Brain Complexity & Nonlinear Dynamics

Exploring Nociceptive-Analgesic Balance and EEG Modulation Patterns During General Anesthesia Using Holo-Hilbert Spectral Analysis

Ho CN, Huang NE, Chen JY, Yang AC. Pain research & management2026:5504074.

Full text · PMCdoi:10.1155/prm/5504074

HHSA revealed two dominant cross-frequency interactions within the alpha-carrier band (8-16 Hz): one modulated by 3-6-Hz (high-delta to theta) and another by 1-2-Hz (low-delta) oscillations, indicating layered modulation under anesthesia.

Identifying Distinct Developmental Patterns of Brain Complexity in Autism: A Cross-Sectional Cohort Analysis Using the Autism Brain Imaging Data Exchange

Chi IJ, Tsai SJ, Chen CH, Yang AC. Psychiatry and clinical neurosciences79(3):98-107.

Full text · PMCdoi:10.1111/pcn.13780

However, these results do not remain after Bonferroni correction.

Exploring morphological similarity and randomness in Alzheimer's disease using adjacent grey matter voxel-based structural analysis

Chen TY, Zhu JD, Tsai SJ, Yang AC. Alzheimer's research & therapy16(1):88.

Full text · PMCdoi:10.1186/s13195-024-01448-1

For the structural randomness, we found significant decreases in the temporal and subcortical areas and significant increases in the occipital and frontal regions.

Causality Network of Infectious Disease Revealed With Causal Decomposition

Sun J, Yuan K, Chen C, Xu H, Wang H, … Yang A (11 authors). IEEE journal of biomedical and health informatics27(7):3657-3665.

doi:10.1109/JBHI.2023.3268081

Our findings, by shedding light on the underlying transmission mechanism of infectious diseases, suggest that causal inference analysis is a promising approach to determine epidemiological interventions.

Progressive brain abnormalities in schizophrenia across different illness periods: a structural and functional MRI study

Shen CL, Tsai SJ, Lin CP, Yang AC. Schizophrenia (Heidelberg, Germany)9(1):2.

Full text · PMCdoi:10.1038/s41537-022-00328-7

Schizophrenia is a chronic brain disorder, and neuroimaging abnormalities have been reported in different stages of the illness for decades.

Brain white matter hyperintensities-predicted age reflects neurovascular health in middle-to-old aged subjects

Huang CC, Chou KH, Lee WJ, Yang AC, Tsai SJ, … Lin CP (8 authors). Age and ageing51(5).

doi:10.1093/ageing/afac106

age-related neurovascular structural and functional impairment is a major aetiology of dementia and stroke in older people.

Reply To: Comments on identifying causal relationships in nonlinear dynamical systems via empirical mode decomposition

Yang AC, Peng CK, Huang NE. Nature communications13(1):2859.

Full text · PMCdoi:10.1038/s41467-022-30360-1

Author reply defending empirical-mode-decomposition causal analysis against published critiques, clarifying when it correctly distinguishes causation from shared external forcing.

Alteration of power law scaling of spontaneous brain activity in schizophrenia

Lee YJ, Huang SY, Lin CP, Tsai SJ, Yang AC. Schizophrenia research238:10-19.

doi:10.1016/j.schres.2021.08.026

These findings suggest that schizophrenia has abnormal brain signal complexity linked to psychotic symptoms.

Remission of depression is associated with asymmetric hemispheric variation in EEG complexity before antidepressant treatment

Tsai HJ, Yang WC, Tsai SJ, Lin CH, Yang AC. Journal of affective disorders281:872-879.

doi:10.1016/j.jad.2020.11.041

This study aimed to explore whether complexity measures of electroencephalogram (EEG) signals vary across the frontal region between patients with or without remission in depression.

Decomposed Temporal Complexity Analysis of Neural Oscillations and Machine Learning Applied to Alzheimer's Disease Diagnosis

Furutani N, Nariya Y, Takahashi T, Noto S, Yang AC, … Kikuchi M (9 authors). Frontiers in psychiatry11:531801.

Full text · PMCdoi:10.3389/fpsyt.2020.531801

Results demonstrated that AD patients had lower complexity on short time scales and higher complexity on long time scales in the alpha band in temporal regions of the brain.

Editorial: Advances in Multi-Scale Analysis of Brain Complexity

Yang AC, Jann K, Michel CM, Wang DJJ. Frontiers in neuroscience14:337.

Full text · PMCdoi:10.3389/fnins.2020.00337

Editorial introducing advances in multi-scale entropy and complexity analysis of brain signals across neuroimaging modalities.

Large-Scale Structural Covariance Networks Predict Age in Middle-to-Late Adulthood: A Novel Brain Aging Biomarker

Kuo CY, Lee PL, Hung SC, Liu LK, Lee WJ, … Lin CP (12 authors). Cerebral cortex (New York, N.Y. : 1991)30(11):5844-5862.

doi:10.1093/cercor/bhaa161

These findings provide empirical evidence supporting the estimation of brain age from a brain network perspective, and demonstrate the clinical feasibility of evaluating neurological diseases hypothesized to be associated with accelerated brain aging.

Validating the Enlarged Kyd Canon: a New Approach

Yang AC. ANQ: A Quarterly Journal of Short Articles, Notes and Reviews.

doi:10.1080/0895769X.2019.1675491

A computational stylometric approach is used to test and validate the enlarged canon of works attributed to the Elizabethan playwright Thomas Kyd, applying quantitative text-analysis methods to questions of literary authorship.

A Strategy to Reduce Bias of Entropy Estimates in Resting-State fMRI Signals

Yang AC, Tsai SJ, Lin CP, Peng CK. Frontiers in neuroscience12:398.

Full text · PMCdoi:10.3389/fnins.2018.00398

Furthermore, an increased relative error of SampEn was associated with an increased coefficient of variation in voxel-wise statistics.

Causal decomposition in the mutual causation system

Yang AC, Peng CK, Huang NE. Nature communications9(1):3378.

Full text · PMCdoi:10.1038/s41467-018-05845-7

Furthermore, we demonstrate the generic applicability of our method to both stochastic and deterministic systems, and show the consistency of causal-decomposition method compared to existing methods, and finally uncover the key mode of causal interactions in both modelled and actual predator-prey systems.

Measuring Brain Complexity During Neural Motor Resonance

Hager BM, Yang AC, Gutsell JN. Frontiers in neuroscience12:758.

Full text · PMCdoi:10.3389/fnins.2018.00758

Conclusions: The current findings suggest that the desynchronization of the mu wave during MR results in a local increase of mu entropy in sensorimotor areas, potentially reflecting a release from alpha inhibition.

Nonlinear dynamical analysis of sleep electroencephalography using fractal and entropy approaches

Ma Y, Shi W, Peng CK, Yang AC. Sleep medicine reviews37:85-93.

doi:10.1016/j.smrv.2017.01.003

The analysis of electroencephalography (EEG) recordings has attracted increasing interest in recent decades and provides the pivotal scientific tool for researchers to quantitatively study brain activity during sleep, and has extended our knowledge of the fundamental mechanisms of sleep physiology.

Topological Pattern Recognition of Severe Alzheimer's Disease via Regularized Supervised Learning of EEG Complexity

Fan M, Yang AC, Fuh JL, Chou CA. Frontiers in neuroscience12:685.

Full text · PMCdoi:10.3389/fnins.2018.00685

In this study, we aim to discover the altered spatio-temporal patterns of EEG complexity associated with AD pathology in different severity levels.

Measuring information-based energy and temperature of literary texts

Chang MC, Yang AC, Stanley HE, Peng CK. Physica A: Statistical Mechanics and its Applications468:783-789.

doi:10.1016/j.physa.2016.11.106

Borrowing concepts from statistical physics, the authors define an information-based 'energy' and 'temperature' of literary texts, providing a thermodynamic-style framework to characterize the complexity and style of written language.

Neural complexity as a potential translational biomarker for psychosis

Hager B, Yang AC, Brady R, Meda S, Clementz B, … Keshavan M (9 authors). Journal of affective disorders216:89-99.

Full text · PMCdoi:10.1016/j.jad.2016.10.016

Furthermore, we found significant differences as well as overlaps of pathologic brain signal complexity between psychotic probands by DSM diagnoses, thus suggesting a biological approach to categorizing psychosis based on functional neuroimaging data.

On Holo-Hilbert spectral analysis: a full informational spectral representation for nonlinear and non-stationary data

Huang NE, Hu K, Yang AC, Chang HC, Jia D, … Wu Z (14 authors). Philosophical transactions. Series A, Mathematical, physical, and engineering sciences374(2065):20150206.

Full text · PMCdoi:10.1098/rsta.2015.0206

The Holo-Hilbert spectral analysis (HHSA) method is introduced to cure the deficiencies of traditional spectral analysis and to give a full informational representation of nonlinear and non-stationary data.

Sensitivity enhancement of task-evoked fMRI using ensemble empirical mode decomposition

Lin SH, Lin GH, Tsai PJ, Hsu AL, Lo MT, … Wu CW (8 authors). Journal of neuroscience methods258:56-66.

doi:10.1016/j.jneumeth.2015.10.009

We found that EEMD method was efficient to enhance the functional sensitivity of evoked fMRI.

Decreased resting-state brain activity complexity in schizophrenia characterized by both increased regularity and randomness

Yang AC, Hong CJ, Liou YJ, Huang KL, Huang CC, … Tsai SJ (11 authors). Human brain mapping36(6):2174-86.

Full text · PMCdoi:10.1002/hbm.22763

These results collectively suggested that resting-state dynamics in schizophrenia exhibit two routes of pathologic change toward regular or random patterns, which contribute to the differences in syndrome domains of psychosis in patients with schizophrenia.

Revealing the brain's adaptability and the transcranial direct current stimulation facilitating effect in inhibitory control by multiscale entropy

Liang WK, Lo MT, Yang AC, Peng CK, Cheng SK, … Juan CH (7 authors). NeuroImage90:218-34.

doi:10.1016/j.neuroimage.2013.12.048

We found that tDCS can further increase the EEG complexity of the frontal lobe.

The APOE ɛ4 allele affects complexity and functional connectivity of resting brain activity in healthy adults

Yang AC, Huang CC, Liu ME, Liou YJ, Hong CJ, … Tsai SJ (10 authors). Human brain mapping35(7):3238-48.

Full text · PMCdoi:10.1002/hbm.22398

These results support the compensatory recruitment hypothesis in older APOE ɛ4 carriers, and confer the impact of the APOE genotype on the temporal dynamics of brain activity in older adults.

The association of physical activity to neural adaptability during visuo-spatial processing in healthy elderly adults: A multiscale entropy analysis

Wang CH, Tsai CL, Tseng P, Yang AC, Lo MT, … Liang WK (10 authors). Brain and cognition92C:73-83.

doi:10.1016/j.bandc.2014.10.006

The results suggest that physical activity may be beneficial for adaptability of brain systems in tasks involving visuo-spatial information.

Cognitive and neuropsychiatric correlates of EEG dynamic complexity in patients with Alzheimer's disease

Yang AC, Wang SJ, Lai KL, Tsai CF, Yang CH, … Fuh JL (10 authors). Progress in neuro-psychopharmacology & biological psychiatry47:52-61.

doi:10.1016/j.pnpbp.2013.07.022

MSE analysis revealed abnormal EEG complexity across short- and long-time scales that were correlated to cognitive and neuropsychiatric assessments.

Complexity of spontaneous BOLD activity in default mode network is correlated with cognitive function in normal male elderly: a multiscale entropy analysis

Yang AC, Huang CC, Yeh HL, Liu ME, Hong CJ, … Tsai SJ (11 authors). Neurobiology of aging34(2):428-38.

doi:10.1016/j.neurobiolaging.2012.05.004

Our findings confirmed the hypothesis that complexity of BOLD activity was correlated with aging and cognitive performance based on MSE analysis, and may provide insights on how dynamics of spontaneous brain activity relates to aging and cognitive function in specific brain regions.

Is mental illness complex? From behavior to brain

Yang AC, Tsai SJ. Progress in neuro-psychopharmacology & biological psychiatry45:253-7.

doi:10.1016/j.pnpbp.2012.09.015

A defining but elusive feature of the human brain is its astonishing complexity.

Clustering heart rate dynamics is associated with β-adrenergic receptor polymorphisms: analysis by information-based similarity index

Yang AC, Tsai SJ, Hong CJ, Wang C, Chen TJ, … Peng CK (7 authors). PloS one6(5):e19232.

Full text · PMCdoi:10.1371/journal.pone.0019232

Our results provide evidence that β(2)-AR polymorphisms are significantly associated with the acceleration/deceleration pattern of heart rate oscillation, reflecting the underlying mode of autonomic nervous system control.

Temporal associations between weather and headache: analysis by empirical mode decomposition

Yang AC, Fuh JL, Huang NE, Shia BC, Peng CK, Wang SJ. PloS one6(1):e14612.

Full text · PMCdoi:10.1371/journal.pone.0014612

We found no associations between the raw time series of weather variables and headache incidence.

Statistical physics approach to categorize biologic signals: from heart rate dynamics to DNA sequences

Peng CK, Yang AC, Goldberger AL. Chaos (Woodbury, N.Y.)17(1):015115.

doi:10.1063/1.2716147

We recently proposed a novel approach to categorize information carried by symbolic sequences based on their usage of repetitive patterns.

Genomic classification using an information-based similarity index: application to the SARS coronavirus

Yang AC, Goldberger AL, Peng CK. Journal of computational biology : a journal of computational molecular cell biology12(8):1103-16.

doi:10.1089/cmb.2005.12.1103

The information based similarity index provides a new tool to measure the similarity between datasets based on their information content and may have a wide range of applications in the large-scale analysis of genomic databases.

Information categorization approach to literary authorship disputes

Yang AC, Peng CK, Yien HW, Goldberger AL. Physica A: Statistical Mechanics and its Applications329(3-4):473-483.

doi:10.1016/S0378-4371(03)00622-X

An information-based similarity index, derived from symbolic-dynamics methods used for physiologic signals, is applied to resolve disputed literary authorship by quantifying the statistical structure of texts.

Linguistic analysis of the human heartbeat using frequency and rank order statistics

Yang AC, Hseu SS, Yien HW, Goldberger AL, Peng CK. Physical review letters90(10):108103.

doi:10.1103/PhysRevLett.90.108103

Complex physiologic signals may carry unique dynamical signatures that are related to their underlying mechanisms.

Simulating healthy human heart rate: a Markovian model

Yang AC, Chang CH, Hseu SS, Yien HW. Computers in Cardiology29:229-232.

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A Markovian model that simulates healthy human heart-rate dynamics by mapping interbeat-interval changes to binary symbols, reproducing short- and long-term fluctuations, circadian rhythm, and heart-rate variability during REM sleep.

Prediction of paroxysmal atrial fibrillation by footprint analysis

Yang AC, Yien HW. Computers in Cardiology28:401-404.

A symbolic-dynamics 'footprint' algorithm applied to single-channel ECG to predict the onset of paroxysmal atrial fibrillation, providing a fully automatic prediction tool based on RR-interval mapping.