Hand motor cortex activation in a patient with congenital mirror movements: a study of the silent period following focal transcranial magnetic stimulation

Cincotta, Massimo; Lori, S.; Gangemi, P.F.; Barontini, F; Ragazzoni, Roberto

doi:10.1016/0924-980x(96)95621-0

Cited by 35 publications

(15 citation statements)

References 24 publications

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“…7 The EMG recordings showed consistently that during intended unilateral contraction mirror activity is less than the intended activity. A contribution from the damaged motor cortex was unlikely because MEP were not elicited from this cortex.…”

Section: Discussionmentioning

confidence: 86%

Reorganization of the motor cortex in a patient with congenital hemiparesis and mirror movements

Cincotta

Borgheresi²,

Liotta³

et al. 2000

Neurology

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Abnormal branching of corticospinal fibers from the unaffected motor cortex is responsible for mirror movements in patients with congenital hemiparesis, but it is unknown which mechanisms enable these patients to lateralize motor activity. Using multiunit electromyographic analysis and transcranial magnetic stimulation, the authors provide evidence for nonbranched crossed and uncrossed corticospinal projections and intracortical inhibition of the mirror hand. They propose that this remarkable reorganization of the unaffected motor cortex helps these patients to reduce mirror movements.

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Section: Discussionmentioning

confidence: 86%

Reorganization of the motor cortex in a patient with congenital hemiparesis and mirror movements

Cincotta

Borgheresi²,

Liotta³

et al. 2000

Neurology

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“…In patients with congenital MM not associated with severe hemispheric lesions, MRCP2, 27–29 and functional neuroimaging studies2, 26, 30, 31 suggested bilateral M1 activation during performance of intended unimanual tasks. By transient interference with M1 function, focal TMS studies confirmed that this abnormal bilateral cortical activation is not just caused, for instance, by sensory feedback from the mirror hand, but truly reflects motor output from bilateral M1 8, 17, 23. Assuming the existence of separate contralateral and ipsilateral corticofugal projections from either M1, Mayer and colleagues28 hypothesised that bilateral motor output could help to reduce the amount of mirror activity by preferentially activating the contralateral projection from the left M1 and the ipsilateral projection from the right M1 during intended unilateral movements of the right hand, and vice versa for the left hand.…”

Section: Discussionmentioning

confidence: 90%

“…Head and cervical spine magnetic resonance imaging were normal. Previous TMS experiments had demonstrated a contribution of both M1 to the motor output during intended unilateral hand movements in both patients 8, 17. Patients and the parents of Patient 1 gave their informed consent to the study.…”

Section: Methodsmentioning

confidence: 99%

“…Persistent congenital MM can be observed in different clinical conditions, ranging from the absence of other neurological abnormalities to severe congenital hemiparesis 1, 2, 5–8. In persistent congenital MM, the neurophysiological hallmark as revealed by focal transcranial stimulation is the presence of fast‐conducting corticospinal pathways connecting abnormally the hand area of one M1 with both sides of the spinal cord 2, 3, 5, 7–26. In patients with persistent congenital MM not associated with severe hemispheric lesions, various techniques such as focal transcranial magnetic stimulation (TMS),8, 17, 23 movement‐related cortical potential (MRCP),2, 27–29 and functional neuroimaging2, 26, 30, 31 suggest in addition a contribution of abnormal bilateral activity in both M1 to the emergence of MM.…”

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confidence: 99%

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Separate ipsilateral and contralateral corticospinal projections in congenital mirror movements: Neurophysiological evidence and significance for motor rehabilitation

et al. 2003

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Abstract:The neurophysiological hallmark of congenital mirror movements (MM) are fast-conducting corticospinal projections from the hand area of one primary motor cortex to both sides of the spinal cord. It is still unclear whether the abnormal ipsilateral projection originates through branching fibres from the normal contralateral projection or constitutes a separate ipsilateral projection. To clarify this question, we used focal paired-pulse transcranial magnetic stimulation to test task-related modulation of short-interval intracortical inhibition (SICI) in the abductor pollicis brevis (APB) muscles of a 15-year-old girl (Patient 1) and a 40-year-old woman (Patient 2) with congenital MM. In both patients, during intended unilateral APB contraction, SICI decreased markedly in the "task" APB but remained unchanged in the "mirror" APB when compared to muscle rest. In contrast, spinal excitability as tested with H reflexes increased similarly in the task and mirror flexor carpi radialis muscles. This dissociation of task-related SICI modulation strongly supports the existence of a separate ipsilateral fast-conducting corticospinal projection. In Patient 1, we tested the functional significance of this separate ipsilateral projection during 7 months of motor rehabilitation training, which was designed to facilitate unilateral finger movements. A marked reduction of MM was observed after training, suggesting that unwanted mirror activity in the ipsilateral pathway can be suppressed by learning.

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“…There is growing evidence suggesting that physiological mirroring depends on the activation of the ipsilateral M1, which normally has a crossed CS tract connecting to the mirror hand [50–52]. This transfer of activation is thought to occur through a transcallosal pathway [1, 20, 34].…”

Section: Mirror Movementsmentioning

confidence: 99%

Interhemispheric Control of Unilateral Movement

2012

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To perform strictly unilateral movements, the brain relies on a large cortical and subcortical network. This network enables healthy adults to perform complex unimanual motor tasks without the activation of contralateral muscles. However, mirror movements (involuntary movements in ipsilateral muscles that can accompany intended movement) can be seen in healthy individuals if a task is complex or fatiguing, in childhood, and with increasing age. Lateralization of movement depends on complex interhemispheric communication between cortical (i.e., dorsal premotor cortex, supplementary motor area) and subcortical (i.e., basal ganglia) areas, probably coursing through the corpus callosum (CC). Here, we will focus on transcallosal interhemispheric inhibition (IHI), which facilitates complex unilateral movements and appears to play an important role in handedness, pathological conditions such as Parkinson's disease, and stroke recovery.

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Hand motor cortex activation in a patient with congenital mirror movements: a study of the silent period following focal transcranial magnetic stimulation

Cited by 35 publications

References 24 publications

Reorganization of the motor cortex in a patient with congenital hemiparesis and mirror movements

Reorganization of the motor cortex in a patient with congenital hemiparesis and mirror movements

Separate ipsilateral and contralateral corticospinal projections in congenital mirror movements: Neurophysiological evidence and significance for motor rehabilitation

Interhemispheric Control of Unilateral Movement

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