Rhythmic Processes Research Articles

Beta oscillations predict the envelope sharpness in a rhythmic beat sequence

Periodic sensory inputs entrain oscillatory brain activity, reflecting a neural mechanism that might be fundamental to temporal prediction and perception. Most environmental rhythms and patterns in human behavior, such as walking, dancing, and speech do not, however, display strict isochrony but are instead quasi-periodic. Research has shown that neural tracking of speech is driven by modulations of the amplitude envelope, especially via sharp acoustic edges, which serve as prominent temporal landmarks. In the same vein, research on rhythm processing in music supports the notion that perceptual timing precision varies systematically with the sharpness of acoustic onset edges, conceptualized in the beat bin hypothesis. Increased envelope sharpness induces increased precision in localizing a sound in time. Despite this tight relationship between envelope shape and temporal processing, it is currently unknown how the brain uses predictive information about envelope features to optimize temporal perception. With the current EEG study, we show that the predicted sharpness of the amplitude envelope is encoded by pre-target neural activity in the beta band (15–25 Hz), and has an impact on the temporal perception of target sounds. We used probabilistic sound cues in a timing judgment task to inform participants about the sharpness of the amplitude envelope of an upcoming target sound embedded in a beat sequence. The predictive information about the envelope shape modulated task performance and pre-target beta power. Interestingly, these conditional beta-power modulations correlated positively with behavioral performance in the timing judgment task and with perceptual temporal precision in a click-alignment task. This study provides new insight into the neural processes underlying prediction of the sharpness of the amplitude envelope during beat perception, which modulate the temporal perception of sounds. This finding could reflect a process that is involved in temporal prediction, exerting top-down control on neural entrainment via the prediction of acoustic edges in the auditory stream.

Hippocampal transcriptome analysis in ClockΔ19 mice identifies pathways associated with glial cell differentiation and myelination.

ClockΔ19 mice demonstrate behavioral characteristics and neurobiological changes that closely resemble those observed in bipolar disorder (BD). Notably, abnormalities in the hippocampus have been observed in patients with BD, yet direct molecular investigation of human hippocampal tissue remains challenging due to its limited accessibility. To model BD, ClockΔ19 mice were employed. Weighted gene co-expression network analysis (WGCNA) was utilized to identify mutation-related modules, and changes in cell populations were determined using the computational deconvolution CIBERSORTx. Furthermore, GeneMANIA and protein-protein interactions (PPIs) were leveraged to construct a comprehensive interaction network. 174 differentially expressed genes (DEGs) were identified, revealing abnormalities in rhythmic processes, mitochondrial metabolism, and various cell functions including morphology, differentiation, and receptor activity. Analysis identified 5 modules correlated with the mutation, with functional enrichment highlighting disturbances in rhythmic processes and neural cell differentiation due to the mutation. Furthermore, a decrease in neural stem cells (NSC), and an increase in astrocyte-restricted precursors (ARP), ependymocytes (EPC), and hemoglobin-expressing vascular cells (Hb-VC) in the mutant mice were observed. A network comprising 12 genes that link rhythmic processes to neural cell differentiation in the hippocampus was also identified. This study focused on the hippocampus of mice, hence the applicability of these findings to human patients warrants further exploration. The ClockΔ19 mutation may disrupt circadian rhythm, myelination, and the differentiation of neural stem cells (NSCs) into glial cells. These abnormalities are linked to altered expression of key genes, including DPB, CIART, NR1D1, GFAP, SLC20A2, and KL. Furthermore, interactions between SLC20A2 and KL might provide a connection between circadian rhythm regulation and cell type transitions.

Auditory Rhythm Encoding during the Last Trimester of Human Gestation: From Tracking the Basic Beat to Tracking Hierarchical Nested Temporal Structures.

Rhythm perception and synchronization to periodicity hold fundamental neurodevelopmental importance for language acquisition, musical behavior, and social communication. Rhythm is omnipresent in the fetal auditory world and newborns demonstrate sensitivity to auditory rhythmic cues. During the last trimester of gestation, the brain begins to respond to auditory stimulation and to code the auditory environment. When and how during this period do the neural capacities for rhythm processing develop? We conducted a cross-sectional study in 46 neonates (24 male) born between 27 and 35 weeks gestational age (wGA), measuring their neural responses to auditory rhythms with high-density electroencephalography during sleep. We developed measures to evaluate neural synchronization to nested rhythmic periodicities, including the fast isochronous beat and slower metrical (beat grouping) structures. We show that neural synchronization to beat and meter becomes stronger with increasing GA, converging on small phase differences between stimulus and neural responses near term, similar to those observed in adults. Dividing the cohort into subpopulations born before and after 33 wGA revealed that both younger and older groups showed neural synchronization to the fast periodicity related to the isochronous beat, whereas only the older group showed significant neural synchronization to the slower meter frequencies related to beat groupings, suggesting that encoding of nested periodicities arrives during late gestation. Together, our results shed light on the rapid evolution of neural coding of external hierarchical auditory rhythms during the third trimester of gestation, starting from the age when the thalamocortical axons establish the first synapses with the cortical plate.

Circadian Rhythm and Blood Pressure: research of the latest circadian rhythm in the treatment of hypertension

The goal of this review was to synthesize present knowledge on the effect of circadian rhythms on blood pressure (BP), circadian misalignment mechanisms that contribute to hypertension, circadian rhythm, and hypertension relationship, the latest research of circadian rhythm diet and pharmacological intervention and assess the possibility of chronotherapy in treatment. BP by modulating biological function is determined by the circadian rhythm process mainly under endogenous control, including the central clock in the suprachiasmatic nucleus (SCN) and peripheral clock. Hypertension has been associated with disruption of this rhythm which is a major cardiovascular disease risk factor. A high risk for adverse cardiovascular outcomes is circadian misalignment, which is reflected mostly by nocturnal nondipping. Shift work, hormone release, dietary habits, and others that affect circadian rhythms seem implicated, according to studies. Bedtime dosing of antihypertensive medications and other forms of chronotherapy have the potential to improve BP control. Time-dependent feeding and lifestyle interventions consistent with circadian rhythms offer benefits for hypertension management, as well. Increasingly, it is recognized that circadian rhythm disruption contributes to hypertension. Because interventions that realign circadian rhythms, including chronotherapy or circadian-aligned lifestyle changes, may decrease cardiovascular risk in hypertensives, they are worthy of further study.

The Impact of Executive Functions and Musicality on Speech Auditory-Motor Synchronization in Adults Who Stutter.

Stuttering is a neurodevelopmental disorder that disrupts the timing and rhythmic flow of speech production. There is growing evidence indicating that abnormal interactions between the auditory and motor cortices contribute to the development of stuttering. The present study investigated speech auditory-motor synchronization in stuttering adults and the influential factors behind it as compared to individuals without stuttering. Sixteen Mandarin-speaking adults with stuttering and 19 fluent controls, who were matched for age, gender, and years of musical training, participated in the current study. Their ability to synchronize vocal speech production with accelerating auditory sequences was assessed using the spontaneous speech-to-speech synchronization test (SSS test). Additionally, all participants conducted a series of standardized behavioral tests to evaluate their musicality and executive functions. Stutterers achieved significantly lower phase locking values in the SSS test compared to nonstuttering controls, indicating a potential rhythmic processing deficit in developmental stuttering. Moreover, the strength of speech auditory-motor synchronization in stutterers was significantly associated with their performance in tasks such as digit span and nonword repetition. This finding further emphasizes the strong link between rhythmic processing and working memory. This study provides compelling evidence for the speech rhythmic deficit in individuals with stuttering by incorporating auditory-motor processes. It would offer valuable insights into the intricate relationship between language and the brain and shed light on the potential benefits of cognitive training for speech intervention in individuals with stuttering difficulties. https://doi.org/10.23641/asha.27984362.

GhCNGC31 is critical for conferring resistance to Verticillium wilt in cotton.

In the past decades, cyclic nucleotide-gated ion channels (CNGCs) have been extensively studied in diploid species Arabidopsis thaliana. However, the functional diversification of CNGCs in crop plants, mostly polyploid, remains poorly understood. In allotetraploid Upland cotton (Gossypium hirsutum), GhCNGC31 is one of the multiple orthologs of AtCNGC2, being present in the plasma membrane, capable of interacting with itself and binding to calmodulins and cyclic nucleotides. GhCNGC31 knockdown plants exhibited slight growth inhibition, and became more susceptible to Verticillium dahliae infection, which was associated with the reduced lignin and flavonoid accumulation, impaired ROS (reactive oxygen species) burst, and down-regulation of defense-related genes PR1, JAZ2, LOX2, and RBOH10. RNA-Seq analysis identified 1817 differentially expressed genes from GhCNGC31 knockdown, of which 1184 (65%) were responsive to V. dahliae infection and accounted for 57% among a total of 2065 V. dahliae-responsive genes identified in this study. These GhCNGC31-regulated genes mainly function with cell wall organization and biogenesis, cellular carbohydrate metabolic or biosynthetic process, cellular component macromolecule biosynthetic process, and rhythmic process. They are significantly enriched in the pathways of plant MAPK signaling, plant-pathogen interaction, phenylpropanoid biosynthesis, and plant hormone signal transduction. A set of transcription factors (TFs) and resistance (R) genes are among the GhCNGC31-regulated genes, which are significantly over-represented with the TCP and WRKY TFs families, as well as with the R genes of T (TIR) and TNL (TIR-NB-LRR) classes. Together, our results unraveled a critical role of GhCNGC31 for conferring resistance to Verticillium wilt in cotton.

Neural processing of rhythmic speech by children with developmental language disorder (DLD): An EEG study

Abstract Sensitivity to rhythmic and prosodic cues in speech has been described as a precursor of language acquisition. Consequently, atypical rhythmic processing during infancy and early childhood has been considered a risk factor for developmental language disorders. Despite many behavioural studies, the neural processing of rhythmic speech has not yet been explored in children with developmental language disorder (DLD). Here, we utilise EEG to investigate the neural processing of rhythmic speech by 9-year-old children with and without DLD. In the current study, we investigate phase entrainment, angular velocity, power, event related potentials (ERPs), phase-amplitude coupling (PAC), and phase-phase coupling (PPC) at three frequency bands selected on the basis of the prior literature, delta, theta, and low gamma. We predicted a different phase of entrainment in the delta band in children with DLD, and also greater theta power, atypical cross-frequency coupling, and possibly atypical gamma-band responses. Contrary to prediction, children with DLD demonstrated significant and equivalent phase entrainment in the delta and theta bands to control children. However, only the control children showed significant phase entrainment in the low gamma band. The children with DLD also exhibited significantly more theta and low gamma power compared to the control children, and there was a significant gamma-band difference in angular velocity between the two groups. Finally, group resultant phase analyses showed that low-frequency phase (delta and theta) affected gamma oscillations differently by group. These EEG data show important differences between children with and without DLD in the neural mechanisms underpinning the processing of rhythmic speech. The findings are discussed in terms of auditory theories of DLD, particularly Temporal Sampling theory.

Time-Restricted Feeding Reinforces Gut Rhythmicity by Restoring Rhythms in Intestinal Metabolism in a Jetlag Mouse Model.

Circadian disturbances result in adverse health effects, including gastrointestinal symptoms. We investigated which physiological pathways in jejunal mucosa were disrupted during chronic jetlag and prevented during time-restricted feeding (TRF). Enteroids from Bmal1+/+ and Bmal1-/- mice were used to replicate the processes that were affected by chronic jetlag and rescued by TRF. C57BL/6J male mice were subjected to chronic jetlag or night-TRF for 4 weeks. An around-the-clock bulk-RNA sequencing study was performed on the jejunal mucosa. Bmal1+/+ and Bmal1-/- mouse enteroids were generated to study the jejunal epithelial clock dependency of rhythmic jejunal processes. Chronic jetlag disrupted the rhythmicity of jejunal clock genes and the jejunal transcriptome, which was partially rescued by TRF. Genes whose rhythm was altered by chronic jetlag but prevented by TRF were primarily associated with nutrient transport, lipid metabolism, ketogenesis, and cellular organization. Invivo, chronic jetlag caused a phase shift in the rhythmic accumulation of neutral lipids and induced a diurnal rhythm in the number of crypt epithelial cells, both of which were prevented by TRF. Invitro, enteroids replicated the invivo rhythmic accumulation of neutral lipids in a clock-dependent manner, whereas the rhythm of S phase proliferation was ultradian in both genotypes of enteroids. This pioneering transcriptomic study demonstrates that TRF acts as a robust entrainer during chronic jetlag, realigning disturbances in the circadian clock and the transcriptome involved in metabolic functions in the jejunal mucosa. Enteroids can replicate the rhythmic accumulation of neutral lipids dependent on the jejunal epithelial clock, enabling these functions to be studied invitro.

Comparative analysis of differentially expressed genes and transcripts in the ovary of yak in estrus and anestrus

Since most yaks have a long postpartum anestrus period, postpartum anestrus is the main factor affecting the reproductive efficiency of yaks. In this study, the third-generation sequencing technology was used to successfully screen differentially expressed genes (DEGs) and differentially expressed transcripts (DETs) in the ovarian tissues of yaks during estrus and anestrus. The functional references of DEGs and DETs were Gene Ontology, Kyoto Encyclopedia of Genes and Genomes, and Clusters of Orthologous Genes database. A total of 1149 DEGs and 2294 DETs were successfully identified. These DEGs and DETs were mainly related to biological processes such as “reproduction”, “reproductive process”, “metabolic process” and “rhythmic process”. Kisspeptin-G protein-coupled receptor was found to be involved in regulating the reproductive cycle of yaks. DEGs and DETs were also related to gonadotropin-releasing hormone (GnRH) signaling pathways such as oocyte meiosis, estrogen signaling pathway, and progesterone-mediated induced oocyte maturation. The results showed that SIRT1, CSNK1A1, SLIT3, INHBA, INSL3, ZP2, Clock, BMP15, Bmal1, KISS1, and LCHGR regulate the postpartum quiescent state and the reproductive cycle of yaks. This study will help to further clarify the reproductive mechanism of yaks at the molecular level and provide certain assistance for the development of animal husbandry.

Filtered Point Processes Tractably Capture Rhythmic And Broadband Power Spectral Structure in Neural Electrophysiological Recordings.

Neural electrophysiological recordings arise from interacting rhythmic (oscillatory) and broadband (aperiodic) biological subprocesses. Both rhythmic and broadband processes contribute to the neural power spectrum, which decomposes the variance of a neural recording across frequencies. Although an extensive body of literature has successfully studied rhythms in various diseases and brain states, researchers only recently have systematically studied the characteristics of broadband effects in the power spectrum. Broadband effects can generally be categorized as 1) shifts in power across all frequencies, which correlate with changes in local firing rates and 2) changes in the overall shape of the power spectrum, such as the spectral slope or power law exponent. Shape changes are evident in various conditions and brain states, influenced by factors such as excitation to inhibition balance, age, and various diseases. It is increasingly recognized that broadband and rhythmic effects can interact on a sub-second timescale. For example, broadband power is time-locked to the phase of <1 Hz rhythms in propofol induced unconsciousness. Modeling tools that explicitly deal with both rhythmic and broadband contributors to the power spectrum and that capture their interactions are essential to help improve the interpretability of power spectral effects. Here, we introduce a tractable stochastic forward modeling framework designed to capture both narrowband and broadband spectral effects when prior knowledge or theory about the primary biophysical processes involved is available. Population-level neural recordings are modeled as the sum of filtered point processes (FPPs), each representing the contribution of a different biophysical process such as action potentials or postsynaptic potentials of different types. Our approach builds on prior neuroscience FPP work by allowing multiple interacting processes and time-varying firing rates and by deriving theoretical power spectra and cross-spectra. We demonstrate several properties of the models, including that they divide the power spectrum into frequency ranges dominated by rhythmic and broadband effects, and that they can capture spectral effects across multiple timescales, including sub-second cross-frequency coupling. The framework can be used to interpret empirically observed power spectra and cross-frequency coupling effects in biophysical terms, which bridges the gap between theoretical models and experimental results.

Examining the Neural Markers of Speech Rhythm in Silent Reading Using Mass Univariate Statistics of EEG Single Trials.

The Implicit Prosody Hypothesis (IPH) posits that individuals generate internal prosodic representations during silent reading, mirroring those produced in spoken language. While converging behavioral evidence supports the IPH, the underlying neurocognitive mechanisms remain largely unknown. Therefore, this study investigated the neurophysiological markers of sensitivity to speech rhythm cues during silent word reading. EEGs were recorded while participants silently read four-word sequences, each composed of either trochaic words (stressed on the first syllable) or iambic words (stressed on the second syllable). Each sequence was followed by a target word that was either metrically congruent or incongruent with the preceding rhythmic pattern. To investigate the effects of metrical expectancy and lexical stress type, we examined single-trial event-related potentials (ERPs) and time-frequency representations (TFRs) time-locked to target words. The results showed significant differences based on the stress pattern expectancy and type. Specifically, words that carried unexpected stress elicited larger ERP negativities between 240 and 628 ms after the word onset. Furthermore, different frequency bands were sensitive to distinct aspects of the rhythmic structure in language. Alpha activity tracked the rhythmic expectations, and theta and beta activities were sensitive to both the expected rhythms and specific locations of the stressed syllables. The findings clarify neurocognitive mechanisms of phonological and lexical mental representations during silent reading using a conservative data-driven approach. Similarity with neural response patterns previously reported for spoken language contexts suggests shared neural networks for implicit and explicit speech rhythm processing, further supporting the IPH and emphasizing the centrality of prosody in reading.

KARYA MUSIK LUNGUN: INTERPRETASI VOKAL ANDUNG BATAK TOBA DALAM KONSEP MUSIK KAMAR

Lungun is a musical work inspired by a tradition in the death ceremony of the Toba Batak people, called the andung tradition. Andung is a song of sadness that expresses one's feelings of grief for a loved one. Andung chanting is chanted by a pangandung (poet) using hata andung verses (Toba Batak fine literature) whose content tells the life history of someone who has died. In its current development, the andung tradition has shifted, and many cannot practice it because many younger generations can no longer speak hata andung, and andung singing which have been replacing with spiritual songs. The analysis of the andung tradition revealed distinct characteristics of the andung melody and the presentation of Gondang Sabangunan music for death ceremonies. The creation of the musical work Lungun aims to find out the musical form and its symbolic meaning. The method used is panca sthiti ngawi sani, which consist of five stages: (1) inspiration (ngawirasa), (2) exploration (ngawacak), (3) conception (ngarencana), (4) execution (ngawangun) and (4) production (ngabah). Lungun's musical work incorporates elements such as the Toba Batak scales, processed andung vocals, hata andung poems, rhythm processing, and Gondang Sabangunan playing techniques into chamber music performances. Lungun music has three parts: part I is mula-mula (beginning), part II is andung (vocal singing), and part III is poda (message). The symbolic meaning expressed in Lungun music refers to the values found in the Toba Batak community: the Dalihan Na Tolu Batak philosophy, the five levels of Toba Batak death, and the seven Toba Batak philosophies.

Research on the Notation of Folk Urtiin Duu

This paper deeply explores the notation of Mongolian folk Urtiin Duu, an intangible cultural heritage, and focuses on how to scientifically and rationally record their unique artistic characteristics. The study points out that the simplified notation has the advantages of being easy to learn and flexible in key changes, and is the preferred choice for notating folk Urtiin Duu. In view of the difficulty in recording the free rhythm of folk Urtiin Duu, a method of grouping a group of sound forms based on the combination of the internal rhythmic rhythm and speed changes is proposed to solve the problem of recording non-equal rhythms. For the notation of the core techniques of the decorative elements of folk Urtiin Duu, such as Tashilaga and Nogula, the concept of the music theory symbol system is changed to accurately express them in order to protect the artistic essence of folk Urtiin Duu. In addition, the importance of the backing words in the singing of folk Urtiin Duu is emphasized, and it is advocated to record the backing words in a comprehensive manner to protect the traditional charm of folk Urtiin Duu. This paper comprehensively considers the selection of musical notation, the processing of rhythm, the application of decorative symbols and the standardized recording of filler words, aiming to provide a more scientific and reasonable musical notation strategy for the educational inheritance of folk Urtiin Duu, and promote the inheritance, protection and development of this precious cultural heritage.

Neural oscillations suggest periodicity encoding during auditory beat processing in the premature brain.

When exposed to rhythmic patterns with temporal regularity, adults exhibit an inherent ability to extract and anticipate an underlying sequence of regularly spaced beats, which is internally constructed, as beats are experienced even when no events occur at beat positions (e.g., in the case of rests). Perception of rhythm and synchronization to periodicity is indispensable for development of cognitive functions, social interaction, and adaptive behavior. We evaluated neural oscillatory activity in premature newborns (n=19, mean age, 32±2.59weeks gestational age) during exposure to an auditory rhythmic sequence, aiming to identify early traces of periodicity encoding and rhythm processing through entrainment of neural oscillations at this stage of neurodevelopment. The rhythmic sequence elicited a systematic modulation of alpha power, synchronized to expected beat locations coinciding with both tones and rests, and independent of whether the beat was preceded by tone or rest. In addition, the periodic alpha-band fluctuations reached maximal power slightly before the corresponding beat onset times. Together, our results show neural encoding of periodicity in the premature brain involving neural oscillations in the alpha range that are much faster than the beat tempo, through alignment of alpha power to the beat tempo, consistent with observations in adults on predictive processing of temporal regularities in auditory rhythms. RESEARCH HIGHLIGHTS: In response to the presented rhythmic pattern, systematic modulations of alpha power showed that the premature brain extracted the temporal regularity of the underlying beat. In contrast to evoked potentials, which are greatly reduced when there is no sounds event, the modulation of alpha power occurred for beats coinciding with both tones and rests in a predictive way. The findings provide the first evidence for the neural coding of periodicity in auditory rhythm perception before the age of term.

Emerging biotechnologies for screening electromechanical signals of cardiomyocytes

AbstractCardiac diseases threaten human health and burden the global healthcare system. Cardiomyocytes (CMs) are considered the ideal model for studying the signal transduction and regulation of cardiac systems. Based on the principle of the rhythmical beating process (excitation‒contraction coupling mechanism of CMs), investigating the mechanical and electrophysiological signals offered new hope for cardiac disease detection, prevention, and treatment. Considerable technological success has been achieved in electromechanical signal recording. However, most drug assessment platforms attach importance to high‐throughput and dynamic monitoring of mechanical or electrical signals while overlooking the measuring principles and physiological significance of the signal. In this review, the development of biosensing platforms for CMs, sensing principles, key measured parameters, measurement accuracy, and limitations are discussed. Additionally, various approaches for the stimulation and measurement of CMs in vitro are discussed to further elucidate the response of these cells to external stimuli. Furthermore, disease modeling and drug screening are used as examples to intuitively demonstrate the contribution of in vitro CM measurement platforms to the biomedical field, thereby further illustrating the challenges and prospects of these sensing platforms.

Reduced precision of motor and perceptual rhythmic timing in autistic adults

Recent results suggest that autistic individuals exhibit reduced accuracy compared to non-autistic peers in temporally coordinating their actions with predictable external cues, e.g., synchronizing finger taps to an auditory metronome. However, it is not yet clear whether these difficulties are driven primarily by motor differences or extend into perceptual rhythmic timing tasks. We recruited autistic and non-autistic participants for an online study testing both finger tapping synchronization and continuation as well as rhythmic time perception (anisochrony detection). We fractionated each participant's synchronization results into parameters representing error correction, motor noise, and internal time-keeper noise, and also investigated error-correcting responses to small metronome timing perturbations. Contrary to previous work, we did not find strong evidence for reduced synchronization error correction. However, we found compelling evidence for noisier internal rhythmic timekeeping in the synchronization, continuation, and perceptual components of the experiment. These results suggest that noisier internal rhythmic timing processes underlie some sensorimotor coordination challenges in autism.

The interplay of music, movement, and culture on rhythm processing

The interplay of music, movement, and culture on rhythm processing

Time-dependent effects of high-fat diet on cognition and cerebral insulin signaling: Window for recovery and potential therapeutic target

While high-fat diet (HFD)-induced obesity is a major threat to global public health, the effect of HFD on cognition and insulin signaling during ageing remains controversial. The aim of this study was to characterize the dynamic alterations in cognition and cerebral insulin signaling during 6-month HFD consumption, and to investigate the potential therapeutic target and optimal timing to rescue obesity-related cognitive deficits. In the present study, impaired memory retention induced by 2-month HFD was recovered after 4 months on HFD. Prolonged (6-month) HFD did not further enhance tau hyperphosphorylation and β-amyloid deposition, which was consistent with the alleviation of memory retention. In brain insulin signaling, 2-month HFD increased IRS-1 and p-IRS-1(Ser307)/IRS-1, while decreasing pAKT(Ser473)/AKT, PI3K and mTOR; 4-month HFD decreased IRS-1 and pAKT(Ser473)/AKT, while increasing AKT; 6-month HFD increased IRS-1, pAKT(Ser473)/AKT, and mTOR, while decreasing p-IRS-1(Ser307)/IRS-1, PI3K and AKT. Notably, bioinformatic analysis revealed a rhythmic process presented only in 4-month HFD group, with Srebf1 emerging as a link between circadian rhythms and insulin signaling pathway. These results suggest that prolonged HFD prevents further cognitive decline and the progression of Alzheimer’s disease (AD)-related pathologies during ageing. Moreover, there may be a window for recovery, in which Srebf1 acts as a self-recovery switch to address obesity-related cognitive disorders in elders.

Electrophysiological Activity Associated with a Cross-Modal Anapaest Rhythm: Evidence for the Vestibular Syncopation Hypothesis

Abstract We report an experiment that tested the vestibular syncopation rhythm hypothesis, which holds that the rhythmic effect of syncopation is a form of vestibular reflexive/automated response to a postural perturbation, for example during locomotion. Electrophysiological signals were recorded from the cerebral cortex and cerebellum during processing of rhythmic sequences in a sample of experienced participants. Recordings were made using four different stimulus modalities, auditory, axial, vestibular and visual, under different rhythmic timing conditions, irregular, regular and syncopated/uncertain. Brain current activity was measured using a model with10-dipole source regions of interest in each of the participants, each modality, each timing condition, and for each beat within the bar of the rhythm. The cross-modal spectral power in the frontal electroencephalogram (EEG) and the cerebellar electrocerebellogram (ECeG) was also analysed. The results show that the brain activity increases from the irregular to the regular and then from the regular to the uncertain timing conditions. However, the vestibular modality induces the greatest total brain activity across the regions of interest and exhibits the highest sensitivity to the interaction of beat structure with the timing conditions in both source currents and spectral power. These data provide further evidence to support the primal role of the vestibular system in human processing of rhythm.

Multidecadal Phase Changes in the Thermodynamic State of the System: Ocean–Atmosphere–Continent

The present-day climate (the recent 100–150 years) obviously constitutes the structure of a global intra-system rhythmic process with an individual rhythm of about 60 years. In turn, each of the rhythms is presented by the two climate phases of about 25–35 years characterized by qualitative differences: one phase is relatively continental, while the other is humid. Globality and quasi-synchronism of environmental changes are accompanied by planetary structures: the Global Atmospheric Oscillation (GAO) in the atmosphere and the Multidecadal Oscillation of the Heat content in the Ocean (MOHO) discovered relatively recently. Unexpected and rapid qualitative phase changes in the climate, which first focused attention in the mid-1970s of the last century, were titled “climate shifts”. The revealed features of the present-day climate are of exceptional scientific and practical interest and deserve the development of methods for predicting the timing of the forthcoming climate shift. Arising unexpectedly and accompanied by rapid significant changes, these shifts identified the problem of understanding the nature and establishing the processes and mechanisms causing them. First of all, of interest are phase changes in the thermodynamic state of the climate system components: the ocean, atmosphere, and continents. As a result of the World Ocean (WO) thermohydrodynamics numerical modelling, it is shown that MOHO is localized in the layer of the main thermocline, where the most important elements of the WO circulation are located. The performed study based on observational data allows us to conclude that, during the phase of the WO thermal discharge (1975–1999), the two key systems of currents, the Kuroshio and the Gulf Stream, were under similar thermodynamic conditions.