Rocking Promotes Sleep in Mice through Rhythmic Stimulation of the Vestibular System

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Tremor Suppression by Rhythmic Transcranial Current Stimulation

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Highlights? Phase-cancelling cortical stimulation attenuates Parkinsonian tremor ? Prolonged stimulation may invoke adaptive mechanisms ? Phase cancellation may provide a generic treatment approach to oscillopathies ? TACS provides a convenient probe of cortical circuit dynamics in humans     

Motor Output Patterns during Random and Rhythmic Stimulation of Locust Thoracic Ganglia

This paper employs new statistical techniques to further analyze the flight control system of grasshoppers. The quantitative results confirm some hypotheses which arise from previous studies of this system. After decapitation and ablation of wing proprioceptors, stimulation of the nerve cord at random intervals can elicit a coordinated response closely resembling the normal flight motor output pattern. The coordinated response begins only after many stimuli and there are usually many cycles of after-discharge. The frequency of the cyclic output is rather low and may be increased only slightly by large increases in stimulus frequency. Input from the stretch receptors is necessary to attain normal wingstroke frequency. Frequency of wingbeat rises with a time constant of about 2 seconds (or about 25 wingbeats) when stretch receptor stimulation is initiated. Frequency decay after cessation of stimulation has about the same time constant. No special phase relationship between stimulation and output is necessary for the increase in frequency or maintenance of normal pattern. When input frequency is adjusted as closely as possible to output frequency it is still not possible to force the output to maintain a particular phase with respect to the stimulation, all phase relationships still occur. In some animals all phases occurred with equal probability; in others a particular phase was preferred. When there was a strong phase preference the normal output pattern was disrupted.     

Alpha-Band Rhythms in Visual Task Performance: Phase-Locking by Rhythmic Sensory Stimulation

Oscillations are an important aspect of neuronal activity. Interestingly, oscillatory patterns are also observed in behaviour, such as in visual performance measures after the presentation of a brief sensory event in the visual or another modality. These oscillations in visual performance cycle at the typical frequencies of brain rhythms, suggesting that perception may be closely linked to brain oscillations. We here investigated this link for a prominent rhythm of the visual system (the alpha-rhythm, 8–12 Hz) by applying rhythmic visual stimulation at alpha-frequency (10.6 Hz), known to lead to a resonance response in visual areas, and testing its effects on subsequent visual target discrimination. Our data show that rhythmic visual stimulation at 10.6 Hz: 1) has specific behavioral consequences, relative to stimulation at control frequencies (3.9 Hz, 7.1 Hz, 14.2 Hz), and 2) leads to alpha-band oscillations in visual performance measures, that 3) correlate in precise frequency across individuals with resting alpha-rhythms recorded over parieto-occipital areas. The most parsimonious explanation for these three findings is entrainment (phase-locking) of ongoing perceptually relevant alpha-band brain oscillations by rhythmic sensory events. These findings are in line with occipital alpha-oscillations underlying periodicity in visual performance, and suggest that rhythmic stimulation at frequencies of intrinsic brain-rhythms can be used to reveal influences of these rhythms on task performance to study their functional roles.     

Effect of Rhythmic Auditory Stimulation on Gait in Parkinsonian Patients with and without Freezing of Gait

Freezing of gait (FOG) in Parkinson''s disease (PD) rises in prevalence when the effect of medications decays. It is known that auditory rhythmic stimulation improves gait in patients without FOG (PD-FOG), but its putative effect on patients with FOG (PD+FOG) at the end of dose has not been evaluated yet. This work evaluates the effect of auditory rhythmic stimulation on PD+FOG at the end of dose. 10 PD+FOG and 9 PD-FOG patients both at the end of dose periods, and 10 healthy controls were asked to perform several walking tasks. Tasks were performed in the presence and absence of auditory sensory stimulation. All PD+FOG suffered FOG during the task. The presence of auditory rhythmic stimulation (10% above preferred walking cadence) led PD+FOG to significantly reduce FOG. Velocity and cadence were increased, and turn time reduced in all groups. We conclude that auditory stimulation at the frequency proposed may be useful to avoid freezing episodes in PD+FOG.     

Rhythmic Acoustic Stimulation as a Method for Regulating the Functional State of the CNS in Young Schoolchildren

The author studied the dynamics of EEG (spectral power density and coherence functions) and autonomic (electrodermal resistance, EDR) indices in young schoolchildren with changes in the functional state of the CNS caused by rhythmic sensory stimulation (acoustic signals with frequencies of 6 and 9 Hz). Both of these signals influenced the CNS and may be used to achieve relaxation. Their comparison demonstrated both similar postrelaxation shifts (increased coherence of distant connections) and frequency-specific phenomena (more numerous significant changes in the respective frequency ranges). Thus, the signal frequency determines the pattern of physiological shifts, influencing the relaxation quality. Low-frequency (6 Hz) stimulation caused more pronounced changes in the CNS, reflected in enhanced EDR, and a stronger increase in the short-term memory volume. The author discusses the frequency-specific neurophysiological mechanisms of the effect of stimulation on the functional state of the brain.     

Effect of Serotonin on Dynamics of Changes of the Shadow Reflex in Lymnaea stagnalis at a Rhythmic Stimulation

The dynamics of the Lymnaea stagnalis defensive response to the shadow stimulation and its changes under the effect of serotonin solution injections were studied. The consecutive shadow stimuli led to development of habituation in the form of decreased summarized responses in groups of the studied molluscs. The diagram of distribution of probabilities of transitions between the mollusc states and the definite types of their responses had characteristic peaks. An injection of serotonin at doses corresponding to 0.5–2 µg/g body weight increased responses of molluscs to the shadow stimuli with a rise of the probability of their appearance. Serotonin (4 µg/g) reduced the mollusc response to the shadow stimulation by decreasing the response probability. The serotonin-induced behavioral changes were observed for about 0.5 h after the injection. This was accompanied by a redistribution of probabilities of the states and types of the responses, which in turn led to a partial shift of the peaks in the diagrams obtained.     

脑电仿生电刺激对缺血性脑卒中失眠症患者睡眠质量的影响

摘要 目的：探讨脑电仿生电刺激对缺血性脑卒中失眠症患者睡眠质量的影响。方法：2018年1月到2019年12月选择在新疆医科大学第六附属医院诊治的缺血性脑卒中失眠症患者120例,根据随机数字表法分为研究组与对照组各60例。对照组给予常规药物治疗,研究组在对照组治疗的基础上给予脑电仿生电刺激治疗,治疗观察4 w,评定患者睡眠质量变化情况。结果：两组治疗后的匹斯堡睡眠质量指数量表（Pittsburgh Sleep Quality Index,PSQI）评分都显著低于治疗前（P<0.05）,研究组评分也显著低于对照组（P<0.05）。治疗后研究组的总有效率为98.3 %,显著高于对照组的85.0 %（P<0.05）。研究组治疗后的左右椎动脉血流速度都显著高于治疗前（P<0.05）,也显著高于对照组（P<0.05）。治疗后两组的Berg平衡量表(Berg balance scale,BBS)与巴氏(Barthel)评分显著高于治疗前（P<0.05）,研究组评分也显著高于对照组（P<0.05）。结论：脑电仿生电刺激在缺血性脑卒中失眠症患者中的应用能改善睡眠质量,提高恢复平衡与日常生活功能,改善脑血流速度,从而提高治疗效果。     

The Rhythmic GABAergic System

GABA is the major inhibitory neurotransmitter in the mammalian brain, and has been implicated in the regulation of a variety of behavioral functions, including biological rhythms. The focus of this minireview is the rhythmic variation of the central GABAergic system, comprising fluctuations of GABA levels and turnover, GABA receptor affinity and postsynaptic activity on the chloride ionophore in rodent's brain. Neurochemical rhythms correlated with diurnal and circadian changes in several behaviors associated with the GABA_A receptor, e.g., anxiolysis-related behavior. GABA is considered to be the principal neurotransmitter of the mammalian circadian system, being present in the suprachiasmatic nuclei and the intergeniculate leaflet. Pharmacological manipulations of GABA_A receptors phase shift circadian rhythms and alter circadian responses to light. Administration of putative modulators of GABA function, like melatonin or neuroactive steroids, affects the timing of biological rhythms. Therefore, not only does the GABAergic system exhibit strong diurnal and circadian variations, but it also serves as one of the key modulators of the circadian apparatus.     

Dynamics of the Adolescent EEG Parameters with Changes in the CNS Functional State (Relaxation) Influenced by Rhythmic Acoustic Stimulation

Age-related specific features of the regulation of the CNS functional state (relaxation) were studied in adolescents between the ages of 14 and 15 years using 6-Hz rhythmic stimulation. The dynamics of the EEG findings (spectral power density, coherence functions) in the quiet wakefulness–relaxation–initial-state cycle was analyzed. The dynamics of the functional state was controlled by changes in the electrodermal resistance (EDR). The data showed that the studied group of adolescents was heterogeneous by the effectiveness of self-regulation: the majority was characterized by marked shifts whose distribution character was close to normal; the others, by mild EDR changes. It was shown that, with the use of rhythmic stimulation, relaxation shifts were more marked than those induced by common psychotherapeutic techniques. The basic relaxation changes in the EEG parameters are related to changes in the coherence function values, i.e., increases in its values, especially those of distant relations (with the focus) of significant connections in the frontal regions. The rate of the occurrence of relaxation changes in the coherence values is substantially higher in the low-frequency band (5 to 7 Hz) than in the EEG -band, constituting 20 to 50% in terms of different relations. The revealed specific features of the relaxation dynamics of the EEG parameters are analyzed in the age-related aspect. The influence of higher structures of the CNS and puberty-related rearrangements in the system of neuroendocrine regulation on the effectiveness of the regulatory function is discussed.     

Evidence for Multiple Rhythmic Skills

Rhythms, or patterns in time, play a vital role in both speech and music. Proficiency in a number of rhythm skills has been linked to language ability, suggesting that certain rhythmic processes in music and language rely on overlapping resources. However, a lack of understanding about how rhythm skills relate to each other has impeded progress in understanding how language relies on rhythm processing. In particular, it is unknown whether all rhythm skills are linked together, forming a single broad rhythmic competence, or whether there are multiple dissociable rhythm skills. We hypothesized that beat tapping and rhythm memory/sequencing form two separate clusters of rhythm skills. This hypothesis was tested with a battery of two beat tapping and two rhythm memory tests. Here we show that tapping to a metronome and the ability to adjust to a changing tempo while tapping to a metronome are related skills. The ability to remember rhythms and to drum along to repeating rhythmic sequences are also related. However, we found no relationship between beat tapping skills and rhythm memory skills. Thus, beat tapping and rhythm memory are dissociable rhythmic aptitudes. This discovery may inform future research disambiguating how distinct rhythm competencies track with specific language functions.     

Rhythmic metrazol activity and cortical spreading depression

The incidence of segments of rhythmic metrazol activity (RMA) in cortical leads and in the thalamus and hippocampus was studied in acute experiments on nine male albino laboratory rats. First of all we studied activity after administering metrazol in an i.p. dose of 50 mg/kg, without any further treatment, and then, after a control recording, we induced cortical spreading depression and observed its effect on the incidence and synchronization of RMA in the individual leads. We came to the conclusion that the thalamus is incapable of isolated production of RMA. The cortex is able to produce RMA without participation by the studied structures of the specific thalamus and hippocampus; RMA probably originates in the cortex itself. Generalization is impaired, but not eliminated, by a cortical block. The hippocampus independently produces another type of rhythmic activity.     

Effects of Somatosensory Stimulation on Dream Content in Gymnasts and Control Participants: Evidence of Vestibulomotor Adaptation in REM Sleep

Somatosensory stimulation of the leg muscles in REM sleep appears to perturb virtual orientation in dream experiences. According to our model of vestibulomotor adaptation (Sauvageau, Nielsen, & Montplaisir, 1996), the dreaming mind attempts to compensate for such destabilizing stimulation by increasing eye movement activity or by modifying dream content, among other possible reactions. Effective compensation may be more easily achieved by participants who are adapted to the disruptive stimulation or who possess highly developed vestibulomotor skills. To examine this possibility, we studied the effects of Somatosensory stimulation on the dreams of 6 gymnasts and 6 control participants aged 9 to 16 years. Results provide some support for the expectations that 1) imposed Somatosensory information is processed by the central nervous system in REM sleep, 2) unilateral stimulation induces an upset in virtual orientation, 3) gymnasts are more resistant to these disruptive effects of stimulation than are control participants, and 4) because of long-term adaptation, the dream content of gymnasts does not differ markedly from that of controls. Though preliminary and in need of replication, the findings are compatible with the notion that the developed vestibular skills of gymnasts protects them to some extent from the effects of a disruptive Somatosensory stimulus during sleep.     

Recurrent Circuitry for Balancing Sleep Need and Sleep

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Mutual Stabilization of Rhythmic Vocalization and Whole-Body Movement

The current study investigated the rhythmic coordination between vocalization and whole-body movement. Previous studies have reported that spatiotemporal stability in rhythmic movement increases when coordinated with a rhythmic auditory stimulus or other effector in a stable coordination pattern. Therefore, the present study conducted two experiments to investigate (1) whether there is a stable coordination pattern between vocalization and whole-body movement and (2) whether a stable coordination pattern reduces variability in whole-body movement and vocalization. In Experiment 1, two coordination patterns between vocalizations and whole-body movement (hip, knee, and ankle joint flexion-on-the-voice vs. joint extension-on-the-voice) in a standing posture were explored at movement frequencies of 80, 130, and 180 beats per minute. At higher movement frequencies, the phase angle in the extension-on-the-voice condition deviated from the intended phase angle. However, the angle of the flexion-on-the-voice was maintained even when movement frequency increased. These results suggest that there was a stable coordination pattern in the flexion-on-the-voice condition. In Experiment 2, variability in whole-body movement and voice-onset intervals was compared between two conditions: one related to tasks performed in the flexion-on-the-voice coordination (coordination condition) that was a stable coordination pattern, and the other related to tasks performed independently (control condition). The results showed that variability in whole-body movement and voice-onset intervals was smaller in the coordination condition than in the control condition. Overall, the present study revealed mutual stabilization between rhythmic vocalization and whole-body movement via coordination within a stable pattern, suggesting that coupled action systems can act as a single functional unit or coordinative structure.