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Jin SH, Lin P, Hallett M. Linear and nonlinear information flow based on time-delayed mutual information method and its application to corticomuscular interaction. Clin Neurophysiol 2009; 121:392-401. [PMID: 20044309 DOI: 10.1016/j.clinph.2009.09.033] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Revised: 09/09/2009] [Accepted: 09/15/2009] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To propose a model-free method to show linear and nonlinear information flow based on time-delayed mutual information (TDMI) by employing uni- and bi-variate surrogate tests and to investigate whether there are contributions of the nonlinear information flow in corticomuscular (CM) interaction. METHODS Using simulated data, we tested whether our method would successfully detect the direction of information flow and identify a relationship between two simulated time series. As an experimental data application, we applied this method to investigate CM interaction during a right wrist extension task. RESULTS Results of simulation tests show that we can correctly detect the direction of information flow and the relationship between two time series without a prior knowledge of the dynamics of their generating systems. As experimental results, we found both linear and nonlinear information flow from contralateral sensorimotor cortex to muscle. CONCLUSIONS Our method is a viable model-free measure of temporally varying causal interactions that is capable of distinguishing linear and nonlinear information flow. With respect to experimental application, there are both linear and nonlinear information flows in CM interaction from contralateral sensorimotor cortex to muscle, which may reflect the motor command from brain to muscle. SIGNIFICANCE This is the first study to show separate linear and nonlinear information flow in CM interaction.
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Affiliation(s)
- Seung-Hyun Jin
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892, USA.
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52
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Gu Y, Dremstrup K, Farina D. Single-trial discrimination of type and speed of wrist movements from EEG recordings. Clin Neurophysiol 2009; 120:1596-600. [PMID: 19535289 DOI: 10.1016/j.clinph.2009.05.006] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Revised: 04/01/2009] [Accepted: 05/09/2009] [Indexed: 11/25/2022]
Abstract
OBJECTIVE The study explored the possibility of identifying movement type and speed from EEG recordings. METHODS EEG signals were acquired from 9 healthy volunteers during imagination of four tasks of the right wrist that involved two speeds (fast and slow) and two types of movement (wrist extension and rotation), each repeated 60 times in random order. Average movement-related cortical potentials (MRCPs) were compared among the four tasks. Moreover, single-trial classification was performed using the rebound rate of MRCP and the power in the mu and beta bands as features. RESULTS The rebound rate of the average MRCPs was greater for faster than for slower movements but did not depend on the type of movement. Accordingly, pairs of tasks executed at different speeds led to lower misclassification rate than pairs of tasks executed at the same speed. The average misclassification rate between task pairs was 21+/-2% for the best channel and task pair. CONCLUSION The task parameter speed can be discriminated in single-trial EEG traces with greater accuracy than the type of movement when tasks are executed at the same joint. SIGNIFICANCE The speed of movement execution may be included among the variables that characterize imagined tasks for brain-computer interface applications.
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Affiliation(s)
- Ying Gu
- Center for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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53
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Tominaga W, Matsubayashi J, Deguchi Y, Minami C, Kinai T, Nakamura M, Nagamine T, Matsuhashi M, Mima T, Fukuyama H, Mitani A. A mirror reflection of a hand modulates stimulus-induced 20-Hz activity. Neuroimage 2009; 46:500-4. [PMID: 19249371 DOI: 10.1016/j.neuroimage.2009.02.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2008] [Revised: 02/07/2009] [Accepted: 02/16/2009] [Indexed: 01/09/2023] Open
Abstract
Mirror therapy is one of the promising rehabilitation therapeutic interventions but the neural basis of the therapeutic effect remains unknown. It has been reported that the 20-Hz rhythmic activity is induced in the primary motor cortex after median nerve stimulation and the amount of the induced activity is decreased when the primary motor cortex is activated. In the present study, to elucidate the neural mechanisms underlying mirror therapy, we investigated whether the mirror reflection of a hand holding a pencil modulates the stimulus-induced 20-Hz activity. Neuromagnetic brain activities were recorded from 11 healthy right-handed subjects while they were viewing their hand holding a pencil or its mirror reflection. The right median nerve was stimulated and the stimulus-induced 20-Hz activity over the left rolandic cortex dominantly innervating right-hand movements was quantified. The stimulus-induced 20-Hz activity was strongly suppressed when subjects viewed the right hand holding a pencil or the mirror reflection of the left hand looking like the right hand holding a pencil, compared with when subjects viewed the left hand holding a pencil or the mirror reflection of the right hand looking like the left hand holding a pencil. These results suggest that the human left primary motor cortex is strongly activated when the subjects view not only the right hand holding a pencil but also the mirror reflection of the left hand looking like the right hand holding a pencil. This may be one of the neural mechanisms responsible for the therapeutic effect of mirror therapy.
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Affiliation(s)
- Wataru Tominaga
- Laboratory of Neurorehabilitation, Department of Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 Kawaracho, Syogoin, Sakyo-ku, Kyoto 606-8507, Japan
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55
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Nagarajan S, Kirsch H, Lin P, Findlay A, Honma S, Berger MS. Preoperative localization of hand motor cortex by adaptive spatial filtering of magnetoencephalography data. J Neurosurg 2008; 109:228-37. [PMID: 18671634 DOI: 10.3171/jns/2008/109/8/0228] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The goal of this study was to examine the sensitivity and specificity in preoperative localization of hand motor cortex by imaging regional event-related desynchronization (ERD) of brainwaves in the β frequency band (15–25 Hz) involved in self-paced movement.
Methods
Using magnetoencephalography (MEG), the authors measured ERD that occurred before self-paced unilateral index finger flexion in 66 patients with brain tumors, epilepsy, and arteriovenous malformations.
Results
The authors applied an adaptive spatial filtering algorithm to MEG data and found that peaks of the tomographic distribution of β-band ERD sources reliably localized hand motor cortex compared with electrical cortical stimulation. They also observed high specificity in estimating contralateral hand motor cortical representations relative to somatosensory cortex. Neither presence nor location of tumor changed the qualitative or quantitative location of motor cortex relative to somatosensory cortex.
Conclusions
An imaging protocol using ERD obtained by adaptive spatial filtering of MEG data can be used for extremely reliable preoperative localization of hand motor cortex.
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Affiliation(s)
| | | | - Peter Lin
- 1Biomagnetic Imaging Laboratory, Department of Radiology, and
- 3Department of Neurology, Stanford University School of Medicine, Stanford, California
| | - Anne Findlay
- 1Biomagnetic Imaging Laboratory, Department of Radiology, and
| | - Susanne Honma
- 1Biomagnetic Imaging Laboratory, Department of Radiology, and
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56
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Chen C, Hsieh J, Wu Y, Lee P, Chen S, Niddam DM, Yeh T, Wu Y. Mutual-information-based approach for neural connectivity during self-paced finger lifting task. Hum Brain Mapp 2008; 29:265-80. [PMID: 17394211 PMCID: PMC6871222 DOI: 10.1002/hbm.20386] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Frequency-dependent modulation between neuronal assemblies may provide insightful mechanisms of functional organization in the context of neural connectivity. We present a conjoined time-frequency cross mutual information (TFCMI) method to explore the subtle brain neural connectivity by magnetoencephalography (MEG) during a self-paced finger lifting task. Surface electromyogram (sEMG) was obtained from the extensor digitorum communis. Both within-modality (MEG-MEG) and between-modality studies (sEMG-MEG) were conducted. The TFCMI method measures both the linear and nonlinear dependencies of the temporal dynamics of signal power within a pre-specified frequency band. Each single trial of MEG across channels and sEMG signals was transformed into time-frequency domain with use of the Morlet wavelet to obtain better temporal spectral (power) information. As compared to coherence approach (linear dependency only) in broadband analysis, the TFCMI method demonstrated advantages in encompassing detection for the mesial frontocentral cortex and bilateral primary sensorimotor areas, clear demarcation of event- and non-event-related regions, and robustness for sEMG - MEG between-modality study, i.e., corticomuscular communication. We conclude that this novel TFCMI method promises a possibility to better unravel the intricate functional organizations of brain in the context of oscillation-coded communication.
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Affiliation(s)
- Chun‐Chuan Chen
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Center for Neuroscience, National Yang‐Ming University, Taipei, Taiwan
| | - Jen‐Chuen Hsieh
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Brain Science, National Yang‐Ming University, Taipei, Taiwan
- Institute of Neuroscience, School of Life Science, National Yang‐Ming University, Taipei, Taiwan
- Center for Neuroscience, National Yang‐Ming University, Taipei, Taiwan
| | - Yu‐Zu Wu
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Neuroscience, School of Life Science, National Yang‐Ming University, Taipei, Taiwan
- Department of Physical Therapy, Tzu‐Chi College of Technology, Hualien, Taiwan
| | - Po‐Lei Lee
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Department of Electrical Engineering, Nation Central University, Jhongli, Taiwan
| | - Shyan‐Shiou Chen
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
| | - David M. Niddam
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Center for Neuroscience, National Yang‐Ming University, Taipei, Taiwan
| | - Tzu‐Chen Yeh
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Brain Science, National Yang‐Ming University, Taipei, Taiwan
- Faculty of Medicine, School of Medicine, National Yang‐Ming University, Taipei, Taiwan
| | - Yu‐Te Wu
- Laboratory of Integrated Brain Research, Department of Medical Research and Education, Taipei Veterans General Hospital, Taipei, Taiwan
- Institute of Brain Science, National Yang‐Ming University, Taipei, Taiwan
- Department of Biomedical Imaging and Radiological Sciences, National Yang‐Ming University, Taipei, Taiwan
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57
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Human brain mapping: hemodynamic response and electrophysiology. Clin Neurophysiol 2008; 119:731-43. [PMID: 18187361 DOI: 10.1016/j.clinph.2007.10.026] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 10/10/2007] [Accepted: 10/18/2007] [Indexed: 02/02/2023]
Abstract
In view of the recent advance in functional neuroimaging, the current status of non-invasive techniques applied for human brain mapping was reviewed by integrating two principles: hemodynamic and electrophysiological, from the viewpoint of clinical neurophysiology. The currently available functional neuroimaging techniques based on hemodynamic principles are functional magnetic resonance imaging (fMRI), positron emission tomography (PET) or single-photon emission computed tomography (SPECT), and near-infrared spectroscopy (NIRS). Electrophysiological techniques include electroencephalography (EEG), magnetoencephalography (MEG), and transcranial magnetic stimulation (TMS). As for the coupling between hemodynamic response and neuronal activity (neurovascular coupling), experimental studies suggest that the hemodynamic response is significantly correlated to neuronal activity, especially local field potential (synaptic activity) rather than spiking activity, within a certain range. The hemodynamic response tends to be more widespread in space and lasts longer in time as compared with the neuronal activity. Since each technique has its own characteristic features especially in terms of spatial and temporal resolution, it is important to adopt the most appropriate technique for solving each specific question, and it is useful to combine two techniques either simultaneously or in separate sessions. As for the multi-modal approach, the combined use of EEG and MEG, EEG and PET, or EEG and fMRI is applied for the simultaneous studies, and for the separate use of two different techniques, the information obtained from fMRI is used for estimating the generator source from EEG or MEG data (fMRI-constrained source estimation). Functional connectivity among different brain areas can be studied by using a single technique such as the EEG coherence or the correlation analysis of fMRI or PET data, or by combining the stimulation technique such as TMS with neuroimaging. Further advance of each technology and improvement in the analysis method will promote the understanding of precise functional specialization and inter-areal coupling, and will contribute to the increased efficacy of rapidly developing physiological treatments of neurological and psychiatric disorders.
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58
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Lebedev MA, O'Doherty JE, Nicolelis MAL. Decoding of temporal intervals from cortical ensemble activity. J Neurophysiol 2007; 99:166-86. [PMID: 18003881 DOI: 10.1152/jn.00734.2007] [Citation(s) in RCA: 128] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Neurophysiological, neuroimaging, and lesion studies point to a highly distributed processing of temporal information by cortico-basal ganglia-thalamic networks. However, there are virtually no experimental data on the encoding of behavioral time by simultaneously recorded cortical ensembles. We predicted temporal intervals from the activity of hundreds of neurons recorded in motor and premotor cortex as rhesus monkeys performed self-timed hand movements. During the delay periods, when animals had to estimate temporal intervals and prepare hand movements, neuronal ensemble activity encoded both the time that elapsed from the previous hand movement and the time until the onset of the next. The neurons that were most informative of these temporal intervals increased or decreased their rates throughout the delay until reaching a threshold value, at which point a movement was initiated. Variability in the self-timed delays was explainable by the variability of neuronal rates, but not of the threshold. In addition to predicting temporal intervals, the same neuronal ensemble activity was informative for generating predictions that dissociated the delay periods of the task from the movement periods. Left hemispheric areas were the best source of predictions in one bilaterally implanted monkey overtrained to perform the task with the right hand. However, after that monkey learned to perform the task with the left hand, its left hemisphere continued and the right hemisphere started contributing to the prediction. We suggest that decoding of temporal intervals from bilaterally recorded cortical ensembles could improve the performance of neural prostheses for restoration of motor function.
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Affiliation(s)
- Mikhail A Lebedev
- Deptartment of Neurobiology, Duke Univiversity, Durham, North Carolina 27100, USA.
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59
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Oishi N, Mima T, Ishii K, Bushara KO, Hiraoka T, Ueki Y, Fukuyama H, Hallett M. Neural correlates of regional EEG power change. Neuroimage 2007; 36:1301-12. [PMID: 17524671 DOI: 10.1016/j.neuroimage.2007.04.030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2005] [Revised: 04/01/2007] [Accepted: 04/07/2007] [Indexed: 11/26/2022] Open
Abstract
To clarify the physiological significance of task-related change of the regional electroencephalogram (EEG) rhythm, we quantitatively evaluated the correlation between regional cerebral blood flow (rCBF) and EEG power. Eight subjects underwent H2 15O positron emission tomography scans simultaneously with EEG recording during the following tasks: rest condition with eyes closed and open, self-paced movements of the right and left thumb and right ankle. EEG signals were recorded from the occipital and bilateral sensorimotor areas. Cortical activation associated with EEG rhythm generation was studied by the correlation between rCBF and EEG power. There were significant negative correlations between the sensorimotor EEG rhythm at 10-20 Hz on each side and the ipsilateral sensorimotor rCBF and between the occipital EEG rhythm at 10-20 Hz and the occipital rCBF. The occipital EEG rhythm showed a positive correlation with the bilateral medial prefrontal rCBF, while the right sensorimotor EEG rhythm showed a positive correlation with the left prefrontal rCBF. In conclusion, decrease in the regional EEG rhythm at 10-20 Hz might represent the neuronal activation of the cortex underlying the electrodes, at least for the visual and sensorimotor areas. The neural network including the prefrontal cortex could play an important role to generate the EEG rhythm.
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Affiliation(s)
- N Oishi
- Human Brain Research Center, Kyoto University Graduate School of Medicine, Kyoto 606-8507, Japan
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60
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Ichikawa A, Yamamoto H, Ono I, Matsubayashi J, Nagamine T, Fukuyama H, Mitani A. Stimulus-related 20-Hz activity of human cortex modulated by the way of presenting hand actions. Neurosci Res 2007; 58:285-90. [PMID: 17467094 DOI: 10.1016/j.neures.2007.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2006] [Revised: 02/28/2007] [Accepted: 03/27/2007] [Indexed: 11/28/2022]
Abstract
The neural mechanisms underlying recognition of presented hand actions are not well understood. Rolandic rhythmic activity of about 20 Hz is reproducibly induced after median nerve stimulation and has been reported to be related to various types of movements including actual movement, motor imagery and action observation. We recorded neuromagnetic brain activity from 11 healthy subjects to investigate whether the way to present hand actions modulates the 20-Hz activity after median nerve stimulation. The stimulus-related 20-Hz activity was prominently evoked in the contralateral sensorimotor cortex around 0.5-1.0 s after median nerve stimulation and was almost completely suppressed during executing actual hand action. The suppression of the stimulus-related 20-Hz activity was also observed during viewing the similar action of another person's hand. Furthermore, the suppression during viewing the action of another person's hand presented in the same direction as the subject's hand was significantly larger than that during viewing it presented in the opposite direction and was closer to that during executing subject's own hand action. These results indicate that the stimulus-related rolandic 20-Hz activity was modulated by the way to present hand actions, and suggest that the 20-Hz activity is related to neural mechanisms underlying recognition of presented hand actions.
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Affiliation(s)
- Ayako Ichikawa
- Department of Occupational Therapy, School of Health Sciences, Faculty of Medicine, Kyoto University, 53 Kawaharamachi, Syogoin, Kyoto 606-8507, Japan
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61
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Shibasaki H, Ikeda A, Nagamine T. Use of magnetoencephalography in the presurgical evaluation of epilepsy patients. Clin Neurophysiol 2007; 118:1438-48. [PMID: 17452007 DOI: 10.1016/j.clinph.2007.03.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Revised: 02/09/2007] [Accepted: 03/08/2007] [Indexed: 12/30/2022]
Abstract
Magnetoencephalography (MEG) is used twofold for presurgical evaluation of patients with medically intractable partial epilepsy; to identify epileptogenic focus and to investigate functions of cortical areas at or near the epileptogenic focus or structural lesion. For the precise localization of the current source of epileptic discharge, the question as to whether MEG is superior to electroencephalography (EEG) is often addressed. To answer this question, so many factors, both biologically and technically related, have to be taken into consideration. The biological factors include the magnitude of epileptic discharge, its distribution over the cortex, depth of its source from the head surface, and the proportion of large pyramidal neurons tangentially oriented with respect to the head surface within the cortical area. The technical factors include the quality of the recording instrument such as the number of sensors and the use of gradiometer vs. magnetometer, the employed method of source analysis, and availability of experts in each institute. As far as the importance of ictal recording is emphasized, long-term video/EEG monitoring is of utmost importance. Thus, it is concluded that, once the epileptogenic focus is identified by the video/EEG monitoring, then MEG is superior to EEG in order to precisely localize the current source of the interictal epileptic discharge. Another question often addressed is whether MEG can replace the invasive intracranial EEG recording or not. In addition to the above-described factors, different coverage of the cortical areas by MEG vs. invasive intracranial EEG recording has to be taken into account to explain some of the recent reports related to this question. MEG can be effectively applied to the investigation of cortical functions near the epileptogenic focus. It is especially so when combined with other non-invasive studies like functional magnetic resonance imaging (fMRI). In addition to the source analysis of magnetic fields related to various events or tasks, analysis of the task-related change of rhythmic cortical oscillations is a useful tool for studying higher cortical functions such as language in the presurgical evaluation.
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Affiliation(s)
- Hiroshi Shibasaki
- Department of Neurology, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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62
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Shibasaki H, Hallett M. What is the Bereitschaftspotential? Clin Neurophysiol 2006; 117:2341-56. [PMID: 16876476 DOI: 10.1016/j.clinph.2006.04.025] [Citation(s) in RCA: 692] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2006] [Revised: 04/28/2006] [Accepted: 04/28/2006] [Indexed: 12/11/2022]
Abstract
Since discovery of the slow negative electroencephalographic (EEG) activity preceding self-initiated movement by Kornhuber and Deecke [Kornhuber HH, Deecke L. Hirnpotentialänderungen bei Willkurbewegungen und passiven Bewegungen des Menschen: Bereitschaftspotential und reafferente Potentiale. Pflugers Archiv 1965;284:1-17], various source localization techniques in normal subjects and epicortical recording in epilepsy patients have disclosed the generator mechanisms of each identifiable component of movement-related cortical potentials (MRCPs) to some extent. The initial slow segment of BP, called 'early BP' in this article, begins about 2 s before the movement onset in the pre-supplementary motor area (pre-SMA) with no site-specificity and in the SMA proper according to the somatotopic organization, and shortly thereafter in the lateral premotor cortex bilaterally with relatively clear somatotopy. About 400 ms before the movement onset, the steeper negative slope, called 'late BP' in this article (also referred to as NS'), occurs in the contralateral primary motor cortex (M1) and lateral premotor cortex with precise somatotopy. These two phases of BP are differentially influenced by various factors, especially by complexity of the movement which enhances only the late BP. Event-related desynchronization (ERD) of beta frequency EEG band before self-initiated movements shows a different temporospatial pattern from that of the BP, suggesting different neuronal mechanisms for the two. BP has been applied for investigating pathophysiology of various movement disorders. Volitional motor inhibition or muscle relaxation is preceded by BP quite similar to that preceding voluntary muscle contraction. Since BP of typical waveforms and temporospatial pattern does not occur before organic involuntary movements, BP is used for detecting the participation of the 'voluntary motor system' in the generation of apparently involuntary movements in patients with psychogenic movement disorders. In view of Libet et al.'s report [Libet B, Gleason CA, Wright EW, Pearl DK. Time of conscious intention to act in relation to onset of cerebral activity (readiness-potential). The unconscious initiation of a freely voluntary act. Brain 1983;106:623-642] that the awareness of intention to move occurred much later than the onset of BP, the early BP might reflect, physiologically, slowly increasing cortical excitability and, behaviorally, subconscious readiness for the forthcoming movement. Whether the late BP reflects conscious preparation for intended movement or not remains to be clarified.
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Affiliation(s)
- Hiroshi Shibasaki
- Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1428, USA.
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63
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Boonstra TW, Daffertshofer A, Peper CE, Beek PJ. Amplitude and phase dynamics associated with acoustically paced finger tapping. Brain Res 2006; 1109:60-9. [PMID: 16860292 DOI: 10.1016/j.brainres.2006.06.039] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 06/12/2006] [Accepted: 06/13/2006] [Indexed: 11/17/2022]
Abstract
To gain insight into the brain activity associated with the performance of an acoustically paced synchronization task, we analyzed the amplitude and phase dynamics inherent in magnetoencephalographic (MEG) signals across frequency bands in order to discriminate between evoked and induced responses. MEG signals were averaged with respect to motor and auditory events (tap and tone onsets). Principal component analysis was used to compare amplitude and phase changes during listening and during paced and unpaced tapping, allowing a separation of brain activity related to motor and auditory processes, respectively. Motor performance was accompanied by phasic amplitude changes and increased phase locking in the beta band. Auditory processing of acoustic stimuli resulted in a simultaneous increase of amplitude and phase locking in the theta and alpha band. The temporal overlap of auditory-related amplitude changes and phase locking indicated an evoked response, in accordance with previous studies on auditory perception. The temporal difference of movement-related amplitude and phase dynamics in the beta band, on the other hand, suggested a change in ongoing brain activity, i.e., an induced response supporting previous results on motor-related brain dynamics in the beta band.
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Affiliation(s)
- T W Boonstra
- Institute for Fundamental and Clinical Human Movement Sciences, Faculty of Human Movement Sciences, Vrije Universiteit, Van der Boechorststraat 9, 1081 BT Amsterdam, The Netherlands.
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64
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Yoshida K, Maezawa H, Nagamine T, Fukuyama H, Murakami K, Iizuka T. Somatosensory evoked magnetic fields to air-puff stimulation on the soft palate. Neurosci Res 2006; 55:116-22. [PMID: 16677731 DOI: 10.1016/j.neures.2006.02.007] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2005] [Revised: 02/03/2006] [Accepted: 02/08/2006] [Indexed: 10/24/2022]
Abstract
Impairment of sensory input to the soft palate has been reported in patients with obstructive sleep apnea syndrome. To investigate the reaction in the central nervous system related to soft palate perception, we measured the somatosensory evoked magnetic fields following air-puff stimulation in seven healthy volunteers by using a helmet-shaped 122-channel neuromagnetometer. The air-puffs were produced using compressed nitrogen and directed to the middle of the soft palate with an intraoral device. To evaluate the laterality of responses we used another appliance in which the air-puffs were directed to the middle and right side of the soft palate. In all the subjects, responses were identified symmetrically in the bilateral parietotemporal regions with a mean latency of about 130 ms from the soft palate stimulation. Prior to this peak, no distinct early responses were observed. There was no significant difference in the responses between the middle and right side stimulation. Corresponding equivalent current dipoles were estimated around the Sylvian fissures. These results suggested that the responses were derived from the second somatosensory areas. In conclusion, we could record long-latency responses to air-puff stimulation of the soft palate in the bilateral second somatosensory areas.
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Affiliation(s)
- Kazuya Yoshida
- Department of Oral and Maxillofacial Surgery, Graduate School of Medicine, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan.
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65
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Abstract
The frequency range between 0.1 and 0.9 Hz was investigated with magnetoelectroencephalography-EEG coregistration in 10 adult patients with epilepsy and five children with other neurologic conditions. In all instances, a dominant rhythm between 0.2 and 0.4 Hz could be observed in the waking and sleeping states. It showed a waxing and waning quality and was unrelated to eye opening or closing but increased in amplitude during sleep. The maximum was usually in the occipital areas but occasionally in the frontal regions. The rhythm was more persistent and better seen in the magnetoelectroencephalogram, but subdelta activity was also discernible in the EEG. The magnetoelectroencephalographic rhythmicity and frequency suggested possible respiration artifact. Two normal control subjects were therefore investigated by electroencephalography while respirations were monitored. A clear relation to respiration was established. It persisted during breath-holding, albeit at lower amplitude. Larger amplitude transients occurred before and at the cessation of breath-holding as well as hyperventilation. An observed frequency increase before voluntary hyperventilation suggests a relation to the readiness potential and event-related desynchronization as well as synchronization. Subdelta frequencies, which can be readily recorded without special DC amplifiers, provide additional information for clinical as well as research data. They may also be an interface between autonomic and voluntary functions, especially in regard to respiration.
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Affiliation(s)
- Ernst Rodin
- Department of Neurology, University of Utah, Salt Lake City, UT 84092, USA.
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66
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Endo H, Kato Y, Kizuka T, Takeda T. A comparison of stimulus synchronous activity in the primary motor cortices of athletes and non-athletes. Exp Brain Res 2006; 174:426-34. [PMID: 16652201 DOI: 10.1007/s00221-006-0477-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2005] [Accepted: 03/25/2006] [Indexed: 10/24/2022]
Abstract
In this study, we measured primary motor cortex (MI) activity during a reaction time task to examine the appearance of MI activity that synchronized with the stimulus presentation (stimulus synchronous MI activity, SSMA). Because brain activity was expected to be enhanced by the repetitive/extensive activation, we hypothesized that the SSMA would be more clearly observable in athletes who were trained to perform reactive movements than in non-athletes. MI activity was measured in ten athletes and ten non-athletes by magnetoencephalography. The tasks were a simple reaction task and a Go/Nogo reaction task in which the subjects were asked to abduct their right index fingers in response to a visual stimulus. The Go/Nogo reaction time task was adopted to confirm the presence of the SSMA, because the MI activity in response to a Nogo stimulus did not overlap with the MI activity that was synchronous with the execution of the movement. The results show that the SSMA was clearly apparent in the athlete group (9/10). In the non-athlete group, however, only three subjects showed the SSMA (3/10). Moreover, the MI activity of the athletes tended to be larger than that of the non-athletes, even though the athletes did not specifically practice these index finger movements during their daily training. We concluded that long-term physical training promotes MI activity and the effects of reactive task repetition were more clearly apparent in the MI activity of the athletes.
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Affiliation(s)
- Hiroshi Endo
- Institute for Human Science and Biomedical Engineering, National Institute of Advanced Industrial Science and Technology, Higashi, Tsukuba, Ibaraki 305-8566, Japan.
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67
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Cheyne D, Bakhtazad L, Gaetz W. Spatiotemporal mapping of cortical activity accompanying voluntary movements using an event-related beamforming approach. Hum Brain Mapp 2006; 27:213-29. [PMID: 16037985 PMCID: PMC6871358 DOI: 10.1002/hbm.20178] [Citation(s) in RCA: 230] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2005] [Accepted: 05/25/2005] [Indexed: 11/07/2022] Open
Abstract
We describe a novel spatial filtering approach to the localization of cortical activity accompanying voluntary movements. The synthetic aperture magnetometry (SAM) minimum-variance beamformer algorithm was used to compute spatial filters three-dimensionally over the entire brain from single trial neuromagnetic recordings of subjects performing self-paced index finger movements. Images of instantaneous source power ("event-related SAM") computed at selected latencies revealed activation of multiple cortical motor areas prior to and following left and right index finger movements in individual subjects, even in the presence of low-frequency noise (e.g., eye movements). A slow premovement motor field (MF) reaching maximal amplitude approximately 50 ms prior to movement onset was localized to the hand area of contralateral precentral gyrus, followed by activity in the contralateral postcentral gyrus at 40 ms, corresponding to the first movement-evoked field (MEFI). A novel finding was a second activation of the precentral gyrus at a latency of approximately 150 ms, corresponding to the second movement-evoked field (MEFII). Group averaging of spatially normalized images indicated additional premovement activity in the ipsilateral precentral gyrus and the left inferior parietal cortex for both left and right finger movements. Weaker activations were also observed in bilateral premotor areas and the supplementary motor area. These results show that event-related beamforming provides a robust method for studying complex patterns of time-locked cortical activity accompanying voluntary movements, and offers a new approach for the localization of multiple cortical sources derived from neuromagnetic recordings in single subject and group data.
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Affiliation(s)
- Douglas Cheyne
- Neuromagnetic Imaging Laboratory, Department of Diagnostic Imaging, Hospital for Sick Children Research Institute, Toronto, Ontario, Canada.
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68
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Kauhanen L, Nykopp T, Sams M. Classification of single MEG trials related to left and right index finger movements. Clin Neurophysiol 2006; 117:430-9. [PMID: 16413826 DOI: 10.1016/j.clinph.2005.10.024] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2005] [Revised: 09/15/2005] [Accepted: 10/22/2005] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Most non-invasive brain-computer interfaces (BCIs) classify EEG signals. Here, we measured brain activity with magnetoencephalography (MEG) with an aim to characterize and classify single MEG trials during finger movements. We also examined whether averaging consecutive trials, or averaging signals from neighboring sensors, would improve classification accuracy. METHODS MEG was recorded in five subjects during lifting the left, right or both index fingers. Trials were classified using features, defined by an expert, from averaged spectra and time-frequency representations. RESULTS Classification accuracy of left vs. right finger movements was 80-94%. In the three-category classification (left, right, both), accuracy was 57-67%. Averaging three consecutive trials improved classification significantly in three subjects. Instead, spatial averaging across neighboring sensors decreased accuracy. CONCLUSIONS The use of averaged signals to find appropriate features for single-trial classification proved useful for the two-class classification. The classification accuracy was comparable to that in previous EEG studies. SIGNIFICANCE MEG provides another useful method to measure brain signals to be used in BCIs. Good performance was obtained when the classified signals were generated by two distinct sources in the left and right hemisphere. The present findings should be extended to multi-task cases involving additional brain areas.
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Affiliation(s)
- L Kauhanen
- Laboratory of Computational Engineering, Helsinki University of Technology, P.O. Box 9203, Espoo 02015 HUT, Finland.
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69
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Abstract
The rolandic mu rhythm consists of two main frequency components: one around 10 Hz and the other around 20 Hz. Reactivity of the mu rhythm, especially its motor cortex 20-Hz component, provides an illuminating window to the involvement of the human sensorimotor system in the loop that connects action and perception with the environment.
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Affiliation(s)
- Riitta Hari
- Brain Research Unit, Low Temperature Laboratory and Advanced Magnetic Imaging Centre, Helsinki University of Technology, Otakaari 3A, Espoo, 02015 TKK, Finland.
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70
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Kilner J, Bott L, Posada A. Modulations in the degree of synchronization during ongoing oscillatory activity in the human brain. Eur J Neurosci 2005; 21:2547-54. [PMID: 15932612 DOI: 10.1111/j.1460-9568.2005.04069.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
When a subject is asked to respond as quickly as possible to a stimulus he/she responds much faster if this stimulus is preceded by a warning cue. This cue enables the subject to anticipate the forthcoming stimulus, initiating neural processes subserving the future perception and processing of the target stimulus and the motor preparation of the associated response action. It has recently been suggested that neuronal activity before such an anticipated target stimulus could be associated with modulations in neuronal synchronization and oscillatory activity. Here we recorded electrical brain activity whilst subjects performed a choice reaction time task, in which one of the stimuli could be predicted with 90% certainty. We show that the prediction of a forthcoming stimulus was associated with an increase in gamma oscillations overlying occipital areas and a decrease in beta oscillations overlying sensorimotor cortex before the stimulus was presented. We suggest that these regionally specific modulations in oscillatory activity reflect the establishment of neural networks that are 'primed' for the future processing of the forthcoming predictable visual stimulus.
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Affiliation(s)
- James Kilner
- Institute for Cognitive Science, Bron cedex, France.
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71
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Tamura Y, Hoshiyama M, Nakata H, Hiroe N, Inui K, Kaneoke Y, Inoue K, Kakigi R. Functional relationship between human rolandic oscillations and motor cortical excitability: an MEG study. Eur J Neurosci 2005; 21:2555-62. [PMID: 15932613 DOI: 10.1111/j.1460-9568.2005.04096.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Synchronization and desynchronization of the neural rhythm in the brain play an important role in the orchestration of perception, motor action and conscious experience. Based on the results of electrocorticographic and magnetoencephalographic (MEG) recordings, it has been considered that human rolandic oscillations originate in the anterior bank of the central sulcus (20-Hz rhythm) and the postcentral cortex (10-Hz rhythm): the 20-Hz oscillation is closely related to motor function, while the 10-Hz rhythm is attributed mainly to sensory function. To test whether the rolandic oscillations are functionally relevant to the motor cortical excitability, we examined effects of 1-Hz repetitive transcranial magnetic stimulation (rTMS) of the left primary motor cortex (M1) on movement-related changes of the rolandic oscillations in 12 normal subjects. MEG data recorded during brisk extension of the right index finger in two different sessions (with and without rTMS conditioning) were compared. Motor-evoked potential (MEP) of the right hand muscle was also measured before and after rTMS to assess the motor cortical excitability. We found that 1-Hz rTMS over M1 significantly reduced the movement-related rebound of the 20-Hz oscillation in association with decreased motor cortical excitability. In particular, movement-related rebound of the 20-Hz rhythm was closely tied with motor cortical excitability. These findings further strengthen the notion of functional relevance of 20-Hz cortical oscillation to motor cortical excitability. In the framework of previous studies, the decrease in movement-related rebound may be regarded as a compensatory reaction to the inhibited cortical activity.
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Affiliation(s)
- Yohei Tamura
- Department of Integrative Physiology, National Institute for Physiological Sciences, Okazaki, Japan.
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72
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Huang MX, Harrington DL, Paulson KM, Weisend MP, Lee RR. Temporal dynamics of ipsilateral and contralateral motor activity during voluntary finger movement. Hum Brain Mapp 2004; 23:26-39. [PMID: 15281139 PMCID: PMC6872033 DOI: 10.1002/hbm.20038] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The role of motor activity ipsilateral to movement remains a matter of debate, due in part to discrepancies among studies in the localization of this activity, when observed, and uncertainty about its time course. The present study used magnetoencephalography (MEG) to investigate the spatial localization and temporal dynamics of contralateral and ipsilateral motor activity during the preparation of unilateral finger movements. Eight right-handed normal subjects carried out self-paced finger-lifting movements with either their dominant or nondominant hand during MEG recordings. The Multi-Start Spatial Temporal multi-dipole method was used to analyze MEG responses recorded during the movement preparation and early execution stage (-800 msec to +30 msec) of movement. Three sources were localized consistently, including a source in the contralateral primary motor area (M1) and in the supplementary motor area (SMA). A third source ipsilateral to movement was located significantly anterior, inferior, and lateral to M1, in the premotor area (PMA) (Brodmann area [BA] 6). Peak latency of the SMA and the ipsilateral PMA sources significantly preceded the peak latency of the contralateral M1 source by 60 msec and 52 msec, respectively. Peak dipole strengths of both the SMA and ipsilateral PMA sources were significantly weaker than was the contralateral M1 source, but did not differ from each other. Altogether, the results indicated that the ipsilateral motor activity was associated with premotor function, rather than activity in M1. The time courses of activation in SMA and ipsilateral PMA were consistent with their purported roles in planning movements.
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Affiliation(s)
- Ming-Xiong Huang
- Center for Functional Brain Imaging, New Mexico VA Health Care System, Albuquerque, New Mexico 87108, USA.
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73
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Takahashi M, Watanabe Y, Haraguchi T, Kawai T, Yamane GY, Abe S, Sakiyama K, Hiraide Y, Lee WH, Ide Y, Ishikawa T. Neuromagnetic analysis of the late phase of the readiness field for precise hand movements using magnetoencephalography. THE BULLETIN OF TOKYO DENTAL COLLEGE 2004; 45:9-17. [PMID: 15346880 DOI: 10.2209/tdcpublication.45.9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The aim of this study was to elucidate the cortical regulation of precise finger movements by using magnetoencephalography, with particular emphasis on the late phase of the readiness field. Magnetic brain signals were recorded non-invasively by 306 channel magnetoencephalography during the following two tasks. The first task, a simple task, was to bend the right thumb once as quickly as possible. The second task, a precise one, was to alternately oppose the thumb with the index finger and the middle finger of right hand. In this study, we confirmed that the differences between the two tasks were observed in the late phase of the readiness field, especially in the magnetic field 600 ms before the onset of movement. The activity of the magnetic field of the precise movement task was higher than the activity of the simple movement task. There were obvious differences in the spatial and temporal aspects of the left hemisphere. In the simple movement, the premotor area or motor area was activated in the late phase of the time window. The average latency from the EMG onset was -98.6+/-34.0 ms (n = 5). In the precise movement, the prefrontal area and the SMA were activated in the early and/or middle phases of the time window. The average latency from the EMG onset was -292.0+/-14.9 ms (n = 3) for the prefrontal cortex and -167.8+/-38.3 ms (n = 4) for the SMA. The premotor area or motor area was activated in the late stage of the RF. The average latency from the EMG onset was -111.6+/-61.4 ms (n = 5). Many studies have been performed on the movement-related readiness field. However, the activity of the prefrontal area and the SMA had not previously been studied in the late phase of the readiness field. Our study indicated that the prefrontal area and the SMA played important roles immediately before the onset of precise finger movement. The integration of the prefrontal area, the SMA, and the premotor area is important for the onset of precise finger movement.
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Affiliation(s)
- Masanori Takahashi
- Oral Health Science Center, Department of Orthopedic Surgery, Ichikawa General Hospital, Tokyo Dental College, 5-11-13 Sugano, Ichikawa, Chiba 272-8513, Japan.
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74
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Jankelowitz SK, Colebatch JG. Movement related potentials in acutely induced weakness and stroke. Exp Brain Res 2004; 161:104-13. [PMID: 15490136 DOI: 10.1007/s00221-004-2051-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2003] [Accepted: 06/02/2004] [Indexed: 10/26/2022]
Abstract
Weakness is a common symptom of neurological illness, and recovery may occur via restorative or compensatory mechanisms. Functional imaging studies have shown varied patterns of activity in motor areas following recovery from stroke. Movement related potentials (MRP) reflect the activity in primary and non-primary motor areas. We recorded MRPs in association with index finger abduction in six normal volunteers before and after induced weakness of a hand muscle and in six stroke patients with subcortical lesions and weakness affecting the arm. In both groups of subjects the greatest change was observed in the motor potential component of the MRP. On average, the motor potential had its greatest amplitude and duration at the time of the greatest weakness and became smaller with recovery. In artificially-induced weakness, the MRP had an earlier onset latency (P=0.042) and a greater early BP component (P=0.05) for the weakened finger. For the stroke subjects overall, the peak and NS' amplitudes were largest for the initial study and declined thereafter. Similar but smaller changes were present for movements of the clinically unaffected side. The increased motor potential is therefore consistent with increased activity in the motor cortex, and this may occur as compensation for weakness in both normals and after stroke.
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Affiliation(s)
- S K Jankelowitz
- Institute of Neurological Sciences and UNSW Clinical School, Prince of Wales Hospital, High Street, Sydney, NSW 2031, Australia
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75
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Shibukawa Y, Shintani M, Kumai T, Suzuki T, Nakamura Y. Cortical neuromagnetic fields preceding voluntary jaw movements. J Dent Res 2004; 83:572-7. [PMID: 15218049 DOI: 10.1177/154405910408300712] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Slow cortical potentials (readiness potentials, RPs) reflecting the central programming of voluntary jaw movements were reported to appear preceding the movements. However, the current source producing the RP has not yet been localized. This study aimed to determine the cortical regions involved in the central programming of bilaterally symmetrical voluntary jaw movements, by locating the current source of the neuromagnetic counterpart of the RP (readiness field, RF). The RFs were found in the fronto-lateral region bilaterally, starting around 860 and 600 ms prior to the onset of masseter and digastric electromyograms (EMGs), respectively, and gradually increasing in magnitude to the peak within 100 ms before the EMG onset. Thus, the RFs appeared long before the reported onset of the excitability increase of pyramidal tract neurons. The current sources producing the RFs were located in the precentral gyrus bilaterally, with no bilateral differences in strength. We conclude that the primary motor cortex is involved bilaterally in central programming as well as in execution of bilaterally symmetrical voluntary jaw movements.
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Affiliation(s)
- Y Shibukawa
- Oral Health Science Center, Tokyo Dental College, Chiba 261-8502, Japan.
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76
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Yamamoto J, Ikeda A, Satow T, Matsuhashi M, Baba K, Yamane F, Miyamoto S, Mihara T, Hori T, Taki W, Hashimoto N, Shibasaki H. Human eye fields in the frontal lobe as studied by epicortical recording of movement‐related cortical potentials. Brain 2004; 127:873-87. [PMID: 14960503 DOI: 10.1093/brain/awh110] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We studied the generator location of premovement subcomponents of movement-related cortical potentials (MRCPs) [Bereitschaftspotential (BP), negative slope (NS') and motor potential (MP)] associated with voluntary, self-paced horizontal saccade in the human frontal lobe. Self-paced horizontal saccade, wrist (or middle finger) extension and foot dorsiflexion were employed in 10 patients (lateral surface of the frontal lobe in seven and mesial in three) as part of the presurgical evaluation, and data of five patients (lateral in four and mesial in three) were used in the final analysis. On the lateral frontal lobe, the maximum BP, NS' or MP with horizontal saccade was seen at or 1-2 cm rostral to the hand, arm or face area of the primary motor cortex (MI) in all four subjects investigated. This area exactly corresponded to the frontal eye field (FEF) identified by electrical stimulation. The amplitude of MRCPs with saccade was smaller than that with hand movements. On the mesial surface, within the supplementary motor area (SMA) proper, BP and/or NS' for horizontal saccade was located 1-2 cm rostral to that for hand and foot movements. BP and/or NS' delineated the supplementary eye field (SEF) at the rostral part of the SMA proper, and SEF partly overlapped with the hand and foot areas of the SMA proper. At the area just rostral to the vertical anterior commissure line and/or the pre-SMA defined by electrical stimulation, BP and/or NS' was seen invariably, regardless of the sites of movements, and in contrast with the SMA proper, there was no somatotopic representation. No clear MPs were elicited by eye movements on the mesial surface. In one of the two subjects whose MRCPs with horizontal saccade were recorded simultaneously from the lateral and mesial surfaces of the frontal lobe, BP from the SEF and pre-SMA preceded that from the FEF. It is concluded that MRCPs with horizontal saccade are useful for defining the FEF, SEF and pre-SMA, and that the SEF and pre-SMA become active in preparation for horizontal saccade earlier than the FEF.
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Affiliation(s)
- Junichi Yamamoto
- Human Brain Research Center, Kyoto University Graduate School of Medicine, Shogoin, Sakyo, Kyoto, Japan
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77
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Zaaroor M, Pratt H, Starr A. Time course of motor excitability before and after a task-related movement. Neurophysiol Clin 2003; 33:130-7. [PMID: 12909391 DOI: 10.1016/s0987-7053(03)00029-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
AIMS OF THE STUDY The time course of motor excitability during a task-related unilateral right thumb movement was studied using sub-threshold transcranial magnetic stimulation (TMS) to the contralateral left motor cortex. The level of stimulation evoked a motor evoked potential (MEP) in the thumb when the subject was at rest in approximately 10% of the trials. METHODS Subjects made a brief right thumb movement to the predictable omission of regularly presented tone bursts allowing experimental definition of TMS relative to the cue to move. Motor cortical excitability was characterized by amplitude and/or probability of eliciting MEPs. RESULTS There were four periods of altered motor excitability during task performance compared to a control resting state: a first period of weak facilitation before movement between -500 to -200 ms, a second period without increased excitability approximately 150 ms before movement onset when MEPs amplitude was below that seen in rest, a third period of strong facilitation between -100 ms before movement and +200 ms after facilitation and a fourth period of weak facilitation between +200 to +500 ms. CONCLUSION These results show that during performance of a task requiring a motor response, motor cortical excitability is increased above resting for hundreds of millisecond before and after the response, except for a transient period between 75 and 150 ms prior to movement onset. The temporal pattern of these excitability changes is compatible with multiple excitatory and inhibitory inputs interacting on motor cortex.
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Affiliation(s)
- M Zaaroor
- Department of Neurosurgery, Rambam Medical Center and Technion-Israel Institute of Technology, Haifa, Israel
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78
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Woldag H, Waldmann G, Schubert M, Oertel U, Maess B, Friederici A, Hummelsheim H. Cortical neuromagnetic fields evoked by voluntary and passive hand movements in healthy adults. J Clin Neurophysiol 2003; 20:94-101. [PMID: 12766681 DOI: 10.1097/00004691-200304000-00002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Neuromagnetic fields were recorded from the left cerebral hemisphere of six healthy right-handed subjects under three different conditions: (1) externally triggered rapid voluntary extension and flexion of the right hand, (2) passive extension and flexion of the right hand, and (3) stimulation of the skin of the right index finger by means of air pressure. Location analysis using the current density analysis did not reveal any differences between motor evoked field I (MEF I) in active and passive movements, and met the maximum of cerebral activation in the contralateral precentral region. In contrast, the sensory evoked field was located clearly in the contralateral postcentral region. Additionally, a significantly shorter latency of MEF I (with respect to movement onset) was observed in flexion compared with extension in both passive and active movements. These results support the assumption that MEF I is generated by cortical activation resulting from proprioceptive, probably muscle spindle, input. The current density analysis has proved to be an appropriate method for investigating movement-related fields. Furthermore, the described method seems to be appropriate for evaluating the processes of cortical reorganization and the influence of neurorehabilitation within longitudinal studies in patients with lesions in motor centers of the brain.
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Affiliation(s)
- Hartwig Woldag
- Neurologisches Rehabilitationszentrum Leipzig, Leipzig University, Germany.
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79
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Kilner JM, Salenius S, Baker SN, Jackson A, Hari R, Lemon RN. Task-dependent modulations of cortical oscillatory activity in human subjects during a bimanual precision grip task. Neuroimage 2003; 18:67-73. [PMID: 12507444 DOI: 10.1006/nimg.2002.1322] [Citation(s) in RCA: 97] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Oscillations are a widespread feature of normal brain activity and have been reported at a variety of different frequencies in different neuronal systems. The demonstration that oscillatory activity is present in motor command signals has prompted renewed interest in the possible functions of synchronous oscillatory activity within the primate sensorimotor system. In the current study, we investigated task-dependent modulations in coupling between sensorimotor cortical oscillators during a bimanual precision grip task. The task required a hold-ramp-hold pattern of grip force to be exerted on a compliant object with the dominant right hand, while maintaining a steady grip with the nondominant hand. We found significant task-related modulation of 15- to 30-Hz coherence between magnetoencephalographic (MEG) activity recorded from the left sensorimotor cortex and electromyographic (EMG) activity in hand muscles on the right side. This coherence was maximal during steady hold, but disappeared during the ramp movements. Interestingly coherence between the right sensorimotor MEG and left-hand EMG showed a similar, although less deeply modulated, task-related pattern, even though this hand was maintaining a simple steady grip. No significant ipsilateral MEG-EMG coherence was observed in the 15- to 30-Hz passband for either hand. These results suggest that the cortical oscillators in the two sensorimotor cortices are independent to some degree but that they may share a common mechanism that attenuates the cortical power in both hemispheres in the 15- to 30-Hz range during movements of one hand. The results are consistent with the hypothesis that oscillatory activity in the motor system is important in resetting the descending motor commands needed for changes in motor state, such as those that occur in the transition from movement to steady grip.
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Affiliation(s)
- J M Kilner
- Sobell Department of Neurophysiology, Institute of Neurology, Queen Square, London, United Kingdom.
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80
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Abstract
Viewing other persons' actions automatically activates brain areas belonging to the mirror-neuron system (MNS) assumed to link action execution and observation. We followed, by magnetoencephalographic cortical dynamics, subjects who observed still pictures of lip forms, on-line imitated them, or made similar forms in a self-paced manner. In all conditions and in both hemispheres, cortical activation progressed in 20-70 ms steps from the occipital cortex to the superior temporal region (where the strongest activation took place), the inferior parietal lobule, and the inferior frontal lobe (Broca's area), and finally, 50-140 ms later, to the primary motor cortex. The signals of Broca's area and motor cortex were significantly stronger during imitation than other conditions. These results demonstrate that still pictures, only implying motion, activate the human MNS in a well-defined temporal order.
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Affiliation(s)
- Nobuyuki Nishitani
- Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, P.O. Box 2200, FIN-02015 HUT, Espoo, Finland.
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81
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Toma K, Mima T, Matsuoka T, Gerloff C, Ohnishi T, Koshy B, Andres F, Hallett M. Movement rate effect on activation and functional coupling of motor cortical areas. J Neurophysiol 2002; 88:3377-85. [PMID: 12466454 DOI: 10.1152/jn.00281.2002] [Citation(s) in RCA: 91] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We investigated changes in the activation and functional coupling of bilateral primary sensorimotor (SM1) and supplementary motor (SMA) areas with different movement rates in eight normal volunteers. An auditory-cued repetitive right-thumb movement was performed at rates of 0.5, 0.75, 1, 2, 3, and 4 Hz. As a control condition, subjects listened to pacing tones with no movements. Electroencephalogram (EEG) was recorded from 28 scalp electrodes and electromyogram was obtained from the hand muscles. The event-related changes in EEG band-power (ERpow: activation of each area) and correlation (ERcor: functional coupling between each pair of cortical areas) were computed every 32 ms. Modulations of ERpow and ERcor were inspected in alpha (8-12 Hz) and beta (16-20 Hz) bands. Motor cortical activation and coupling was greater for faster movements. With increasing movement rate, the timing relationship between movement and tone switched from synchronization (for 0.5-1 Hz) to syncopation (for 3-4 Hz). The results suggested that for slow repetitive movements (0.5-1 Hz), each individual movement is separately controlled, and EEG activation and coupling of the motor cortical areas were immediately followed by transient deactivation and decoupling, having clear temporal modulation locked to each movement. In contrast, for fast repetitive movements (3-4 Hz), it appears that the rhythm is controlled and the motor cortices showed sustained EEG activation and continuous coupling.
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Affiliation(s)
- Keiichiro Toma
- Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, Maryland 20892-1428, USA
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82
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Increased synchronization of cortical oscillatory activities between human supplementary motor and primary sensorimotor areas during voluntary movements. J Neurosci 2002. [PMID: 11717371 DOI: 10.1523/jneurosci.21-23-09377.2001] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In human, both primary and nonprimary motor areas are involved in the control of voluntary movements. However, the dynamics of functional coupling among different motor areas has not been fully clarified yet. Because it has been proposed that the functional coupling among cortical areas might be achieved by the synchronization of oscillatory activity, we investigated the electrocorticographic coherence between the supplementary motor and primary sensorimotor areas (SMA and S1-M1) by means of event-related partial coherence analysis in 11 intractable epilepsy patients. We found premovement increase of coherence between the SMA proper and S1-M1 at the frequency of 0-33 Hz and between the pre-SMA and S1-M1 at 0-18 Hz. Coherence between the SMA proper and M1 started to increase 0.9 sec before the movement onset and peaked 0.3 sec after the movement. There was no systematic difference within the SMA (SMA proper vs pre-SMA) or within the S1-M1, in terms of the time course as well as the peak value of coherence. The phase spectra revealed near-zero phase difference in 57% (20 of 35) of region pairs analyzed, and the remaining pairs showed inconsistent results. This increase of synchronization between multiple motor areas in the preparation and execution of voluntary movements may reflect the multiregional functional interactions in human motor behavior.
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84
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Nikouline VV, Linkenkaer-Hansen K, Huttunen J, Ilmoniemi RJ. Interhemispheric phase synchrony and amplitude correlation of spontaneous beta oscillations in human subjects: a magnetoencephalographic study. Neuroreport 2001; 12:2487-91. [PMID: 11496135 DOI: 10.1097/00001756-200108080-00040] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Interhemispheric phase synchrony and amplitude correlation of beta oscillations were studied with MEG in a resting condition. The left and right hemisphere beta oscillations exhibited phase-locking with a phase-lag near zero degrees. The index of synchronization was strongest when these oscillations had large amplitude. Functionally, we interpret the phase synchrony on the basis of bilaterality of movement organization. A positive interhemispheric correlation was also found for the amplitude of spontaneous beta oscillations over long time intervals (> 1 s). The low-frequency correlation of spontaneous rhythmic activity may be the source of the low-frequency correlations of the hemodynamic responses in homologous areas that have been reported previously and have been interpreted as functional connectivity between these areas.
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Affiliation(s)
- V V Nikouline
- BioMag Laboratory, Medical Engineering Centre, Helsinki University Central Hospital, Helsinki, PO Box 340, FIN-00029 HUS, Finland
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85
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Zaaroor M, Pratt H, Starr A. Influence of task-related ipsilateral hand movement on motor cortex excitability. Clin Neurophysiol 2001; 112:908-16. [PMID: 11336908 DOI: 10.1016/s1388-2457(01)00516-8] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE The time course of the right motor cortex excitability in relation to a task-related voluntary right thumb twitch was studied using sub-threshold transcranial magnetic stimulation (TMS) to the right motor cortex. METHODS Motor excitability was studied in 8 adult subjects who made a brief right thumb twitch to the predictable omission of every fifth tone in a series of tones 2.5 s apart. This paradigm avoided an overt sensory cue, while allowing experimental control of TMS timing relative to both movement and the cue to move. Motor excitability was characterized by several measures of motor evoked potentials (MEPs) recorded from the left thenar eminence in response to TMS over the right scalp with a 9 cm coil: probability of eliciting MEPs, incidence of MEPs and amplitude of MEPs. RESULTS All subjects showed suppression of motor excitability immediately following a voluntary right thumb twitch (ipsilateral response), and up to 1 s after it. However, two distinctly different effects on motor excitability were observed before the response: two subjects showed excitation, beginning about 500 ms before response until 300 ms after it, followed by the post-movement suppression; 6 subjects displayed pre-movement suppression, beginning about 600 ms before the response and persisting for the duration. CONCLUSIONS The net effect of an ipsilateral response on motor cortex can be either inhibitory or excitatory, changing with time relative to the response. These findings are compatible with two separate processes, inhibitory and excitatory, which interact to determine motor excitability ipsilateral to the responding hand.
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Affiliation(s)
- M Zaaroor
- Department of Neurology, University of California, Irvine, CA 92697, USA
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86
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Leocani L, Toro C, Zhuang P, Gerloff C, Hallett M. Event-related desynchronization in reaction time paradigms: a comparison with event-related potentials and corticospinal excitability. Clin Neurophysiol 2001; 112:923-30. [PMID: 11336910 DOI: 10.1016/s1388-2457(01)00530-2] [Citation(s) in RCA: 110] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVES To study cortical activity in different motor tasks, we compared event-related desynchronization (ERD) and event-related potentials (ERPs) in different reaction time (RT) paradigms with the time course of corticospinal excitability. METHODS Nine right-handed, normal subjects performed right or left thumb extensions in simple, choice and go/no go auditory RT paradigms. Eight subjects had participated in a previous study evaluating changes in corticospinal excitability during the same paradigms. Twenty-nine EEG channels with electrooculogram and bilateral EMG monitoring were collected. ERPs and ERD of 10 and 18-22 Hz bands were obtained with respect to tone administration and EMG onset. RESULTS Trials with movement showed lateralized ERP components, corresponding to the motor potential (MP), both in the averages on the tone and on EMG. The MP corresponded well in time and location to the rise in corticospinal excitability on the moving side observed in the previous study. Sensorimotor ERD, followed by event-related synchronization (ERS), was present for trials with movements and for the no go. ERD was present contralaterally during movement preparation and in no go trials, while it was bilateral during motor execution. No go ERD was followed more rapidly by ERS than in trials with movement. This finding suggests that in no go trials, there is a brief active process in the sensorimotor areas. ERD and ERS do not correspond, respectively, in time and location to increases and decreases in corticospinal excitability. In fact, ERD is bilateral during movement execution, when corticospinal inhibition of the side at rest is observed. Contralateral no go ERS occurs later than corticospinal inhibition, which is bilateral. CONCLUSIONS These findings may suggest that ERD is compatible with both corticospinal activation and inhibition, ERS indicating the removal of either, resulting in cortical idling.
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Affiliation(s)
- L Leocani
- Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Building 10, Room 5N226, 10 Center Drive MSC 1428, Bethesda, MD 20892-1428, USA
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87
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Kunieda T, Ikeda A, Ohara S, Yazawa S, Nagamine T, Taki W, Hashimoto N, Shibasaki H. Different activation of presupplementary motor area, supplementary motor area proper, and primary sensorimotor area, depending on the movement repetition rate in humans. Exp Brain Res 2000; 135:163-72. [PMID: 11131500 DOI: 10.1007/s002210000519] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In order to clarify the functional role of the supplementary motor area (SMA) and its rostral part (pre-SMA) in relation to the rate of repetitive finger movements, we recorded movement-related cortical potentials (MRCPs) directly from the surface of the mesial frontal lobe by using subdural electrode grids implanted in four patients with intractable partial epilepsy. Two subregions in the SMA were identified based on the anatomical location and the different response to cortical stimulation. In three of the four subjects, we also recorded MRCPs from the surface of the lateral convexity covering the primary sensorimotor areas (SI-MI), which were defined by cortical stimulation and SEP recording. The subjects extended the middle finger or opposed the thumb against other fingers of the same hand at a self-paced rate of 0.2 Hz (slow) and 2 Hz (rapid), each in separate sessions. As a result, pre-and postmovement potentials were clearly seen at the SI-MI in both slow- and rapid-rate movements. By contrast, in the SMA, especially in the pre-SMA, premovement potentials were not seen and postmovement potentials were seldom seen in the rapid rate movement. In the slow-rate condition, pre- and postmovement potentials were clearly seen in both the pre-SMA and the SMA proper. In conclusion, the SMA, especially the pre-SMA, is less activated electrophysiologically in the rapid-rate movements, while the SI-MI remains active regardless of the movement rate.
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Affiliation(s)
- T Kunieda
- Department of Brain Pathophysiology, Kyoto University School of Medicine, Japan
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88
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Erdler M, Beisteiner R, Mayer D, Kaindl T, Edward V, Windischberger C, Lindinger G, Deecke L. Supplementary motor area activation preceding voluntary movement is detectable with a whole-scalp magnetoencephalography system. Neuroimage 2000; 11:697-707. [PMID: 10860797 DOI: 10.1006/nimg.2000.0579] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Despite the fact that the knowledge about the structure and the function of the supplementary motor area (SMA) is steadily increasing, the role of the SMA in the human brain, e.g., the contribution of the SMA to the Bereitschaftspotential, still remains unclear and controversial. The goal of this study was to contribute further to this discussion by taking advantage of the increased spatial information of a whole-scalp magnetoencephalography (MEG) system enabling us to record the magnetic equivalent of the Bereitschaftspotential 1, the Bereitschaftsfeld 1 (BF 1) or readiness field 1. Five subjects performed a complex, and one subject a simple, finger-tapping task. It was possible to record the BF 1 for all subjects. The first appearance of the BF 1 was in the range of -1.9 to -1.7 s prior to movement onset, except for the subject performing the simple task (-1 s). Analysis of the development of the magnetic field distribution and the channel waveforms showed the beginning of the Bereitschaftsfeld 2 (BF 2) or readiness field 2 at about -0.5 s prior to movement onset. In the time range of BF 1, dipole source analysis localized the source in the SMA only, whereas dipole source analysis containing also the time range of BF 2 resulted in dipole models, including dipoles in the primary motor area. In summary, with a whole-head MEG system, it was possible for the first time to detect SMA activity in healthy subjects with MEG.
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Affiliation(s)
- M Erdler
- Department of Clinical Neurology, General Hospital, Vienna, A-1090, Austria
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89
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Stancák A, Feige B, Lücking CH, Kristeva-Feige R. Oscillatory cortical activity and movement-related potentials in proximal and distal movements. Clin Neurophysiol 2000; 111:636-50. [PMID: 10727915 DOI: 10.1016/s1388-2457(99)00310-7] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES Event-related desynchronization (ERD) of alpha- and beta-rhythms, the post-movement beta-synchronization and the cortical movement-related potentials were analyzed in distal (finger) and proximal (shoulder) movements. METHODS EEG was recorded in 7 healthy right-handed men using a 59-channel whole-head EEG system while subjects performed self-paced movements. RESULTS The amplitude of the Bereitschaftspotential (BP) was greater over the central midline area and smaller over the contralateral sensorimotor hand area in shoulder than in finger movements. The maximal alpha- and beta-ERD was localized at parietal electrodes in shoulder movements and over the left and right sensorimotor hand area in finger movements. The post-movement beta-ERS was greater in shoulder than in finger movements, especially at the electrode located 3.5 cm left of the central midline electrode. A significant correlation between the slope of the terminal portion of the BP (negative slope) and amplitude of the post-movement beta-synchronization was observed in shoulder but not in finger movements. CONCLUSIONS Enhancement of BP over the central midline electrode suggests increased activation of the supplementary motor area in proximal movements. The spatial distribution of the alpha- and beta-ERD and of the post-movement beta-ERS shows topographic differences which may refer to the somatotopic organization of the primary sensorimotor cortex with shoulder representation medial to hand and fingers. The correlation between the negative slope and the post-movement beta-ERS in proximal movements supports the view that the brief post-movement inhibition over the motor cortical area is related to the pre-movement activation of that area.
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Affiliation(s)
- A Stancák
- Department of Normal, Pathological and Clinical Physiology, Third Faculty of Medicine, Charles University, Ke Karlovu 4, 120 00, Prague, Czech Republic.
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90
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Dammers J, Ioannides AA. Neuromagnetic localization of CMV generators using incomplete and full-head biomagnetometer. Neuroimage 2000; 11:167-78. [PMID: 10694459 DOI: 10.1006/nimg.1999.0524] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Contingent magnetic variation (CMV) data were recorded in three healthy male subjects using a 2 x 37 biomagnetometer system. The experiment was repeated for one of the subjects using a 151 whole-head biomagnetometer; the same auditory GO/NOGO choice reaction time paradigm as in the first experiment was used, extended to include repetitions of identical runs and additional control conditions. Magnetic field tomography was applied to the averaged data of each subject, for each run and condition (e.g., GO/NOGO). An independent estimate of the current density in the brain was obtained every few milliseconds. The slow components were emphasized by integrating the square of the current density vector, pixel by pixel, revealing in each subject activity in the auditory cortex, sensorimotor cortex, inferior prefrontal area, and posterior inferior parietal area. The intersubject variability was large, but looking across subjects the auditory and sensorimotor cortex (which were best covered by the two probes) were consistently identified in each subject as contributing to the generation of the early and late slow CMV components. These findings were confirmed by the whole-head single-subject experiment, in which slow activity was also identified in the supplementary motor area (SMA) and posterior cingulate cortex (PCC), areas very likely missed in the first experiment because of the limited view of the twin system. The PCC and particularly the SMA activations were substantially reduced when identical runs were repeated.
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Affiliation(s)
- J Dammers
- Department of Physics, Institute of Medicine Research Centre Jülich, Jülich, 52425, Germany
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91
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Abstract
The generation mechanism of movement-evoked fields (MEFs) is poorly known and the existence of ipsilateral MEFs is still in dispute. We recorded whole-scalp neuromagnetic activity from eight subjects who were pressing response keys alternately with the right 2nd and 4th digits, while keeping the left palm on the table containing the keys. Clear ipsilateral MEFs peaked 58 +/- 2 ms after the key touch, with sources in the hand area of the right primary somatosensory cortex. The ipsilateral MEFs decreased to half size when the resting left hand was palm up on the table. However, very similar responses were obtained when another person operated the response keys and the subjects just kept their left palm on the table. No signals were elicited when the subjects only viewed these actions with no hand contact to the table. The results indicate that the MEFs receive a strong contribution from tactile input. In our experiment the ipsilateral sensorimotor activation was triggered by the movement-related vibrations transmitted to the resting hand.
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Affiliation(s)
- R Hari
- Low Temperature Laboratory, Helsinki University of Technology, Espoo, FIN-02015 HUT, Finland.
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92
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Sartory G, Gillessen V, Grotemeyer KH, Elbert T. The Contingent Magnetic Variation in Migraine. J PSYCHOPHYSIOL 1999. [DOI: 10.1027//0269-8803.13.4.215] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Abstract Migraine is characterized by an increased contingent negative variation. Separate comparisons of the early and late component showed that it was the former rather than the latter that was elevated. The function and localization of the early component are as yet poorly understood. The magneto-encephalogram was recorded in 16 patients with migraine and 17 healthy control subjects during a forewarned reaction time task. Neuromagnetic data were recorded with a 37-channel neuromagnetometer with the sensors being placed above the left hemisphere contralaterally to the side of the acoustic stimulation and the motor reaction. Subjects responded to the second of two low intensity sound stimuli that were administered with an interval of 4.5 s. Migraine patients exhibited a significantly higher amplitude of the early component of the contingent magnetic variation (CMV) than controls. Groups did not differ with regard to the amplitude of the late component. Modeling the sources with a single moving equivalent current dipole (ECD) provided a high goodness of fit for the M100 (magnetic N1) in both groups and for the early component of the CMV in migraineurs but not controls. The activity of the early component was centered medially with respect to the M100-ECDs and more laterally so in migraine patients than in controls.
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Affiliation(s)
- G. Sartory
- Clinical Psychology, University of Wuppertal
| | | | | | - T. Elbert
- Department of Psychology, University of Konstanz, Germany
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93
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Chen R, Hallett M. The time course of changes in motor cortex excitability associated with voluntary movement. Can J Neurol Sci 1999; 26:163-9. [PMID: 10451737 DOI: 10.1017/s0317167100000196] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The excitability of the motor cortex is modulated before and after voluntary movements. Transcranial magnetic stimulation studies showed increased corticospinal excitability from about 80 and 100 ms before EMG onset for simple reaction time and self-paced movements, respectively. Following voluntary movements, there are two phases of increased corticospinal excitability from 0 to approximately 100 ms and from approximately 100 to 160 ms after EMG offset. The first phase may correspond to the frontal peak of motor potential in movement-related cortical potentials studies and the movement-evoked magnetic field I (MEFI) in magnetoencephalographic (MEG) studies, and likely represents a time when decreasing output from the motor cortex falls below that required for activation of spinal motoneurons, but is still above resting levels. The second phase of increased corticospinal excitability may be due to peripheral proprioceptive inputs or may be centrally programmed representing a subthreshold, second agonist burst. This may correspond to the MEFII in MEG studies. Corticospinal excitability was reduced below baseline levels from about 500 to 1,000 ms after EMG offset, similar to the timing of increase in the power (event-related synchronization, ERS) of motor cortical rhythm. Similarly, motor cortex excitability is reduced at the time of ERS of motor cortical rhythm following median nerve stimulation. These findings support the hypothesis that ERS represents an inactive, idling state of the cortex. The time course of cortical activation is abnormal in movement disorders such as Parkinson's disease and dystonia, reflecting abnormalities in both movement preparation and in cortical excitability following movement.
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Affiliation(s)
- R Chen
- Division of Neurology, University Health Network, Toronto, Ontario, Canada
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94
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Praamstra P, Schmitz F, Freund HJ, Schnitzler A. Magneto-encephalographic correlates of the lateralized readiness potential. BRAIN RESEARCH. COGNITIVE BRAIN RESEARCH 1999; 8:77-85. [PMID: 10407197 DOI: 10.1016/s0926-6410(99)00008-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
To determine the onset of movement-related EEG activity accompanying stimulus-induced movements, it is commonly isolated from overlapping stimulus-related activity by a subtraction procedure, yielding the lateralized readiness potential (LRP). In order to elucidate the generation of the LRP and to explore whether magnetoencephalographic (MEG) measures have advantages over the LRP as a measure of response selection, MEG activity was recorded in four healthy adults during self-paced and stimulus-induced hand movements. Self-paced movements were preceded by readiness fields in all subjects, explained by sources in contralateral and (for 2/8 response sides) also ipsilateral hemispheres. Movement-related activity preceding stimulus-induced movements could only be modeled adequately when stimulus-related activity was removed by subtracting MEG signals for left and right hand movements. Thus identified source locations showed no systematic deviation from the sources for readiness fields, supporting a generation of the movement-related activity in primary motor cortex. The corresponding source waveforms allowed latency determinations of motor cortex activity as markers for response-choice timing. MEG thus provides information on the time course of hand-specific motor cortex activation for each hemisphere separately, where the electro-encephalographic LRP provides a composite measure for both hemispheres.
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Affiliation(s)
- P Praamstra
- Department of Neurology, Heinrich-Heine Universität, Düsseldorf, Germany.
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95
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Abstract
Cooperation between vision and somatomotor behavior, such as manual exploration of objects, suggests close functional coupling between the visual and sensorimotor systems. We observed this type of interaction in human volunteers during binocular rivalry while following the level of sensorimotor mu rhythm with a whole-scalp neuromagnetometer. The observers viewed a weak vertical grating in the lower visual field of one eye and a strong horizontal grating in the same spatial window of the other eye. When stationary, the weak grating was permanently invisible because of its low contrast and spatial frequency. A sudden brief drifting movement of the weak grating wiped out the dominant grating, and the weak grating became visible for less than the 3-s interval between the movements. The postcentral 8- to 15-Hz mu rhythm was found in six of nine observers, and its level increased transiently by 10-15%, starting about 450 ms after the beginning of the movement. The mu level was also enhanced by the actual disappearance of the stronger stimulus, when it occurred in random order with the rivalry stimuli. Identical visual motion, when not accompanied by a perceptual dominance change, produced only minor effects on the mu rhythm. Our results show that a change in visual percept, even with no real or imagined motor response, is associated with modified activity of the postcentral gyrus. This modification may reflect visuohaptic interactions and/or activity of the distributed cortical network implementing visually guided movements.
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Affiliation(s)
- S Vanni
- Brain Research Unit, Low Temperature Laboratory, Helsinki University of Technology, Espoo, Finland
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96
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Activities of the primary and supplementary motor areas increase in preparation and execution of voluntary muscle relaxation: an event-related fMRI study. J Neurosci 1999. [PMID: 10212312 DOI: 10.1523/jneurosci.19-09-03527.1999] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Brain activity associated with voluntary muscle relaxation was examined by applying event-related functional magnetic resonance imaging (fMRI) technique, which enables us to observe change of fMRI signals associated with a single motor trial. The subject voluntarily relaxed or contracted the right upper limb muscles. Each motor mode had two conditions; one required joint movement, and the other did not. Five axial images covering the primary motor area (M1) and supplementary motor area (SMA) were obtained once every second, using an echoplanar 1.5 tesla MRI scanner. One session consisted of 60 dynamic scans (i.e., 60 sec). The subject performed a single motor trial (i.e., relaxation or contraction) during one session in his own time. Ten sessions were done for each task. During fMRI scanning, electromyogram (EMG) was monitored from the right forearm muscles to identify the motor onset. We calculated the correlation between the obtained fMRI signal and the expected hemodynamic response. The muscle relaxation showed transient signal increase time-locked to the EMG offset in the M1 contralateral to the movement and bilateral SMAs, where activation was observed also in the muscle contraction. Activated volume in both the rostral and caudal parts of SMA was significantly larger for the muscle relaxation than for the muscle contraction (p < 0.05). The results suggest that voluntary muscle relaxation occurs as a consequence of excitation of corticospinal projection neurons or intracortical inhibitory interneurons, or both, in the M1 and SMA, and both pre-SMA and SMA proper play an important role in motor inhibition.
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97
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Villa AE, Tetko IV, Hyland B, Najem A. Spatiotemporal activity patterns of rat cortical neurons predict responses in a conditioned task. Proc Natl Acad Sci U S A 1999; 96:1106-11. [PMID: 9927701 PMCID: PMC15358 DOI: 10.1073/pnas.96.3.1106] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Precise and repeated spike-train timings within and across neurons define spatiotemporal patterns of activity. Although the existence of these patterns in the brain is well established in several species, there has been no direct evidence of their influence on behavioral output. To address this question, up to 15 neurons were recorded simultaneously in the auditory cortex of freely moving rats while animals waited for acoustic cues in a Go/NoGo task. A total of 235 significant patterns were detected during this interval from an analysis of 13 hr of recording involving over 1 million spikes. Of particular interest were 129 (55%) patterns that were significantly associated with the type of response the animal made later, independent of whether the response was that prompted by the cue because the response occurred later and the cue was chosen randomly. Of these behavior-predicting patterns, half (59/129) were associated with an enhanced tendency to go in response to the stimulus, and for 11 patterns of this subset, trials including the pattern were followed by significantly faster reaction time than those lacking the pattern. The remaining behavior-predicting patterns were associated with an enhanced NoGo tendency. Overall mean discharge rates did not vary across trials. Hence, these data demonstrate that particular spatiotemporal patterns predict future behavioral responses. Such presignal activity could form templates for extracting specific sensory information, motor programs prespecifying preference for a particular act, and/or some intermediate, associative brain process.
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Affiliation(s)
- A E Villa
- Laboratoire de Neuro-Heuristique, Institut de Physiologie, Université de Lausanne, 7 Rue du Bugnon, CH-1005, Switzerland.
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98
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Gerloff C, Uenishi N, Nagamine T, Kunieda T, Hallett M, Shibasaki H. Cortical activation during fast repetitive finger movements in humans: steady-state movement-related magnetic fields and their cortical generators. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1998; 109:444-53. [PMID: 9851302 DOI: 10.1016/s0924-980x(98)00045-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To study the cortical physiology of fast repetitive finger movements. METHODS We recorded steady-state movement-related magnetic fields (ssMRMFs) associated with self-paced, repetitive, 2-Hz finger movements in a 122-channel whole-head magnetometer. The ssMRMF generators were determined by equivalent current dipole (ECD) modeling and co-registered with anatomical magnetic resonance images (MRIs). RESULTS Two major ssMRMF components occurred in proximity to EMG onset: a motor field (MF) peaking at 37+/-11 ms after EMG onset, and a postmovement field (post-MF), with inverse polarity, peaking at 102+/-13 ms after EMG onset. The ECD for the MF was located in the primary motor cortex (M1), and the ECD for the post-MF in the primary somatosensory cortex (S1). The MF was probably closely related to the generation of corticospinal volleys, whereas the post-MF most likely represented reafferent feedback processing. CONCLUSIONS The present data offer further evidence that the main phasic changes of cortical activity occur in direct proximity to repetitive EMG bursts in the contralateral M1 and S1. They complement previous electroencephalography (EEG) findings on steady-state movement-related cortical potentials (ssMRCPs) by providing more precise anatomical information, and thereby enhance the potential value of ssMRCPs and ssMRMFs for studying human sensorimotor cortex activation non-invasively and with high temporal resolution.
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Affiliation(s)
- C Gerloff
- Human Motor Control Section, Medical Neurology Branch, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD 20892-1428, USA
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99
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Chen R, Yaseen Z, Cohen LG, Hallett M. Time course of corticospinal excitability in reaction time and self-paced movements. Ann Neurol 1998; 44:317-25. [PMID: 9749597 DOI: 10.1002/ana.410440306] [Citation(s) in RCA: 294] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We used transcranial magnetic stimulation (TMS) to study the time course of corticospinal excitability before and after brisk thumb abduction movements, either in a simple reaction time (RT) paradigm or self-paced. Premovement increase in corticospinal excitability began about 20 msec earlier for self-paced compared with simple RT movements. For both simple RT and self-paced movements after electromyographic (EMG) offset, there was a first period of increased excitability from 0 to 100 msec, followed by a second period from 100 to 160 msec. Corticospinal excitability was decreased from about 500 to 1,000 msec after EMG offset for both types of movements. Our results show that motor preparation that begins 1.5 to 2 seconds before self-paced movement is not associated with increased corticospinal excitability. The first phase of increased corticospinal excitability after EMG offset may be due to activity of motor cortex neuron subthreshold for activating spinal motor neurons, and the second phase may reflect a subthreshold second agonist burst. The period of decreased corticospinal excitability after movement corresponds to the onset of event-related synchronization (ERS) of electroencephalographic signals in the 20-Hz band, and supports the hypothesis that ERS may be related to an inactive, idling state of the motor cortex.
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Affiliation(s)
- R Chen
- Human Cortical Physiology Unit, Human Motor Control Section, National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD, USA
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Stancák A, Riml A, Pfurtscheller G. The effects of external load on movement-related changes of the sensorimotor EEG rhythms. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1997; 102:495-504. [PMID: 9216482 DOI: 10.1016/s0013-4694(96)96623-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The effects of external load opposing brisk voluntary extension of the right index finger on the EEG rhythms in the left and right sensorimotor hand area were studied in 13 right-handed subjects. Four levels of external loads corresponding to the weights of 0 g (no load), 30 g, 80 g and 130 g were used. The effects of external load on EEG rhythms were the following: (i) prior to movement, the desynchronisation of beta-rhythms (18-25 Hz) over the contralateral sensorimotor area was greater under the two largest loads as compared to the 0 g load. However, beta-desynchronisation at ipsilateral electrodes was larger under the 80 g load than under the 130 g load, presumably due to a transcallosally mediated inhibition exerted by the highly excited contralateral motor area; (ii) the mu-rhythm desynchronisation continued over both hemispheres for about 0.3-0.4 s after movement and the largest load was accompanied by the longest mu-rhythm desynchronisation; (iii) the post-movement beta-synchronisation was also longer under the heaviest load (130 g) as compared to the no-load condition (0 g), especially in subjects who prolonged their total movement time under the heaviest load. The results show that (i) the movement-related desynchronisation and synchronisation of sensorimotor EEG rhythms is influenced by external load opposing finger movement, and (ii) the effects of external load differ for the mu- and beta-rhythms.
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Affiliation(s)
- A Stancák
- Department of Medical Informatics, University of Technology, Graz, Austria.
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