scholarly journals Plasticity of the Cortical Motor System

2008 ◽  
Vol 20 (1) ◽  
pp. 5-22 ◽  
Author(s):  
Bogdan Sadowski
Keyword(s):  
Motor Cortex ◽  
Motor System ◽  
Primary Motor Cortex ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Long Term Potentiation ◽  
Skill Learning ◽  
Dynamic Features ◽  
Cortical Motor

Plasticity of the Cortical Motor SystemThe involvement of brain plastic mechanisms in the control of motor functions under normal and pathological conditions is described. These mechanisms are based on a similar principle as the neuronal models of neuronal plasticity - long-term potentiation (LTP), and long-term depression (LTD). In the motor cortex, LTP-like phenomena play a role in strengthening synaptic connections between pyramidal neurons. LTD is important for the elimination of unnecessary inputs to the cortex. The dynamic features of the primary motor cortex activity depend on particular neuronal interconnectivity within this area. The pyramidal cells send horizontal collaterals to adjacent subregions of the primary motor cortex, and so can either excite or inhibit remote pyramidal cells. These connections can expand or shrink depending on actual physiological demands, and play a role in skill learning.

scholarly journals Heat-Evoked Experimental Pain Induces Long-Term Potentiation-Like Plasticity in Human Primary Motor Cortex

2012 ◽  
Vol 23 (8) ◽  
pp. 1942-1951 ◽  
Author(s):  
A. Suppa ◽  
A. Biasiotta ◽  
D. Belvisi ◽  
L. Marsili ◽  
S. La Cesa ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Experimental Pain ◽  
Long Term Potentiation ◽  
Term Potentiation

Inducing Homeostatic-Like Plasticity in Human Motor Cortex Through Converging Corticocortical Inputs

2009 ◽  
Vol 102 (6) ◽  
pp. 3180-3190 ◽  
Author(s):  
Monika Pötter-Nerger ◽  
Sarah Fischer ◽  
Claudia Mastroeni ◽  
Sergiu Groppa ◽  
Günther Deuschl ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Median Nerve ◽  
Primary Motor Cortex ◽  
Premotor Cortex ◽  
Long Term Potentiation ◽  
Corticospinal Excitability ◽  
Human Motor Cortex ◽  
Induced Changes ◽  
Homeostatic Response

Transcranial stimulation techniques have revealed homeostatic-like metaplasticity in the hand area of the human primary motor cortex (M1HAND) that controls stimulation-induced changes in corticospinal excitability. Here we combined two interventional protocols that induce long-term depression (LTD)–like or long-term potentiation (LTP)–like plasticity in left M1HAND through different afferents. We hypothesized that the left M1HAND would integrate LTP- and LTD-like plasticity in a homeostatic fashion. In ten healthy volunteers, low-intensity repetitive transcranial magnetic stimulation (rTMS) of the left dorsal premotor cortex (PMD) was first applied to produce an LTP-like increase (5 Hz rTMS) or LTD-like decrease (1 Hz rTMS) in corticospinal excitability in left M1HAND via premotor-to-motor inputs. Following PMD rTMS, paired-associative stimulation (PAS) was applied to the right median nerve and left M1HAND to induce spike-time–dependent plasticity in sensory-to-motor inputs to left M1HAND. We adjusted the interstimulus interval to the N20 latency of the median nerve somatosensory-evoked cortical potential to produce an LTP-like increase (PASN20+2ms) or an LTD-like decrease (PASN20−5ms) in corticospinal excitability. The amplitude of motor-evoked potentials was recorded from intrinsic hand muscles to assess stimulation-induced changes in corticospinal excitability. Premotor-to-motor preconditioning triggered a homeostatic response to subsequent sensory-to-motor PAS. After facilitatory 5 Hz rTMS, “facilitatory” PASN20+2ms suppressed corticospinal excitability. Likewise, “inhibitory” PASN20−5ms facilitated corticospinal excitability after “inhibitory” 1 Hz rTMS. There was a negative linear relationship between the excitability changes induced by PMD rTMS and those elicited by subsequent PAS. Excitability changes were not paralleled by changes in performance during a finger-tapping task. These results provide evidence for a homeostatic response pattern in the human M1HAND that integrates acute plastic changes evoked through different “input channels.”

scholarly journals Reversed timing-dependent associative plasticity in the human brain through interhemispheric interactions

2013 ◽  
Vol 109 (9) ◽  
pp. 2260-2271 ◽  
Author(s):  
Virginia Conde ◽  
Henning Vollmann ◽  
Marco Taubert ◽  
Bernhard Sehm ◽  
Leonardo G. Cohen ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Human Brain ◽  
Primary Motor Cortex ◽  
Long Term Potentiation ◽  
Spike Timing ◽  
In Vivo Model ◽  
Sensorimotor Network ◽  
Median Nerve Stimulation

Spike timing-dependent plasticity (STDP) has been proposed as one of the key mechanisms underlying learning and memory. Repetitive median nerve stimulation, followed by transcranial magnetic stimulation (TMS) of the contralateral primary motor cortex (M1), defined as paired-associative stimulation (PAS), has been used as an in vivo model of STDP in humans. PAS-induced excitability changes in M1 have been repeatedly shown to be time-dependent in a STDP-like fashion, since synchronous arrival of inputs within M1 induces long-term potentiation-like effects, whereas an asynchronous arrival induces long-term depression (LTD)-like effects. Here, we show that interhemispheric inhibition of the sensorimotor network during PAS, with the peripheral stimulation over the hand ipsilateral to the motor cortex receiving TMS, results in a LTD-like effect, as opposed to the standard STDP-like effect seen for contralateral PAS. Furthermore, we could show that this reversed-associative plasticity critically depends on the timing interval between afferent and cortical stimulation. These results indicate that the outcome of associative stimulation in the human brain depends on functional network interactions (inhibition or facilitation) at a systems level and can either follow standard or reversed STDP-like mechanisms.

scholarly journals Familiarity with a Tool Influences Peripersonal Space and Primary Motor Cortex Excitability of Muscles Involved in Haptic Contact

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
M Biggio ◽  
A Bisio ◽  
L Avanzino ◽  
P Ruggeri ◽  
M Bove
Keyword(s):  
Motor Cortex ◽  
Multisensory Integration ◽  
Primary Motor Cortex ◽  
Cortical Excitability ◽  
Peripersonal Space ◽  
Motor Representation ◽  
Cortical Motor ◽  
Motor Cortex Excitability ◽  
Long Term Experience

Abstract Long-term experience with a tool stably enlarges peripersonal space (PPS). Also, gained experience with a tool modulates internal models of action. The aim of this work was to understand whether the familiarity with a tool influences both PPS and motor representation. Toward this goal, we tested in 13 expert fencers through a multisensory integration paradigm the embodiment in their PPS of a personal (pE) or a common (cE) épée. Then, we evaluated the primary motor cortex excitability of proximal (ECR) and distal (APB) muscles during a motor imagery (MI) task of an athletic gesture when athletes handled these tools. Results showed that pE enlarges subjects’ PPS, while cE does not. Moreover, during MI, handling tools increased cortical excitability of ECR muscle. Notably, APB’s cortical excitability during MI only increased with pE as a function of its embodiment in PPS. These findings indicate that the familiarity with a tool specifically enlarges PPS and modulates the cortical motor representation of those muscles involved in the haptic contact with it.

Reliability of robotic transcranial magnetic stimulation motor mapping

2021 ◽  
Vol 125 (1) ◽  
pp. 74-85
Author(s):  
Adrianna Giuffre ◽  
Cynthia K. Kahl ◽  
Ephrem Zewdie ◽  
James G. Wrightson ◽  
Anna Bourgeois ◽  
...  
Keyword(s):  
Transcranial Magnetic Stimulation ◽  
Motor Cortex ◽  
Magnetic Stimulation ◽  
Primary Motor Cortex ◽  
Motor Mapping ◽  
Cortical Motor ◽  
Short And Long Term ◽  
Motor Maps ◽  
Absolute Reliability

Robotic transcranial magnetic stimulation (TMS) is a noninvasive and safe tool that produces cortical motor maps—individualized representations of the primary motor cortex (M1) topography—that may reflect developmental and interventional plasticity. This study is the first to evaluate short- and long-term relative and absolute reliability of TMS mapping outcomes at various M1 excitability levels using novel robotic neuronavigated TMS.

scholarly journals Noninvasive brain stimulation can elucidate and interact with the mechanisms underlying motor learning and retention: implications for rehabilitation

2014 ◽  
Vol 111 (5) ◽  
pp. 897-899 ◽  
Author(s):  
Mark R. Hinder ◽  
Paola Reissig ◽  
Hakuei Fujiyama
Keyword(s):  
Motor Cortex ◽  
Motor Learning ◽  
Brain Stimulation ◽  
Motor Skill ◽  
Primary Motor Cortex ◽  
Motor Task ◽  
Long Term Potentiation ◽  
Noninvasive Brain Stimulation ◽  
Term Potentiation

Seminal work in animals indicates that learning a motor task results in long-term potentiation (LTP) in primary motor cortex (M1) and a subsequent occlusion of LTP induction (Rioult-Pedotti et al. J Neurophysiol 98: 3688–3695, 2007). Using various forms of noninvasive brain stimulation in conjunction with a motor learning paradigm, Cantarero et al. ( J Neurosci 33: 12862–12869, 2013) recently provided novel evidence to support the hypothesis that retention of motor skill is contingent upon this postlearning occlusion.

scholarly journals Organization of cortical and thalamic input to inhibitory neurons in mouse motor cortex

2021 ◽  
Author(s):  
Sandra U Okoro ◽  
Roman U Goz ◽  
Brigdet W. Njeri ◽  
Madhumita Harish ◽  
Catherine F. Ruff ◽  
...  
Keyword(s):  
Motor Cortex ◽  
Primary Motor Cortex ◽  
Pyramidal Neurons ◽  
Pyramidal Cells ◽  
Inhibitory Neurons ◽  
Inhibitory Interneurons ◽  
Thalamic Input ◽  
Thalamic Projections ◽  
A Cell ◽  
Feedforward Inhibition

Understanding how feedforward inhibition regulates movement requires knowing how cortical and thalamic projections connect to inhibitory interneurons in primary motor cortex (M1). We quantified excitatory synaptic input from sensory cortex and thalamus onto two main classes of M1 inhibitory interneurons across all cortical layers: parvalbumin (PV) expressing fast-spiking cells and somatostatin (SOM) expressing low-threshold-spiking cells. Each projection innervated M1 interneurons with a unique laminar profile. While pyramidal neurons were excited by these cortical and thalamic inputs in the same layers, different interneuron types were excited in a distinct, complementary manner, suggesting feedforward inhibition from different inputs proceeds selectively via distinct circuits. Specifically, somatosensory cortex (S1) inputs primarily targeted PV+ neurons in upper layers (L2/3) but SOM+ neurons in middle layers (L5). Somatosensory thalamus (PO) inputs primarily targeted PV+ neurons in middle layers (L5). Our results show that long-range excitatory inputs target inhibitory neurons in a cell type-specific manner which contrasts with input to neighboring pyramidal cells. In contrast to feedforward inhibition providing generic inhibitory tone in cortex, circuits are selectively organized to recruit inhibition matched to incoming excitatory circuits.

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