Rhythmic Oscillations Research Articles

Features of blood`s microcirculation at physical loads

This research deals with the study of blood microcirculation peculiarities.Materials and methods. 72 students of Bogdan Khmelnytsky Melitopol State Pedagogical University, aged 18–19, were examined. The experimental research consisted of the study of blood microcirculation functional state by means of Laser Doppler flowmetry (LDF) method. It helped to evaluate the state of tissue blood-circulation and to detect individual-typological peculiarities of blood microcirculation under the influence of physical activity (before and after exercise).Results. Three types of blood microcirculation were identified by using LDF-metry. The normoemic type of blood microcirculation, characterized by the superposition of oscillatory rhythms and reflected the balance of the mechanisms of regulation of microcirculation. The hyperemic type, characterized by a «monotonous» LDF-gram with a high parameter of microcirculation, which reflects the relative predominance of metabolic mechanisms in the regulation of microcirculation. The hypoemic type, characterized by a «monotonous» LDF-gram with a low parameter of the microcirculation parameter, which reflects the decrease of vasomotor mechanisms in the regulation of microcirculation. According to the LDF-metric data, the examined students under intensive physical activity have a significant increase in microcirculatory status: by 6 % of the microcirculation parameter, by 28 % of the mean square deviation and by 45 % of the initial value of the coefficient of variation.Conclusions. This dynamics of microcirculation shows that under the influence of physical exertion, a person creates significant functional reserves for the redistribution of blood flow and for more perfect intraorgan capillary blood flow. It was found, that in the process of physical activity, morpho-functional rearrangements of the human cardiovascular system occur. This reaction is formed by several components of blood microcirculation: blood flow in the transport direction, regulating blood supply in accordance with the needs of tissues and the exchange component of the histochemical barrier

Ambivalent Affines: Law Like Literature

This short essay will dwell upon the ‘law of literature and the literature of law’, as illuminated in the enduring scholarship and intellectual legacy of Peter Fitzpatrick. Reading with Fitzpatrick, we must grapple with a law that is both constituted and subverted by recourse to the supplement of fiction. These ambivalent ‘affines’, law and literature, share in an oscillatory rhythm: each is constituted and enlivened by an unbounded exteriority, yet each must be rendered normatively determinate. I reflect upon the ways in which Fitzpatrick’s account of ‘law like literature’ grasps and hones the methodological challenge implicit in this reading: to read law as literature and literature as law. Yet further, I extend a reading of Fitzpatrick’s scholarship that acknowledges this fictive law as not merely susceptible to but constituted by decoloniality.

Expression of antimicrobial peptide genes oscillates along day/night rhythm protecting mice skin from bacteria.

Antimicrobial peptides (AMPs) are important components of the innate immune system and are involved in skin protection against environmental insults and in wound healing. Herein, we assessed the gene expression of chemerin (Rarres2), cathelicidin CRAMP (Camp), and three β-defensins (Defb1, Defb3, and Defb14) in mouse skin during light/dark cycle (LD 12:12) and constant darkness (DD). Next, we examined the survival of bacteria applied on the skin at specific times during the day. We found that the expression of Rarres2, Camp, and Defb1 was the highest at 4h after the beginning of darkness, during high activity of mice. These rhythms, however, were not maintained under DD in the skin but were present in the liver. This indicated that in the case of skin, a circadian input was masked by daily changes of light in the environment. In contrast, Defb3 and Defb14 showed the highest mRNA levels when the mice slept, and these rhythmic mRNA oscillations were maintained under DD. This shows that Rarres2, Camp, and Defb1 levels in the skin are correlated with high locomotor activity in mice and they are controlled by daily changes of light and dark. Alternatively, oscillations in the mRNA levels of Defb3 and Defb14 seem to protect skin and heal wounds during sleep. These rhythms are maintained under DD, indicating that they are regulated by a circadian clock. Our study suggests that daily AMP expression affects the survival of bacteria on the surface of skin, which depends on the phase of AMP cycling.

A CORDIC based real-time implementation and analysis of a respiratory central pattern generator

Central pattern generators (CPGs) are dedicated neural circuits which can generate rhythmic motor patterns even in absence of sensory input with extraordinary robustness and flexibility. In this paper, a biologically realistic model of a respiratory CPG with four neurons is implemented on a reconfigurable Field-Programmable Gate Array (FPGA) system. Considering the limitations of hardware resources, we first propose a modified respiratory CPG model with Coordinate Rotation Digital Computer (CORDIC) algorithm to save limited resources and reduce complexity. And then, all the multipliers are replaced with a method which is appropriate and effective for hardware implementation to avoid the use of the area-intensive multipliers. The implementation results show that rhythmic oscillations are successfully generated by the respiratory CPG network and the resource utilization is greatly reduced, which shows the potential for building large-scale spiking neural networks. The proposed high-performance and real-time implementation of the respiratory CPG network on the FPGA system can speed up the process to gain new insights into the respiratory network and can also be developed into applications for respiratory rhythm generation and modulation.

Impact of the Potential Antitumor Agent 2-(4-Hydroxyphenyl) Amino-1,4-Naphthoquinone (Q7) on Vasomotion Is Mediated by the Vascular Endothelium, But Not Vascular Smooth Muscle Cell Metabolism.

Vasomotion is defined as rhythmic oscillations in arterial diameter that regulate the blood flow and blood pressure. Because antitumor treatment may impair vascular functions and increase the blood pressure, we sought to evaluate whether a new naphthoquinone derivative, postulated as an antitumor agent, manifests adverse effects on vascular function. In this article, we evaluated the toxicity of 2-(4-hydroxyphenyl) amino-1,4-naphthoquinone (Q7) and its effects on vascular vasomotion in 3 models of vascular structure: endothelial cells, aortic ring, and smooth muscle cells. Although showing nontoxic effects, Q7 inhibited the formation of capillary-like structures of the EA.hy926 endothelial cell line grown on Matrigel. In exvivo experiments with aortic rings precontracted with phenylephrine (PE, 10-6 M), Q7 (10-5 M) significantly (P < 0.05) reduced vascular rhythmic contractions induced by the acetylcholine (ACh; 10-7-10-5 M), whereas sodium nitroprusside (a nitric oxide donor; 10-8 M) recovered the vasomotion. Furthermore, Q7 (10-5 M) did not decrease KCl-induced vascular rhythmic contractions in the aortic rings precontracted with BaCl2 (a nonselective K+ channel blocker; 10-3 M). Vascular smooth muscle cells (A7r5) preincubated with Q7 (10-5 M) for 3 hours also demonstrated a reduced glucose uptake. However, the Adenosine Triphosphate content was unaffected, suggesting that the rapid reduction in vasomotion observed in vascular reactivity experiments did not involve cellular metabolism but may be due to faster mechanisms involving endothelial nitric oxide and K+ channels leading to oscillations in intracellular Ca2+. In summary, the naphthoquinone derivative Q7 presents low cytotoxicity yet may alter the endothelial cell response and vasomotion in the absence of changes in smooth muscle cell metabolism.

Ulcerative Lesions of the Mucosa Gastro-Duodenal Zone in Victims of the Chernobyl Accident: Some Features of the Etiology, Pathogenesis and Clinical Signs Identified in the Third of the Century After the Disaster

Ulcerative Lesions of the Mucosa Gastro-Duodenal Zone in Victims of the Chernobyl Accident: Some Features of the Etiology, Pathogenesis and Clinical Signs Identified in the Third of the Century After the Disaster

Direct measurement of the rhythmic motions of the human head identifies a third rhythm

IntroductionCentral to the osteopathic cranial field, and at the same time controversial, is the concept of a unique rhythmic movement believed to originate from a primary respiratory mechanism (PRM). Further, the PRM is reported to manifest as a cranial rhythmic impulse (CRI) on the living human skull. This study explores the rhythmic oscillations of the human head measured directly as physical movements. The aim is to investigate the existence of a third rhythm distinct from the head movements caused by respiratory breathing and arterial pulsing, in an objective and purely experimental study. ExperimentalIn 50 healthy individuals, rhythmic oscillations of the head were measured in real-time for 42 min in a supine resting state without any intervention. A newly developed machine for tracking rhythmic movements was used for measurements. ResultsIn all individuals, a third rhythm was distinguished as separate from the arterial and respiratory rhythm at all times. The third rhythm was observed as a dynamic physiological phenomenon with a narrow range in resting healthy individuals with a mean of 6.16 cycles/minute (4.25–7.07). The significant contribution to the amplitude of the measured movements was the respiratory breathing and this third rhythm, whereas the contribution from the arterial pulsing were minor. ConclusionThe present study demonstrates the existence, and normative range of a third physical rhythm detected on the human head. Having developed an objective approach to studying this third rhythm might form the future basis for clinical and physiological studies of craniosacral function and dysfunction.

Increased Purkinje Cell Complex Spike and Deep Cerebellar Nucleus Synchrony as a Potential Basis for Syndromic Essential Tremor. A Review and Synthesis of the Literature.

We review advances in understanding Purkinje cell (PC) complex spike (CS) physiology that suggest increased CS synchrony underlies syndromic essential tremor (ET). We searched PubMed for papers describing factors that affect CS synchrony or cerebellar circuits potentially related to tremor. Inferior olivary (IO) neurons are electrically coupled, with the degree of coupling controlled by excitatory and GABAergic inputs. Clusters of coupled IO neurons synchronize CSs within parasagittal bands via climbing fibers (Cfs). When motor cortex is stimulated in rats at varying frequencies, whisker movement occurs at ~10Hz, correlated with synchronous CSs, indicating that the IO/CS oscillatory rhythm gates movement frequency. Intra-IO injection of the GABAA receptor antagonist picrotoxin increases CS synchrony, increases whisker movement amplitude, and induces tremor. Harmaline and 5-HT2a receptor activation also increase IO coupling and CS synchrony and induce tremor. The hotfoot17 mouse displays features found in ET brains, including cerebellar GluRδ2 deficiency and abnormal PC Cf innervation, with IO- and PC-dependent cerebellar oscillations and tremor likely due to enhanced CS synchrony. Heightened coupling within the IO oscillator leads, through its dynamic control of CS synchrony, to increased movement amplitude and, when sufficiently intense, action tremor. Increased CS synchrony secondary to aberrant Cf innervation of multiple PCs likely also underlies hotfoot17 tremor. Deep cerebellar nucleus (DCN) hypersynchrony may occur secondary to increased CS synchrony but might also occur from PC axonal terminal sprouting during partial PC loss. Through these combined mechanisms, increased CS/DCN synchrony may plausibly underlie syndromic ET.

Neurodegeneration exposes firing rate dependent effects on oscillation dynamics in computational neural networks

Traumatic brain injury (TBI) can lead to neurodegeneration in the injured circuitry, either through primary structural damage to the neuron or secondary effects that disrupt key cellular processes. Moreover, traumatic injuries can preferentially impact subpopulations of neurons, but the functional network effects of these targeted degeneration profiles remain unclear. Although isolating the consequences of complex injury dynamics and long-term recovery of the circuit can be difficult to control experimentally, computational networks can be a powerful tool to analyze the consequences of injury. Here, we use the Izhikevich spiking neuron model to create networks representative of cortical tissue. After an initial settling period with spike-timing-dependent plasticity (STDP), networks developed rhythmic oscillations similar to those seen in vivo. As neurons were sequentially removed from the network, population activity rate and oscillation dynamics were significantly reduced. In a successive period of network restructuring with STDP, network activity levels returned to baseline for some injury levels and oscillation dynamics significantly improved. We next explored the role that specific neurons have in the creation and termination of oscillation dynamics. We determined that oscillations initiate from activation of low firing rate neurons with limited structural inputs. To terminate oscillations, high activity excitatory neurons with strong input connectivity activate downstream inhibitory circuitry. Finally, we confirm the excitatory neuron population role through targeted neurodegeneration. These results suggest targeted neurodegeneration can play a key role in the oscillation dynamics after injury.

Spinning the Spatiotemporal Profile of Transcription Factors Via Intermittent Fasting

Intermittent fasting is a safe strategy to improve health, but its specific mechanisms are not fully understood. Considering that transcription factors (TFs) determine the response to environmental signals, here, we profiled the circadian transcriptome of 600 samples in mice to provide an atlas of TFs in biological space, time, and feeding regimen. Results showed that 80% of TFs display daily rhythms in expression. Intermittent fasting triggered more than 90% of TFs to oscillate somewhere in the body and repartitioned their tissue-specific expression. A single round of fasting and repeated fasting caused evidently different effects on TFs. Intriguingly, 196 TFs illustrated a duration-dependent linear correlation in expression with fasting or refeeding time at the cutoff of the determination coefficient (R2) in linear regression > 0.7. This atlas offers a reference and resource to understand how TFs and intermittent fasting may contribute to circadian rhythm oscillation and bring about specific health benefits.

Влияние умеренной физической нагрузки на взаимосвязь вариабельности сердечного ритма с уровнем кровяного давления и гемодинамическими функциями у женщин, страдающих гипертонической болезнью

Aim. To study the relationship between heart rate variability (HRV), blood pressure and hemodynamic functions in women with essential hypertension (EH) receiving a drug therapy alone (EH-1) or in combination with regular courses of kinesitherapy (EH-2). Methods. The study included 72 women with EH. The EH-1 group consisted of 37 women with stage II arterial hypertension. The EH-2 group consisted of 35 women with stage II arterial hypertension who underwent 3-4 1.5-month courses of kinesitherapy (controlled moderate physical activity) on a regular basis for 2-3 years. Hemodynamics was studied with a miniature Dynamic Light Scattering (mDLS) sensor from Elfi-Tech (Rehovot, Israel), which measures signals initiated by the skin blood flow by decomposing the signal into frequency components associated with different hemodynamic sources. Information on the RR interval variability was extracted from the pulse component of mDLS signal, and indicators of heart rate variability were calculated. A Hemodynamic Index (HI) was introduced. The HI dependence on shear rate was interpreted by matching each frequency band with a specific shear rate (HI1, low-frequency; HI2, intermediate; HI3, high-frequency). The following relative (RHI, Relative Hemodynamic Index) and oscillatory (OHI, Oscillatory Hemodynamic Indexes) indexes were used: neurological (NEUR), Mayer (MAYER), respiratory (RESP), and pulse (PULSE) ones. The HRV indexes included HR (Heart Rate), PWR (Power, total oscillation power), LF (Low Frequency), HF (High Frequency), SDNN (Standard Deviation of the Normal-to-Normal), RMSSD (Root Mean Square of the Successive Differences). CVI (Cardiac Vagal Index), and CSI (Cardiac Sympathetic Index). Results. In women who were on drug therapy alone (EH-1), negative relationships were found for LF and LF/HF with systolic, mean and pulse pressure. For EH-2, PWR, LF, and HF negatively correlated with pulse pressure. For EH-1, HR positively correlated with the hemodynamic indices HI1 and RHI2 and negatively correlated with RHI3; RMSSD negatively correlated with RHI3; and HF negatively correlated with HI1/HI3. For patients with EH-2, negative correlations were observed for SDNN and RHI1, PWR and RHI1; positive correlations were found between PWR and HI2; HI3, RHI2, HF and RHI3; and between LF/HF and HI1/HI3. HF negatively correlated with HI1/HI3 and with RHI1. LF/HF negatively correlated with RHI3, and CSI negatively correlated with RHI3. In patients with EH-1, SDNN, PWR, LF, HF, CVI, and NEUR_HI1 were directly related, which indicated an effect of these factors on the endothelial blood flow (HI1). In the EH-2 group, only positive correlations were found between LF, HF, and NEUR_HI3. In EH-1 patients, all oscillatory rhythms influenced BP; this influence could be both negative (for MAYER_HI1, PULSE_HI2) and positive (for MAYER_ HI2, RESP_HI3). In EH-2 patients, no relationship was found between blood pressure and oscillatory indices. Conclusion. The smaller number of factors influencing blood pressure and hemodynamics in the EH-2 group compared to the EH-1 group was more beneficial and favorable, which ensured faster and steadier normalization of blood pressure.

A novel time-dimension and circadian rhythm-dependent strategy for pharmacodynamic evaluation of Uncaria in the regulation of neurotransmitter circadian metabolic homeostasis in spontaneously hypertensive rats

In the present study, we aimed to use metabolomics platforms to examine circadian-regulated neurotransmitters across a 24-h day and the effects of Uncaria administration on daily rhythmicity in order to establish a strategy for evaluating the spatiotemporal efficacy evaluation strategy of Uncaria. By using targeted ultrahigh performance liquid chromatography-mass spectrometry metabolomics, we quantified 32 neurotransmitter metabolites every 4 h over 24 h. To assess 24-h metabolite rhythmicity, we performed cosinor analysis. The expression of hypothalamic rhythm genes was detected by reverse transcription polymerase chain reaction (RT-PCR). Data revealed circadian loss of many neurotransmitters during the entire circadian cycle in the serum of group M, indicating that hypertension causes circadian rhythm disorders. Cosinor analysis of the rhythmic oscillations of the levels of 32 neurotransmitters in the three groups showed that the metabolite rhythms peaked at approximately the same time of day (ZT4 and ZT16). Moreover, the amplitudes of the metabolite rhythms were altered. After treatment with Uncaria, the amplitudes of 13 neurotransmitters reverted to normal. The change trends in the hypothalamic rhythm genes confirmed the rhythm changes in neurotransmitters. Collectively, a novel pharmacodynamic evaluation strategy was established to dynamically observe the holistic effects of Uncaria on 32 circulating neurotransmitters within 24 h from the perspective of time dimension.

Nested oscillations and brain connectivity during sequential stages of feature-based attention

Brain mechanisms of visual selective attention involve both local and network-level activity changes at specific oscillatory rhythms, but their interplay remains poorly explored. Here, we investigate anticipatory and reactive effects of feature-based attention using separate fMRI and EEG recordings, while participants attended to one of two spatially overlapping visual features (motion and orientation). We focused on EEG source analysis of local neuronal rhythms and nested oscillations and on graph analysis of connectivity changes in a network of fMRI-defined regions of interest, and characterized a cascade of attentional effects at multiple spatial scales. We discuss how the results may reconcile several theories of selective attention, by showing how β rhythms support anticipatory information routing through increased network efficiency, while reactive α-band desynchronization patterns and increased α-γ coupling in task-specific sensory areas mediate stimulus-evoked processing of task-relevant signals.

Theta Synchronization of Phonatory and Articulatory Systems in Marmoset Monkey Vocal Production

Human speech shares a 3-8-Hz theta rhythm across all languages [1-3]. According to the frame/content theory of speech evolution, this rhythm corresponds to syllabic rates derived from natural mandibular-associated oscillations [4]. The underlying pattern originates from oscillatory movements of articulatory muscles [4, 5] tightly linked to periodic vocal fold vibrations [4, 6, 7]. Such phono-articulatory rhythms have been proposed as one of the crucial preadaptations for human speech evolution [3, 8, 9]. However, the evolutionary link in phono-articulatory rhythmicity between vertebrate vocalization and human speech remains unclear. From the phonatory perspective, theta oscillations might be phylogenetically preserved throughout all vertebrate clades [10-12]. From the articulatory perspective, theta oscillations are present in non-vocal lip smacking [1, 13, 14], teeth chattering [15], vocal lip smacking [16], and clicks and faux-speech [17] in non-human primates, potential evolutionary precursors for speech rhythmicity [1, 13]. Notably, a universal phono-articulatory rhythmicity similar to that in human speech is considered to be absent in non-human primate vocalizations, typically produced with sound modulations lacking concomitant articulatory movements [1, 9, 18]. Here, we challenge this view by investigating the coupling of phonatory and articulatory systems in marmoset vocalizations. Using quantitative measures of acoustic call structure, e.g., amplitude envelope, and call-associated articulatory movements, i.e., inter-lip distance, we show that marmosets display speech-like bi-motor rhythmicity. These oscillations are synchronized and phase locked at theta rhythms. Our findings suggest that oscillatory rhythms underlying speech production evolved early in the primate lineage, identifying marmosets as a suitable animal model to decipher the evolutionary and neural basis of coupled phono-articulatory movements.

The intergenerational toxic effects on offspring of medaka fish Oryzias melastigma from parental benzo[a]pyrene exposure via interference of the circadian rhythm

Benzo[a]pyrene (BaP), a widely existed polycyclic aromatic hydrocarbon pollutant in aquatic environment, has toxic effects on marine animals and their generations, but the intergenerational immunotoxic mechanism underlying has not been clearly understood. In the study, the offspring of marine medaka (oryzias melastigma) which were exposed to 0.5 μg L−1 BaP suffered from circadian rhythm oscillation disorders and severe DNA damage. Many clock-associated genes like per1 were significantly modulated in offspring, both per1 and p53 were significantly inhibited that altered the progression of cell cycle and inhibited DNA repair, which possibly resulted in the increased mortality of offspring. The hypermethylation of the per1 promotor and abnormal levels of N6-methyladenosine (m6A) suggested that the underlying mechanism was probably related to the epigenetic modification. Moreover, the offspring from paternal BaP exposure had more severe DNA damage and a higher degree of hypermethylation than those from maternal exposure. F1 larvae from BaP-exposed parents were more sensitive to BaP exposure, showing that the expression of immune and metabolism-related genes were significantly up-regulated. Taken together, the parental toxicity induced by BaP could be passed to F1 generation and the mechanism underlying was probably associated with a characteristic circadian rhythm disorder.

Neuroimaging and electrophysiology meet invasive neurostimulation for causal interrogations and modulations of brain states

Deep brain stimulation (DBS) has developed over the last twenty years into a highly effective evidenced-based treatment option for neuropsychiatric disorders. Moreover, it has become a fascinating tool to provide illustrative insights into the functioning of brain networks. New anatomical and pathophysiological models of DBS action have accelerated our understanding of neurological and psychiatric disorders and brain functioning. The description of the brain networks arose through the unique ability to illustrate long-range interactions between interconnected brain regions as derived from state-of-the-art neuroimaging (structural, diffusion, and functional MRI) and the opportunity to record local and large-scale brain activity at millisecond temporal resolution (microelectrode recordings, local field potential, electroencephalography, and magnetoencephalography).In the first part of this review, we describe how neuroimaging techniques have led to current understanding of DBS effects, by identifying and refining the DBS targets and illustrate the actual view on the relationships between electrode locations and clinical effects. One step further, we discuss how neuroimaging has shifted the view of localized DBS effects to a modulation of specific brain circuits, which has been possible from the combination of electrode location reconstructions with recently introduced network imaging methods. We highlight how these findings relate to clinical effects, thus postulating neuroimaging as a key factor to understand the mechanisms of DBS action on behavior and clinical effects. In the second part, we show how invasive electrophysiology techniques have been efficiently integrated into the DBS set-up to precisely localize the neuroanatomical targets of DBS based on distinct region-specific patterns of neural activity. Next, we show how multi-site electrophysiological recordings have granted a real-time window into the aberrant brain circuits within and beyond DBS targets to quantify and map the dynamic properties of rhythmic oscillations. We also discuss how DBS alters the transient synchrony states of oscillatory networks in temporal and spatial domains during resting, task-based and motion conditions, and how this modulation of brain states ultimately shapes the functional response. Finally, we show how a successful decoding and management of electrophysiological proxies (beta bursts, phase-amplitude coupling) of aberrant brain circuits was translated into adaptive DBS stimulation paradigms for a targeted and state-dependent invasive electrical neuromodulation.

Interaction between Tea Polyphenols and Intestinal Microbiota in Host Metabolic Diseases from the Perspective of the Gut-Brain Axis.

Tea polyphenols (TP) have shown multiple biological activities and the ability to modulate the composition and function of intestinal microbiota. Certain human metabolic diseases are engendered by the disruption of the circadian rhythm. Circadian rhythm oscillations exist in both intestinal microbiota and hypothalamus. The brain-gut-microbiome axis enables intestinal microorganisms to communicate with the brain. The close reciprocity between intestinal microbiota and circadian rhythm supplies a new opportunity for TP to regulate circadian-rhythm-related diseases relying on intestinal microbiota. Therefore, based on the potential bidirectional association of the brain and gut microbes, this review mainly discussed the interaction between TP and intestinal microbiota from the perspective of the gut-brain axis (GBA) to improve the theory of metabolic diseases prevention.

Modulation of cortical slow oscillatory rhythm by GABAB receptors: an in vitro experimental and computational study.

Key points We confirm that GABAB receptors (GABAB‐Rs) are involved in the termination of Up‐states; their blockade consistently elongates Up‐states.GABAB‐Rs also modulate Down‐states and the oscillatory cycle, thus having an impact on slow oscillation rhythm and its regularity.The most frequent effect of GABAB‐R blockade is elongation of Down‐states and subsequent decrease of oscillatory frequency, with an increased regularity. In a quarter of cases, GABAB‐R blockade shortened Down‐states and increased oscillatory frequency, changes that are independent of firing rates in Up‐states.Our computer model provides mechanisms for the experimentally observed dynamics following blockade of GABAB‐Rs, for Up/Down durations, oscillatory frequency and regularity. The time course of excitation, inhibition and adaptation can explain the observed dynamics of the network.This study brings novel insights into the role of GABAB‐R‐mediated slow inhibition on the slow oscillatory activity, which is considered the default activity pattern of the cortical network. Slow wave oscillations (SWOs) dominate cortical activity during deep sleep, anaesthesia and in some brain lesions. SWOs are composed of periods of activity (Up states) interspersed with periods of silence (Down states). The rhythmicity expressed during SWOs integrates neuronal and connectivity properties of the network and is often altered under pathological conditions. Adaptation mechanisms as well as synaptic inhibition mediated by GABAB receptors (GABAB‐Rs) have been proposed as mechanisms governing the termination of Up states. The interplay between these two mechanisms is not well understood, and the role of GABAB‐Rs controlling the whole cycle of the SWO has not been described. Here we contribute to its understanding by combining in vitro experiments on spontaneously active cortical slices and computational techniques. GABAB‐R blockade modified the whole SWO cycle, not only elongating Up states, but also affecting the subsequent Down state duration. Furthermore, while adaptation tends to yield a rather regular behaviour, we demonstrate that GABAB‐R activation desynchronizes the SWOs. Interestingly, variability changes could be accomplished in two different ways: by either shortening or lengthening the duration of Down states. Even when the most common observation following GABAB‐Rs blocking is the lengthening of Down states, both changes are expressed experimentally and also in numerical simulations. Our simulations suggest that the sluggishness of GABAB‐Rs to follow the excitatory fluctuations of the cortical network can explain these different network dynamics modulated by GABAB‐Rs.

Phase- and amplitude-coupling are tied by an intrinsic spatial organization but show divergent stimulus-related changes

Functional connectivity (FC), thought to provide a window into neural communication, has become a core focus in the study of brain function and cognition. However, there is no consensus on how to conceptualize large-scale FC in electrophysiology. Phase coupling (PhC), defined as coupling between the phases of two signals, reflects the synchronization of rhythmic oscillation cycles. Conversely, amplitude coupling (AmpC), defined as coupling between the envelopes of two signals, reflects correlation of activation amplitude. Despite quantifying different electrophysiological properties, the relationship between PhC and AmpC remains largely unknown. We assessed spatial and temporal correspondence between PhC and AmpC over 5 canonical frequency bands during a cue-based motor task using electrocorticography (ECoG) in 18 patients (8 females) undergoing presurgical monitoring. Significant correspondence between the spatial pattern of PhC and AmpC was detected during stimulus processing across all subjects and frequency bands (R ​≈ ​0.50 for theta, decreasing with increasing frequency). The cross-measure spatial correlation vanished almost entirely when accounting for the portion of FC equally present during pre- and post-stimulus intervals, suggesting that the spatial correlations reflect intrinsic FC independent of stimulus processing. Stimulus-related processing modulated both PhC and AmpC, however in a spatially independent manner. Examining the linear temporal correlation, we found no evidence for linear dependence between PhC and AmpC. Supporting the robustness of our findings, results extended to a verb generation task in a second ECoG dataset of 6 subjects. We conclude that PhC and AmpC reflect intrinsic FC similarly across space, but exhibit divergent stimulus-related FC changes over space and time.

Oscilopatología en Trastornos del Espectro Autista

El lenguaje como vehículo del desarrollo humano incide de importante manera en los procesos sociales, que figuran de forma determinante en el establecimiento de condiciones de vida y bienestar óptimas. Estudios modernos han encontrado que las habilidades que hacen del lenguaje una actividad de compleja integración multisensorial están determinadas por los ritmos de oscilación de las diferentes ondas cerebrales descritas desde las neurociencias. En la literatura se ha descrito un patrón anormal de oscilaciones, responsable de las deficiencias comunicativas en individuos con Trastornos del Espectro Autista y que junto con sus déficits sociales dan como resultado un perfil típicamente característico. Las ondas cerebrales demuestran tener incidencia en la manera en que se regulan los estados mentales que posibilitan tareas de alta demanda cognitiva como el aprendizaje, la comunicación y la comprensión del discurso, dificultades generalizadas en esta población. Los hallazgos aquí presentados, producto de una juiciosa revisión bibliográfica, se caracterizan dentro de la fonoaudiología haciendo posible aterrizar los procesos de intervención a las necesidades lingüísticas y cognitivas específicas de estos individuos, valiéndose de mecanismos biológicos y dando como posible resultado, procedimientos de mayor relevancia y eficacia, que mejoren la calidad de vida de los usuarios y motiven, además, a los profesionales en fonoaudiología y área afines, a ampliar su conocimiento en este interesante campo.