Schizophrenia—a parameters’ game?

Rǎdulescu, Anca

doi:10.1016/j.jtbi.2008.05.009

Cited by 10 publications

(20 citation statements)

References 113 publications

(121 reference statements)

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“…As a start, we verify that this extended paradigm is consistent with our prior modeling results (Rǎdulescu, 2008), in which we have considered the behavior of a two-dimensional prefrontallimbic system under perturbations. In accordance to this prior work, we interpret the strength of amygdalar self-inhibition to be related to the individual's trait anxiety (or the capacity of suppressing arousal under mild constant stressors).…”

Section: Model Behavior Without Autoimmunitysupporting

confidence: 85%

“…In our previous work, we considered wide, but stable oscillations to be a sign of trait anxiety rather than a mark of a psychotic mental disorder. It is when these oscillations get more dramatic in time (i.e., when the trajectories are being repelled away from an equilibrium or cycle) that we interpreted the system's behavior to bare the signature of psychosis (Rǎdulescu, 2008). This is a plausible view, since functional units of the brain will then continue to periodically enter psychotic ranges of hyper or hypo-activation and thus produce the imminent positive or negative symptoms.…”

Section: Results-analysis and Simulationsmentioning

confidence: 98%

“…These produce brain neurotoxicity (Weinberger and McClure, 2002) and further hippocampus damage (Pavlides et al, 2002), at the level of neurogenesis (Herbert et al, 2006;Wong and Herbert, 2005) and of hippocampal-PFC synaptic transmission (Cerqueira et al, 2007). This is possibly the main degenerative cycle in neoschizophrenia, which the author has discussed in previous work (Rǎdulescu, 2008).…”

Section: Vulnerability and Prefrontal-limbic Dysregulationmentioning

confidence: 93%

“…In our previous work (Rǎdulescu, 2008), we have related neoschizophrenia to a vulnerability of the inhibitory limbic/ prefrontal module reinforced by neurotoxic effects of stressinduced hypercortisolemia. In this section we will describe a phenomenological model which, although still based on this limbic vulnerability, will also reflect some of the more subtle physiological mechanisms discussed in the Introduction.…”

Section: Methods-construction Of the Mathematical Modelmentioning

confidence: 99%

“…We have chosen to represent the ''direct'' glutamatergic and GABA-mediated connections between regions in a linear fashion, consistent with our previous work. The indirect/slower acting influences (such as the neural effects of cortisol, autoimmunity triggered degeneration or dopaminemodulated activity) are all nonlinear terms (Rǎdulescu, 2008).…”

Section: Methods-construction Of the Mathematical Modelmentioning

confidence: 99%

See 4 more Smart Citations

A multi-etiology model of systemic degeneration in schizophrenia

Rǎdulescu

2009

Journal of Theoretical Biology

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Section: Model Behavior Without Autoimmunitysupporting

confidence: 85%

Section: Results-analysis and Simulationsmentioning

confidence: 98%

Section: Vulnerability and Prefrontal-limbic Dysregulationmentioning

confidence: 93%

Section: Methods-construction Of the Mathematical Modelmentioning

confidence: 99%

Section: Methods-construction Of the Mathematical Modelmentioning

confidence: 99%

See 3 more Smart Citations

A multi-etiology model of systemic degeneration in schizophrenia

Rǎdulescu

2009

Journal of Theoretical Biology

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Power spectrum scale invariance identifies prefrontal dysregulation in paranoid schizophrenia

Rǎdulescu¹,

Rubin²,

Strey³

et al. 2011

Human Brain Mapping

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Theory and experimental evidence suggest that complex living systems function close to the boundary of chaos, with erroneous organization to an improper dynamical range (too stiff or chaotic) underlying system-wide dysregulation and disease. We hypothesized that erroneous organization might therefore also characterize paranoid schizophrenia, via optimization abnormalities in the prefrontal-limbic circuit regulating emotion. To test this, we acquired fMRI scans from 35 subjects (N = 9 patients with paranoid schizophrenia and N = 26 healthy controls), while they viewed affect-valent stimuli. To quantify dynamic regulation, we analyzed the power spectrum scale invariance (PSSI) of fMRI time-courses and computed the geometry of time-delay (Poincaré) maps, a measure of variability. Patients and controls showed distinct PSSI in two clusters (k(1) : Z = 4.3215, P = 0.00002 and k(2) : Z = 3.9441, P = 0.00008), localized to the orbitofrontal/medial prefrontal cortex (Brodmann Area 10), represented by β close to white noise in patients (β ≈ 0) and in the pink noise range in controls (β ≈ -1). Interpreting the meaning of PSSI differences, the Poincaré maps indicated less variability in patients than controls (Z = -1.9437, P = 0.05 for k(1) ; Z = -2.5099, P = 0.01 for k(2) ). That the dynamics identified Brodmann Area 10 is consistent with previous schizophrenia research, which implicates this area in deficits of working memory, executive functioning, emotional regulation and underlying biological abnormalities in synaptic (glutamatergic) transmission. Our results additionally cohere with a large body of work finding pink noise to be the normal range of central function at the synaptic, cellular, and small network levels, and suggest that patients show less supple responsivity of this region.

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Quantifying the Dynamics of Central Systemic Degeneration in Schizophrenia

Rǎdulescu

2011

Handbook of Schizophrenia Spectrum Disorders, Volume I

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Schizophrenia—a parameters’ game?

Cited by 10 publications

References 113 publications

A multi-etiology model of systemic degeneration in schizophrenia

A multi-etiology model of systemic degeneration in schizophrenia

Power spectrum scale invariance identifies prefrontal dysregulation in paranoid schizophrenia

Quantifying the Dynamics of Central Systemic Degeneration in Schizophrenia

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