motor cortex
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- MeSH
- bolest etiologie chirurgie MeSH
- elektrická stimulace metody přístrojové vybavení MeSH
- lidé středního věku MeSH
- lidé MeSH
- management bolesti MeSH
- motorické korové centrum MeSH
- neúspěšná terapie MeSH
- předoperační péče MeSH
- thalamus MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- mužské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
- přehledy MeSH
Cílem práce bylo hodnocení souvislosti mezi excitabilitou motorického a vizuálního kortexu. Pomocí neuronavigované transkraniální magnetické stimulace (TMS, Magstim Rapid) za použití jednoho pulzu (SP) nebo párových pulzu (PP) cílené na pravou vizuální kuru byl hodnocen práh pro indukci fosfénu u 11 dobrovolníku. Standardní metodika pak byla použita pro hodnocení motorického prahu (MT). Fosfény se podařilo indukovat pomocí techniky SP (medián = 48 %, IQR = 44,5–52,0) i PP (medián = 44 %, IQR=39,5–48,0) TMS. Práh pro fosfény indukované PP byl nižší nežli v případě SP (U = 28,0, p ? 0,05). Byla nalezena pozitivní korelace mezi MT a SP fosfénovým prahem (r = 0,597, p ? 0,05) a MT nekoreloval s PP prahy. Vzdálenost cívky od povrchu mozku pak nebyla ve vztahu k MT, SP ani PP fosfénovým prahům. Naše nálezy potvrzují vztah mezi MT a fosfénovým prahem hodnoceným pomocí jednotlivých pulzu nad okcipitálním kortexem vpravo za horizontálního umístění cívky. Navržená metodika muže být použita v experimentech, které hodnotí kortikální excitabilitu vizuální kůry. SP fosfénový práh představuje potenciální standard pro interindividuální srovnání poi TMS experimentech visuální kůry v klinických populacích.
The aim of the study was to investigate the relationship between excitability of motor and visual cortex. Using neuronavigated singlepulse (SP) and paired-pulse (PP) transcranial magnetic stimulation (TMS, Magstim Rapid) over right visual cortex the phosphene thresholds were measured in 11 subjects. Standard methodology was used to identify the motor threshold (MT). In all subjects the phosphenes were induced by both SP (median = 48%, IQR = 44,5–52,0) and PP (medián = 44 %, IQR=39,5–48,0) TMS. The PP phosphene thresholds were lower than the SP thresholds (U = 28,0, p ? 0,05). We found the positive correlation between MT and SP phosphene threshold (r = 0,597, p ? 0,05) but not for MT and PP. The distance of coil position from the brain surface did not correlate with MT, SP nor PP phosphene threshold. Our findings confirm the relationship between MT a phosphene threshold measured by the use of single-pulse technique over right occipital cortex with horizontal position of coil. The propose methodology should be used in experiments where cortical excitability of visual cortex is measured. SP phosphene threshold is proposed as a potential standard for inter-individual comparison in visual TMS experiments in ppatientspatients.
Autoři prezentují kazuistiku chronické stimulace motorické mozkové kůry u nemocné s talamickou bolestí. Článek popisuje efekt léčby, ale zároveň rozebírá nežádoucí účinky a zvažuje další perspektivy této metody.
Chronic motor cortex stimulation was applied in a patient with intractable thalamic pain. The article presents a description of the method as well as an analysis of its unfavourable side effects. The prospects of this method are discussed.
- MeSH
- bolest MeSH
- elektrická stimulace metody MeSH
- elektrody MeSH
- finanční podpora výzkumu jako téma MeSH
- lidé středního věku MeSH
- lidé MeSH
- management bolesti MeSH
- mozková kůra MeSH
- thalamus MeSH
- výsledek terapie MeSH
- Check Tag
- lidé středního věku MeSH
- lidé MeSH
- ženské pohlaví MeSH
- Publikační typ
- kazuistiky MeSH
- přehledy MeSH
OBJECTIVE: Adaptive interactions with the outer world necessitate effective connections between cognitive and executive functions. The primary motor cortex (M1) with its control of the spinal cord motor apparatus and its involvement in the processing of cognitive information related to motor functions is one of the best suited structures of this cognition-action connection. The question arose whether M1 might be involved also in situations where no overt or covered motor action is present. METHODS: The EEG data analyzed were recorded during an oddball task in one epileptic patient (19 years) with depth multilead electrodes implanted for diagnostic reasons into the M1 and several prefrontal areas. RESULTS: The main result was the finding of an evoked response to non-target stimuli with a pronounced late component in all frontal areas explored, including three loci of the M1. The late component was implicated in the evaluation of predicted and actual action and was synchronized in all three precentral loci and in the majority of prefrontal loci. CONCLUSION: The finding is considered as direct evidence of functional involvement of the M1 in cognitive activity not related to motor function. SIGNIFICANCE: Our results contribute to better understanding of neural mechanisms underlying cognition.
- MeSH
- elektroencefalografie metody MeSH
- kognice fyziologie MeSH
- lidé MeSH
- mladý dospělý MeSH
- motorické korové centrum fyziologie MeSH
- světelná stimulace metody MeSH
- zrakové evokované potenciály fyziologie MeSH
- Check Tag
- lidé MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
OBJECTIVES: The aim of the study was to describe the effect of motor cortex stimulation (MCS) on pain thresholds in deafferentated rats. SETTINGS AND DESIGN: The effect of MCS was studied in 18 deafferentated and 14 intact laboratory rats, using a standardised plantar test and tail-flick latencies. Two inoxious stimulation electrodes were implanted subdurally over the cerebral cortex and a C5-Th1 dorsal root rhizotomy was performed on the left side. Pain thresholds were measured before and after cortical stimulation. The data were analysed with ANOVA for repeated measures. RESULTS: MCS in intact animals evoked no changes in pain thresholds except for the contralateral forelimb, in which the pain threshold increased after MCS. Following deafferentation, pain thresholds increased in both plantar test and tail-flick in comparison to baseline values. When MCS was applied to the deafferentated animals, the pain thresholds returned to baseline levels. The effect of MCS disappeared within 24 hours. MAIN FINDINGS: 1. MCS in intact animals evoked hypoesthesia in the corresponding contralateral forelimb; 2. deafferentation itself increased pain thresholds in the unaffected limbs; 3. under MCS, pain thresholds in deafferentated rats were not different from pre-dafferentation values; 4. the effect of MCS disappeared in 24 hours and oscillated. CONCLUSIONS: Our results show a similar effect of the stimulation in man and experimental animals despite the differences in the organisation of the cerebral cortex. The use of laboratory animals is promising for further studies in the field of involved antalgic mechanisms of MCS.
- MeSH
- denervace MeSH
- elektrická stimulace MeSH
- financování organizované MeSH
- kauzalgie patofyziologie MeSH
- krysa rodu rattus MeSH
- motorické korové centrum fyziologie MeSH
- nociceptory klasifikace MeSH
- potkani Long-Evans MeSH
- práh bolesti fyziologie MeSH
- rizotomie MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- zvířata MeSH
OBJECTIVES AND METHODS: Excitability changes in the primary motor cortex in 17 spinal-cord injured (SCI) patients and 10 controls were studied with paired-pulse transcranial magnetic stimulation. The paired pulses were applied at inter-stimulus intervals (ISI) of 2 ms and 15 ms while motor evoked potentials (MEP) were recorded in the biceps brachii (Bic), the abductor pollicis brevis (APB) and the tibialis anterior (TA) muscles. RESULTS: The study revealed a significant decrease in cortical motor excitability in the first weeks after SCI concerning the representation of both the affected muscles innervated from spinal segments below the lesion, and the spared muscles rostral to the lesion. In the patients with motor-incomplete injury, but not in those with motor-complete injury, the initial cortical inhibition of affected muscles was temporarily reduced 2-3 months following injury. The degree of inhibition in cortical areas representing the spared muscles was observed to be smaller in patients with no voluntary TA activity compared to patients with some activity remaining in the TA. Surprisingly, motor-cortical inhibition was observed not only at ISI 2 ms but also at ISI 15 ms. The inhibition persisted in patients who returned for a follow-up measurement 2-3 years later. CONCLUSION: The present data showed different evaluation of cortical excitability between patients with complete and incomplete spinal cord lesion. Our results provide more insight into the pathophysiology of SCI and contribute to the ongoing discussion about the recovery process and therapy of SCI patients.
- MeSH
- analýza rozptylu MeSH
- časové faktory MeSH
- dospělí MeSH
- eferentní nervové dráhy fyziologie patofyziologie MeSH
- kosterní svaly inervace fyziologie MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- motorické evokované potenciály fyziologie MeSH
- motorické korové centrum fyziologie MeSH
- nervový útlum fyziologie MeSH
- neurony eferentní fyziologie MeSH
- poranění míchy patofyziologie MeSH
- referenční hodnoty MeSH
- studie případů a kontrol MeSH
- transkraniální magnetická stimulace MeSH
- Check Tag
- dospělí MeSH
- lidé středního věku MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Since recently, it is possible, using noninvasive cortical stimulation, such as the protocol of paired associative stimulation (PAS), to induce the plastic changes in the motor cortex, in humans that mimic Hebb's model of learning. Application of TMS conjugated with peripheral electrical stimulation at strictly coherent temporal manner lead to convergence of inputs in the sensory-motor cortex, with the consequent synaptic potentiation or weakening, if applied repetitively. However, when optimal interstimulus interval (ISI) for induction of LTP-like effects is applied as a single pair, Motor evoked potential (MEP) amplitude inhibition is observed, the paradigm known as short-latency afferent inhibition (SLAI). Aiming to resolve this paradox, PAS protocols were applied, with 200 repetitions of TMS pulses paired with median nerve electrical stimulation, at ISI equal to individual latencies of evoked response of somatosensory cortex (N(20)) (PAS(LTP)), and at ISI of N(20) shortened for 5 msec (PAS(LTD)) - protocols that mimic LTP-like changes in the human motor cortex. MEP amplitudes before, during and after interventions were measured as an indicator based on output signals originating from the motor system. Post-intervention MEP amplitudes following the TMS protocols of PAS(LTP) and PAS(LTD) were facilitated and depressed, respectively, contrary to MEP amplitudes during intervention. During PAS(LTP) MEP amplitudes were significantly decreased in case of PAS(LTP), while in the case of PAS(LTD) an upward trend was observed. In conclusions, a possible explanation for the seemingly paradoxical effect of PAS can be found in the mechanism of homeostatic modulation of plasticity. Those findings indicate the existence of complex relationships in the development of plasticity induced by stimulation, depending on the level of the previous motor cortex excitability.
- MeSH
- dospělí MeSH
- elektrická stimulace metody přístrojové vybavení MeSH
- elektromyografie metody přístrojové vybavení MeSH
- experimenty na lidech MeSH
- financování organizované MeSH
- homeostáza fyziologie MeSH
- lidé MeSH
- motorické korové centrum fyziologie MeSH
- nervus medianus fyziologie MeSH
- neuroplasticita fyziologie MeSH
- somatosenzorické evokované potenciály fyziologie MeSH
- statistika jako téma MeSH
- transkraniální magnetická stimulace metody využití MeSH
- zápěstí fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
