scholarly journals Synchronization between motor cortex and spinal motoneuronal pool during the performance of a maintained motor task in man.

1995 ◽  
Vol 489 (3) ◽  
pp. 917-924 ◽  
Author(s):  
B A Conway ◽  
D M Halliday ◽  
S F Farmer ◽  
U Shahani ◽  
P Maas ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor Task ◽  
Motoneuronal Pool

Abstract TP441: Neurovascular Coupling is Impaired in Cerebral Amyloid Angiopathy

Stroke ◽  
2013 ◽  
Vol 44 (suppl_1) ◽  
Author(s):  
Stefano Peca ◽  
Cheryl R McCreary ◽  
Emily Donaldson ◽  
Karla Sanchez ◽  
Anna Charlton ◽  
...  
Keyword(s):  
White Matter ◽  
Motor Cortex ◽  
Primary Motor Cortex ◽  
White Matter Lesion ◽  
Motor Task ◽  
Neurovascular Coupling ◽  
Occipital Lobe ◽  
Amyloid Angiopathy ◽  
Bold Response ◽  
Cerebral Amyloid

Introduction: Cerebral amyloid angiopathy (CAA) is marked by accumulation of vascular beta-amyloid which is toxic to smooth muscle cells. An animal study and a pilot study in humans suggest decreased vasodilation in CAA. We studied patients with CAA and matched controls to determine whether neurovascular coupling is impaired in CAA. Methods: Patients with CAA and controls underwent task-related fMRI with a visual task (viewing a flashing alternating checkerboard pattern) or a motor task (tapping the fingers of the dominant hand) using a block design, and visual evoked potentials (VEPs). CAA patients were diagnosed by Boston criteria and had normal corrected visual acuity, no visual field deficits and no paresis of the dominant arm. Controls were recruited by community advertising and were matched by gender and age (±5 years) to CAA cases. Results: Eighteen CAA patients (12 M, 6F; 72±7 yrs) and eighteen controls (12 M, 6F; 70±7 yrs) were studied. For the visual task, CAA patients had reduced activity in the occipital lobe (Figure) and lower amplitude of the BOLD response vs. controls (28% reduced, p=0.005). By contrast, for the motor task CAA patients had a similar response of the primary motor cortex vs. controls (9.6% reduced BOLD response, p=0.53). VEP P100 latencies and amplitudes did not differ between CAA and controls (p=0.49 and p=0.74). Lower visual cortex BOLD amplitudes were correlated with greater white matter lesion volumes in CAA (r=-0.66, p=0.003). Conclusions: Neurovascular coupling is impaired in the occipital lobe in CAA. BOLD signal amplitudes are reduced despite normal evoked potentials, suggesting impaired vasodilation. The association with white matter lesion volume raises the possibility that impaired vasodilation may be involved in the pathogenesis of these lesions. BOLD responses in the primary motor cortex in CAA were not reduced, likely reflecting the known posterior predominance of CAA with lesser involvement of the frontal lobe.

scholarly journals Optogenetically induced spatiotemporal gamma oscillations and neuronal spiking activity in primate motor cortex

2015 ◽  
Vol 113 (10) ◽  
pp. 3574-3587 ◽  
Author(s):  
Yao Lu ◽  
Wilson Truccolo ◽  
Fabien B. Wagner ◽  
Carlos E. Vargas-Irwin ◽  
Ilker Ozden ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Microelectrode Array ◽  
Motor Task ◽  
Optical Power ◽  
Gamma Oscillations ◽  
Constant Stimulus ◽  
Spatiotemporal Patterns ◽  
Gamma Activity ◽  
Cortical Function ◽  
Optogenetic Stimulation

Transient gamma-band (40–80 Hz) spatiotemporal patterns are hypothesized to play important roles in cortical function. Here we report the direct observation of gamma oscillations as spatiotemporal waves induced by targeted optogenetic stimulation, recorded by intracortical multichannel extracellular techniques in macaque monkeys during their awake resting states. Microelectrode arrays integrating an optical fiber at their center were chronically implanted in primary motor (M1) and ventral premotor (PMv) cortices of two subjects. Targeted brain tissue was transduced with the red-shifted opsin C1V1(T/T). Constant (1-s square pulses) and ramp stimulation induced narrowband gamma oscillations during awake resting states. Recordings across 95 microelectrodes (4 × 4-mm array) enabled us to track the transient gamma spatiotemporal patterns manifested, e.g., as concentric expanding and spiral waves. Gamma oscillations were induced well beyond the light stimulation volume, via network interactions at distal electrode sites, depending on optical power. Despite stimulation-related modulation in spiking rates, neuronal spiking remained highly asynchronous during induced gamma oscillations. In one subject we examined stimulation effects during preparation and execution of a motor task and observed that movement execution largely attenuated optically induced gamma oscillations. Our findings demonstrate that, beyond previously reported induced gamma activity under periodic drive, a prolonged constant stimulus above a certain threshold may carry primate motor cortex network dynamics into gamma oscillations, likely via a Hopf bifurcation. More broadly, the experimental capability in combining microelectrode array recordings and optogenetic stimulation provides an important approach for probing spatiotemporal dynamics in primate cortical networks during various physiological and behavioral conditions.

Interaction Between Finger Opposition Movements and Aftereffects of 1Hz-rTMS on Ipsilateral Motor Cortex

2009 ◽  
Vol 101 (3) ◽  
pp. 1690-1694 ◽  
Author(s):  
Laura Avanzino ◽  
Marco Bove ◽  
Andrea Tacchino ◽  
Carlo Trompetto ◽  
Carla Ogliastro ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor Performance ◽  
Magnetic Stimulation ◽  
Voluntary Movement ◽  
Motor Behavior ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Motor Task ◽  
The Other ◽  
Experimental Conditions ◽  
Opposition Movements

One-hertz repetitive transcranial magnetic stimulation (1Hz-rTMS) over ipsilateral motor cortex is able to modify up to 30 min the motor performance of repetitive finger opposition movements paced with a metronome at 2 Hz. We investigated whether the long-lasting rTMS effect on motor behavior can be modulated by subsequent engagement of the contralateral sensorimotor system. Motor task was performed in different experimental conditions: immediately after rTMS, 30 min after rTMS, or when real rTMS was substituted with sham rTMS. Subjects performing the motor task immediately after rTMS showed modifications in motor behavior ≤30 min after rTMS. On the other hand, when real rTMS was substituted with sham stimulation or when subjects performed the motor task 30 min after the rTMS session, the effect was no longer present. These findings suggest that the combination of ipsilateral 1Hz-rTMS and voluntary movement is crucial to endure the effect of rTMS on the movement itself, probably acting on synaptic plasticity-like mechanism. This finding might provide some useful hints for neurorehabilitation protocols.

Motor cortex excitability and fatigue in multiple sclerosis: a transcranial magnetic stimulation study

2005 ◽  
Vol 11 (3) ◽  
pp. 316-321 ◽  
Author(s):  
J Liepert ◽  
D Mingers ◽  
C Heesen ◽  
T Bäumer ◽  
C Weiller
Keyword(s):  
Multiple Sclerosis ◽  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Task ◽  
Time Interval ◽  
Membrane Excitability ◽  
Motor Cortex Excitability ◽  
Fatigue Severity

We investigated electrophysiological correlates of fatigue in patients with multiple sclerosis (MS). Transcranial magnetic stimulation (TMS) was used to explore motor excitability in three groups of subjects: MS patients with fatigue (MS-F), MS patients without fatigue (MS-NF) and healthy control subjects. All participants had to perform a fatiguing hand-grip exercise. TMS was performed prior to and after the exercise. Prior to the motor task, MS-F patients had less inhibition in the primary motor cortex compared to both other groups. Postexercise, intracortical inhibition was still reduced in the MS-F patients compared to the MS-NF patients. In MS-F patients the postexercise time interval for normalization of the motor threshold was correlated with the fatigue severity. We conclude that MS patients with fatigue have an impairment of inhibitory circuits in their primary motor cortex. The results also indicate that fatigue severity is associated with an exercise-induced reduction of membrane excitability.

IMMUNOLOCALIZATION OF c-fos IN MOTOR CORTEX OF RATS DURING ADAPTATION TO A COMPLEX MOTOR TASK 334

1996 ◽  
Vol 28 (Supplement) ◽  
pp. 56
Author(s):  
B. Nelson ◽  
J. Buggy ◽  
H. Williams ◽  
D. Essig
Keyword(s):  
Motor Cortex ◽  
Motor Task ◽  
Complex Motor

Corticocortical and thalamocortical responses of neurons in the monkey primary motor cortex and their relation to a trained motor task

1994 ◽  
Vol 71 (2) ◽  
pp. 550-560 ◽  
Author(s):  
H. Aizawa ◽  
J. Tanji
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Motor Task ◽  
Reaching Movements ◽  
Response Latencies ◽  
Implanted Electrodes ◽  
Thalamic Stimulation ◽  
Primary Sensory Cortex ◽  
Activity Onset ◽  
Stimulation Of

1. We studied the responsiveness of neurons in the primary motor cortex (MI) of monkeys (Macacafuscata) to electrical stimulation of the supplementary motor area (SMA), primary sensory cortex (SI), and the ventral subnucleus of the thalamus (VPLo) with chronically implanted electrodes. 2. All neurons examined in this study were characterized by their relation to a motor task performed by the animals. They responded to stimulation of the cortical or thalamic area with excitation from one area alone (n = 128) or from multiple areas (n = 84) of all combinations. In a majority of neurons, response latencies to both cortical and thalamic stimulation were within 5 ms. 3. A vast majority of neurons (80%) that were active during a preparatory period for forthcoming reaching movements were activated by SMA stimulation. They were activated only infrequently by SI or thalamic stimulation. 4. Movement-related neurons (active immediately before and during reaching movements) were activated by thalamic, SI, or SMA stimulation or by any combination of those stimuli. More than half of the movement-related neurons activated exclusively by either thalamic or SMA stimulation exhibited activity onset times earlier than those observed in the earliest muscles. By contrast, most movement-related neurons that responded only to SI stimulation were late in their activity onset. 5. These findings suggest that the SMA input to MI is important in developing a preparatory type of activity in MI, whereas the thalamus (VPLo) provides substantial inputs in movement execution. The roles played by inputs from SI and SMA in relation to motor execution are debatable and are discussed here with reference to previous reports.

Reduced activation and altered laterality in two neuroleptic-naive catatonic patients during a motor task in functional MRI

1999 ◽  
Vol 29 (4) ◽  
pp. 997-1002 ◽  
Author(s):  
G. NORTHOFF ◽  
D. F. BRAUS ◽  
A. SARTORIUS ◽  
D. KHORAM-SEFAT ◽  
M. RUSS ◽  
...  
Keyword(s):  
Magnetic Resonance ◽  
Motor Cortex ◽  
Pulse Sequence ◽  
Motor Task ◽  
Contralateral Side ◽  
Magnetic Resonance Images ◽  
Healthy Controls ◽  
Functional Magnetic Resonance ◽  
Normal Pattern ◽  
The Right

Background. Catatonia, a symptom complex with motor, affective and cognitive symptoms seen in a variety of psychotic conditions and with organic disease, was examined using a motor task using functional magnetic resonance imaging (fMRI).Methods. Two acute catatonic patients and two age- and sex-matched healthy controls performed sequential finger opposition (SFO) after being medicated with 2 mg of lorazepam (i.v.). Functional magnetic resonance images were collected using a gradient echo pulse sequence (EPI).Results. Patients with catatonia showed reduced motor activation of the contralateral motor cortex during SFO of the right hand, ipsilateral activation was similar for patients and controls. There were no differences in the activation of the SMA. During left hand activation the right-handed catatonic patients showed more activation in the ipsilateral cortex, a reversal from the normal pattern of activation in which the contralateral side shows four to five times more activation than the ipsilateral side.Conclusions. In catatonic patients there is a decreased activation in motor cortex during a motor task compared to matched medicated healthy controls. In addition activation of the non-dominant side, left-handed activity in right-handed patients, results in a total reversal of the normal pattern of lateral activation suggesting a disturbance in hemispheric localization of activity during a catatonic state.

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