Recurrent Quantification Analysis Based Study of Wide-Field Calcium Imaging Data in Relation to Brain's Wake/Sleep Condition

Wide-Field Calcium Images (WFCI) directly reflect neuronal excitation, but their poor frame rate could be a drawback for time series analysis. This work was aimed at exploring the diagnostic capability retained by a time series obtained from calcium imaging data. To that purpose, we analyzed publicly available data from 2.88 hour continuous recordings of calcium images obtained from seven mice at different wake/sleep stages. Data were obtained from the Physionet portal and were submitted to Recurrence Quantification Analysis (RQA). The association between retrosplenial and parietal areas was also assessed. Nonlinear RQA analysis allowed to identify the right retrosplenial and parietal areas as particularly sensitive to changes in sleep walking condition. Specifically, our results suggested that the RQA feature lmean decreases in non-REM sleep_1 stage as compared to waking stage. Sleep (both sleep_1 stage and REM) apparently elicits an increase in the association between retrosplenial and parietal areas. Overall, these results suggest that RQA and association analysis are appropriate to assess modifications associated to changes in brain condition, in spite of the low sampling rate of WFCI signals.

Las Imágenes de Calcio de Campo Ancho (Wide-Field Calcium Images, WFCI) reflejan directamente la excitación neuronal, pero su escasa resolución temporal pudiera resultar un impedimento para el análisis de series temporales. El presente trabajo tuvo por finalidad explorar la capacidad diagnostica que retiene una serie temporal extraída de imágenes de calcio. Para ello, se estudió una base de datos disponible en la red que contiene registros de 2.88 horas de duración de imágenes de calcio correspondientes a 7 ratones transgénicos a diferentes estadios de sueño/vigilia. Los datos fueron descargados del portal Physionet y sometidos a Análisis de Cuantificación Recurrente (Recurrent Quantification Analysis, RQA). La asociación entre las áreas retrosplenial y parietal derechas fue también evaluada. El análisis no lineal mediante RQA permitió identificar las áreas retrosplenial y parietal derechas como zonas particularmente sensibles a cambios en el estado de sueño/vigilia. Específicamente, nuestros resultados sugieren que el índice l mean se redujo en el estadio 1 de sueño no REM en comparación con el estado de vigilia. El estado de sueño, tanto REM como no-REM aparentemente induce un reforzamiento en la apreciación entre las áreas retrosplenial y parietal derechas. En su conjunto, estos resultados apuntan que el análisis de RQA y de asociación entre áreas son pertinentes para sensar las modificaciones asociadas a cambios en el estado del cerebro, a pesar de la baja resolución temporal de las señales WFCI.

Association between Abnormal Electrocardiogram and Less Complex Heart Rate Variability Estimated by the Correlation Dimension / Asociación entre Electrocardiograma Anormal y Menor Complejidad de la Variabilidad de la Frecuencia Cardiaca Estimada Mediante la Dimensión de Correlación

Objective: To compare the correlation dimension (CD) of heart rate variability (HRV) in adults with and without abnormal electrocardiogram (ECG). Methods: A 24-hr Holter and a standard ECG were recorded from 100 university workers. After exclusion of 10 recordings with more than 5% of false RR intervals, a total of 90 subjects (age 46.2±8.7 years old, 45 were women) were included in the study. Two cardiologists classified 29 standard ECG as abnormal. CD was calculated from HRV time-series of 10,000 beats in the morning (from 11am), afternoon (from 5pm) and night (from 2am). Demographical characteristics were compared by ANOVA (considering ECG diagnosis and sex as independent factors) or by Fisher's exact test. Mean CD values were compared by analysis of variance considering as independent factors the ECG diagnosis, sex and time of day. Results: All demographical characteristics were similar except for a higher proportion of males with abnormal ECG (69%) than with normal ECG (41%). CD was not different with respect to the time of day, but it was higher in subjects with normal ECG (10.86 ± 2.41) than those with abnormal ECG (10.20 ± 2.48), and it was also higher in females than males: 11.04 ± 2.14 versus 10.63 ± 2.71 (normal ECG group), 10.84 ± 2.41 versus 9.92 ± 2.44 (abnormal ECG group). Conclusion: The finding of abnormal ECG is associated with HRV decreased complexity in adults.

Objetivo: Comparar la dimensión de correlación (DC) de la variabilidad de la frecuencia cardiaca (VFC) entre adultos con electrocardiograma (ECG) normal y anormal. Métodos: Se registró un Holter de 24 horas y un electrocardiograma (ECG) estándar de 100 trabajadores universitarios. Después de la exclusión de 10 registros con más de 5% de intervalos RR falsos, se incluyeron en el estudio a 90 sujetos (edad 46.2±8.7 años, 45 mujeres). Dos cardiólogos clasificaron 29 ECG estándar como anormales. La DC se calculó en series de tiempo de VFC de 10,000 latidos en la mañana (desde las 11:00), tarde (desde las 17:00) y noche (desde las 2:00). Las características demográficas fueron comparadas mediante análisis de varianza (considerando diagnóstico de ECG y sexo como factores independientes) o con prueba exacta de Fisher. Los valores promedio de DC fueron comparados con análisis de varianza considerando como factores independientes el diagnóstico de ECG, sexo y hora del día. Resultados: Las características demográficas fueron similares excepto por mayor proporción de hombres con ECG anormal (69%) que normal (41%). La DC no fue diferente con respecto a la hora del día, pero fue mayor en sujetos con ECG normal (10.86 ± 2.41) que con ECG anormal (10.20 ± 2.48), y también fue mayor en mujeres que en hombres: 11.04 ± 2.14 vs 10.63 ± 2.71 (grupo de ECG normal), 10.84 ± 2.41 vs 9.92 ± 2.44 (grupo de ECG anormal). Conclusión: El hallazgo de ECG anormal en adultos está asociado con menor complejidad de la VFC.

Análisis no lineal de la frecuencia cardíaca fetal / Nonlinear analysis of fetal heart rate

Evaluar el comportamiento de la frecuencia cardíaca fetal a través del análisis no lineal en fetos sanos y con restricción del crecimiento intrauterino. Unidad de Perinatología, Departamento Clínico Integral de la Costa, Escuela de Medicina y Departamento de Matemáticas, Facultad de Ciencias y Tecnología, Universidad de Carabobo. Se trata de una investigación observacional, analítica, de corte transversal; se analizaron 60 registros de la frecuencia cardíaca fetal de 40 fetos sanos y de 20 fetos con restricción del crecimiento intrauterino entre las 30 y 42 semanas de gestación. Cada registro de la frecuencia cardíaca fetal en papel se convirtió a formato digital; se estableció la complejidad de cada registro de la frecuencia cardíaca fetal obtenida a través de los métodos de la asimetría del tiempo de reverso y el máximo exponente de Lyapunov. Se utilizó la dimensión de correlación (D2) para cuantificar el comportamiento caótico. Se determinó la complejidad de los registros de la frecuencia cardíaca fetal obtenidos; la dimensión de correlación de los fetos con restricción del crecimiento intrauterino (0,90 ± 0,03) fue menor que la calculada en los fetos sanos (0,93 ± 0,02), probándose su significancia estadística (P = 0,012). La correlación de dimensión disminuidas en fetos con restricción del crecimiento nos indica que la regulación de su dinámica cardíaca es menos compleja, probablemente está limitada la integridad del control del sistema cardiovascular y por ende su capacidad de adaptación frente a noxas externas o internas, estableciendo que el análisis no lineal permite diferenciar los fetos sanos de los fetos con restricción del crecimiento intrauterino.

To evaluate the behavior of the fetal frequency cardiac through nonlinear analysis in healthy fetuses and with intrauterine growth restriction. Unidad de Perinatología, Departamento Clínico Integral de la Costa, Escuela de Medicina y Departamento de Matemáticas, Facultad de Ciencias y Tecnología, Universidad de Carabobo. This work is an observational, analytical investigation, of cross-section; 60 registries of the fetal heart rate of 40 normal fetuses and 20 intrauterine growth restricted fetuses between 30 and 42 gestation weeks were analyzed. Each registry in paper of the fetal heart rate became to digital format; in the search of the possible complex behavior of each monitoring records was applied the asymmetry of the reverse time and the maximum exponent of Lyapunov. The chaotic behavior of each one of them by means of the dimension of correlations was quantified (D2). Was given the complexity of the fetal heart rate records; the correlation dimension of intrauterine growth restricted fetuses (0.90 ± 0.03), was lower than of the normal fetuses (0.93 ± 0.02) proving its statistical significance (P = 0.002). The correlation dimension diminished in intrauterine growth restricted fetuses indicates that the regulation of its cardiac dynamics is less complex, probably is limited the integrity of the cardiovascular control and therefore its capacity of adaptation to external or internal noxas, establishing that the nonlinear analysis allows differentiating the healthy fetuses from intrauterine growth restricted fetuses.

Ciencias de la complejidad y caos como herramientas en el análisis de la proliferación de vectores y zoonosis / Sciences of complexity and chaos to analyze vectors and zoonosis

En el presente trabajo se discuten los fundamentos de las ciencias de la complejidad y caos como herramientas en el análisis la proliferación de vectores y zoonosis. En la primera parte del artículo se describen los fundamentos y antecedentes de las ciencias de la complejidad, como una visión diferente para entender y analizar a los sistemas dinámicos, conceptos que han existido desde hace varios siglos y están relacionados con las ideas acerca del origen de la vida misma, que romperán con los paradigmas de la linealidad y el reduccionismo. Se ejemplifica con la utilización de la geometría fractal, mundo pequeño y los análisis de series de tiempo, entre otras herramientas, para entender el comportamiento de los sistemas caóticos que se presentan en la diseminación de enfermedades de origen zoonótico. Se concluye que la mayoría de los contagios, así como la diseminación de enfermedades transmitidas por los animales, tienen tendencia caótica. Dado que 75 % de las enfermedades emergentes son de origen zoonótico, las herramientas de las ciencias de la complejidad y la no linealidad resultan indispensables para entender el dinamismo y comportamientode la diseminación de estas patologías.

The present paper discusses the fundamentals of the sciences of complexity and chaos as tools in the proliferation of vectors and zoonosis. The first part of the article discusses the rationale and history of the sciences of complexity, a different view as to understand and analyze dynamic systems. These concepts explain the dynamics of the origin of life itself and break the paradigms of linearity and reductionism. This is exemplified by using fractal geometry, the law of the small world and time series analysis among other tools to understand the behavior of chaotic systems, which are presented in the form of the spread of zoonotic diseases. We conclude that most infections and the spread of diseases transmitted by animals tend towards being chaotic, and it is mentioned that 75% of emerging diseases are zoonotic in origin. Therefore, the tools are not linear. They are indispensable for understanding the dynamic behavior of the spread of these diseases.

Variabilidad del patrón respiratorio durante la carga elástica inspiratoria / Variability of breathing pattern during inspiratory elastic load

La ventilación pulmonar en humanos tiene una variabilidad respiración a respiración no lineal, compleja y caótica. El objetivo del trabajo fue: caracterizar la variabilidad del patrón respiratorio en perros (n: 8) anestesiados respirando bajo carga elástica umbral (CEU) inspiratoria (7 a 50 cm H2O). Con el flujo, presión traqueal y esofágica, se analizaron: tiempo inspiratorio (Ti), ritmo [tiempo espiratorio (Te); tiempo total (Ttot), y Ti/Ttot] e impulso central (Vt/Ti), variables relacionadas [volumen corriente (Vt) y ventilación pulmonar (Ve)]. Se determinaron: variabilidad grosera (varianzas), oscilaciones de baja frecuencia (análisis espectral) y memoria a corto plazo (análisis de autocorrelación). La CEU produjo disminución de la varianza de medias en Te, Ttot, Vt y Vt/Ti (p < 0.05). La media de las varianzas del Ti/Ttot aumentó (p < 0.005) y disminuyó para el Vt y el Vt/Ti (p < 0.05). En general, el porcentaje de oscilaciones de baja frecuencia (OB%) disminuyó (p < 0.02). Durante CEU alta, las variables de ritmo no cambiaron el porcentaje de registros con autocorrelación (AU%), pero el Vt y variables relacionadas disminuyeron los AU% (p < 0.005). Hubo correlación positiva (r: 0.955, p< 0.001) entre OB% y AU% en Vt y variables relacionadas, pero las variables de ritmo no mostraron correlación. En conclusión: La CEU indujo un patrón respiratorio más monótono. La memoria a corto plazo disminuyó en la fase inspiratoria y aumentó en la espiratoria. Estos cambios ocurrieron bajo anestesia, sugiriendo que ciertas estructuras suprapontinas pueden no ser imprescindibles para la generación de estos cambios.

In humans, lung ventilation exhibits breath-to-breath variability and dynamics that are nonlinear, complex and chaotic. Our objective was to characterize the breathing pattern variational activity in anesthetized dogs (n: 8) breathing through threshold inspiratory elastic load (7 to 50 cm H2O). Starting from flow signal and tracheal and esophageal pressures, we analyzed inspiratory time (Ti), timing (expiratory time, Te; total time, Ttot; and Ti/Ttot) and central drive (Vt/Ti) and variables related to it (tidal volume, Vt and pulmonary ventilation, Ve). We measured gross variability (variances), low frequency oscillations (spectral analysis), and short term memory (autocorrelation analysis). Loading decreased variance of the mean values of Te, Ttot, Vt and Vt/Ti (p < 0.05); the mean of variances for Ti/Ttot increased (p < 0.005) while it decreased for Vt and Vt/Ti (p < 0.05). In general, percent of data recordings with low frequency oscillations (OB%) decreased (p < 0.02). During heavy load, timing parameters percent of data recordings with autocorrelations (AU%) did not change, but Vt and its related parameters decreased their AU% (p < 0.005). There was a positive correlation (r: 0.955, p < 0.001) between the existence of low frequency oscillations and autocorrelations for Vt and its related parameters, while timing variables did not show such a correlation. In conclusion, threshold elastic load induced a monotonous respiratory pattern. The short term memory decreased during inspiratory stage while increased during expiratory stage. These changes occurred during anesthesia suggesting that certain suprapontine structures may not be obligatory to induce them.

Cortical Information Transmission during Tic Suppression in Boys with Tourette's Disorder / 신경정신의학

OBJECTIVES: Tourette's Disorder (TD) is a chronic neuropsychiatric disorder characterized by multiple motor and vocal tics with onset in childhood. The aim of this study was to ascertain the increased cortical information transmission in frontal area during tic suppression in drug naive boys with TD using new nonlinear analysis of EEGs, be called Transfer Entropy (TE) which can detect the directed exchange of information between two systems. METHODS: Subjects were 11 drug naive boys with DSM-IV diagnosis of TD and 10 control boys. Clinical assessments were performed, and EEGs were recorded from 19 scalp loci of the international 10-20 systems. TE was estimated by EEG timeseries data after noise reduction. TE difference between TD and control during resting state and between tic suppression and resting state in TD were investigated. RESULTS: Elevated TE was found in extensive channels, including frontal, central and temporal channels (F7, Fz, F8,Cz, C3, P3, T3, and T4) in resting state of Tourette's disorder compared to normal controls. During tic suppression elevated TE was found in more extensive and asymmetrical channels especially prefrontal area (Fp1, Fp2, F3, Fz, F7, F8, Cz, C4, C5, T3, and T4). CONCLUSION: These findings suggest that pathogenesis of Tourette's disorder involve impaired cortical neuronal modulation in subcortical neural circuits. EEG analysis of TE may be a useful tool to investigation of cortical mechanism of psychiatric illness.

Nonlinear Dynamics of EEG in Pilocarpine-induced Status Epilepticus

BACKGROUND: Pilocarpine-induced status epilepticus (SE) model shows stereotypic EEG changes and behavioral characteristics. Although neuronal damages and therapeutic responses are also dependent on SE stages, the dynamical aspect of underlying neuronal interaction according to the SE stages has not been studied. We applied nonlinear analysis to the EEG recorded from pilocarpine-induced SE model to characterize nonlinear dynamics of different SE stage and to correlate therapeutic response with correlation dimension (D2). METHODS: Ten male Spraque-Dawley rats weighing 150-250g were used in this experiment. EEG was continuously recorded during SE and was classified into 6 stages as follows: baseline (BS), transitional (TR), discrete seizure (DS), continuous ictal discharges (CID), early periodic epileptiform discharges (EP), and late periodic epileptiform discharges (LP). High dose diazepam (20 mg/kg) was injected at the LP stage. SEs of 5 rats (control group) was controlled by diazepam and those of the rest (failed group) were failed to stop status epilepticus. RESULTS: Mean D2 value decreased progressively with fluctuation and was significantly different for SE stage (df=5, F=11.594, p=0.000). Independent t-test showed that the difference of D2 value between the controlled and failed group was significant at CID (df=40, t=2.591, p=0.013) and LP stage (df=49, t=-2.425, p=0.019). CONCLUSIONS: These results suggest that nonlinear dynamical change at the late half of SE stage is one of the contributing factors determining therapeutic responsiveness in pilocarpine-induced SE model.

Nonlinear Dynamics of EEG in Pilocarpine-induced Status Epilepticus

BACKGROUND: Pilocarpine-induced status epilepticus (SE) model shows stereotypic EEG changes and behavioral characteristics. Although neuronal damages and therapeutic responses are also dependent on SE stages, the dynamical aspect of underlying neuronal interaction according to the SE stages has not been studied. We applied nonlinear analysis to the EEG recorded from pilocarpine-induced SE model to characterize nonlinear dynamics of different SE stage and to correlate therapeutic response with correlation dimension (D2). METHODS: Ten male Spraque-Dawley rats weighing 150-250g were used in this experiment. EEG was continuously recorded during SE and was classified into 6 stages as follows: baseline (BS), transitional (TR), discrete seizure (DS), continuous ictal discharges (CID), early periodic epileptiform discharges (EP), and late periodic epileptiform discharges (LP). High dose diazepam (20 mg/kg) was injected at the LP stage. SEs of 5 rats (control group) was controlled by diazepam and those of the rest (failed group) were failed to stop status epilepticus. RESULTS: Mean D2 value decreased progressively with fluctuation and was significantly different for SE stage (df=5, F=11.594, p=0.000). Independent t-test showed that the difference of D2 value between the controlled and failed group was significant at CID (df=40, t=2.591, p=0.013) and LP stage (df=49, t=-2.425, p=0.019). CONCLUSIONS: These results suggest that nonlinear dynamical change at the late half of SE stage is one of the contributing factors determining therapeutic responsiveness in pilocarpine-induced SE model.

Investigation of the clinical diagnostic value of 50-step chaometry for coronary heart disease / 中国实用内科杂志

Objective To evaluate the clinical diagnostic value of a new nonlinear detection of index for coronary heart disease.Methods The inpatients suspected with coronary heart disease were randomly selected from March 2008 to February 2009 in the departments of The First Affiliated Hospital of Harbin Medical University,after routine examination.The time was fixed in the night before coronary angiography for data acquisition.Those whose number of cardiac RR interval (utilization) was less than 90% were removed and eventually a total of 124 cases were selected.Basing on gold standard (coronary angiography),the patients were divided into a group of 53 cases of coronary heart disease,middle group of 38 cases and the control group of 33 cases.In a stable state,the supine subjects were under the 12-lead ECG monitoring for 30 minutes to obtain RR interval data,and after careful examination data were blindly transferred to professionals who filtered the data,analyzed them with formula of 50-step chaometry(50SCM)and output.Finally,the date were analyzed with statistical methods.Results Between the three groups there was significant difference in 50SCM(P

A Pilot Study on Electromyographic Biofeedback Mechanism by Nonlinear Analysis / 中国心理卫生杂志

Objective: To study the mechanism of electromyographic (EMG) biofeedback. Methods: The EMG and electroencephalographic (EEG) signals were recorded dynamically during the course of EMG biofeedback. Changes of EMG amplitude and frequency during EMG biofeedback were assessed with linear analysis. We also applied the nonlinear analysis, approximate entropy (ApEn) of EMG signals and Cross Approximate entropy (Cross-ApEn) between EMG and EEG signals, to assess regularities in EMG and correlation between EMG and EEG. Results: With the processing of EMG biofeedback, the maximum, minimum and mean amplitude of EMG signals decreased significantly (F=3.85~25.59,P