Macroscale variation in resting-state neuronal activity and connectivity assessed by simultaneous calcium imaging, hemodynamic imaging and electrophysiology

Murphy, Matthew C.,Chan, Kevin C.,Kim, Seong-Gi,Vazquez, Alberto L. Elsevier 2018 NeuroImage Vol.169 No.-

<P><B>Abstract</B></P> <P>Functional imaging of spontaneous activity continues to play an important role in the field of connectomics. The most common imaging signal used for these experiments is the blood-oxygen-level-dependent (BOLD) functional MRI (fMRI) signal, but how this signal relates to spontaneous neuronal activity remains incompletely understood. Genetically encoded calcium indicators represent a promising tool to study this problem, as they can provide brain-wide measurements of neuronal activity compared to point measurements afforded by electrophysiological recordings. However, the relationship between the calcium signal and neurophysiological parameters at the mesoscopic scale requires further systematic characterization. Therefore, we collected simultaneous resting-state measurements of electrophysiology, along with calcium and hemodynamic imaging, in lightly anesthetized mice to investigate two aims. First, we examined the relationship between each imaging signal and the simultaneously recorded electrophysiological signal in a single brain region, finding that both signals are better correlated with multi-unit activity compared to local field potentials, with the calcium signal possessing greater signal-to-noise ratio and regional specificity. Second, we used the resting-state imaging data to model the relationship between the calcium and hemodynamic signals across the brain. We found that this relationship varied across brain regions in a way that is consistent across animals, with delays increasing by600 ms towards posterior cortical regions. Furthermore, while overall functional connectivity (FC) measured by the hemodynamic signal is significantly correlated with FC measured by calcium, the two estimates were found to be significantly different. We hypothesize that these differences arise at least in part from the observed regional variation in the hemodynamic response. In total, this work highlights some of the caveats needed in interpreting hemodynamic-based measurements of FC, as well as the need for improved modeling methods to reduce this potential source of bias.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We acquired simultaneous electrophysiology and imaging in lightly anesthetized mice. </LI> <LI> Both calcium and hemodynamic signals are correlated with neuronal activity. </LI> <LI> Multi-unit activity was the best electrophysiological correlate of both signals. </LI> <LI> The hemodynamic versus calcium relationship varied significantly by brain region. </LI> <LI> Estimates of connectivity derived from two signals were correlated but different. </LI> </UL> </P>

Perioperative hemodynamic protective assessment of adaptive support ventilation usage in pediatric surgical patients

Dmytriiev Dmytro,Melnychenko Mykola,Dobrovanov Oleksandr,Nazarchuk Oleksandr,Vidiscak Marian 대한중환자의학회 2022 Acute and Critical Care Vol.37 No.4

Background: The aim of this study was to evaluate the hemodynamic protective effects of perioperative ventilation in pressure-controlled ventilation (PCV) and adaptive support ventilation (ASV) modes based on non-invasive hemodynamic monitoring indicators.Methods: The study included 32 patients who were scheduled for planned open abdominal surgery. Depending on the chosen ventilation strategy, patients were included in two groups of PCV mode ventilation (n=14) and ASV mode ventilation (n=18). The hemodynamic effects of the ventilation strategies were assessed by estimated continuous cardiac output (esCCO) and cardiac index (esCCI). Results: Preoperative cardiac output (CO) was 6.1±1.3 L/min in group 1 patients and 6.3±0.8 L/min in group 2 patients, and preoperative cardiac index (CI) was 3.9±0.4 mL/m2 in group 1 patients and 3.8±0.8 mL/m2 in group 2 patients. The ejection fraction (EF) in group 1 subjects was 55.4%±0.3%; this rate was 56.5%±0.5% in group 2 subjects. Group 1 patients experienced a 14.7% CO decrease to 5.2±0.7 L/min, a 17.9% CI decrease to 3.2±0.6 mL/m2, and a 12.8% mean arterial pressure decrease to 82.3±9.4 mm Hg 30 minutes after the start of surgery. One hour after the start of surgery, the CO mean values of group 2 patients were lower than baseline by 7.9% and differed from the dynamics of patients in group 1, in whom CO was lower than baseline by 13.1%. At the end of the operation, the CO values were lower than baseline by 11.5% and 6.3% in patients of groups 1 and 2, respectively. Our data showed that the changes in EF during and after surgery correlated with CO indicators determined by the esCCO.Conclusions: In our study, perioperative ventilation in ASV mode was more protective than PCV mode and was characterized by lower tidal volume (16.2%) and driving pressure (ΔP) (12.1%). Hemodynamically-controlled mechanical ventilation reduces the negative impact of cardiopulmonary interactions.

Comparison of the effects of remifentanil-based general anesthesia and popliteal nerve block on postoperative pain and hemodynamic stability in diabetic patients undergoing distal foot amputation : A retrospective observational study

Kim, Na Young,Lee, Ki-Young,Bai, Sun Joon,Hong, Jung Hwa,Lee, Jinwoo,Park, Jong Min,Kim, Shin Hyung Wolters Kluwer Health 2016 Medicine Vol.95 No.29

<P><B>Abstract</B></P><P>Diabetic foot ulcer is the most common cause of diabetes-associated nontraumatic lower extremity amputation. Most patients who undergo lower extremity amputation for a diabetic foot have had diabetes for a long time and suffer from multiorgan disorder; thus, it can be a challenge to ensure sufficient anesthetic and analgesic effects while maintaining stable hemodynamics. Recently, peripheral nerve block has gained popularity owing to its attenuating effects of systemic concerns. This retrospective observational study aimed to compare the effects of remifentanil-based general anesthesia (GEA) and popliteal nerve block (PNB) on postoperative pain and hemodynamic stability in diabetic patients undergoing distal foot amputation.</P><P>A total of 59 consecutive patients with a diabetic foot who underwent distal foot amputation between January 2012 and May 2014 were retrospectively reviewed. Patients received remifentanil-based GEA (GEA group, n = 32) or PNB (PNB group, n = 27). The primary outcomes were to evaluate postoperative analgesic effects and perioperative hemodynamics. Also, postoperative pulmonary complications and 6-month mortality were assessed as secondary outcomes.</P><P>Significant differences in pain scores using numeric rating scale were observed between the groups in a linear mixed model analysis (<I>P</I><SUB>Group×Time</SUB> = 0.044). Even after post hoc analysis with the Bonferroni correction, the numeric rating scale scores were significantly lower in the PNB group. Furthermore, patients in the PNB group required less pethidine during the first 6 hours after surgery (27 ± 28 vs 9 ± 18 mg; <I>P</I> = 0.013). The GEA group had a lower mean blood pressure (Bonferroni-corrected <I>P</I> < 0.01), despite receiving more ephedrine (<I>P</I> < 0.001). Significantly more patients in the GEA group suffered from postoperative pneumonia and required the management in intensive care unit (<I>P</I> = 0.030 and 0.038, respectively). However, the groups did not differ in terms of 6-month mortality.</P><P>This study demonstrated that compared with remifentanil-based GEA, PNB might be a favorable option for diabetic patients undergoing distal foot amputation, despite the lack of significant mortality benefits, as PNB was associated with improved postoperative analgesia, hemodynamic stability, and a low incidence of pulmonary complications during the immediate postoperative period, especially in high-risk patients.</P>

Critical bounds on noise and SNR for robust estimation of real-time brain activity from functional near infra-red spectroscopy

Aqil, Muhammad,Jeong, Myung Yung Elsevier 2018 NeuroImage Vol.176 No.-

<P><B>Abstract</B></P> <P>The robust characterization of real-time brain activity carries potential for many applications. However, the contamination of measured signals by various instrumental, environmental, and physiological sources of noise introduces a substantial amount of signal variance and, consequently, challenges real-time estimation of contributions from underlying neuronal sources. Functional near infra-red spectroscopy (fNIRS) is an emerging imaging modality whose real-time potential is yet to be fully explored. The objectives of the current study are to (i) validate a time-dependent linear model of hemodynamic responses in fNIRS, and (ii) test the robustness of this approach against measurement noise (instrumental and physiological) and mis-specification of the hemodynamic response basis functions (amplitude, latency, and duration). We propose a linear hemodynamic model with time-varying parameters, which are estimated (adapted and tracked) using a dynamic recursive least square algorithm. Owing to the linear nature of the activation model, the problem of achieving robust convergence to an accurate estimation of the model parameters is recast as a problem of parameter error stability around the origin. We show that robust convergence of the proposed method is guaranteed in the presence of an acceptable degree of model misspecification and we derive an upper bound on noise under which reliable parameters can still be inferred. We also derived a lower bound on signal-to-noise-ratio over which the reliable parameters can still be inferred from a channel/voxel. Whilst here applied to fNIRS, the proposed methodology is applicable to other hemodynamic-based imaging technologies such as functional magnetic resonance imaging.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Robust real-time estimation of time-varying activity parameters. </LI> <LI> Deals with the trial-to-trial variability (noises and model misspecifications). </LI> <LI> Robust convergence of activity parameters by stabilizing their estimation error dynamics. </LI> <LI> Robustness of the proposed method is guaranteed against bounded disturbances and SNR. </LI> <LI> The permissible limits of disturbances and SNR are revealed to sustain the basic statistics. </LI> </UL> </P>

Air-plethysmography를 이용한 한국여성의 임신에 따른 하지정맥의 혈류역학적 변화 관찰

박기혁 ( Park Gi Hyeog ),고석봉 ( Go Seog Bong ),허창규 ( Heo Chang Gyu ) 대한산부인과학회 2004 Obstetrics & Gynecology Science Vol.47 No.1

Objective : The purpose of this study was to research the physiologic effects of pregnancy on lower extremity venous hemodynamics. Methods : Forty-eight limbs of twenty four women in third trimester were studied with air plethysmography (APG) and duplex s

Numerical Model for Cerebrovascular Hemodynamics with Indocyanine Green Fluorescence Videoangiography

Hwayeong Cheon,Young Je Son,Sung Bae Park,Pyoung-Seop Shim,Joo-Hiuk Son,Hee-Jin Yang 대한신경외과학회 2023 Journal of Korean neurosurgical society Vol.66 No.4

Objective : The use of indocyanine green videoangiography (ICG-VA) to assess blood flow in the brain during cerebrovascular surgery has been increasing. Clinical studies on ICG-VA have predominantly focused on qualitative analysis. However, quantitative analysis numerical modelling for time profiling enables a more accurate evaluation of blood flow kinetics. In this study, we established a multiple exponential modified Gaussian (multi-EMG) model for quantitative ICG-VA to understand accurately the status of cerebral hemodynamics. Methods : We obtained clinical data of cerebral blood flow acquired the quantitative analysis ICG-VA during cerebrovascular surgery. Varied asymmetric peak functions were compared to find the most matching function form with clinical data by using a nonlinear regression algorithm. To verify the result of the nonlinear regression, the mode function was applied to various types of data. Results : The proposed multi-EMG model is well fitted to the clinical data. Because the primary parameters—growth and decay rates, and peak center and heights—of the model are characteristics of model function, they provide accurate reference values for assessing cerebral hemodynamics in various conditions. In addition, the primary parameters can be estimated on the curves with partially missed data. The accuracy of the model estimation was verified by a repeated curve fitting method using manipulation of missing data. Conclusion : The multi-EMG model can possibly serve as a universal model for cerebral hemodynamics in a comparison with other asymmetric peak functions. According to the results, the model can be helpful for clinical research assessment of cerebrovascular hemodynamics in a clinical setting.

심근세포를 기반으로 한 심혈관 혈류역학 시스템 모델의 개발

전형민(Jun Hyung Min),심은보(Shim Eun Bo) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11

In this paper we developed an integrated model of cardiovascular system for the analysis of circulatory hemodynamics. Excitation contraction coupling in cardiac cells are implemented by the membrane potential (excitation) and cross-bridge dynamics models. By combining this ventricular cell model with a lumped circulation model, we examined how blood pressure dynamics in the atrium, ventricle and aorta are related to the cellular processes. The time courses of the hemodynamic properties, as well as the volume-pressure trajectory of the left ventricle, were well reproduced. Our multi-scale cardiovascular model, which covers from cardiac cells to the circulatory system, simulates the typical characteristics of heart mechanics, such as the pressure-volume relationship, stroke volume, and the effect of the increased maximum free calcium concentration on cardiovascular hemodynamics.

좌심실 보조장치의 관 삽입술 방법에 따른 환자의 심혈관 응답 예측

송진호(Jin-Ho Song),임기무(Ki Moo Lim),최성욱(Seong Wook Choi),심은보(Eun Bo Shim) 대한기계학회 2009 대한기계학회 춘추학술대회 Vol.2009 No.11

Using a simulation model. we assessed the effect of LVAD cannulation on patient's cardiovascular response. Hemodynamic model and autonomic nerve control were included in the simulation code. By solving numerically several cannulation methods such as from left atrium to ascending aorta, from left atrium to descending aorta. from left ventricle to ascending aorta. from left ventricle to descending aorta. and from ascending aorta to descending aorta we compared the cardiovascular response according to the method. Computational results showed that the connection method from left atrium to ascending aorta was optimal in view of hemodynamics.

Influence of Parent Artery Segmentation and Boundary Conditions on Hemodynamic Characteristics of Intracranial Aneurysms

Yufeng Hua,김용배,오제훈 연세대학교의과대학 2015 Yonsei medical journal Vol.56 No.5

Purpose: The purpose of this study is to explore the influence of segmentation of the upstream and downstream parent artery and hemodynamic boundary conditions (BCs) on the evaluated hemodynamic factors for the computational fluid dynamics (CFD) analysis of intracranial aneurysms. Materials and Methods: Three dimensional patient-specific aneurysm models were analyzed by applying various combinations of inlet and outlet BCs. Hemodynamic factors such as velocity pattern, streamline, wall shear stress, and oscillatory shear index at the systolic time were visualized and compared among the different cases. Results: Hemodynamic factors were significantly affected by the inlet BCs while there was little influence of the outlet BCs. When the inlet length was relatively short, different inlet BCs showed different hemodynamic factors and the calculated hemodynamic factors were also dependent on the inlet length. However, when the inlet length (L) was long enough (L>20D, where D is the diameterof inlet section), the hemodynamic factors became similar regardless of the inlet BCs and lengths. The error due to differentinlet BCs was negligible. The effect of the outlet length on the hemodynamic factors was similar to that of the inlet length. Conclusion: Simulated hemodynamic factors are highly sensitive to inlet BCs and upstream parent artery segmentation. The resultsof this work can provide an insight into how to build models and to apply BCs for more accurate estimation of hemodynamic factors from CFD simulations of intracranial aneurysms.

노인여성에서 신체구성과 혈류동태 지표들의 관련성 및 공통성

오봉석(Bong Seok Oh) 한국사회체육학회 2013 한국사회체육학회지 Vol.0 No.53

The main purpose of this study is to find the relations and common factors regarding the body composition and hemodynamic variables. The subjects were 257 elderly Korean women (mean age 69.32 years). Body composition measurement items were minerals, muscle mass(MM), fat mass(FM), body fat percentage(BFP), waist-hip ratio(WHR) and body mass index(BMI). Hemodynamic factors were systolic blood pressure(SBP), diastolic blood pressure(DBP), resting heart rate(HR), pulse wave korotkoff sound systolic time(TP-KS), pressure rate product(PRP), stroke volume(SV), cardiac output(CO), cardiac index(CI) and total peripheral resistance(TPR). Data assessment for Pearson`s correlations and common factors was analyzed using SPSS (ver. 19.0). The results are as follows. First, there was no significant correlations between body compositions and hemodynamic variables in elderly Korean women. Second, MM and WHR were significantly related to all of body compositions. There were statistically significant positive relationships between MM and obesity. Third, hemodynamic variables such as SBP, HR, PRP, CO were TPR modulators which affect blood circulations throughout whole-body. Fourth, arteriosclerosis index(TP-KS) displayed a negative relationship with HR, however there were no any significant correlations between TP-KS, body compositions and hemodynamic variables. Fifth, measuring body compositions and hemodynamic items such as FM, minerals, CO, DBP, HR can be used to help figure out most of the body composition and hemodynamic conditions in elderly Korean women. In summary, the relationships between body compositions and hemodynamic variables were no significance, which suggests that the body compositions and hemodynamic elements in elderly Korean women should be interpreted and took care of as a independent factor for elderly health management. Controling muscle mass and abdominal obesity would be helpful for managing all of body composition and elderly health. Mild obesity in elderly Korean women may have positive effects on keeping muscle mass and expanding lifespan. Senile arteriosclerosis may be more affected by other components than body compositions and hemodynamic variables.