scholarly journals Integrity of corpus callosum is essential for the cross-hemispheric propagation of sleep slow waves: a high-density EEG study in split-brain patients

2019 ◽  
Author(s):  
Giulia Avvenuti ◽  
Giacomo Handjaras ◽  
Monica Betta ◽  
Jacinthe Cataldi ◽  
Laura Sophie Imperatori ◽  
...  
Keyword(s):  
Wave Propagation ◽  
White Matter ◽  
Corpus Callosum ◽  
Slow Wave ◽  
Nrem Sleep ◽  
High Density ◽  
Slow Waves ◽  
Wave Parameter ◽  
P Value ◽  
The Cross

AbstractThe slow waves of NREM-sleep (0.5-4Hz) reflect experience-dependent plasticity and play a direct role in the restorative functions of sleep. Importantly, slow waves behave as traveling waves and their propagation is assumed to reflect the structural properties of white matter connections. Based on this assumption, the corpus callosum (CC) may represent the main responsible for cross-hemispheric slow wave propagation. To verify this hypothesis, here we studied a group of patients who underwent total callosotomy due to drug-resistant epilepsy. Overnight high-density (hd)-EEG recordings (256 electrodes) were performed in five totally callosotomized in-patients (CP; 40-53y, 2F), in three control non-callosotomized neurological in-patients (NP; 44-66y, 2F, 1M epileptic), and in an additional sample of 24 healthy adult subjects (HS; 20-47y, 13F). Data were inspected to select NREM-sleep epochs and artefactual or non-physiological activity was rejected. Slow waves were detected using an automated algorithm and their properties and propagation patterns were computed. For each slow wave parameter and for each patient, the relative z-score and the corresponding p-value were calculated with respect to the distribution represented by the HS-group. Group differences were considered significant only when a Bonferroni corrected P < 0.05 was observed in all the CP and in none of the NP. A regression-based adjustment was used to exclude potential confounding effects of age. Slow wave density, amplitude, slope and propagation speed did not differ across CP and HS. In all CP slow waves displayed a significantly reduced probability of cross-hemispheric propagation and a stronger inter-hemispheric asymmetry. Moreover, we found that the incidence of large slow waves tended to differ across hemispheres within individual NREM epochs, with a relative predominance of the right over the left hemisphere in both CP and HS. The absolute magnitude of this inter-hemispheric difference was significantly greater in CP relative to HS. This effect did not depend on differences in slow wave origin within each hemisphere across groups. Present results indicate that the integrity of the CC is essential for the cross-hemispheric traveling of sleep slow waves, supporting the assumption of a direct relationship between white matter structural integrity and cross-hemispheric slow wave propagation. Our findings also imply a prominent role of cortico-cortical connections, rather than cortico-subcortico-cortical loops, in slow wave cross-hemispheric synchronization. Finally, this data indicate that the lack of the CC does not lead to differences in sleep depth, in terms of slow wave generation/origin, across brain hemispheres.

The corpus callosum is essential for the cross-hemispheric propagation of sleep slow waves: a high-density EEG study in totally callosotomized patients

2019 ◽  
Vol 64 ◽  
pp. S18
Author(s):  
G. Avvenuti ◽  
G. Handjaras ◽  
M. Betta ◽  
J. Cataldi ◽  
L.S. Imperatori ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
High Density ◽  
Slow Waves ◽  
The Cross

scholarly journals Integrity of Corpus Callosum Is Essential for the Cross-Hemispheric Propagation of Sleep Slow Waves: A High-Density EEG Study in Split-Brain Patients

2020 ◽  
Vol 40 (29) ◽  
pp. 5589-5603
Author(s):  
Giulia Avvenuti ◽  
Giacomo Handjaras ◽  
Monica Betta ◽  
Jacinthe Cataldi ◽  
Laura Sophie Imperatori ◽  
...  
Keyword(s):  
Corpus Callosum ◽  
High Density ◽  
Slow Waves ◽  
Split Brain ◽  
The Cross

scholarly journals Abnormal gastric slow waves in patients with functional dyspepsia assessed by multichannel electrogastrography

2001 ◽  
Vol 280 (6) ◽  
pp. G1370-G1375 ◽  
Author(s):  
Xuemei Lin ◽  
Jiande Z. Chen
Keyword(s):  
Wave Propagation ◽  
Functional Dyspepsia ◽  
Slow Wave ◽  
Single Channel ◽  
Slow Waves ◽  
Lower Percentage ◽  
Healthy Controls ◽  
Fasting State ◽  
Gastric Slow Wave ◽  
Gastric Slow Waves

The aim of this study was to utilize multichannel electrogastrography to investigate whether patients with functional dyspepsia had impaired propagation or coordination of gastric slow waves in the fasting state compared with healthy controls. The study was performed in 10 patients with functional dyspepsia and 11 healthy subjects. Gastric myoelectrical activity was measured by using surface electrogastrography with a specially designed four-channel device. The study was performed for 30 min or more in the fasting state. Special computer programs were developed for the computation of the propagation and coupling of the gastric slow wave. It was found that, compared with the healthy controls, the patients showed a significantly lower percentage of slow wave propagation (58.0 ± 8.9 vs. 89.9 ± 2.6%, P < 0.002) and a significantly lower percentage of slow wave coupling (46.9 ± 4.4 vs. 61.5 ± 6.9%, P < 0.04). In addition, the patients showed inconsistencies in the frequency and regularity of the gastric slow wave among the four-channel electrogastrograms (EGGs). It was concluded that patients with functional dyspepsia have impaired slow wave propagation and coupling. Multichannel EGG has more information than single-channel EGG for the detection of gastric myoelectrical abnormalities.

scholarly journals Bidirectional Interaction of Hippocampal Ripples and Cortical Slow Waves Leads to Coordinated Spiking Activity During NREM Sleep

2020 ◽  
Vol 31 (1) ◽  
pp. 324-340
Author(s):  
Pavel Sanda ◽  
Paola Malerba ◽  
Xi Jiang ◽  
Giri P Krishnan ◽  
Jorge Gonzalez-Martinez ◽  
...  
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Slow Wave Sleep ◽  
Nrem Sleep ◽  
Slow Waves ◽  
Slow Oscillation ◽  
Cortical Input ◽  
Sharp Wave ◽  
Up States ◽  
Intracranial Recordings

Abstract The dialogue between cortex and hippocampus is known to be crucial for sleep-dependent memory consolidation. During slow wave sleep, memory replay depends on slow oscillation (SO) and spindles in the (neo)cortex and sharp wave-ripples (SWRs) in the hippocampus. The mechanisms underlying interaction of these rhythms are poorly understood. We examined the interaction between cortical SO and hippocampal SWRs in a model of the hippocampo–cortico–thalamic network and compared the results with human intracranial recordings during sleep. We observed that ripple occurrence peaked following the onset of an Up-state of SO and that cortical input to hippocampus was crucial to maintain this relationship. A small fraction of ripples occurred during the Down-state and controlled initiation of the next Up-state. We observed that the effect of ripple depends on its precise timing, which supports the idea that ripples occurring at different phases of SO might serve different functions, particularly in the context of encoding the new and reactivation of the old memories during memory consolidation. The study revealed complex bidirectional interaction of SWRs and SO in which early hippocampal ripples influence transitions to Up-state, while cortical Up-states control occurrence of the later ripples, which in turn influence transition to Down-state.

Slow waves actively propagate at submucosal surface of circular layer in canine colon

1990 ◽  
Vol 259 (2) ◽  
pp. G258-G263 ◽  
Author(s):  
K. M. Sanders ◽  
R. Stevens ◽  
E. Burke ◽  
S. W. Ward
Keyword(s):  
Wave Propagation ◽  
Slow Wave ◽  
Proximal Colon ◽  
Slow Waves ◽  
Pacemaker Cells ◽  
Transverse Axis ◽  
Active Mechanism ◽  
Conduction Velocities ◽  
Circular Layer ◽  
Thin Band

Colonic slow waves originate from pacemaker cells along the submucosal surface of the circular layer in the dog proximal colon. These events propagate in a nonregenerative manner into the bulk of the circular layer. Conduction velocities consistent with an active mechanism for slow-wave propagation in the longitudinal and circumferential axes of the colon have been reported. Experiments were performed using intracellular recording techniques on canine colonic muscles to determine the regenerative pathway for slow-wave propagation. In a thin band of muscle adjacent to the submucosal border of the circular layer, slow-wave amplitude was independent of distance from a pacing source, and events propagated at a rate of approximately 17 mm/s in the long axis of the circular fibers and 6 mm/s in the transverse axis of the circular fibers. These findings suggest that slow waves propagate in a regenerative manner in this region. Slow waves decayed as they conducted through regions from which the pacemaker cells had been removed with space constants of a few millimeters. Thus the integrity of the thin pacemaker region along submucosal surface is critical for propagation of slow waves and the organization of motility into segmental contractions.

scholarly journals 1133 The Recovery of Sleep Oscillations in Acute to Chronic Traumatic Brain Injury

SLEEP ◽  
2020 ◽  
Vol 43 (Supplement_1) ◽  
pp. A431-A431
Author(s):  
E Sanchez ◽  
C Duclos ◽  
S Van Der Maren ◽  
H El-Khatib ◽  
C Arbour ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Slow Wave ◽  
Nrem Sleep ◽  
Slow Waves ◽  
Hospital Environment ◽  
Chronic Stage ◽  
Orthopedic Injuries ◽  
The Brain ◽  
Sleep Cycles

Abstract Introduction Slow waves and spindles are essential oscillations occurring during NREM sleep that may be disrupted by moderate to severe traumatic brain injury (TBI). We investigated these oscillations in the acute and chronic trauma stage. Methods Four groups were tested with whole-night polysomnography: hospitalized patients with acute TBI (n=10, 29.7±13.8y) or severe orthopedic injuries (n=15, 39.9±17.1y), chronic TBI including 9 returning from the acute TBI group (n=43, 31.9±13.5y), and healthy controls (n=36, 30.5±12.7y). Characteristics for slow waves (density, amplitude, slope, frequency, duration) and spindles (density, amplitude, frequency, duration) were quantified over N2 and N3 sleep for the first three sleep cycles, and groups were compared using one-way ANOVAs. Results One-way ANOVAs showed group effects only for slow wave density (F=4.11 to 6.04, p=0.009 to 0.0008)) and spindle density (F=3.3 to 8.8, p=0.02 to 0.00003). These effects were present for the 2nd and 3rd sleep cycles, but not the 1st. More specifically, slow wave density in acute TBI was higher than in controls, and returned to normal levels in the chronic stage. Conversely, spindle density in acute TBI was lower than in controls and returned to normal levels in the chronic stage. No group difference was observed for the orthopedic group. Conclusion Our results suggest that immediately after a severely disruptive event such as a TBI, the brain needs additional deeper sleep to recover, resulting in more slow waves but also in less spindles. These changes are only present in the 2nd and 3rd sleep cycles, reflecting an absence of the expected dissipation of slow waves, which may suggest increased homeostatic sleep pressure due to the brain injury. Limits to interpretation include the hospital environment and medication, but the absence of changes in the orthopedic group under similar conditions emphasizes the effect of the brain injury itself. Support Canadian Institutes of Health Research (CIHR) and Fonds de Recherche Québec-Santé (FRQS)

scholarly journals High-resolution mapping of gastric slow-wave recovery profiles: biophysical model, methodology, and demonstration of applications

2017 ◽  
Vol 313 (3) ◽  
pp. G265-G276 ◽  
Author(s):  
N. Paskaranandavadivel ◽  
L. K. Cheng ◽  
P. Du ◽  
J. M. Rogers ◽  
G. O’Grady
Keyword(s):  
Wave Propagation ◽  
Wavelet Transform ◽  
High Resolution ◽  
Slow Wave ◽  
Recovery Phase ◽  
Slow Waves ◽  
Gastric Slow Wave ◽  
High Resolution Mapping ◽  
Resolution Mapping ◽  
Extracellular Potentials

Slow waves play a central role in coordinating gastric motor activity. High-resolution mapping of extracellular potentials from the stomach provides spatiotemporal detail on normal and dysrhythmic slow-wave patterns. All mapping studies to date have focused exclusively on tissue activation; however, the recovery phase contains vital information on repolarization heterogeneity, the excitable gap, and refractory tail interactions but has not been investigated. Here, we report a method to identify the recovery phase in slow-wave mapping data. We first developed a mathematical model of unipolar extracellular potentials that result from slow-wave propagation. These simulations showed that tissue repolarization in such a signal is defined by the steepest upstroke beyond the activation phase (activation was defined by accepted convention as the steepest downstroke). Next, we mapped slow-wave propagation in anesthetized pigs by recording unipolar extracellular potentials from a high-resolution array of electrodes on the serosal surface. Following the simulation result, a wavelet transform technique was applied to detect repolarization in each signal by finding the maximum positive slope beyond activation. Activation-recovery (ARi) and recovery-activation (RAi) intervals were then computed. We hypothesized that these measurements of recovery profile would differ for slow waves recorded during normal and spatially dysrhythmic propagation. We found that the ARi of normal activity was greater than dysrhythmic activity (5.1 ± 0.8 vs. 3.8 ± 0.7 s; P < 0.05), whereas RAi was lower (9.7 ± 1.3 vs. 12.2 ± 2.5 s; P < 0.05). During normal propagation, RAi and ARi were linearly related with negative unit slope indicating entrainment of the entire mapped region. This relationship was weakened during dysrhythmia (slope: −0.96 ± 0.2 vs −0.71 ± 0.3; P < 0.05). NEW & NOTEWORTHY The theoretical basis of the extracellular gastric slow-wave recovery phase was defined using mathematical modeling. A novel technique utilizing the wavelet transform was developed and validated to detect the extracellular slow-wave recovery phase. In dysrhythmic wavefronts, the activation-to-recovery interval (ARi) was shorter and recovery-to-activation interval (RAi) was longer compared with normal wavefronts. During normal activation, RAi vs. ARi had a slope of −1, whereas the weakening of the slope indicated a dysrhythmic propagation.

Peripheral pacemakers and patterns of slow wave propagation in the canine small intestine in vivo

2005 ◽  
Vol 83 (11) ◽  
pp. 1031-1043 ◽  
Author(s):  
Wim J.E.P Lammers ◽  
Luc Ver Donck ◽  
Jan A.J Schuurkes ◽  
Betty Stephen
Keyword(s):  
Wave Propagation ◽  
Small Intestine ◽  
Slow Wave ◽  
Electrode Array ◽  
Canine Model ◽  
Slow Waves ◽  
Velocity Amplitude ◽  
Local Site ◽  
Propagation Pattern

In an anesthetized, open-abdomen, canine model, the propagation pattern of the slow wave and its direction, velocity, amplitude, and frequency were investigated in the small intestine of 8 dogs. Electrical recordings were made using a 240-electrode array from 5 different sites, spanning the length of the small intestine. The majority of slow waves propagated uniformly and aborally (84%). In several cases, however, other patterns were found including propagation in the oral direction (11%) and propagation block (2%). In addition, in 69 cases (3%), a slow wave was initiated at a local site beneath the electrode array. Such peripheral pacemakers were found throughout the entire intestine. The frequency, velocity, and amplitude of slow waves were highest in the duodenum and gradually declined along the intestine reaching lowest values in the distal ileum (from 17.4 ± 1.7 c/min to 12.2 ± 0.7 c/min; 10.5 ± 2.4 cm/s to 0.8 ± 0.2 cm/s, and 1.20 ± 0.35 mV to 0.31 ± 0.10 mV, respectively; all p < 0.001). Consequently, the wavelength of the slow wave was strongly reduced from 36.4 ± 0.8 cm to 3.7 ± 0.1 cm (p < 0.001). We conclude that the patterns of slow wave propagation are usually, though not always, uniform in the canine small intestine and that the gradient in the wavelength will influence the patterns of local contractions.Key words: slow waves, conduction velocity, peripheral pacemakers, wavelength.

scholarly journals Schizophrenia-associated variation at ZNF804A correlates with altered experience-dependent dynamics of sleep slow-waves and spindles in healthy young adults

2020 ◽  
Author(s):  
Ullrich Bartsch ◽  
Laura J Corbin ◽  
Charlotte Hellmich ◽  
Michelle Taylor ◽  
Kayleigh E Easey ◽  
...  
Keyword(s):  
Slow Wave ◽  
Memory Consolidation ◽  
Neural Circuit ◽  
Activity Patterns ◽  
Nrem Sleep ◽  
Slow Waves ◽  
Network Activity ◽  
Healthy Population ◽  
Adult Males ◽  
Performance Improvements

ABSTRACTBackgroundThe rs1344706 polymorphism in ZNF804A is robustly associated with schizophrenia (SZ), yet brain and behavioral phenotypes related to this variant have not been extensively characterized. In turn, SZ is associated with abnormal non-rapid eye movement (NREM) sleep neurophysiology. To examine whether rs1344706 is associated with intermediate neurophysiological traits in the absence of disease, we assessed the relationship between genotype, sleep neurophysiology, and sleep-dependent memory consolidation in healthy participants.MethodsWe recruited healthy adult males, with no history of psychiatric disorder, from the Avon Longitudinal Study of Parents and Children (ALSPAC) birth cohort. Participants were homozygous for either the SZ-associated ‘A’ allele (N=25) or the alternative ‘C’ allele (N=22) at rs1344706. Actigraphy, polysomnography (PSG) and a motor sequencing task (MST) were used to characterize daily activity patterns, sleep neurophysiology and sleep-dependent memory consolidation.ResultsAverage MST learning and sleep-dependent performance improvements were similar across genotype groups, but with increased variability in the AA group. CC participants showed increased slow-wave and spindle amplitudes, plus augmented coupling of slow-wave activity across recording electrodes after learning. Slow-waves and spindles in those with the AA genotype were insensitive to learning, whilst slow-wave coherence decreased following MST training.ConclusionWe describe evidence that rs1344706 polymorphism in ZNF804A is associated with changes in experience- and sleep-dependent, local and distributed neural network activity that supports offline information processing during sleep in a healthy population. These findings highlight the utility of sleep neurophysiology in mapping the impacts of SZ-associated variants on neural circuit oscillations and function.

scholarly journals Hypothermia-treated neonates with hypoxic-ischemic encephalopathy: Optimal timing of quantitative ADC measurement to predict disease severity

2016 ◽  
Vol 30 (1) ◽  
pp. 28-35 ◽  
Author(s):  
Yauk K Lee ◽  
Alex Penn ◽  
Mahesh Patel ◽  
Rajul Pandit ◽  
Dongli Song ◽  
...  
Keyword(s):  
White Matter ◽  
Basal Ganglia ◽  
Corpus Callosum ◽  
Mr Imaging ◽  
Time Window ◽  
Optimal Time ◽  
P Value ◽  
Adc Value ◽  
Hypothermia Treatment ◽  
Adc Values

To determine the optimal time window for MR imaging with quantitative ADC measurement in neonatal HIE after hypothermia treatment, a retrospective review was performed on consecutive hypothermia-treated term neonates with HIE, with an initial and follow-up MR imaging within the first two weeks of life. Three neuroradiologists categorized each set of MR imaging as normal, mild, moderate or severe HIE based on a consensus review of the serial imaging. The lowest ADC values from the white matter, corpus callosum, and basal ganglia/thalamus were measured. The ADC values between mild-moderate and severe HIE were compared using a Student’s t-test over a range of different time windows. A total of 33 MR imaging examinations were performed on 16 neonates that included three normal, four mild, five moderate, and four severe HIE. The time window of 3–10 days showed a statistically significant decrease in ADC value in severe HIE compared to mild-moderate HIE in all three locations, respectively: white matter 0.5 ± 0.22 versus 0.83 ± 0.27 ( p value 0.01), corpus callosum 0.69 ± 0.19 versus 0.91 ± 0.17 ( p value 0.01), and basal ganglia/thalamus 0.63 ± 0.16 versus 0.98 ± 0.06 ( p value <0.01). The range of 3–10 days is the optimal time window for MR imaging with quantitative ADC after hypothermia treatment.

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