Myogenic Oscillations in Rabbit Ocular Vasculature Are Very Low Frequency

Delgado, Esmeralda; Marques-Neves, Carlos; Rocha, Isabel; Sales-Luís, José; Silva-Carvalho, L

doi:10.1159/000351629

Cited by 3 publications

(4 citation statements)

References 29 publications

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“… Müller et al (2003) identified mean very low frequency oscillation spectral peak of 0.021 Hz in transcranial Doppler (TCD) flow. Arteriogenic oscillations exhibiting central frequencies of 0.033 and 0.066 (0.045) Hz analogous to waves observed in middle cerebral artery-derived cerebral blood flow may be observed in rabbit external ophthalmic artery ( Delgado et al, 2013 ). Acute hypoxia (15% O 2 ) enhanced spectral power of very low frequency oscillations in cerebral blood flow volume and mean arterial blood pressure in otherwise healthy subjects ( Iwasaki et al, 2007 ), perhaps through acidosis-mediated relaxation of vascular smooth muscle and vasodilation, amplifying oscillatory trough dips.…”

Section: Very Low Frequency Oscillations In Human Electroencephalogramentioning

confidence: 86%

RETRACTED: Mechanisms Contributing to the Generation of Mayer Waves

Ghali

2020

Front. Neurosci.

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Mayer waves may synchronize overlapping propriobulbar interneuronal microcircuits constituting the respiratory rhythm and pattern generator, sympathetic oscillators, and cardiac vagal preganglionic neurons. Initially described by Sir Sigmund Mayer in the year 1876 in the arterial pressure waveform of anesthetized rabbits, authors have since extensively observed these oscillations in recordings of hemodynamic variables, including arterial pressure waveform, peripheral resistance, and blood flow. Authors would later reveal the presence of these oscillations in sympathetic neural efferent discharge and brainstem and spinal zones corresponding with sympathetic oscillators. Mayer wave central tendency proves highly consistent within, though the specific frequency band varies extensively across, species. Striking resemblance of the Mayer wave central tendency to the species-specific baroreflex resonant frequency has led the majority of investigators to comfortably presume, and generate computational models premised upon, a baroreflex origin of these oscillations. Empirical interrogation of this conjecture has generated variable results and derivative interpretations. Sinoaortic denervation and effector sympathectomy variably reduces or abolishes spectral power contained within the Mayer wave frequency band. Refractorines of Mayer wave generation to barodeafferentation lends credence to the hypothesis these waves are chiefly generated by brainstem propriobulbar and spinal cord propriospinal interneuronal microcircuit oscillators and likely modulated by the baroreflex. The presence of these waves in unitary discharge of medullary lateral tegmental field and rostral ventrolateral medullary neurons (contemporaneously exhibiting fast sympathetic rhythms [2–6 and 10 Hz bands]) in spectral variability in vagotomized pentobarbital-anesthetized and unanesthetized midcollicular (i.e., intercollicular) decerebrate cats supports genesis of Mayer waves by supraspinal sympathetic microcircuit oscillators. Persistence of these waves following high cervical transection in vagotomized unanesthetized midcollicular decerebrate cats would seem to suggest spinal sympathetic microcircuit oscillators generate these waves. The widespread presence of Mayer waves in brainstem sympathetic-related and non-sympathetic-related cells would seem to betray a general tendency of neurons to oscillate at this frequency. We have thus presented an extensive and, hopefully cohesive, discourse evaluating, and evolving the interpretive consideration of, evidence seeking to illumine our understanding of origins of, and insight into mechanisms contributing to, the genesis of Mayer waves. We have predicated our arguments and conjectures in the substance and matter of empirical data, though we have occasionally waxed philosophical beyond these traditional confines in suggesting interpretations exceeding these limits. We believe our synthesis and interpretation of the relevant literature will fruitfully inspire future studies from the perspective of a more intimate appreciation and conceptualization of network mechanisms generating oscillatory variability in neuronal and neural outputs. Our evaluation of Mayer waves informs a novel set of disciplines we term quantum neurophysics extendable to describing subatomic reality. Beyond informing our appreciation of mechanisms generating sympathetic oscillations, Mayer waves may constitute an intrinsic property of neurons extant throughout the cerebrum, brainstem, and spinal cord or reflect an emergent property of interactions between arteriogenic and neuronal oscillations.

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Section: Very Low Frequency Oscillations In Human Electroencephalogramentioning

confidence: 86%

RETRACTED: Mechanisms Contributing to the Generation of Mayer Waves

Ghali

2020

Front. Neurosci.

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“…Interestingly, the frequency band of 0.073–0.198 Hz in tumours has been suggested to be caused primarily by vascular myogenic activity in vasomotion2829. Further study is needed to determine whether this frequency band detected via BOLD has the same implications.…”

Section: Discussionmentioning

confidence: 99%

“…Prior to ROI definition, the tumour tissue was divided into three nearly concentric regions (centre, transition and periphery regions) from the tumour centre to periphery as equally as possible by an experienced radiologist (M.J.W) according to previous studies32. As the transition area within a tumour was difficult to be differentiated from the tumour centre and peripheral regions29, we intended not to use it as an ROI. Within tumours, ROIs were only chosen from the tumour centre and periphery.…”

Section: Methodsmentioning

confidence: 99%

Characterizing the Blood Oxygen Level-Dependent Fluctuations in Musculoskeletal Tumours Using Functional Magnetic Resonance Imaging

Duan

Wang

Sun

et al. 2016

Sci Rep

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This study characterized the blood oxygen level-dependent (BOLD) fluctuations in benign and malignant musculoskeletal tumours via power spectrum analyses in pre-established low-frequency bands. BOLD MRI and T1-weighted imaging (T1WI) were collected for 52 patients with musculoskeletal tumours. Three ROIs were drawn on the T1WI image in the tumours’ central regions, peripheral regions and neighbouring tissue. The power spectrum of the BOLD within each ROI was calculated and divided into the following four frequency bands: 0.01–0.027 Hz, 0.027–0.073 Hz, 0.073–0.198 Hz, and 0.198–0.25 Hz. ANOVA was conducted for each frequency band with the following two factors: the location of the region of interest (LoR, three levels: tumour “centre”, “peripheral” and “healthy tissue”) and tumour characteristic (TC, two levels: “malignant” and “benign”). There was a significant main effect of LoR in the frequencies of 0.073–0.198 Hz and 0.198–0.25 Hz. These data were further processed with post-hoc pair-wise comparisons. BOLD fluctuations at 0.073–0.198 Hz were stronger in the peripheral than central regions of the malignant tumours; however, no such difference was observed for the benign tumours. Our findings provide evidence that the BOLD signal fluctuates with spatial heterogeneity in malignant musculoskeletal tumours at the frequency band of 0.073–0.198 Hz.

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“…Interestingly, the frequency band of 0.073-0.198 Hz in tumors has been suggested to be caused primarily by vascular myogenic activity in vasomotion (45)(46)(47)(48)(49). Vasomotion is a phenomenon of blood flow in normal tissue, which in vivo is associated with the rhythmic oscillations in vessel diameter (26,59).…”

Section: Discussionmentioning

confidence: 99%

Comparing the blood oxygen level–dependent fluctuation power of benign and malignant musculoskeletal tumors using functional magnetic resonance imaging

et al. 2022

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PurposeThe aim of this study is to compare the blood oxygen level–dependent (BOLD) fluctuation power in 96 frequency points ranging from 0 to 0.25 Hz between benign and malignant musculoskeletal (MSK) tumors via power spectrum analyses using functional magnetic resonance imaging (fMRI).Materials and methodsBOLD-fMRI and T1-weighted imaging (T1WI) of 92 patients with benign or malignant MSK tumors were acquired by 1.5-T magnetic resonance scanner. For each patient, the tumor-related BOLD time series were extracted, and then, the power spectrum of BOLD time series was calculated and was then divided into 96 frequency points. A two-sample t-test was used to assess whether there was a significant difference in the powers (the “power” is the square of the BOLD fluctuation amplitude with arbitrary unit) of each frequency point between benign and malignant MSK tumors. The receiver operator characteristic (ROC) analysis was used to assess the diagnostic capability of distinguishing between benign and malignant MSK tumors.ResultsThe result of the two-sample t-test showed that there was significant difference in the power between benign and malignant MSK tumor at frequency points of 58 (0.1508 Hz, P = 0.036), 59 (0.1534 Hz, P = 0.032), and 95 (0.247 Hz, P = 0.014), respectively. The ROC analysis of mean power of three frequency points showed that the area of under curve is 0.706 (P = 0.009), and the cutoff value is 0.73130. If the power of the tumor greater than or equal to 0.73130 is considered the possibility of benign tumor, then the diagnostic sensitivity and specificity values are 83% and 59%, respectively. The post hoc analysis showed that the merged power of 0.1508 and 0.1534 Hz in benign MSK tumors was significantly higher than that in malignant ones (P = 0.014). The ROC analysis showed that, if the benign MSK tumor was diagnosed with the power greater than or equal to the cutoff value of 1.41241, then the sensitivity and specificity were 67% and 68%, respectively.ConclusionThe mean power of three frequency points at 0.1508, 0.1534, and 0.247 Hz may potentially be a biomarker to differentiate benign from malignant MSK tumors. By combining the power of 0.1508 and 0.1534 Hz, we could better detect the difference between benign and malignant MSK tumors with higher specificity.

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Myogenic Oscillations in Rabbit Ocular Vasculature Are Very Low Frequency

Cited by 3 publications

References 29 publications

RETRACTED: Mechanisms Contributing to the Generation of Mayer Waves

RETRACTED: Mechanisms Contributing to the Generation of Mayer Waves

Characterizing the Blood Oxygen Level-Dependent Fluctuations in Musculoskeletal Tumours Using Functional Magnetic Resonance Imaging

Comparing the blood oxygen level–dependent fluctuation power of benign and malignant musculoskeletal tumors using functional magnetic resonance imaging

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