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Reactive control of precision grip does not depend on fast transcortical reflex pathways in X-linked Kallmann subjects

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JOURNAL OF PHYSIOLOGY-LONDON 2000年第3期527卷 641-652页

作者： Harrison, LM Mayston, LJ Johansson, RS UCL Dept Physiol London WC1E 6BT England Umea Univ IMB Physiol Sect SE-90187 Umea Sweden

1. It has been shown that subjects maintain grasp stability by automatically regulating grip force in response to loads applied tangentially to a manipulandum held using a precision grip. Signals from cutaneous mechanoreceptors convey the information necessary for both the initiation and scaling of responses. The central neural pathways that support these grip reactions are unknown. However, the latency of the increase in force is similar to that of 'long-latency' transcortical reflexes recorded from muscles following muscle stretch or electrical stimulation of digital nerves. 2. This study assessed the importance of fast transcortical pathways for reactive grip responses by examining these responses in subjects with X-linked Kallmann's syndrome (XKS). Subjects were selected whose corticospinal projection, as assessed by magnetic brain stimulation, is essentially ipsilateral, and in whom the long-latency reflex components following digital nerve stimulation are only found contralateral to the stimulated side. 3. Despite this anomaly of the fast corticospinal pathway, these XKS subjects responded in the same way as control subjects;grip response latencies were similar and responses were appropriately scaled. However, the non-operating hand of these XKS subjects often mirrored the grip force changes of the operating hand. Reflex force mirroring was most marked during the first 50 ms and the force output was always less than 20% of that of the operating hand. 4. We conclude, firstly, that somatosensory driven precision grip responses that support grasp stability do not depend on fast conducting corticospinal pathways in these subjects and, secondly that such responses do not use those 'long-latency' reflex pathways probed by cutaneomuscular reflexes elicited by electrical stimulation of digital nerves.

关键词：电刺激肌电描记术指/神经支配指/生理学基因连锁/遗传学握力/生理学卡尔曼综合征/遗传学卡尔曼综合征/病理生理学机械感受器/生理学运动皮质/生理学神经通路/生理学反射/生理学反射牵张/生理学 X染色体/遗传学成年人老年人女(雌)性人类男(雄)性中年人

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Representation of manipulable man-made objects in the dorsal stream

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NEUROIMAGE 2000年第4期12卷 478-484页

作者： Chao, LL Martin, A NIMH Lab Brain & Cognit Bethesda MD 20892 USA

We used fMRI to examine the neural response in frontal and parietal cortices associated with viewing and naming pictures of different categories of objects. Because tools are commonly associated with specific hand movements, we predicted that pictures of tools, but not other categories of objects, would elicit activity in regions of the brain that store information about motor-based properties. We found that viewing and naming pictures of tools selectively activated the left ventral premotor cortex (BA 6). Single-unit recording studies in monkeys have shown that neurons in the rostral part of the ventral premotor cortex (canonical F5 neurons) respond to the visual presentation of graspable objects, even in the absence of any subsequent motor activity. Thus, the left ventral premotor region that responded selectively to tools in the current study may be the human homolog of the monkey canonical F5 area. Viewing and naming tools also selectively activated the left posterior parietal cortex (BA 40). This response is similar to the firing of monkey anterior intraparietal neurons to the visual presentation of graspable objects. In humans and monkeys, there appears to be a close link between manipulable objects and information about the actions associated with their use. The selective activation of the left posterior parietal and left ventral premotor cortices by pictures of tools suggests that the ability to recognize and identify at least one category of objects (tools) may depend on activity in specific sites of the ventral and dorsal visual processing streams.

关键词：半球优势大脑/生理学设备和供应额叶/生理学磁共振成像心理过程/生理学运动皮质/生理学人名顶叶/生理学视知觉/生理学成年人女(雌)性人类男(雄)性

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Effects of lexicality, frequency, and spelling-to-sound consistency on the functional anatomy of reading

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NEURON 1999年第1期24卷 205-218页

作者： Fiez, JA Balota, DA Raichle, ME Petersen, SE Univ Pittsburgh Dept Psychol Pittsburgh PA 15260 USA Univ Pittsburgh Dept Neurosci Pittsburgh PA 15260 USA Univ Pittsburgh Ctr Neural Basis Cognit Pittsburgh PA 15260 USA Washington Univ Sch Med Dept Neurol & Neurol Surg St Louis MO 63110 USA Washington Univ Sch Med Dept Anat & Neurobiol St Louis MO 63110 USA Washington Univ Sch Med Dept Radiol St Louis MO 63110 USA Washington Univ Dept Psychol St Louis MO 63110 USA

Functional neuroimaging was used to investigate three factors that affect reading performance: first, whether a stimulus is a word or pronounceable nonword (lexicality), second, how often a word is encountered (frequency), and third, whether the pronunciation has a predictable spelling-to-sound correspondence (consistency). Comparisons between word naming (reading) and visual fixation scans revealed stimulus-related activation differences in seven regions. A left frontal region showed effects of consistency and lexicality, indicating a role in orthographic to phonological transformation. Motor cortex showed an effect of consistency bilaterally, suggesting that motoric processes beyond high-level representations of word phonology influence reading performance. Implications for the integration of these results into theoretical models of word reading are discussed.

关键词：脑/解剖学和组织学脑/诊断显像脑/生理学小脑/生理学额叶/生理学扣带回/生理学运动皮质/生理学语音学阅读体层摄影术发射型计算机词汇成年人女(雌)性人类男(雄)性

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Impairments in prehension produced by early postnatal sensory motor cortex activity blockade

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JOURNAL OF NEUROPHYSIOLOGY 2000年第2期83卷 895-906页

作者： Martin, JH Donarummo, L Hacking, A Columbia Univ Ctr Neurobiol & Behav New York NY 10032 USA New York State Psychiat Inst & Hosp New York NY 10032 USA

Impairments in prehension produced by early postnatal sensory motor cortex activity blockade. J. Neurophysiol. 83: 895-906, 2000. This study examined the effects of blocking neural activity in sensory motor cortex during early postnatal development on prehension. We infused muscimol, either unilaterally or bilaterally, into the sensory motor cortex of cats to block activity continuously between postnatal weeks 3-7. After stopping infusion, we trained animals to reach and grasp a cube of meat and tested behavior thereafter. Animals that had not received muscimol infusion (unilateral saline infusion;age-matched) reached for the meat accurately with small end-point errors. They grasped the meat using coordinated digit flexion followed by forearm supination on 82.7% of trials. Performance using either limb did not differ significantly. In animals receiving unilateral muscimol infusion, reaching and grasping using the limb ipsilateral to the infusion were similar to controls. The limb contralateral to infusion showed significant increases in systematic and variable reaching end-point errors, often requiring subsequent corrective movements to contact the meat. Grasping occurred on only 14.8% of trials, replaced on most trials by raking without distal movements. Compensatory adjustments in reach length and angle, to maintain end-point accuracy as movements were started from a more lateral position, were less effective using the contralateral limb than ipsilateral limb. With bilateral inactivations, the form of reaching acid grasping impairments was identical to that produced by unilateral inactivation, but the magnitude of the reaching impairments was less. We discuss these results in terms of the differential effects of unilateral and bilateral inactivation on corticospinal tract development. We also investigated the degree to which these prehension impairments after unilateral blockade reflect control by each hemisphere. In animals that had received unilateral blockade b

关键词：年龄因素条件反射(心理学)/生理学关键期(心理学) 摄食行为/生理学前肢/生理学功能偏侧化/生理学 GABA激动剂/药理学运动皮质/药物作用运动皮质/生长和发育运动皮质/生理学运动技能/药物作用运动技能/生理学蝇蕈醇/药理学精神运动性行为/生理学躯体感觉皮质/药物作用躯体感觉皮质/生长和发育躯体感觉皮质/生理学空间知觉/生理学动物猫

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INTRACELLULAR SYNAPTIC POTENTIALS OF PRIMATE MOTOR CORTEX NEURONS DURING VOLUNTARY MOVEMENT

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BRAIN RESEARCH 1979年第1期163卷 33-48页

作者： MATSUMURA, M KYOTO UNIV PRIMATE RES INST DEPT NEUROPHYSIOL INUYAMA AICHI 484 JAPAN

An intracellular recording technique was applied to the precentral motor cortex of the unanesthetized, chronically behaving monkey [Macaca mulatta]. Postsynaptic potentials [PSP], responsible for an initiation of the voluntary movement, were recorded. In total, 22 pyramidal trace neurons (PTN) and 41 non-pyramidal tract neurons (non-PTN) were successfully penetrated in 5 monkeys while the monkey was performing a flexion-extension wrist movement after a visual cue (reaction time, 200-350 ms). The neurons showed a negative membrane potential shift of at least 30 mV for > 30 s. A slowly rising PSP appeared 80-180 ms after the visual cue, and was 70-180 ms prior to an onset of the movement. Spike activities were superimposed upon this slow PSP with 20-80 ms rise time and 2-6 mV depolarization (8 PTN and 6 non-PTN). Since these depolarizations were variable in magnitude and latency, these were considered to be summated potentials of small E[excitatory]PSP and hidden I[inhibitory]PSP. Membrane resistance was measured from an IR [internal resistance] drop by a hyperpolarizing current (1.2 .times. 10-9 A) passed through a recording electrode, and was 3.5 .+-. 1.7 ***. in 18 PTN and 4.5 .+-. 2.5 ***. in 28 non-PTN. There was a linear relationship in PTN between membrane resistance and antidromic latency from the pontine pyramid. Because of the time course of PSP, their possible dendritic origins were discussed.

关键词：类人猿亚目细胞内液/生理学恒河猴膜电位运动皮质/生理学运动(Movement) 神经元/生理学锥体束/生理学反应时间/生理学突触/生理学腕/神经支配动物

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SPECIFIC AND NONSPECIFIC MULTIPLE UNIT ACTIVITIES DURING ONSET OF PENTYLENTETRAZOL SEIZURES .1. INTACT ANIMALS

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EPILEPSIA 1975年第2期16卷 207-214页

作者： VELASCO, F VELASCO, M ESTRADAVILLANUEVA, F MACHADO, JP INST MEXICANO SEGUIRO SOCIAL SCI RES DEPTDIV NEUROPHYSMEXICO CITY 73032MEXICO

A quantitative evaluation of specific and nonspecific multiple unit activity (MUA) before and during pentylenetetrazol-induced EEG tonic-clonic discharges (OTCD) was made at four levels of the CNS: cortical, thalamic, mesencephalic, and pontine. In addition, MUA of sciatic nerve was recorded to detect possible spinal cord efferent discharges. At all levels, sustained increase in specific and nonspecific multiple unit activity preceded EEG and sciatic nerve discharges induced by pentylenetetrazol. Increments in nonspecific MUA occurred sooner and were larger than those of specific MUA, and increments in mesencephalic nonspecific MUA occurred sooner and were larger than those of other cortical, thalamic, and pontine nonspecific MUAs. This sequence of neuronal activation suggests that pentylenetetrazol seizures are initiated in nonspecific structures at the mesencephalic level.

关键词：脑电描记术中脑/药物作用中脑/生理学微电极运动皮质/药物作用运动皮质/生理学神经传导神经通路戊四唑脑桥/药物作用脑桥/生理学坐骨神经/药物作用坐骨神经/生理学发作/化学诱导立体定位技术丘脑/药物作用丘脑/生理学时间因素动物猫男(雄)性

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INPUT TO PRIMATE MOTOR CORTEX FROM POSTERIOR PARIETAL CORTEX (AREA 5) .1. DEMONSTRATION BY RETROGRADE TRANSPORT

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BRAIN RESEARCH 1978年第2期157卷 325-330页

作者： STRICK, PL KIM, CC NIMH NEUROPHYSIOL LAB BETHESDA MD 20014 USA SUNY UPSTATE MED CTR DEPT NEUROSURG SYRACUSE NY 13210 USA SUNY UPSTATE MED CTR DEPT PHYSIOL SYRACUSE NY 13210 USA

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Mesial motor areas in self-initiated versus externally triggered movements examined with fMRI:: Effect of movement type and rate

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JOURNAL OF NEUROPHYSIOLOGY 1999年第6期81卷 3065-3077页

作者： Deiber, MP Honda, M Ibañez, V Sadato, N Hallett, M NINDS Human Motor Control Sect Med Neurol Branch NIH Bethesda MD 20892 USA Ctr Explorat & Rech Med Emiss Positons INSERM F-69003 Lyon France Fukui Med Sch Dept Radiol Fukui 91011 Japan

The human frontomesial cortex reportedly contains at least four cortical areas that are involved in motor control: the anterior supplementary motor area (pre-SMA), the posterior SMA (SMA proper, or SMA), and, in the anterior cingulate cortex, the rostral cingulate zone (RCZ) and the caudal cingulate zone (CCZ). We used functional magnetic resonance imaging (fMRI) to examine the role of each of these mesial motor areas in self-initiated and visually triggered movements. Healthy subjects performed self-initiated movements of the right fingers (self-initiated task, SI). Each movement elicited a visual signal that was recorded. The recorded sequence of visual signals was played back, and the subjects moved the right fingers in response to each signal (visually triggered task, VT). There were two types of movements: repetitive (FIXED) or Sequential (SEQUENCE), performed at two different rates: SLOW or FAST. The four regions of interest (pre-SMA, SMA, RCZ, CCZ) were traced on a high-resolution MRI of each subject's brain. Descriptive analysis, consisting of individual assessment of significant activation, revealed a bilateral activation in the four mesial structures for all movement conditions, but SI movements were more efficient than VT movements. The more complex and more rapid the movements, the smaller the difference in activation efficiency between the SI and the VT tasks, which indicated an additional processing role of the mesial motor areas involving both the type and rate of movements. Quantitative analysis was performed on the spatial extent of the area activated and the percentage of change in signal amplitude. In the pre-SMA, activation was more extensive for SI than for VT movements, and for fast than for slow movements;the extent of activation was larger in the ipsilateral pre-SMA. In the SMA, the difference was not significant in the extent and magnitude of activation between SI and VT movements, but activation was more extensive for sequential than for fi

关键词：脑图指/神经支配指/生理学功能偏侧化/生理学磁共振成像模型神经学运动皮质/解剖学和组织学运动皮质/生理学运动(Movement)/生理学精神运动性行为/生理学成年人女(雌)性人类男(雄)性中年人

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Effects of red nucleus microstimulation on the locomotor pattern and timing in the intact cat: A comparison with the motor cortex

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JOURNAL OF NEUROPHYSIOLOGY 1999年第5期81卷 2297-2315页

作者： Rho, MJ Lavoie, S Drew, T Univ Montreal Dept Physiol Montreal PQ H3C 3J7 Canada

To determine the extent to which the rubrospinal tract is capable of modifying locomotion in the intact cat, we applied microstimulation (cathodal current, 330 Hz;pulse duration 0.2 ms;maximal current, 25 mu A) to the red nucleus during locomotion. The stimuli were applied either as short trains (33 ms) of impulses to determine the capacity of the rubrospinal tract to modify the level of electromyographic (EMG) activity in different flexors and extensors at different phases of the step cycle or as long trains (200 ms) of pulses to determine the effect of the red nucleus on cycle timing. Stimuli were also applied with the cat at rest (33-ms train). This latter stimulation evoked short-latency (average = 11.8-19.0 ms) facilitatory responses in all of the physiological flexor muscles of the forelimb that were recorded;facilitatory responses were also common in the elbow extensor, lateral head of triceps but were rare in the physiological wrist and digit extensor, palmaris longus. Responses were still evoked in most muscles when the current was decreased to near threshold (3-10 mu A). Stimulation during locomotion with the short trains of stimuli evoked shorter-latency (average = 6.0-12.5 ms) facilitatory responses in flexor muscles during the swing phase of locomotion and, except in the case of the extensor digitorum communis, evoked substantially smaller responses in stance. The same stimuli also evoked facilitatory responses in the extensor muscles during swing and produced more complex effects involving both facilitation and suppression in stance. Increasing the duration of the train to 200 ms modified the amplitude and duration of the EMG activity of both flexors and extensors but had little significant effect on the cycle duration. In contrast, whereas stimulation of the motor cortex with short trains of stimuli during locomotion had very similar effects to that of the red nucleus, increasing the train duration to 200 ms frequently produced a marked reset of the s

关键词：电刺激/方法肌电描记术四肢运动活动/生理学运动皮质/生理学肌骨骼/生理学红核/生理学休息时间因素动物猫男(雄)性

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Motor cortical activity during drawing movements: Population representation during spiral tracing

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JOURNAL OF NEUROPHYSIOLOGY 1999年第5期82卷 2693-2704页

作者： Moran, DW Schwartz, AB Inst Neurosci San Diego CA 92121 USA

Monkeys traced spirals on a planar surface as unitary activity was recorded from either premotor or primary motor cortex. Using the population vector algorithm, the hand's trajectory could be accurately visualized with the cortical activity throughout the task. The time interval between this prediction and the corresponding movement varied linearly with the instantaneous radius of curvature;the prediction interval was longer when the path of the finger was more curved (smaller radius). The intervals in the premotor cortex fell into two groups, whereas those in the primary motor cortex formed a single group. This suggests that the change in prediction interval is a property of a single population in primary motor cortex, with the possibility that this outcome is due to the different properties generated by the simultaneous action of separate subpopulations in premotor cortex. Electromyographic (EMG) activity and joint kinematics were also measured in this task. These parameters varied harmonically throughout the task with many of the same characteristics as those of single cortical cells. Neither the lags between joint-angular velocities and hand Velocity nor the lags between EMG and hand velocity could explain the changes in prediction interval between cortical activity and hand velocity. The simple spatial and temporal relationship between cortical activity and finger trajectory suggests that the figural aspects of this task are major components of cortical activity.

关键词：脑图肌电描记术关节/神经支配猕猴运动活动/生理学运动皮质/生理学肌骨骼/神经支配神经元/生理学精神运动性行为/生理学反应时间动物

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