The Experts below are selected from a list of 16065 Experts worldwide ranked by ideXlab platform
Jun Tanji - One of the best experts on this subject based on the ideXlab platform.
-
Binary-coded monitoring of a behavioral sequence by cells in the pre-Supplementary Motor Area
The Journal of neuroscience : the official journal of the Society for Neuroscience, 2006Co-Authors: Keisetsu Shima, Jun TanjiAbstract:To regulate the temporal structure of a series of behavioral sequences involving multiple actions, it is essential to monitor the progress of the entire behavioral process. To identify the involvement of three cortical Motor Areas in monitoring behavioral sequences, we examined neuronal activity while monkeys sequentially performed a series of Motor tasks in accordance with a predetermined behavioral schedule that included a numerical structure. We found that neurons in the pre-Supplementary Motor Area exhibited activity that appeared to monitor the performance of the behavioral trials in a binary-coded manner. One-half of the activity represented odd-numbered trials within a behavioral sequence, whereas the other one-half represented even-numbered trials. Such neuronal activity, resembling the operation of binary counting elements widely used for constructing artificial computing devices, was rare in the Supplementary Motor Area or in the primary Motor cortex.
-
Comparison of neuronal activity in the Supplementary Motor Area and primary Motor cortex.
Cognitive Brain Research, 1996Co-Authors: Jun Tanji, Hajime MushiakeAbstract:Neuronal activity in the Supplementary Motor Area (SMA) and primary Motor cortex (MI) have been compared in many experiments during performance of many different Motor tasks. On one hand, the activity in both Areas may appear similar, especially when the Motor task is simple. On the other hand, if the Motor tasks are more demanding, neuronal activity in the SMA exhibits a variety of complex relationship to many different aspects of Motor behavior, while the activity in MI is mostly related to execution of Motor task itself. Of particular interest is the neuronal activity in the SMA during preparation and execution of Motor tasks when no external cues for the retrieval of appropriate Motor act is available. Temporal sequencing of multiple movements is a typical example of the kind of Motor task that requires profound activity in the SMA.
-
New concepts of the Supplementary Motor Area.
Current opinion in neurobiology, 1996Co-Authors: Jun TanjiAbstract:Abstract The Supplementary Motor Area, although traditionally defined as a single Motor Area, is not viewed as including at least three different Areas that can be distinguished anatomically and physiologically. The differential use of these three Areas for various Motor behaviors has been the subject of recent studies that are beginning to provide novel concepts of the functional differentiation of each Area.
-
Role for Supplementary Motor Area cells in planning several movements ahead
Nature, 1994Co-Authors: Jun Tanji, Keisetsu ShimaAbstract:To achieve a volitional goal, we need to execute multiple movements in a specific temporal order. After repetitive performance of a particular sequence of movements, we are able to memorize and execute the whole sequence without external guidance. Where and how in the brain do we store information necessary for the orderly performance of multiple movements? We have found a group of cells in the cerebral cortex of monkeys whose activity is exclusively related to a sequence of multiple movements performed in a particular order. Such cellular activity exists in the Supplementary Motor Area, but not in the primary Motor cortex. We propose that these cells contribute a signal about the order of forthcoming multiple movements, and are useful for planning and coding of several movements ahead.
-
The Supplementary Motor Area in the cerebral cortex.
Neuroscience research, 1994Co-Authors: Jun TanjiAbstract:Abstract The Supplementary Motor Area (SMA) occupies an expanse of frontal agranular cortex rostral to the primary Motor cortex (MI), largely in the mesial surface of the hemisphere. It is basically organized topographically, although the topography is not as apparent as in the MI. The traditionally defined SMA is now regarded as including two separate Areas. The caudal part (SMA proper or F3) projects directly to the MI and to the spinal cord. The rostral part (pre-SMA or F6) is more remote from MI and receive projections from the prefrontal cortex and the cingulate Motor Areas. The Supplementary eye field (SEF) is a small Area separate from either the SMA or pre-SMA. The SEF is connected to cortical and subcortical Areas related to oculoMotor control. The SMA is active when subjects perform distal as well as proximal limb movement. Although the SMA is active in relation to relatively simple Motor tasks, the functional significance of this relation to ‘simple’ movement is debatable. The SMA activity is subject to functional plasticity. The SMA is more active than the primary Motor cortex if Motor tasks are demanding in certain respects. Similarities of lesion effects of the SMA and basal ganglia suggests their intimate relation linked anatomically by the cortico-basal ganglia loops. Studies in both human subjects and in subhuman primates indicate the importance of the SMA in Motor tasks that demand retrieval of Motor memory. The SMA appears also crucial in temporal organization of movements, especially in sequential performance of multiple movements.
Hiroshi Shibasaki - One of the best experts on this subject based on the ideXlab platform.
-
Propagation of tonic posturing in Supplementary Motor Area (SMA) seizures.
Epilepsy research, 2004Co-Authors: Shinji Ohara, Takashi Nagamine, Akio Ikeda, Shogo Yazawa, Takeharu Kunieda, Waro Taki, Junnya Taki, Susumu Miyamoto, Nobuo Hashimoto, Hiroshi ShibasakiAbstract:We analyzed ictal Motor symptoms in 10 patients diagnosed to have Supplementary Motor Area (SMA) seizures based on ictal encephalographic (EEG) findings and ictal clinical semiology. Inclusion criteria were (1) EEG seizure pattern in the vertex for the scalp recording or in the Area over and/or adjacent to SMA for epicortical recording and (2) ictal Motor semiology characterized, as previously reported, by sudden and a brief tonic posturing of extremities and trunk mainly occurring during sleep without loss of consciousness. In 50% (5/10) of the patients, tonic posturing began in one part of the body and moved to other part(s) in 5-10s. Unlike Jacksonian march seen in seizures involving the primary sensoriMotor Area (S1-M1), it spread in no accordance with the somatotopy in S1-M1. The sequential propagation of tonic posturing may represent the somatotopic organization within the SMA proper.
-
Somesthetic function of Supplementary Motor Area during voluntary movements.
Neuroreport, 1999Co-Authors: Tatsuya Mima, Takashi Nagamine, Akio Ikeda, Shogo Yazawa, Takeharu Kunieda, Waro Taki, Hiroshi ShibasakiAbstract:To clarify the somesthetic functions of the Supplementary Motor Area (SMA), we recorded the cortical potentials following the median nerve electric stimulation directly from the SMA and investigated the modulation caused by voluntary movements in two patients with intractable SMA seizures. The evoked potentials over the SMA consisted of positive (61.5 ms) and negative (100.0 ms) peaks, which were enlarged by voluntary movements of the stimulated hand. The present finding is in strong contrast with the attenuation (gating) of the response at the primary sensoriMotor Area (SM1) and suggests that the voluntary movements differently modulate the somatosensory functions of SMA and SM1.
-
Supplementary Motor Area seizure resembling sleep disorder
Sleep, 1996Co-Authors: Naoko Tachibana, Akio Ikeda, Akiyo Shinde, Ichiro Akiguchi, Jun Kimura, Hiroshi ShibasakiAbstract:Two patients presented with a complaint of frequent sudden arousals during sleep followed by tachypnea and palpitation associated with stiffness in the upper extremities in one case and by elevation of the left lower limb in the other. All night video-electroencephalogram (EEG) polysomnography (VPSG) confirmed the diagnosis of seizure arising from the Supplementary Motor Area (SMA seizure) in both cases. Carbamazepine (CBZ) produced remarkable improvement both in clinical seizures and in their subjective sleep quality. Repeated polysomnography after treatment showed a clear improvement in sleep architecture with higher percentages of slow wave sleep. SMA seizure could disturb nocturnal sleep and is one of the important differential diagnoses for a patient complaining of frequent arousals associated with Motor disturbance during sleep.
-
both primary Motor cortex and Supplementary Motor Area play an important role in complex finger movement
Brain, 1993Co-Authors: Hiroshi Shibasaki, Norihiro Sadato, Hugh Lyshkow, Yoshiharu Yonekura, Manabu Honda, Takashi Nagamine, Shugo Suwazono, Yasuhiro Magata, Akio Ikeda, Masahito MiyazakiAbstract:SUMMARY In order to clarify the roles played by the primary Motor cortex and the Supplementary Motor Area in the execution of complex sequential and simple repetitive finger movements, regional cerebral blood flow (rCBF) was measured with PET using 15O-labelled water in five normal subjects. The PET data of each individual subject co-registered to his own MRI, was analysed. Compared with the resting condition, the mean rCBF was markedly increased in the contralateral sensoriMotor cortex (MI-SI) and moderately increased in the contralateral cingulate gyrus and putamen in both the simple and complex Motor tasks. During the complex Motor task, in addition to the above, the mean rCBF was markedly increased in the Supplementary Motor Area and the contralateral preMotor Area, and moderately increased in the ipsilateral M1-S1 and cerebellum. In the Supplementary Motor Area, there was a moderate rCBF increase also during the simple task. However, comparison of the mean rCBF increase against the resting condition between the two tasks revealed a greater increase during the complex task than in the other only in the Supplementary Motor Area and the ipsilateral M1-S1. Thus, in agreement with our previous electrophysiological findings, not only the Supplementary Motor Area but also the M1-S1 seems to play an important role in the execution of complex sequential finger movements.
F.-xavier Alario - One of the best experts on this subject based on the ideXlab platform.
-
The role of the Supplementary Motor Area (SMA) in word production.
Brain research, 2006Co-Authors: F.-xavier Alario, Hanna Chainay, Stephane Lehericy, Laurent D. CohenAbstract:The Supplementary Motor Area (SMA) is a key structure for behavioral planning and execution. Recent research on Motor control conducted with monkeys and humans has put to light an anatomical and functional distinction between pre-SMA and SMA-proper. According to this view, the pre-SMA would be involved in higher level processes while the SMA-proper would be more closely tied to Motor output. We extended this general framework to the verbal domain, in order to investigate the role of the SMA in speech production. We conducted two speech production experiments with fMRI where we manipulated parameters such as familiarity, complexity or constraints on word selection. The results reveal a parcellation of the SMA into three distinct regions, according to their involvement in different aspects of word production. More specifically, following a rostrocaudal gradient, we observed differential activations related to lexical selection, linear sequence encoding and control of Motor output. A parallel organization was observed in the dorsolateral frontal cortex. By refining its anatomical and functional parcellation, these results clarify the roles of the SMA in speech production.
-
The role of the Supplementary Motor Area (SMA) in word production
Brain Research, 2006Co-Authors: F.-xavier Alario, Hanna Chainay, Stephane Lehericy, Laurent CohenAbstract:The Supplementary Motor Area (SMA) is a key structure for behavioral planning and execution. Recent research on Motor control conducted with monkeys and humans has put to light an anatomical and functional distinction between pre-SMA and SMA-proper. According to this view, the pre-SMA would be involved in higher level processes while the SMA-proper would be more closely tied to Motor output. We extended this general framework to the verbal domain, in order to investigate the role of the SMA in speech production. We conducted two speech production experiments with fMRI where we manipulated parameters such as familiarity, complexity or constraints on word selection. The results reveal a parcellation of the SMA into three distinct regions, according to their involvement in different aspects of word production. More specifically, following a rostrocaudal gradient, we observed differential activations related to lexical selection, linear sequence encoding and control of Motor output. A parallel organization was observed in the dorsolateral frontal cortex. By refining its anatomical and functional parcellation, these results clarify the roles of the SMA in speech production. © 2005 Elsevier B.V. All rights reserved.
Laurent D. Cohen - One of the best experts on this subject based on the ideXlab platform.
-
The role of the Supplementary Motor Area (SMA) in word production.
Brain research, 2006Co-Authors: F.-xavier Alario, Hanna Chainay, Stephane Lehericy, Laurent D. CohenAbstract:The Supplementary Motor Area (SMA) is a key structure for behavioral planning and execution. Recent research on Motor control conducted with monkeys and humans has put to light an anatomical and functional distinction between pre-SMA and SMA-proper. According to this view, the pre-SMA would be involved in higher level processes while the SMA-proper would be more closely tied to Motor output. We extended this general framework to the verbal domain, in order to investigate the role of the SMA in speech production. We conducted two speech production experiments with fMRI where we manipulated parameters such as familiarity, complexity or constraints on word selection. The results reveal a parcellation of the SMA into three distinct regions, according to their involvement in different aspects of word production. More specifically, following a rostrocaudal gradient, we observed differential activations related to lexical selection, linear sequence encoding and control of Motor output. A parallel organization was observed in the dorsolateral frontal cortex. By refining its anatomical and functional parcellation, these results clarify the roles of the SMA in speech production.
Laurent Cohen - One of the best experts on this subject based on the ideXlab platform.
-
The role of the Supplementary Motor Area (SMA) in word production
Brain Research, 2006Co-Authors: F.-xavier Alario, Hanna Chainay, Stephane Lehericy, Laurent CohenAbstract:The Supplementary Motor Area (SMA) is a key structure for behavioral planning and execution. Recent research on Motor control conducted with monkeys and humans has put to light an anatomical and functional distinction between pre-SMA and SMA-proper. According to this view, the pre-SMA would be involved in higher level processes while the SMA-proper would be more closely tied to Motor output. We extended this general framework to the verbal domain, in order to investigate the role of the SMA in speech production. We conducted two speech production experiments with fMRI where we manipulated parameters such as familiarity, complexity or constraints on word selection. The results reveal a parcellation of the SMA into three distinct regions, according to their involvement in different aspects of word production. More specifically, following a rostrocaudal gradient, we observed differential activations related to lexical selection, linear sequence encoding and control of Motor output. A parallel organization was observed in the dorsolateral frontal cortex. By refining its anatomical and functional parcellation, these results clarify the roles of the SMA in speech production. © 2005 Elsevier B.V. All rights reserved.
