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PubMed1989

The use of dynamic electromyography to evaluate motor control in the hands of adults who have spasticity caused by brain injury.

A dynamic electromyographic analysis of grasp and release, performed on forty-eight upper extremities of forty-two adults who had had injury to the brain causing spasticity, showed volitional motor control of the finger flexors in 80 per cent and active extension of the fingers in 60 per cent. The flexor pollicis longus showed volitional control in 75 per cent of the hands and the extensor pollicis longus showed active control in 50 per cent. The extensor carpi radialis longus acted as an appropriate stabilizer of the wrist in 85 per cent of the extremities. Fourteen muscles had out-of-phase activity that could not be detected on clinical examination. The position of the elbow did not appreciably influence the electromyographic pattern of motor control in the hand.

Adolescent↗
PubMed1987

[Value of bifocal stereotaxic destruction in case of dyskinesia in patients with a motor deficit of cerebral origin].

Authors report a study concerning 12 dyskinetic patients with cerebral palsy. The clinical pre-operative examination shows that many signs and symptoms are associated: volitional and postural dyskinesia, athetosis and dystonia, pyramidal deficit and spasticity. Talairach's stereotactic methodology has been used for bifocal (VPL thalamic nucleus and internal pallidum) Yttrium 90 implantation. After stereotactic bifocal lesions, involuntary movements have been reduced in 45.5% of cases and have disappeared in 27% of cases. Impairment of previous motor deficit has been observed in 3% of cases; volitional and postural dyskinesia seems to be the most curable symptomatology. Clinical results in athetoid involuntary movements and dystonia are less rewarding. Because of important anatomical modifications often observed cerebral palsy patients, the authors stress the interest of individual acute neurophysiological study and discuss about the stereotactic targets and the modalities of destruction. They insist upon the necessity of rigorous selection of indications based on acute clinical examination in the perspective of improvement of global functional capacities.

Adolescent↗
PubMed1988

[Voluntary activity of the neck muscles in patients with spastic torticollis].

The authors investigated the characteristics of motor disorders in patients with spastic torticollis. The study involved registration of volitional tensions of the neck muscles in isometric conditions, i.e., when the patient's head was rigidly fixed with regard to the body. Using a tensometric dynamometer the following three moments of force were measured: one responsible for bending the head forward or backward; the second, for bending the head to the right or left shoulder; and the third, for turning the head round the longitudinal axis. The electrical activity of the neck muscles was recorded with the help of surface electrodes. It has been established that the development of volitional efforts by the neck muscles under isometric conditions is difficult or impossible if directed to the side where the patient's forcible turn of the head is directed.

Chronic Disease↗
PubMed1972

Role of prefrontal and anterior temporal cortex in social behavior and affect in monkeys.

Prefrontal or anterior temporal but not cingulate cortex lesions lead to major deficits in all aspects of social behavior including maternal protectiveness, aggressiveness, group cohesiveness, defense of territory, maintenance of hierarchical status, and, even, sexual behavior. Lesions of visual association cortex, on the other hand, fail to produce such deficits. Rather, these deficits appear to be spedfically emotional in nature and not related to impairments in perceptual or sensory functions. Prefrontal and anterior temporal cortical lesions also produce major losses in both facial expressions and in vocalizations suggesting these functions in the rhesus monkey participate primarily in emotional and socia1 communications. In keeping with this interpretation, present studies show a major difficulty in bringing rhesus monkey vocalizations under instrumental or conditioned control. Thus, in this species, there exists a major difficulty of access between the volitional control mechanisms of the cortex and the vocalization apparatus. The present findings support the hypothesis of a duel control of the face and voice in man whereby there still exists prominently the emotional or affective element which mediates all involuntary or spontaneously emotive expressions of feeling. This more primitive and aged mechanism for face and voice control utilizes quite different neural control mechanisms than does the more recently derived system which provides for a volitional face and voice control. This more recent system has developed embedded wlithin the posteriorly located analytic and mnemonic cortical tissues and provides for communications between individuals within the species at symbolic, verbal levels.

Affect↗
PubMed1981

[Clinical picture of the late stages of sluggishly-progressing schizophrenia in advanced age].

Under examination there were 190 patients over 60 years of the age suffering from sluggishly progressing schizophrenia and observed at dispensaries for the long time. The course of the psychopathological disorders characteristic of that disease was followed in them for many decades. At the late age a tendency to a regression of most productive symptoms, a certain enlivening of the emotional-volitional sphere, and exaggeration of the signs of the personality structure deformity was revealed. Two types of the negative disorders are specified: one with prevalence of intellectual-volitional impairments (prognostically less favourable), and the other with prevalence of affective changes (prognostically more favourable). Comparative results of studying the time course of the personality's post-process changes in 158 ambulatory patients of the same age are also presented.

Age Factors↗
PubMed1980

Current investigations in headache.

The responses of supraorbital (SA), superficial temporal (TA), and digital (F) arterial beds and heart rate were studied in 5 normal subjects and 10 migraineurs when hand temperature was increased by volition and/or by heat. In normal subjects, volitional digital arterial dilation coincided with vasoconstriction in SA and TA. In migraineurs, the response varied. Bradycardia resulted in most subjects except in unimproved migraineurs. Heat-induced hand vasodilation led to dilation in SA and TA and to tachycardia. In the 8 migraineurs who improved clinically, the finger temperature feedback training apparently did not result in conditioning of a single autonomic response (i.e. digital vasocilation), but in a general decrease of the sympathetic tonic outflow. Improvement in migraine could also be correlated with improvement in psychological tests, with MMPI scores indicative of neurosis, significantly improving in those patients who learned and practiced the BF technique. A pilot study aimed at detection of serum complement alterations in migraine does not suggest a diminished level of the inhibitor of the first component and further inquiry into the possible serum complement abnormalities in migraineurs is in process. The possible relationships between the vasomotor changes in migraine, the reduction in sympathetic tonic outflow evoked by biofeedback, and their psycho-physiological significance have been discussed. An integrated, interpretative fusion of these data is proposed. A new conditioned vasomotor reflex, which we have termed the relaxation reflex, has been described. It should be explored whether BF has more wide applications in the treatment of other "psychosomatic" disorders characterized by vasomotor abnormalities and increased sympathetic tone.

Adult↗
PubMed1995

[Control mechanisms of locomotor movements from a viewpoint of behavioral control].

Locomotor movements are generally considered to be established by integrating the activities of the neuronal mechanisms related to each of the "automatic" and "volitional" control. As one of the neuronal mechanisms contributing to such integration, the possible roles played by the ponto-medullary reticular formation have recently been reexamined. As is well established, cells in the ponto-medullary reticular formation are related to arousal behavior, and the reticular formation itself is one of the major sources for generalized motor drive. In intact, awake cats, electrical stimulation delivered directly or indirectly to the reticular formation can evoke locomotor movements accompanied by an "alerting response" and preceded by postural adjustments adequate for locomotion. Microinjection of bethanechol, a short-acting cholinergic agonist, into the pontine reticular formation results in a peculiar modification of posture and, as a consequence, locomotor movements, even changing the arousal level of the animals. The cats with bilateral tegmental lesions in the pons exhibit locomotor movements during a state of rapid eye movement sleep without atonia. It is conceivable that the ponto-medullary reticular formation contributes greatly to the integration of neuronal activities related to automatic and volitional control of locomotor movements so as to establish a goal-directed behavioral locomotor movement.

Animals↗
PubMedDate not supplied

Artificial feedforward as preparatory motor control in postictal hemiparesis.

One of the most important disturbances in spastic hemiparesis is the lack of reciprocal inhibition and the insufficient and inadequate preparatory programming of this inhibition. In 40 patients with postical hemiparesis some preparatory procedures foregoing the volitional movement attempt were assumed. The movement was extension of the wrist and the intended reciprocal inhibition was that in the wrist flexors. The procedures were extensor muscle vibration or electrostimulation which produce contraction of the wrist extensors and reciprocal inhibition in the wrist flexors. A conditioning has been attempted of these effects achieved at spinal level to the existing ipsilateral and spared contralateral cortical influences during a volitional extension of the wrist. In this way an artificial feedforward have been created, with favourable results in motor reeducation of wrist movements.

Cerebrovascular Disorders↗
PubMed1993

Alterations of motor evoked potentials by thalamotomy.

To evaluate the effect of stereotactic thalamotomy on the function of the corticospinal tract, we studied motor evoked potentials (MEPs) recorded by surface electromyography (EMG) in the left extensor carpi radialis (ECR) and flexor carpi radialis (FCR) with magnetic stimulation of the contralateral motor cortex in a 43-year-old patient with a severe postural and resting tremor of the left hand. The patient was diagnosed eight years previously with left hemiparkinsonism. The tremor was unresponsive to various medications. After thalamotomy the tremor had disappeared, confirmed by EMG studies. MEP latencies at rest were normal and did not change after thalamotomy. Volitional contraction of either ECR or FCR shortened the latency of the corresponding MEP before and after thalamotomy. However, before thalamotomy responses at rest were less well synchronized and followed by EMG silence with subsequent long duration tonic after discharges. Furthermore, during voluntary contraction the responses only slightly enhanced. After surgery MEPs at rest in both muscles were more synchronized and after-discharges had disappeared. Moreover, with volitional contraction of either ECR of FCR, the MEPs enhanced more dramatically. The silent periods (SPs) following the MEP during sustained voluntary contraction were longer after thalamotomy. The consistent MEP latencies suggest that the conduction of the pyramidal tract is unaffected by thalamotomy. The better synchronized responses, the alleviation of after-discharges and the longer SPs in this patient with hemiparkinsonism following thalamotomy suggest an improved sensorimotor integration, which may be the result of a reduced thalamic input onto suprasegmental levels.

Adult↗
PubMed1996

Catecholamine response to maximal exercise following 16 days of simulated microgravity.

INTRODUCTION: We tested the hypothesis that the elevated peak heart rate (HR) response to maximal exercise following microgravity exposure is associated with increased plasma levels of catecholamines. METHODS: To do this, plasma norepinephrine (NE) and epinephrine (E) were measured in venous blood samples obtained from 7 subjects before and immediately after graded supine cycle exercise to volitional fatigue performed prior to and at the conclusion of 16 d of 6 degrees head-down tilt (HDT). RESULTS: Resting HR was increased (p = 0.014) following HDT (56 +/- 3 to 63 +/- 2 bpm), but pre-exercise NE concentration (217 +/- 18 pg.ml-1) was not different (p = 0.224) from that measured before HDT (183 +/- 23 pg.ml-1). Peak exercise HR was greater (p = 0.001) after simulated microgravity exposure compared to pre-HDT (181 +/- 3 bpm vs. 172 +/- 4 bpm). NE measured at volitional fatigue was 64% higher (p = 0.004) after HDT compared to that measured prior to HDT (1337 +/- 181 vs. 2191 +/- 189 pg.ml-1 for pre- and post-HDT, respectively). Plasma E concentration at exhaustion was unchanged by microgravity exposure. CONCLUSIONS: Our observation of greater levels of plasma NE and peak exercise HR suggests that sympathetic influences on cardiac chronotropic control may be altered by exposure to prolonged microgravity.

Adult↗
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↗
PubMed1997

[Movement and behavioral disorders in anterior cerebral artery territory infarction].

Anterior cerebral artery territory infarction, which affects the medial frontal lobe and anterior part of the corpus callosum, may cause disinhibitory movement and behavioral disorders. The pathophysiology of disinhibitory movement and behavioral disorders was discussed in relation to the role of the frontal lobe in motor control and hemispheric asymmetry of motor functions. Instinctive grasp reaction is the prototype of disjunctive motor disinhibition syndromes, and diagnostic dyspraxia and compulsive manipulation of tools are the most illustrative forms. Diagnostic dyspraxia can be defined as uncontrolled cross-purposeful actions of the left hand triggered by voluntary activities of the left hand. In compulsive manipulation of tools, a patient, with the right hand, grasp and use tolls placed in front of them against the patient's will. The left hand often restrains the unintentional movement of the right hand in accordance with the patient's will. Utilization and imitation behaviors described by Lhermitte et al belong to disinhibitory behavioral disorders, in which volition of the patient or an individual as a whole is involved. External stimuli reflexively provoke the patient's will to act. The behaviors accordant with the will, even if inappropriate, are not compulsive, but the easily-raised volition in response to the stimuli is pathological. These disinhibitory disorders differ from disjunctive motor disinhibition syndromes because of lack of inconsistency between will and manifested behavior. Lesions in the frontal lobes has been suggested to be responsible for utilization and imitation behaviors.

Cerebral Infarction↗
PubMed1998

[The relationship between the perceived threat of environmental problems and the formation of action intentions].

The results of a study using questionnaires at two measuring points in high schools in North Germany are reported and discussed. This article analyzes the students' reasons and motivation for more or less environmentally friendly behavior. An integrated theoretical concept of motivation for human action formed the theoretical basis. The action genesis process was subdivided into the phases of forming motives, intentions and volition. Following a presentation of this theoretical concept and its definition with regard to competing and compatible theoretical hypotheses, the methodological procedure is described whereby the various motivation structures of the pupils questioned were analyzed. Mixed distribution models were used which allow modelling of complex multivariate relationships (latent class analysis and mixed Rasch models). The results show strong positive relationships among the variables of the motivation, the intention and the volition phases, but with isolated area-specific motivation patterns and moderator effects of certain cognitive variables.

Adaptation, Psychological↗
PubMed1998

A functional magnetic resonance imaging study of tic suppression in Tourette syndrome.

BACKGROUND: The inability to inhibit unwanted behaviors and impulses produces functional debility in a broad range of neuropsychiatric disorders. A potentially important model of impulse control is volitional tic suppression in Tourette syndrome. METHODS: Tic suppression was studied in 22 adult subjects with Tourette syndrome by using functional magnetic resonance imaging. Images acquired during periods of voluntary tic suppression were compared with images acquired when subjects allowed the spontaneous expression of their tics. The magnitudes of signal change in the images were then correlated with measures of the severity of tic symptoms. CONCLUSIONS: Significant changes in signal intensity were seen in the basal ganglia and thalamus and in anatomically connected cortical regions believed to subserve attention-demanding tasks. The magnitudes of regional signal change in the basal ganglia and thalamus correlated inversely with the severity of tic symptoms. These findings suggest that the pathogenesis of tics involves an impaired modulation of neuronal activity in subcortical neural circuits.

Adolescent↗
PubMed1998

Diagnostic yield of stimulation and voluntary single-fiber electromyography in myasthenia gravis.

Voluntary and stimulation single-fiber electromyography were performed in the extensor digitorum communis muscle of 15 myasthenic patients. The increase in mean and individual mean consecutive difference as well as the proportion of blocking in the volitional activation were greater than in the stimulation method. These differences may be explained in part by the different degree of alteration in large as compared with small motor units in patients with myasthenia gravis.

Aged↗
PubMed1983

Magnetic fields of the human brain (Bereitschaftsmagnetfeld) preceding voluntary foot and toe movements.

Voluntary movements are preceded by a slow electrical potential of the brain (Bereitschafts-potential, BP) or readiness potential. The BP is accompanied by a magnetic field shift of similar time characteristics (Bereitschaftsmagnetfeld, BM). The BM preceding volitional right foot or toe movements was recorded from anterior, posterior, and lateral positions of the scalp using a SQUID (Superconducting Quantum Interference Device) third-order gradiometer. Controls were implemented to reduce head movements, which were simultaneously recorded with a mechanograph. The results showed that movements of the lower extremities are also preceded by a BM. However, contrary to finger movements, BMs with field lines directed into the head were found predominantly for foot movements and exclusively for toe movements. The BM preceding foot movements was maximum over a position 2 cm left of the vertex, i.e., contralateral to the movement. Two centimeters right of the vertex it was smaller, thus exhibiting a normal contralateral preponderance and not sharing the paradoxical side preponderance of the electrical BP preceding foot or toe movements. The BM preceding toe movements was only apparent at the vertex and was smaller than the one preceding foot movement. This may suggest a source that is located still deeper in the brain than with foot movements.

Brain↗
PubMed1987

Voluntary smooth eye movements with foveally stabilized targets.

We investigated the capacity of 6 humans to make voluntary smooth eye movements with a horizontally stabilized foveal point target. When the target was viewed on a dark field, all subjects were able to make smooth oscillatory eye movements when they attempted to imitate their own normal pursuit of sinusoidal target movement (0.2-0.7 Hz) directly preceding the stabilization on the fovea. The frequency of the imitating eye movement was in general lower than the frequency of normal pursuit by 2-35%. While fixating a foveally stabilized point target superimposed on a large, sinusoidally moving non-stabilized background, all subjects were able to make either no eye movements, eye movements nearly in phase with or eye movements nearly in counterphase with the background movement depending on the instruction to imagine the target as head-stationary, moving in phase, or moving in counterphase with the background. The accuracy of the frequency of the smooth eye movement with the stabilized target on the moving background was higher than during imitation of pursuit on the dark field but the precision of the frequency was lower than during normal pursuit. When the background moved pseudo-randomly all subjects could voluntarily inhibit their smooth eye movements or could make smooth eye movements in phase with the background. Only 2 subjects showed a limited ability to make smooth eye movements opposite to the pseudo-random background movement. The results suggest that with predictable background movement the volition of the subject rather than the movement of the background determines the eye movements when the subject looks at the foveally stabilized target.

Eye Movements↗
PubMed1975

[Whistler for two voices (sound of whistle produced by man) (author's transl)].

"Double tone whistling" is the rare ability to produce two different tones of whistle with the mouth at the same time and with volitional intervalls between two tones: melodies being whistled this way sound therefore as two voices. With two persons who have this ability we could tape several melodies, analyse them and conclude from this the origin of the two single tones. Beside that we also could analyse a case of "tripletone" melodies and compare it with the results of our sonogramms. The recordings were analysed with the AF-spectrum-analyser Songraph 6061 B. From the interpretation of the patterns follows: In nearly all cases there is a "switching over" between two tones (see Figs. 1, 4, 5). The intervall between the two tones is not fixed but harmonic. Listening to this gives the impression of tremolo. One of our persons could even continue whistling are tone after the change over to the other tone for a short time (about 50 msec). You get the impression of "switching over" even when only listening to the recording of the double-tone whistling of person 2. As mentioned above, we were able to analyse the "melodies for three voices" as indicated by Scheminzky (1957). "Double tone whistling" and independent humming at a lower frequency form this three voices of the "three voice melody". In opposition to Scheminzky's conjecture, a changing over and not a continuous side by side of the two single tones is the basis of this "doubletone whistling". The results of our analysis are: Person 1 seems to be able to form two resonant rooms in the mouth cavity with the tongue with two resonance frequencies. Person 2 could indicate two kinds of whistle at two voices: a) The tongue is being moved forth and back in the rhythm of the switching over. b) The tongue is being fixed and the cheeks change the shape of the mouth-cavity in the rhythm of the change over.

Acoustics↗