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G Schalow

Publications and source records attributed to G Schalow.

At least 19 recordsLinked to original sources
PubMed2006

Surface EMG- and coordination dynamics measurements-assisted cerebellar diagnosis in a patient with cerebellar injury.

Cerebellar diagnostic was performed in a patient who had suffered severe cerebellar injury, using kinesiologic (coordination dynamics) and electrophysiologic (surface EMG (sEMG)) means. Since the right cerebellum had been completely destroyed, significant coordination problems (especially on the right side) were expected to be found in addition to balance problems. As compared to a healthy person, coordination between arms and legs was 80% up to 300% worse. Unexpectedly, no pronounced impairment of coordination of the right arm and right leg was found (with respect to the remaining limbs) as a result of the lost right cerebellum. The values of coordination dynamics measured for the right arm and the right leg for exercising in the forward and backward direction were as good as or even better than those obtained for the left side. However, sEMG disclosed a strong impairment of antagonistic muscle activation (spinocerebellum) between the tibialis anterior and the gastrocnemius muscles on the right side upon exercising the legs only on the special coordination dynamics therapy device (similar to a stationary bicycle). The muscles of the right-sided leg worked worse than those of the left-sided leg. But upon exercising both legs and arms on the special device (more integratively), the antagonistic muscle activation improved in the poor right leg by 36% in the short-term memory but not in the good left leg (symmetry improvement). These kinesiological and electrophysiological measurements show that there was no clear ipsilateral correlation between the cerebellum and the laterality of body functions. For different kinds of supported walking sEMG motor programs worsened with the reduction of the support. Probably the damaged vestibulocerebellum could not sufficiently coordinate balance any more with walking When swinging and jumping on the springboard, sEMG motor programs were best for jumping in anti-phase, where maybe more inhibition is activated. It is concluded that coordination measurements and sEMG are powerful tools to evaluate the outcome of cerebellar injury and to provide a diagnostic tool to quantify improvements in the CNS functioning as a result of the coordination dynamics therapy.

Arm↗
PubMed2005

Integrative re-organization mechanism for reducing tremor in Parkinson's disease patients.

A special movement therapy, called coordination dynamics therapy, has been reported to have the potential to improve central nervous system (CNS) functioning in Parkinson's disease patients. Electromyography using surface electrodes (sEMG) showed that the rhythmic muscle activity leading to Parkinsonian tremor was generated in the patients by the impairment of two kinds of inhibition. First, some premotor spinal oscillators organized themselves in the CNS neuronal networks without strong adequate input and second, the oscillators synchronized their firing to give rise to rhythmic muscle activity and tremor. In this paper it will be shown that highly coordinated arm and leg movements, generated when exercising on a special coordination dynamics therapy device, can reduce Parkinsonian tremor in amplitude and frequency and improve CNS functioning in the short-term memory. sEMG measurements showed upon exercising on the special coordination dynamics therapy device that the motor program improved in the short-term memory and tremor muscle activity became coordinated with the volitional motor program and reduced in size and frequency. Higher load exercising seemed to better reduce tremor muscle activity, probably because the physiologic CNS organization was more integrative then and could 'bind' stronger simultaneous pathologic tremor activity. Moreover, the rhythmic synchronized motor unit firing in different arm and leg muscles was synchronized or coordinated and changed in frequency and amplitude. It is concluded that the integrative re-organization mechanism to reduce Parkinsonian tremor is the phase and frequency coordination between neuron firing of the physiologic neuronal network state, generated by the highly coordinated arm and leg movements, and the simultaneous pathologic tremor network state, generated by the uninhibited neurons, firing synchronized oscillatory.

Aged↗
PubMed2005

Cerebral palsy improvement achieved by coordination dynamics therapy.

Low-intensity coordination dynamics therapy, including crawling, treadmill walking, jumping on spring-board and exercising on a special coordination dynamics therapy device, was applied for 3 months (4 hours therapy per week) to 8 cerebral palsy patients (average age 15 years, range 7-27). All patients improved. The organization of the CNS, quantified by the low-load coordination dynamics between arm and leg turning movements, when exercising on the special coordination dynamics therapy device, improved by 46 +/- 17% (range 33-60%) for forward and by 48 +/- 15% (range 22-66%) for backward moving. Also improved the exercised crawling, jumping and walking, although not as much as the CNS organization quantified by coordination dynamics. The motor programs of the tibialis anterior, gastrocnemius, biceps brachii, and triceps brachii muscles, measured by surface electromyography (sEMG), improved only little. Evidence is provided for sEMG being a very suitable tool for optimizing the movement performance and the therapy since sEMG records show under what exercise conditions the recorded motor programs are best. However coordination dynamics, i.e. the integrative parameter for quantifying CNS organization, is better to show the progress in CNS functioning than movement and EMG improvements. When the patients stopped therapy, the value of their coordination dynamics, worsened 24% after 6 months. In one patient the coordination dynamics therapy was continued intensively for further 3 month, including 20 hours exercise per week. The value of the coordination dynamics even improved altogether by 85% and 82% for forward and backward turning movements respectively, and simultaneously movements, vegetative (sleep) and higher mental functions (aggressivity, learning capacity) showed strong improvements. The improvements of coordination dynamics for low-intensity therapy (46%, for forward movements) and additional high-intensity therapy (85%) lie within the recovery range for stroke (70%) and brain injury (69%) after 3 months of intensive coordination dynamics therapy. There is therefore indication that the CNS functioning in cerebral palsy patients can be improved by learning as much as the CNS functioning can be repaired by re-learning in stroke and brain injury. The improvement of the CNS functioning suggests that cerebral palsy can partly be cured if intensive coordination dynamics therapy is administered for 1 to 2 years. It is further suggested that inabilities, including mental inability, are diseases which can partly be cured rather than inabilities.

Adolescent↗
PubMed2005

Tapering of human nerve fibres.

To determine the tapering of human nerve fibres, rostral and caudal root pieces of cauda equina nerve roots were removed and nerve fibre diameter distributions were constructed for 4 myelin sheath thickness ranges for the two sites, and compared with each other. The reduction of the group diameter in the different alpha-motoneuron groups was 0.2 % per 13 cm. Accounting for systematic errors, there may be even less tapering. An identified single nerve fibre showed no tapering. Further, there is indication that gamma-motoneurons, preganglionic sympathetic and parasympathetic fibres and skin afferents also reduce their fibre diameter by 0.2 % per 13 cm or less. Consequently, a nerve fibre with a diameter of 10 microm would be reduced to approximately 9.8 microm at 1m from the cell soma. Preganglionic parasympathetic fibres were found to be represented in roots S1 to S5. At similar distances from the spinal cord, the mean diameter of ventral root alpha1-motoneuron (FF) axons increased from the thoracic towards the lumbo-sacral region before decreasing again in the lower sacral region. Usually no alpha1-motoneuron axons were found in S5 roots. The diameter distribution of unmyelinated nerve fibres of a ventral S5 root showed three peaks at 0.25, 0.95 and 1.2 microm. The unmyelinated fibres with diameters around 0.25 microm may represent parasympathetic fibres. In six selected areas of the ventral S5 root, 6.6 times more unmyelinated nerve fibres than myelinated fibres were found on the average.

Aged↗
PubMed2004

Improvement in Parkinson's disease patients achieved by coordination dynamics therapy.

Eight patients in whom Parkinson's disease had set on 5 to 10 years earlier underwent low intensity coordination dynamics therapy with on average 4 hours per week for 2.5 months. The ongoing pharmaco-therapy and the conventional fitness training for 1 to 2 hours per week were not changed. With the coordination dynamics therapy the functioning of the central nervous system (CNS) of the Parkinson's disease patients improved by 35%, as quantified by coordination dynamics measurements. Following 3 months of no coordination dynamics therapy, but further ongoing pharmaco-therapy and fitness training the CNS functioning worsened again by 21%. It is concluded that pharmaco-therapy and conventional fitness training alone cannot prevent the worsening of the CNS functioning in progressing Parkinson's disease, but additional coordination dynamics therapy can.

Aged↗
PubMed2003

Low-load coordination dynamics in athletes, physiotherapists, gymnasts, musicians and patients with spinal cord injury, after stroke, traumatic brain lesion and with cerebral palsy.

Low-load coordination dynamics were measured in athletes, physiotherapists, gymnasts, musicians and patients after stroke, traumatic brain injury and spinal cord lesion during exercise on a special coordination dynamic therapy device to quantify differences in central nervous system (CNS) organization between healthy subjects and patients with CNS injury. In healthy humans coordination dynamics (arrhythmicity of turning) varied between 5.2 and 6.0 for forward and between 6.9 and 10.7 1/s for backward turning. The frequency of turning varied between 1.24 (athletes) and 1.49 Hz (musicians) for forward and between 1.11 and 1.25 Hz for backward turning. Apart from the poor rhythmicity of backward turning among physiotherapists, gymnasts and musicians, inter-group differences were small in comparison to intra-group variation. In patients with spinal cord lesion the coordination dynamics value was 8.3 for forward and 11.0 for backward turning. The frequencies for forward and backward turning were 1.20 and 1.20 Hz respectively. The values for coordination dynamics and frequency of turning thus did only slightly differ from those measured for healthy subjects. The patients after stroke, traumatic brain injury and cerebral palsy had much higher coordination dynamic values (20.4, 22.9 and 30 1/s respectively) and lower forward (0.85, 0.93, and 0.52 Hz) and backward turning frequencies (0.98, 1.06, 0.42 Hz), suggesting strongly pathologic CNS organization. Low-load coordination dynamics (20N) are thus useful to measure progress in CNS organization due to therapy in patients with CNS injury.

Adult↗
PubMed2003

High-load coordination dynamics in athletes, physiotherapists, gymnasts, musicians and patients with CNS injury.

High-load coordination dynamics were measured in athletes, physiotherapists, gymnasts, musicians, patients with spinal cord injury and a patient with multiple sclerosis during exercise on a special coordination dynamic therapy device to quantify improvement in the central nervous system (CNS) organization due to therapy in patients and to quantify differences in the CNS organization between healthy subjects and patients with CNS injury. The values of high-load coordination dynamics for the group of athletes were two times better than those of physiotherapists, gymnasts and musicians, but still two times poorer than the best value achieved so far in a patient with a spinal cord injury after 10 months of continuous intensive coordination dynamics therapy. Especially the physiotherapists, gymnasts and musicians had poor coordination between arms and legs for the difficult intermediate coordinations between pace and trot gait for high load. Exhaustion of the CNS and improvement of CNS functioning in the short-term memory could be made visible using hysteresis-like curves for load increase and decrease. When not receiving therapy, patients with CNS injury could not turn at high loads, and showed poor coordination at lower loads only. After exercising 7,000 coordinated arm and leg movements per month, the CNS organization for high load improved in 3 healthy subjects by 36%. In patients with CNS injury, such improvements of high-load coordination dynamics took several months of intensive coordination dynamics therapy including 350,000 coordinated movements per months. The rate of learning may differ in healthy subjects and patients very approximately by a factor of 50 depending on the severity of the injury. On the other hand however, the high-load coordination between arms and legs, necessary for walking could be improved during therapy even in patients with multiple sclerosis, with the consequence that they could manage better in every day life.

Adult↗
PubMed2003

Coordination dynamics in Parkinson's disease patients and healthy subjects quantified by the coordination dynamics recording method and sEMG.

Coordination dynamics were measured in Parkinson's disease patients to quantify central nervous system (CNS) dysfunction. The low-load coordination dynamics in the patients were impaired by 56% for forward and 44% for backward moving in comparison to a control group of similar age. Exercising at higher load was only partly possible. When the disease preferentially affected one side of the body, the coordination dynamics were worse for the affected side. A dexterity test showed that coordination of hand and arm movements could be improved in the short-term memory when exercising on the special coordination dynamics recording and therapy device. Simultaneously taken surface EMG (sEMG) showed that the motor pattern was impaired in the Parkinson's disease patients. sEMG recordings showed further that the fast fatigable muscle fibre activation was impaired. FF-type muscle fibres were already activated for low load in one and not at all in another muscle. In conclusion, coordination between motoneuron firings and between arm and leg movements were found to be impaired in Parkinson's disease patients.

Aged↗
PubMed2001

On-line measurement of human CNS re-organization.

Based on measurements of relative phase and frequency coordination of time-space distributed firing of neurons in the human nervous system, methods have been developed with which it is possible to functionally re-organize the lesioned or not optimally functioning human central nervous system (CNS) and to measure on-line the organization (the coordination dynamics) of the CNS non-invasively. By measuring the present coordination dynamics at different times with ongoing coordination dynamic therapy when exercising on a special coordination dynamic therapy device, the progress in re-organization of the lesioned CNS can be quantified. The coordination dynamic recording method is derived from measurements of natural firing patterns of single neurons in the human CNS. The method is explained with load changes in the healthy CNS and with essential improvement in CNS organization following coordination dynamic therapy in traumatic brain lesion, spinal cord lesion, stroke, cerebral palsy, and myelomeningocele. Evaluations of CNS re-organization are discussed with respect to usefullness and ethics.

Adult↗
PubMed2001

Time axis calibration in human CNS organization for judging dysfunction.

Based on measurements of relative phase and frequency coordination between the firings of neurons in the human central nervous system (CNS) with the single-nerve fibre action potential recording method a coordination dynamic recording method could be developed with which it is possible to measure the coordination dynamics between arms, legs and trunk non-invasively when exercising on a special coordination dynamic therapy device. To analyze integrative functions when the human CNS is generating different coordinated movements of arms and legs, a time axis calibration is needed, which catches relevant CNS organization. Repeatedly occurring characteristic movement states are found in the pace and trot gait coordination when exercising continuously on the special coordination dynamic therapy device. CNS organization dynamics is thus projected onto the changing coordination dynamics of arm and leg movement. The collective variable for measuring the coordination dynamics of a physiologically and pathologically functioning CNS, when performing coordinated arm and leg movements with changing coordination between arms and legs including pace and trot gait coordination and all intermediate coordination, is the amplitude of variation of the frequency of turning (delta f) and of its time derivative (delta df/dt). When a volunteer exercises on the special coordination dynamic therapy and recording device, it was found that the healthy CNS can generate all possible coordinations between arms and legs with small turning frequency variation (small delta f and delta df/dt). But the lesioned CNS cannot any more generate all coordinations with small frequency variation, that means easily. Often the easy pace and trot gait coordinations can be performed by the patient with small frequency variation but not the difficult intermediate coordinations or, depending on the CNS lesion, the patient can only perform pace or trot gait coordination easily or the change from the pace to the trot gait and not from trot to pace gait coordinations can be performed easily. In the most severe cases the arrhythmicity is so large that the patient starts to stop turning or cannot turn the levers any more. Also time drifting CNS organizations can be identified with this time axis calibration; the easy coordinations appear at different coordinations with ongoing time. Improvements of the coordination dynamics and deterioration of the coordination dynamics with stress were measured in the short-term memory. It is discussed that stress deteriorates relearned CNS organization in the short-term memory apart from relearned automatisms.

Action Potentials↗
PubMed2000

Reorganization of the human central nervous system.

The key strategies on which the discovery of the functional organization of the central nervous system (CNS) under physiologic and pathophysiologic conditions have been based included (1) our measurements of phase and frequency coordination between the firings of alpha- and gamma-motoneurons and secondary muscle spindle afferents in the human spinal cord, (2) knowledge on CNS reorganization derived upon the improvement of the functions of the lesioned CNS in our patients in the short-term memory and the long-term memory (reorganization), and (3) the dynamic pattern approach for re-learning rhythmic coordinated behavior. The theory of self-organization and pattern formation in nonequilibrium systems is explicitly related to our measurements of the natural firing patterns of sets of identified single neurons in the human spinal premotor network and re-learned coordinated movements following spinal cord and brain lesions. Therapy induced cell proliferation, and maybe, neurogenesis seem to contribute to the host of structural changes during the process of re-learning of the lesioned CNS. So far, coordinated functions like movements could substantially be improved in every of the more than 100 patients with a CNS lesion by applying coordination dynamic therapy. As suggested by the data of our patients on re-learning, the human CNS seems to have a second integrative strategy for learning, re-learning, storing and recalling, which makes an essential contribution of the functional plasticity following a CNS lesion. A method has been developed by us for the simultaneous recording with wire electrodes of extracellular action potentials from single human afferent and efferent nerve fibres of undamaged sacral nerve roots. A classification scheme of the nerve fibres in the human peripheral nervous system (PNS) could be set up in which the individual classes of nerve fibres are characterized by group conduction velocities and group nerve fibre diameters. Natural impulse patterns of several identified single afferent and efferent nerve fibres (motoneuron axons) were extracted from multi-unit impulse patterns, and human CNS functions could be analyzed under physiologic and pathophysiologic conditions. With our discovery of premotor spinal oscillators it became possible to judge upon CNS neuronal network organization based on the firing patterns of these spinal oscillators and their driving afferents. Since motoneurons fire occasionally for low activation and oscillatory for high activation, the coherent organization of subnetworks to generate macroscopic function is very complex and for the time being, may be best described by the theory of coordination dynamics. Since oscillatory firing has also been observed by us in single motor unit firing patterns measured electromyographically, it seems possible to follow up therapeutic intervention in patients with spinal cord and brain lesions not only based on the activity levels and phases of motor programs during locomotion but also based on the physiologic and pathophysiologic firing patterns and recruitment of spinal oscillators. The improvement of the coordination dynamics of the CNS can be partly measured directly by rhythmicity upon the patient performing rhythmic movements coordinated up to milliseconds. Since rhythmic dynamic, coordinated, stereotyped movements are mainly located in the spinal cord and only little supraspinal drive is necessary to initiate, maintain, and terminate them, rhythmic, dynamic, coordinated movements were used in therapy to enforce reorganization of the lesioned CNS by improving the self-organization and relative coordination of spinal oscillators (and their interactions with occasionally firing motoneurons) which became pathologic in their firing following CNS lesion. Paraparetic, tetraparetic spinal cord and brain-lesioned patients re-learned running and other movements by an oscillator formation and coordination dynamic therapy. Our development in neurorehabilitation is in accordance with those of theoretical and computational neurosciences which deal with the self-organization of neuronal networks. In particular, jumping on a springboard 'in-phase' and in 'anti-phase' to re-learn phase relations of oscillator coupling can be understood in the framework of the Haken-Kelso-Bunz coordination dynamic model. By introducing broken symmetry, intention, learning and spasticity in the landscape of the potential function of the integrated CNS activity, the change in self-organization becomes understandable. Movement patterns re-learned by oscillator formation and coordination dynamic therapy evolve from reorganization and regeneration of the lesioned CNS by cooperative and competitive interplay between intrinsic coordination dynamics, extrinsic therapy related inputs with physiologic re-afferent input, including intention, motivation, supervised learning, interpersonal coordination, and genetic constraints including neurogenesis. (ABSTRACT TRUNCATED)

Animals↗
PubMed1998

Neuronal reorganization through oscillator formation training in patients with CNS lesions.

A method has been developed for the simultaneous recording with wire electrodes of extracellular action potentials from single human afferent and efferent nerve fibres of undamaged sacral nerve roots. A classification scheme of the human peripheral nervous system (PNS) could be set up in which the individual classes of nerve fibres are characterized by group conduction velocities and group nerve fibre diameters. Natural impulse patterns of several identified single afferent and efferent nerve fibres can be extracted from the multi-unit impulse patterns, and human central nervous system (CNS) functions can be analyzed under physiologic and pathophysiologic conditions. With the discovery of premotor spinal oscillators it became possible to judge upon CNS neuronal network functions based on the firing patterns of these spinal oscillators. Since oscillatory firing has also been observed in electromyographic (EMG) single motor unit firing patterns, it seems possible to follow up therapeutic intervention in patients with spinal cord lesion not only based on the activity levels and phases of motor programs during locomotion but also based on the physiologic and pathophysiologic firing patterns and recruitment of spinal oscillators. Since rhythmic, dynamic, stereotyped, symmetric movements are mainly located in the spinal cord and only little supraspinal drive is necessary to initiate, maintain (especially), and terminate them, rhythm training methods were used to enforce reorganization of the CNS following spinal cord and CNS lesions to improve the self-organization and relative coordination of spinal oscillators which became pathologic in their firing following CNS lesion. Paraparetic, tetraparetic and brain-lesioned patients relearned running and other movements by an oscillator formation training. This development in neurorehabilitation is in accordance with those of theoretical and computational neurosciences which consider self-organization of neuronal networks. In particular, jumping on a springboard 'in phase' and 'in antiphase' to relearn phase relations of oscillator coupling can be understood in the Haken-Kelso-Bunz model. By introducing broken symmetry, intention, learning and spasticity in the landscape of the potential function of the integrated CNS activity, the change in self-organization becomes understandable. In conclusion, movement patterns relearned by oscillator formation training evolve from reorganization, and perhaps regeneration, of the lesioned CNS by cooperative and competitive interplay between intrinsic coordination dynamics, extrinsic training-related inputs with physiologic re-afferent input, including intention and supervised learning, and genetic constraints including neurogenesis.

Biological Clocks↗
PubMed1996

Classification, oscillatory and alternating oscillatory firing of alpha 1 (FF) and alpha 2-motoneurons (FR) in patients with spinal cord lesion.

Single-nerve fibre action potentials (APs) were recorded extracellularly from sacral nerve roots of people with spinal cord lesion (patients with paraplegia). Single-fibre APs of certain fibres were identified by the conduction velocity and the AP waveform, and simultaneous impulse patterns were extracted from the summed impulse traffic and analysed with respect to spacio-temporal relationships. The velocity values of components of compound APs, induced by electrical nerve root stimulation or electrical intravesical stimulation, were similar to the group conduction velocity values obtained from single-nerve fibre APs of natural impulse traffic. When changing the root temperature in one case from 32 degrees C to 35.5 degrees C, the group conduction velocities changed in the following way: secondary muscle spindle afferents (SP2): 40 m/s (32 degrees C) to 50 m/s (35.5 degrees C); bladder stretch afferents (S1): 31.3 to 40 m/s; bladder tension afferents (ST): 25 to 33.8 m/s; mucosal afferents (M): 12.5 to 13.8 m/s; alpha 1:-; alpha 2-motoneurons: 40 to 50 m/s; alpha 3: 33 to 40 m/s. The group conduction velocities showed different temperature dependence apart from SP2 fibres and alpha 2-motoneurons, which were therefore used for calibration. The distance between two Pacinian corpuscle (PC) receptors in a sacral dermatome of one paraplegic patient was calculated to be approximately 20 mm. A similar distance between PC receptors was found in a brain-dead individual. Receptor densities seem therefore to remain unchanged following spinal cord lesion. Motoneurons fired irregularly repeatedly with impulse trains. In paraplegics the oscillation periods and the interspike intervals of the impulse trains varied much more than observed for brain-dead and normal individuals. Motoneurons could therefore not always be identified by their pattern of oscillatory firing. Alternating long and short oscillation periods (T) could be measured in an oscillatory firing alpha 1 (T = 125 ms) and alpha 2-motoneuron (T = 150 ms). In both cases the average difference between the alternating oscillation periods was 5 ms. Tremor, alternating long and short oscillation periods, cellular oscillator properties, and recurrent excitation and inhibition are discussed with respect to the oscillator theory of the functioning of the human central nervous system. Mathematical predictions from populations of interacting biological oscillators are compared to measurements on neuronal network data.

Action Potentials↗
PubMed1996

Mono- and polysynaptic drive of oscillatory firing alpha 1 (FF) and alpha 2-motoneurons (FR) in a patient with spinal cord lesion.

Single-nerve fibre action potentials (APs) were recorded extracellularly from lower sacral nerve roots of patients with spinal cord lesions (paraplegics), and simultaneous single-fibre impulse patterns of alpha 1 (FF) and alpha 2-motoneurons (FR) and primary and secondary muscle spindle afferents were analyzed. An alpha 1-motoneuron was activated in a time-locked manner by a primary spindle afferent fibre to fire oscillatory with an oscillation period of 110 to 140 ms. The distribution width for the time-locking (phase) was approx. 3 ms, which is interpreted as monosynaptic activation. A phase-correlated firing of a secondary muscle spindle afferent fibre gave rise to an additional oscillation period of the oscillatory firing alpha 1-motoneuron, when the primary fibre ceased firing. The phase distribution width was approx. 80 ms, and therefore indicates polysynaptic drive. The drive of the oscillatory firing alpha 1-motoneuron thus included a monosynaptic from a primary and a polysynaptic activation from a secondary muscle spindle afferent fibre. An alpha 2-motoneuron was simultaneously activated to fire oscillatory by a different secondary spindle afferent fibre. The phase distribution width between them was approx. 120 ms, which indicates polysynaptic drive. The alpha 1 and alpha 2-motoneurons fired in the occasional firing mode and in the transient and continuous oscillatory firing mode. Upon touch, pin-prick and bladder and anal catheter pulling, the alpha 1-motoneuron changed its firing rate more quickly than did the alpha 2-motoneuron. Thus, the alpha 1-motoneuron fired more dynamically than did the alpha 2-motoneuron. Synchronous oscillatory firing of the alpha 1 and alpha 2-motoneurons occurred transiently during pin-pricking. It is discussed that transient synchronization of oscillatory firing motoneurons points to relative coordination of self-organized oscillatory firing motoneuronal networks to generate locomotion and other integrative functions. It is further discussed that loss of specific properties of spinal oscillators following spinal cord lesion may give rise to pathologic synchronization, and in this way to disorders in movement.

Action Potentials↗
PubMed1996

Reflex stimulation of continuously oscillatory firing alpha and gamma-motoneurons in patients with spinal cord lesion.

Single nerve-fibre action potentials (APs) were recorded extracellularly from lower human sacral nerve roots, and simultaneous single-fibre impulse patterns of alpha and gamma-motoneurons and secondary muscle spindle afferents were analysed. Identified alpha and gamma-motoneurons fired oscillatory, due to the sustained stretch reflex of the external sphincters induced by an anal catheter (and, possibly, the bladder catheter). The motoneurons and the secondary muscle spindle afferents transiently synchronized their firing upon repetitive touch, pin-prick and dimpling stimulation of the perianal skin inside the anal reflex area, by reducing the duration of their oscillation period until resetting of the oscillation cycle. In one case, the anal reflex area extended approximately 6 cm laterally from the anus. The responses to pin-prick stimulation were different from those to touch stimulation in three aspects. Firstly, the response time till the shortening of the oscillation period was longer than the oscillation period (approximately 100 ms) for pin-prick, and it was shorter for touch. Second, the response to pain stimulus was longer (shortening of several oscillation periods) and stronger than for touch stimulation. Pin-prick stimulation reduced the oscillation period to between 5 and 40 ms (mean = 18 ms), and touch stimulation to between 8 and 28 ms (mean = 15 ms). Third, transient synchronization of afferents and efferents was most pronounced for pin-prick stimulation. The shortest latency following touch was approx. 10 ms when measuring from the afferent volley running in the direction of the spinal cord, and 30 ms when measuring from the beginning of the skin touch. It is discussed that repetitive touch stimulation reinforced the sustained stretch reflex of the anal sphincter which is possible with no network reorganization (variation of the same network state) and therefore fast, whereas repetitive pin-prick stimulation replaced the sustained stretch reflex by the protection reaction of the anal sphincter (change from one network state to a different one) which made time consuming network reorganization necessary. Different sacral reflexes were analysed by studying time-related activation changes of group conduction velocities in velocity distributions. During the reflex response to stretch of the external anal sphincter, the alpha 2-motoneurons (FR) (and the secondary muscle spindle afferents) were strongly activated whereas upon eliciting the bulbocavernosus reflex (squeezing of the glans penis) the alpha 3-motoneurons (S) were mainly activated. Sacral reflexes are discussed with respect to the organization and reorganization of preformated neuronal networks, and the synchronization of oscillatory firing networks is discussed with respect to the overlapping of synfire chains.

Action Potentials↗
PubMed1996

External loops of human premotor spinal oscillators identified by simultaneous measurements of interspike intervals and phase relations.

Single nerve-fibre action potentials (APs) were recorded extracellularly from alpha and gamma-motoneurons and secondary muscle spindle afferents from a ventral S4 nerve root (some afferents are contained in lower sacral motor roots) in an individual with traumatic spinal cord lesion sub TH1. Simultaneous interspike intervals (IIs) of, and phases between, the APs of 5 nerve fibres were measured, and distributions were constructed. The II distributions were of a broad peak type. Phase distributions showed 1 to 3 peaks interpreted as phase relations between the firings of the nerve fibres. Under certain phase relations, the rhythmic firing of alpha and gamma-motoneurons is further interpreted as an interaction of oscillatory firing neuronal subnetworks driving alpha and gamma-motoneurons. Following repetitive touch and pin-prick stimulation in- and outside the anal reflex area, the II distributions of alpha and gamma-motoneurons and of secondary spindle afferents assimilated partly or fully, while preserving their phase relations. This coordinated firing is interpreted as the oscillatory firing of alpha neuronal networks building up an external loop to the periphery via the gamma-loop. Upon touch, pin-prick, and anal reflex stimulation, and anal and bladder catheter pulling, the values and the number of the phase relations changed. Mostly two phase relations per oscillation cycle were observed. Two phase relations probably represent the physiologic case for the somatic nervous system. Only one phase relation was found when full synchronization of all units occurred. Three phase relations were found when the parasympathetic nervous system division interacted with the somatic one. Based on data obtained from brain-dead individuals it is discussed that the increased synchronization and instability in the number and the values of phase relations suggested pathologic functioning of the caudal functionally disconnected spinal cord in patients with spinal cord lesions: Oscillatory firing neuronal networks, which lost their specific properties, interacted more easily and unspecifically with other oscillatory firing networks. Further, it is discussed that physiologic tremor is caused by chance synchronization of oscillatory firing neuronal networks and therefore originates in the central nervous system (CNS). Since spinal oscillators build up external loops to the periphery, it is suggested that in patients with incomplete spinal cord lesions it should be possible to re-preformate oscillatory firing neuronal networks by a rhythm training, to reduce spasticity and to re-train useful movements, especially locomotion.

Afferent Pathways↗
PubMed1996

Electromyographic identification of spinal oscillator patterns and recouplings in a patient with incomplete spinal cord lesion: oscillator formation training as a method to improve motor activities.

A patient with a strongly lesioned spinal cord, sub C5, relearned running, besides improving other movements, by an oscillator formation training (rhythmic, dynamic, stereotyped exercise). After 45 days of jumping on a springboard and other rhythm trainings, the patient was able to run 90 m in 41 s (7.9 km/h) (even 9.3 km/h 3 years after the lesion) besides marching (5.7 km/h), cycling, playing tennis and skiing. FF-type (alpha 1) (f = 8.3-11.4 Hz) and FR-type (alpha 2) (f = 6.7 Hz) motor unit firings were identified by electromyography (EMG) with surface electrodes by their oscillatory firing patterns in this patient. In EMG literature, the alpha 2-oscillatory firing is called "myokymic discharging". Alternating long and short oscillation periods were measured in FF-type motor units, with changing focus (change from long/short to short/long oscillation periods). The alternating mean period durations differed by approximately 10 ms. Transient synchronization of oscillatory firing FF-type motor units was observed with up to two phase relations per oscillation cycle. In recumbent position, the phase change in synchronization of two oscillatory firing motor units in the soleus muscle of one leg correlated with the change from alternating to symmetrical oscillatory firing of a third motor unit in the soleus muscle of the other leg. This measurement indicates that the alternating oscillatory firing of premotor neuronal networks is correlated with synchronization of oscillatory firing neuronal subnetworks, i.e., with coupling changes of oscillators, and is not due to reciprocal inhibition of half-centre oscillators as suggested by the change from alternating to symmetrical oscillatory firing. Coupling changes of oscillatory firing subnetworks to generate macroscopic (integrative) network functions are therefore a general organization form of the central nervous system (CNS), and are not related to rhythmic movements like walking or running only. It is proposed that synchronization of spinal oscillators, phase changes in synchronization, changes from alternating to symmetrical firing and backwards, and changes in the focus of alternating oscillatory firing are, among others, physiologic coupling rules of the human CNS to generate, by ongoing coupling changes of oscillatory firing subnetworks, integrative functions such as rhythmic and non-rhythmic movements. One phase relation between two oscillatory firing alpha 1-motor units was preserved from one volitional leg muscle activation (isometric contraction) to the subsequent one. Since running times improved upon successive runs for 90 m, the spinal cord seems to be able to store pattern organization for seconds up to minutes. Controlled and uncontrolled oscillatory firing of alpha 1-motor units in volitionally activated leg muscles were observed in this patient, which indicated that there still were pathologic recruitments of subnetworks after re-learning running and other movements. During walking, running, and jumping on a springboard, the activation patterns of the vastus lateralis, hamstrings, tibialis anterior, peronaeus longus, peronaeus brevis and soleus muscles were recorded (surface electromyography) to be still pathologic in accordance with partly still pathologic joint rotation angles measured kinematically. Especially upon running, the left knee joint flexion was reduced in swing by a rather permanent activity of the rectus femoris combined with an extra burst of the vastus lateralis in mid-swing. The recorded abnormalities are due to modification of the motor program rather than to muscle weakness per se. A further improvement of the movements of the patient seems possible by improving the motor program, i.e., by improving the functioning of the spinal pattern generators.(ABSTRACT TRUNCATED)

Accidents, Traffic↗