaching movement changes location, the ensemble representation of the movement changes nearly monotonically, and the individual neurons comprising the representation exhibit strong, nonmonotonic transients. These transients serve as internal recurrent signals that force the ensemble representation to change more rapidly than if it were limited by the time constants of individual neurons. These transients, if they exist, could be observed in experiments that require only slight modifications of the standard paradigm used to investigate movement representation in the motor cortex.

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