Auditory rhythmicity enhances movement and speech motor control in patients with Parkinson's disease.
Explore the source record for details and available documents.
SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
The interlick interval distribution of rats while ingesting maltose under real and sham feeding conditions and while ingesting seven concentrations of sucrose under real feeding conditions was analyzed. The analysis revealed that the licking behavior of rats is organized into bursts of licking at a high rate. These bursts occurred in clusters that were separated by brief (250-500 ms) interruptions. The clusters were separated by intervals that ranged from 500 ms to many hundreds of seconds. Sham feeding increased the length of the meal by increasing the number but not the size of the clusters. Increasing the concentration of sucrose increased monotonically the size of the clusters but varied the number of clusters as an inverted-V-shaped function. This analysis revealed the details of the central nervous system's control over ingestive behavior.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Rhythmic movement patterns have served as a model case for developing a synergetic theory of biological coordination. In part I of this work we extended the approach to environmentally-specified and learned movement patterns on the level of the collective variable relative phase. Here we show that an identical strategy may be applied to the same problem at the level of the component oscillators. Coordinative patterns and their dynamics are derived from the coupled component dynamics and their interaction with the environment. Thus, behavioral patterns are shown to arise in a purely self-organized fashion. New directions for further research (e.g. dynamics of action-perception systems) follow from the oscillator theory. Finally the relationship between our approach and other kinds of analyses of temporal order (e.g. phase resetting) is addressed.
The digastric reflex was elicited in lightly anesthetized juvenile rabbits by electrical stimulation of the tongue. The reflex was depressed by maintained intraoral mechanical stimuli and facilitated by transient intraoral mechanical stimuli applied using a vinyl tube in the buccal sulcus. Intraoral mechanical stimuli were also used to elicit rhythmic oral activities; these were of four types but only the two most easily distinguished types were studied further. One type, elicited by agitating a soft vinyl tube in the buccal sulcus (the tube was then taken further into the mouth by the animal and chewed), was categorized as "transport/chew"; another type, most easily elicited by fluid passed down the stationary tube (which was then removed), was categorized as "liquid." When initiated, the two rhythmic activities continued with no further external stimulation although the intraoral self-stimulation differed. When the digastric reflex was elicited during rhythmic movements, the response was phasically modulated. More than 80% of the digastric reflex responses elicited during jaw closure in "liquid" cycles were less than control values but less than 60% of responses elicited in the same phase of "transport/chew" cycles were less than control values; the difference was significant (P less than 0.001; chi 2). The findings were consistent with two hypotheses: that sensory input, generated by the animal during the rhythmic oral movements, modulates the reflex; and that stimuli initiating particular rhythmic oral movements select one of a number of potential modes of operation of the pattern generator, each with its characteristic pattern of modulation of the digastric reflex.
The amplitudes and signs of cutaneous reflexes are modulated during rhythmic movements of the arms and legs (during walking and arm or leg cycling for instance). This reflex modulation is frequently independent of the background muscle activity and may involve central pattern generator (CPG) circuits. The purpose of the present study was to investigate the nature and degree of coupling between the upper limbs during arm cycling, with regard to the regulation of cutaneous reflexes. Responses to electrical stimulations of the right, superficial radial nerve (five 1 ms pulses, 300 Hz) were recorded bilaterally in six arm muscles of eight participants during arm cycling involving only the limb ipsilateral to the stimulation, only the limb contralateral to the stimulation, and bilateral movement when the limbs were both in-phase and 180 degrees out of phase. The pattern of cutaneous reflex modulation throughout the arm cycle was independent of the functional state of the limb contralateral to the recording site, irrespective of whether recordings were made ipsilateral or contralateral to the stimulation. Furthermore, cutaneous reflexes were significantly (p<0.05) modulated with arm position in only 8% of cases in which the limb containing the responding muscle was either stationary or being moved passively by the experimenter. The results show that there is relatively weak coupling between the arms with regard to the regulation of cutaneous reflexes during rhythmic, cyclical arm movements. This suggests a loose connection between the CPGs for each arm that regulate muscle activity and reflex amplitude during rhythmic movement.
The organization and pattern of cutaneous reflex modulation is unknown during rhythmic cyclical movements of the human upper limbs. On the assumption that these cyclic arm movements are central pattern generator (CPG) driven as has been suggested for leg movements such as walking, we hypothesized that cutaneous reflex amplitude would be independent of electromyographic (EMG) muscle activation level during rhythmic arm movement (phase-dependent modulation, as is often the case in the lower limb during locomotion). EMG was recorded from eight muscles crossing the human shoulder, elbow, and wrist joints while whole arm rhythmic cyclical movements were performed. Cutaneous reflexes were evoked with trains of electrical stimulation delivered at non-noxious intensities (approximately 2 x threshold for radiating paresthesia) to the superficial radial nerve innervating the lateral portion of the back of the hand. Phasic bursts of rhythmic muscle activity occurred throughout the movement cycle. Rhythmic EMG and kinematic patterns were similar to what has been seen in the human lower limb during locomotor activities such as cycling or walking: there were extensive periods of reciprocal activation of antagonist muscles. For most muscles, cutaneous reflexes were modulated with the movement cycle and were strongly correlated with the movement-related background EMG amplitude. It is concluded that cutaneous reflexes are primarily modulated by the background muscle activity during rhythmic human upper limb movements, with only some muscles showing phase-dependent modulation.
Vertical and horizontal jaw movements along with lateral pterygoid (PT) and anterior digastric (DIG) muscle electromyogram (EMG) activity were recorded in anesthetized guinea pigs during electrical stimulation of the masticatory area of cortex. Both repetitive stimulation at 25 Hz and short pulse-train stimulation (3 pulse, 500 Hz) delivered 2/s produced jaw opening with a horizontal component contralateral to the side of cortex stimulated in addition to short latency (7-12 ms) evoked EMG bursts in the ipsilateral PT muscle and in the DIG muscles bilaterally. Evidence was also obtained which indicated that both types of cortical stimulation resulted in time-locked inhibition of the contralateral PT muscle. Unlike each short train of stimulus pulses, however, each pulse in the repetitive train did not evoke jaw movement and EMG bursts of a consistent amplitude. Rather, repetitive stimulation produced rhythmical movements of the jaw associated with recurrent periods of activity and inactivity in the EMG records. These results demonstrate the presence of a corticotrigeminal pathway between masticatory cortex and PT motoneurons in addition to a similar pathway to DIG motoneurons, and suggest that both pathways are similarly modulated by a central pattern generator to produce rhythmical jaw movements.
Rhythmic movement patterns between the hands in response to environmental signals are studied in normal (musicians and nonmusicians) and split-brain subjects. Only two phase-locked states - in-phase and anti-phase - are shown to be stable for all subjects. Split-brain subjects show an even greater attraction to these patterns, thus providing no support for the notion that reduced cortical interaction between the hemispheres allows for independent visuomotor control of the hands in such tasks. Moreover, differences in trajectories produced by normal individuals and those without an intact corpus callosum are remarkable. The resultant patterns of coordination afford 1) a generalization of previous results on intrisincally generated rhythmic behavior to environmentally-specified movement patterns; and 2) a discussion of neural mechanisms underlying stable phase relations.
Despite that deep brain stimulation (DBS) of the globus pallidus internus (GPi) is emerging as the favored intervention for patients with medically intractable dystonia, the pathophysiological mechanisms of dystonia are largely unclear. In eight patients with primary dystonia who were treated with bilateral chronic pallidal stimulation, we correlated symptom-related electromyogram (EMG) activity of the most affected muscles with the local field potentials (LFPs) recorded from the globus pallidus electrodes. In 5 dystonic patients with mobile involuntary movements, rhythmic EMG bursts in the contralateral muscles were coherent with the oscillations in the pallidal LFPs at the burst frequency. In contrast, no significant coherence was seen between EMG and LFPs either for the sustained activity separated out from the compound EMGs in those 5 cases, or in the EMGs in 3 other cases without mobile involuntary movements and rhythmic EMG bursts. In comparison with the resting condition, in both active and passive movements, significant modulation in the GPi LFPs was seen in the range of 8-16 Hz. The finding of significant coherence between GPi oscillations and rhythmic EMG bursts but not sustained tonic EMG activity suggests that the synchronized pallidal activity may be directly related to the rhythmic involuntary movements. In contrast, the sustained hypertonic muscle activity may be represented by less synchronized activity in the pallidum. Thus, the pallidum may play different roles in generating different components of the dystonic symptom complex.