Dimensional complexity of EEG brain mechanisms in untreated schizophrenia

Koukkou, M.; Lehmann, Dietrich; Wackermann, Jiřı́; Dvořák, Ivan; Henggeler, B.

doi:10.1016/0006-3223(93)90167-c

Cited by 123 publications

(63 citation statements)

References 32 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…This is consistent with a functional disconnection in schizophrenia in the sense that at least some studies show that the correlation dimension is elevated in schizophrenia (e.g. Koukkou et al, 1993). Again it should be noted that a functional disconnection syndrome does not necessarily imply a reduced number of anatomical connections but simply an abnormal influence of one neuronal population over another.…”

Section: Theoretical Neurobiologysupporting

confidence: 80%

The disconnection hypothesis

Friston

1998

Schizophrenia Research

791

469

View full text Add to dashboard Cite

This article reviews the disconnection hypothesis of schizophrenia and presents a mechanistic account of how dysfunctional integration among neuronal systems might arise. This neurobiological account is based on the central role played by neuronal plasticity in shaping the connections and the ensuing dynamics that underlie brain function. The particular hypothesis put forward here is that the pathophysiology of schizophrenia is expressed at the level of modulation of associative changes in synaptic efficacy; specifically the modulation of plasticity in those brain systems responsible for emotional learning and memory, in the post-natal period. This modulation is mediated by ascending neurotransmitter systems that: (i) have been implicated in schizophrenia; and (ii) are known to be involved in consolidating synaptic connections during learning. The proposed pathophysiology would translate, in functional terms, into a disruption of the reinforcement of adaptive behaviour that is consistent with the disintegrative aspects of schizophrenic neuropsychology.

show abstract

Section: Theoretical Neurobiologysupporting

confidence: 80%

The disconnection hypothesis

Friston

1998

Schizophrenia Research

791

469

View full text Add to dashboard Cite

show abstract

“…Karl Friston (1996) performed a simulation study trying to replicate the network characteristics of a "schizophrenic brain". A previous study showed higher complexity values in the EEG of patients with schizophrenia (Koukkou et al 1993), and Friston tested the hypothesis that these higher complexity values were associated with a disconnection syndrome. According to his results, the more disconnected a network the higher correlation dimension values.…”

Section: Introductionmentioning

confidence: 99%

The correlation between white-matter microstructure and the complexity of spontaneous brain activity: A difussion tensor imaging-MEG study

Fernández¹,

Ríos-Lago²,

Abásolo³

et al. 2011

NeuroImage

View full text Add to dashboard Cite

The advent of new signal processing methods, such as non-linear analysis techniques, represents a new perspective which adds further value to brain signals' analysis. Particularly, Lempel-Ziv's Complexity (LZC) has proven to be useful in exploring the complexity of the brain electromagnetic activity. However, an important problem is the lack of knowledge about the physiological determinants of these measures. Although a correlation between complexity and connectivity has been proposed, this hypothesis was never tested in vivo.Thus, the correlation between the microstructure of the anatomic connectivity and the functional complexity of the brain needs to be inspected. In this study we analysed the correlation between LZC and fractional anisotropy (FA), a scalar quantity derived from diffusion tensors that is particularly useful as an estimate of the functional integrity of myelinated axonal fibers, in a group of sixteen healthy adults (all female, mean age 65.56 ± 6.06 years, interval 58-82). Our results showed a positive correlation between FA and LZC scores in regions including clusters in the splenium of the corpus callosum, cingulum, parahipocampal regions and the sagittal stratum. This study supports the notion of a positive correlation between the functional complexity of the brain and the microstructure of its anatomical connectivity. Our investigation proved that a combination of neuroanatomical and neurophysiological techniques may shed some light on the underlying physiological determinants of brain's oscillations.

show abstract

“…Numerous complexity measures have been proposed (see Tononi et al, 1998) including: dimensional complexity, algorithmic complexity, neural complexity, fractal dimension, first Lyapunov component, correlation dimension, Lempel-Ziv Complexity (LZC), etc. (Elbert et al, 1992;Koukkou et al, 1993;Jeong et al, 1998;Kim et al, 2000;Kotini and Anninos, 2002;Li et al, 2008). For example, the dimensional complexity refers to the classical method of the so-called correlation dimension.…”

Section: Introductionmentioning

confidence: 99%

“…However, many studies revealed a pattern of increased complexity values, especially in frontal areas, in SCH patients (Elbert et al, 1992;Saito et al, 1998;Na et al, 2002;Irisawa et al, 2006;Li et al, 2008). This may be related to the increased "irregularity" of SCH patients' behaviour (Koukkou et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

Lempel–Ziv complexity in schizophrenia: A MEG study

Fernández

López‐Ibor

Turrero

et al. 2011

Clinical Neurophysiology

View full text Add to dashboard Cite

SchizophreniaLempel-Ziv complexity Magnetoencephalography Neurodevelopmental Neurodegenerative• Schizophrenic patients show higher complexity values as compared to controls.• Schizophrenic patients showed a tendency to reduced complexity values as a function of age while controls showed the opposite tendency.• The tendency observed in schizophrenic patients parallels the tendency observed in Alzheimer disease patients. ABSTRACTObjective: The neurodevelopmental-neurodegenerative debate is a basic issue in the field of the neuropathological basis of schizophrenia (SCH). Neurophysiological techniques have been scarcely involved in such debate, but nonlinear analysis methods may contribute to it. Methods: Fifteen patients (age range 23-42 years) matching DSM IV-TR criteria for SCH, and 15 sex-and age-matched control subjects (age range 23-42 years) underwent a resting-state magnetoencephalographic evaluation and Lempel-Ziv complexity (LZC) scores were calculated. Results: Regression analyses indicated that LZC values were strongly dependent on age. Complexity scores increased as a function of age in controls, while SCH patients exhibited a progressive reduction of LZC values. A logistic model including LZC scores, age and the interaction of both variables allowed the classification of patients and controls with high sensitivity and specificity. Conclusions: Results demonstrated that SCH patients failed to follow the "normal" process of complexity increase as a function of age. In addition, SCH patients exhibited a significant reduction of complexity scores as a function of age, thus paralleling the pattern observed in neurodegenerative diseases. Significance: Our results support the notion of a progressive defect in SCH, which does not contradict the existence of a basic neurodevelopmental alteration.

show abstract

Dimensional complexity of EEG brain mechanisms in untreated schizophrenia

Cited by 123 publications

References 32 publications

The disconnection hypothesis

The disconnection hypothesis

The correlation between white-matter microstructure and the complexity of spontaneous brain activity: A difussion tensor imaging-MEG study

Lempel–Ziv complexity in schizophrenia: A MEG study

Contact Info

Product

Resources

About