scholarly journals Inducing LTD-Like Effect in the Human Motor Cortex with Low Frequency and Very Short Duration Paired Associative Stimulation: An Exploratory Study

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Prachaya Srivanitchapoom ◽  
Jung E. Park ◽  
Nivethida Thirugnanasambandam ◽  
Pattamon Panyakaew ◽  
Vesper Fe Marie Ramos ◽  
...  
Keyword(s):  
Synaptic Plasticity ◽  
Motor Cortex ◽  
Short Duration ◽  
Repeated Measures ◽  
Low Frequency ◽  
Long Term Potentiation ◽  
Paired Associative Stimulation ◽  
Human Motor Cortex ◽  
Human Motor

Introduction.Paired associative stimulation (PAS) is an established technique to investigate synaptic plasticity in the human motor cortex (M1). Classically, to induce long-term depression- (LTD-) or long-term potentiation-like effects in the human M1, studies have used low frequency and long duration trains of PAS. In the present study, we explored an LTD-like effect using very short duration and low frequency ofPAS10 msprotocols in human M1.Methods.Six protocols of low frequencyPAS10 ms(ranging from 0.2 Hz to 1 Hz) were investigated with very short durations of 1 and 2 minutes stimulation. Six healthy volunteers were included in each protocol. We obtained motor-evoked potentials from right abductor pollicis brevis muscle before and after applyingPAS10 msup to 30 minutes. After we foundPAS10 msprotocol which induced an LTD-like effect, we tested that protocol on additional 5 subjects.Results.One-way repeated-measures ANOVA showed that only the group of 1-minute stimulation of 0.25 Hz induced an LTD-like effect. When adding the additional subjects, the effect remained and lasted for 30 minutes.Conclusion.Low frequency and very short duration ofPAS10 mspotentially induced an LTD-like effect in human M1. With further verification, this method might be useful for research relating to synaptic plasticity by reducing the duration of study and minimizing subject discomfort.

146. Preceding repetitive stimulation diminishes long-term potentiation-like plasticity in human motor cortex

2009 ◽  
Vol 120 (1) ◽  
pp. e61
Author(s):  
I. Delvendahl ◽  
N. Jung ◽  
M. Cronjaeger ◽  
F. Mainberger ◽  
N. Kuhnke ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Long Term Potentiation ◽  
Repetitive Stimulation ◽  
Human Motor Cortex ◽  
Term Potentiation ◽  
Human Motor

Exploring the effect of inducing long-term potentiation in the human motor cortex on motor learning

2011 ◽  
Vol 4 (3) ◽  
pp. 137-144 ◽  
Author(s):  
Tarek K. Rajji ◽  
Shi-Kai Liu ◽  
Marina V. Frantseva ◽  
Benoit H. Mulsant ◽  
Jessica Thoma ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Motor Learning ◽  
Long Term Potentiation ◽  
Human Motor Cortex ◽  
Term Potentiation ◽  
Human Motor

Mechanisms of human motor cortex facilitation induced by subthreshold 5-Hz repetitive transcranial magnetic stimulation

2013 ◽  
Vol 109 (12) ◽  
pp. 3060-3066 ◽  
Author(s):  
Martin Sommer ◽  
Milena Rummel ◽  
Christoph Norden ◽  
Holger Rothkegel ◽  
Nicolas Lang ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Repetitive Transcranial Magnetic Stimulation ◽  
Long Term Potentiation ◽  
Human Motor Cortex ◽  
Term Potentiation ◽  
Human Motor ◽  
Extensor Carpi Radialis

Our knowledge about the mechanisms of human motor cortex facilitation induced by repetitive transcranial magnetic stimulation (rTMS) is still incomplete. Here we used pharmacological conditioning with carbamazepine, dextrometorphan, lorazepam, and placebo to elucidate the type of plasticity underlying this facilitation, and to probe if mechanisms reminiscent of long-term potentiation are involved. Over the primary motor cortex of 10 healthy subjects, we applied biphasic rTMS pulses of effective posterior current direction in the brain. We used six blocks of 200 pulses at 5-Hz frequency and 90% active motor threshold intensity and controlled for corticospinal excitability changes using motor-evoked potential (MEP) amplitudes and latencies elicited by suprathreshold pulses before, in between, and after rTMS. Target muscle was the dominant abductor digiti minimi muscle; we coregistered the dominant extensor carpi radialis muscle. We found a lasting facilitation induced by this type of rTMS. The GABAergic medication lorazepam and to a lesser extent the ion channel blocker carbamazepine reduced the MEP facilitation after biphasic effective posteriorly oriented rTMS, whereas the N-methyl-d-aspartate receptor-antagonist dextrometorphan had no effect. Our main conclusion is that the mechanism of the facilitation induced by biphasic effective posterior rTMS is more likely posttetanic potentiation than long-term potentiation. Additional findings were prolonged MEP latency under carbamazepine, consistent with sodium channel blockade, and larger MEP amplitudes from extensor carpi radialis under lorazepam, suggesting GABAergic involvement in the center-surround balance of excitability.

A Temporally Asymmetric Hebbian Rule Governing Plasticity in the Human Motor Cortex

2003 ◽  
Vol 89 (5) ◽  
pp. 2339-2345 ◽  
Author(s):  
Alexander Wolters ◽  
Friedhelm Sandbrink ◽  
Antje Schlottmann ◽  
Erwin Kunesch ◽  
Katja Stefan ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Median Nerve ◽  
Cortical Excitability ◽  
Long Term Potentiation ◽  
Long Term Depression ◽  
Human Motor Cortex ◽  
Motor Cortical Excitability ◽  
Human Motor ◽  
Motor Cortical

Synaptic plasticity is conspicuously dependent on the temporal order of the pre- and postsynaptic activity. Human motor cortical excitability can be increased by a paired associative stimulation (PAS) protocol. Here we show that it can also be decreased by minimally changing the interval between the two associative stimuli. Corticomotor excitability of the abductor pollicis brevis (APB) representation was tested before and after repetitively pairing of single right median nerve simulation with single pulse transcranial magnetic stimulation (TMS) delivered over the optimal site for activation of the contralateral APB. Following PAS, depression of TMS-evoked motor-evoked potentials (MEPs) was induced only when the median nerve stimulation preceded the TMS pulse by 10 ms, while enhancement of cortical excitability was induced using an interstimulus interval of 25 ms, suggesting an important role of the sequence of cortical events triggered by the two stimulation modalities. Experiments using F-wave studies and electrical brain stem stimulation indicated that the site of the plastic changes underlying the decrease of MEP amplitudes following PAS (10 ms) was within the motor cortex. MEP amplitudes remained depressed for approximately 90 min. The decrease of MEP amplitudes was blocked when PAS(10 ms) was performed under the influence of dextromethorphan, an N-methyl-d-aspartate-receptor antagonist, or nimodipine, an L-type voltage-gated calcium-channel antagonist. The physiological profile of the depression of human motor cortical excitability following PAS(10 ms) suggests long-term depression of synaptic efficacy to be involved. Together with earlier findings, this study suggests that strict temporal Hebbian rules govern the induction of long-term potentiation/long-term depression-like phenomena in vivo in the human primary motor cortex.

Preceding repetitive stimulation diminishes long-term potentiation-like plasticity in human motor cortex

2008 ◽  
Vol 39 (01) ◽  
Author(s):  
I Delvendahl ◽  
N Jung ◽  
M Cronjaeger ◽  
F Mainberger ◽  
N Kuhnke ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Long Term Potentiation ◽  
Repetitive Stimulation ◽  
Human Motor Cortex ◽  
Term Potentiation ◽  
Human Motor
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