Primary motor cortex LTP/LTD-like plasticity in probable corticobasal syndrome

Whether the primary motor cortex (M1) contributes to the pathophysiology of corticobasal syndrome (CBS) remains unclear. In this study in patients with probable CBS, we tested whether M1 plasticity contributes to the pathophysiology of symptoms in the contralateral “less affected” limb, manifesting only parkinsonism, and in the contralateral “more affected” limb, manifesting parkinsonism plus other motor and nonmotor symptoms. In Experiment 1, we applied intermittent/continuous theta-burst stimulation (iTBS/cTBS) over the M1 contralateral to the less affected limb in 17 patients. In Experiment 2, we applied iTBS/cTBS over the M1 contralateral to the more affected limb in 14 of the 17 patients. We measured iTBS/cTBS-induced plasticity as reflected by motor-evoked potential (MEP) changes. Data were compared with those obtained in 17 healthy subjects (HS). In Experiment 1, TBS over the M1 contralateral to the less affected limb disclosed reduced plasticity in patients than in HS. In Experiment 2, in 5 of 14 patients we recorded abnormally low-amplitude MEPs, preventing the evaluation of plasticity in the M1 contralateral to the more affected limb. In the remaining nine patients, TBS disclosed abnormal plasticity characterized by high intersubject variability. In these nine patients, the response to TBS correlated with specific patients' clinical features. In the present study in patients with probable CBS, we have demonstrated heterogeneous abnormalities of M1 that contribute to the pathophysiology of this condition.

Download Full-text

Obesity is Associated with Reduced Plasticity of the Human Motor Cortex

Brain Sciences ◽

10.3390/brainsci10090579 ◽

2020 ◽

Vol 10 (9) ◽

pp. 579

Author(s):

Sophia X. Sui ◽

Michael C. Ridding ◽

Brenton Hordacre

Keyword(s):

Motor Cortex ◽

Evoked Potential ◽

Cortical Excitability ◽

Motor Evoked Potential ◽

Healthy Weight ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Weight Group ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

Obesity is characterised by excessive body fat and is associated with several detrimental health conditions, including cardiovascular disease and diabetes. There is some evidence that people who are obese have structural and functional brain alterations and cognitive deficits. It may be that these neurophysiological and behavioural consequences are underpinned by altered plasticity. This study investigated the relationship between obesity and plasticity of the motor cortex in people who were considered obese (n = 14, nine males, aged 35.4 ± 14.3 years) or healthy weight (n = 16, seven males, aged 26.3 ± 8.5 years). A brain stimulation protocol known as continuous theta burst transcranial magnetic stimulation was applied to the motor cortex to induce a brief suppression of cortical excitability. The suppression of cortical excitability was quantified using single-pulse transcranial magnetic stimulation to record and measure the amplitude of the motor evoked potential in a peripheral hand muscle. Therefore, the magnitude of suppression of the motor evoked potential by continuous theta burst stimulation was used as a measure of the capacity for plasticity of the motor cortex. Our results demonstrate that the healthy-weight group had a significant suppression of cortical excitability following continuous theta burst stimulation (cTBS), but there was no change in excitability for the obese group. Comparing the response to cTBS between groups demonstrated that there was an impaired plasticity response for the obese group when compared to the healthy-weight group. This might suggest that the capacity for plasticity is reduced in people who are obese. Given the importance of plasticity for human behaviour, our results add further emphasis to the potentially detrimental health effects of obesity.

Download Full-text

Speed of processing in the primary motor cortex: A continuous theta burst stimulation study

Behavioural Brain Research ◽

10.1016/j.bbr.2013.12.022 ◽

2014 ◽

Vol 261 ◽

pp. 177-184 ◽

Cited By ~ 4

Author(s):

Bimal Lakhani ◽

David A.E. Bolton ◽

Veronica Miyasike-daSilva ◽

Albert H. Vette ◽

William E. McIlroy

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Speed Of Processing ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

Download Full-text

The effect of continuous theta burst stimulation over premotor cortex on circuits in primary motor cortex and spinal cord

Clinical Neurophysiology ◽

10.1016/j.clinph.2009.01.003 ◽

2009 ◽

Vol 120 (4) ◽

pp. 796-801 ◽

Cited By ~ 62

Author(s):

Ying-Zu Huang ◽

John C. Rothwell ◽

Chin-Song Lu ◽

JiunJie Wang ◽

Yi-Hsin Weng ◽

...

Keyword(s):

Spinal Cord ◽

Motor Cortex ◽

Primary Motor Cortex ◽

Premotor Cortex ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

Download Full-text

P22.3 A comparison of two different continuous theta burst stimulation paradigms applied to the human primary motor cortex

Clinical Neurophysiology ◽

10.1016/s1388-2457(11)60564-6 ◽

2011 ◽

Vol 122 ◽

pp. S157

Author(s):

M.R. Goldsworthy ◽

M.C. Ridding

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

Download Full-text

Selective modulation of left primary motor cortex excitability after continuous theta burst stimulation to right primary motor cortex and bimanual training

Behavioural Brain Research ◽

10.1016/j.bbr.2014.04.041 ◽

2014 ◽

Vol 269 ◽

pp. 138-146 ◽

Cited By ~ 6

Author(s):

Jason L. Neva ◽

Amaya M. Singh ◽

Michael Vesia ◽

W. Richard Staines

Keyword(s):

Motor Cortex ◽

Primary Motor Cortex ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Motor Cortex Excitability ◽

Selective Modulation ◽

Bimanual Training ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

Download Full-text

M1 disruption delays motor processes but not deliberation about action choices

10.1101/501205 ◽

2018 ◽

Author(s):

Gerard Derosiere ◽

David Thura ◽

Paul Cisek ◽

Julie Duque

Keyword(s):

Motor Cortex ◽

Decision Process ◽

Primary Motor Cortex ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Sham Stimulation ◽

Motor Processes ◽

The Impact ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

AbstractDecisions about actions typically involve a period of deliberation that ends with the commitment to a choice and the motor processes overtly expressing that choice. Previous studies have shown that neural activity in sensorimotor areas, including the primary motor cortex (M1), correlates with deliberation features during action selection. Yet, the causal contribution of these areas to the decision process remains unclear. Here, we investigated whether M1 determines choice commitment, or whether it simply reflects decision signals coming from upstream structures and instead mainly contributes to the motor processes that follow commitment. To do so, we tested the impact of a disruption of M1 activity, induced by continuous theta burst stimulation (cTBS), on the behavior of human subjects in (1) a simple reaction time (SRT) task allowing us to estimate the duration of the motor processes and (2) a modified version of the tokens task (Cisek et al., 2009), which allowed us to estimate subjects’ time of commitment as well as accuracy criterion. The efficiency of cTBS was attested by a reduction in motor evoked potential amplitudes following M1 disruption, as compared to those following a sham stimulation. Furthermore, M1 cTBS lengthened SRTs, indicating that motor processes were perturbed by the intervention. Importantly, all of the behavioral results in the tokens task were similar following M1 disruption and sham stimulation, suggesting that the contribution of M1 to the deliberation process is potentially negligible. Taken together, these findings favor the view that M1 contribution is downstream of the decision process.New and noteworthyDecisions between actions are ubiquitous in the animal realm. Deliberation during action choices entails changes in the activity of the sensorimotor areas controlling those actions, but the causal role of these areas is still often debated. Using continuous theta burst stimulation, we show that disrupting the primary motor cortex (M1) delays the motor processes that follow instructed commitment but does not alter volitional deliberation, suggesting that M1 contribution may be downstream of the decision process.

Download Full-text

Motor cortex disruption delays motor processes but not deliberation about action choices

Journal of Neurophysiology ◽

10.1152/jn.00163.2019 ◽

2019 ◽

Vol 122 (4) ◽

pp. 1566-1577 ◽

Cited By ~ 7

Author(s):

Gerard Derosiere ◽

David Thura ◽

Paul Cisek ◽

Julie Duque

Keyword(s):

Motor Cortex ◽

Decision Process ◽

Primary Motor Cortex ◽

Theta Burst Stimulation ◽

Burst Stimulation ◽

Sham Stimulation ◽

Motor Processes ◽

The Impact ◽

Theta Burst ◽

Continuous Theta Burst Stimulation

Decisions about actions typically involve a period of deliberation that ends with the commitment to a choice and the motor processes overtly expressing that choice. Previous studies have shown that neural activity in sensorimotor areas, including the primary motor cortex (M1), correlates with deliberation features during action selection. However, the causal contribution of these areas to the decision process remains unclear. Here, we investigated whether M1 determines choice commitment or whether it simply reflects decision signals coming from upstream structures and instead mainly contributes to the motor processes that follow commitment. To do so, we tested the impact of a disruption of M1 activity, induced by continuous theta burst stimulation (cTBS), on the behavior of human subjects in 1) a simple reaction time (SRT) task allowing us to estimate the duration of the motor processes and 2) a modified version of the tokens task (Cisek P, Puskas GA, El-Murr S. J Neurosci 29: 11560–11571, 2009), which allowed us to estimate subjects’ time of commitment as well as accuracy criterion. The efficiency of cTBS was attested by a reduction in motor evoked potential amplitudes following M1 disruption compared with those following a sham stimulation. Furthermore, M1 cTBS lengthened SRTs, indicating that motor processes were perturbed by the intervention. Importantly, all of the behavioral results in the tokens task were similar following M1 disruption and sham stimulation, suggesting that the contribution of M1 to the deliberation process is potentially negligible. Taken together, these findings favor the view that M1 contribution is downstream of the decision process. NEW & NOTEWORTHY Decisions between actions are ubiquitous in the animal realm. Deliberation during action choices entails changes in the activity of the sensorimotor areas controlling those actions, but the causal role of these areas is still often debated. With the use of continuous theta burst stimulation, we show that disrupting the primary motor cortex (M1) delays the motor processes that follow instructed commitment but does not alter volitional deliberation, suggesting that M1 contribution may be downstream of the decision process.

Download Full-text