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PubMed1976

Depression and marital interaction.

A family-systems model of depression is presented and discussed. In this model, the intrapsychic concept of cognitive schema and the interpersonal concepts of social stimulation and social reingorcement are integrated within a systems-theory perspective. The effects of positive and negative feedback are delineated, and a concept of depression-triggering and depression-maintaining feedback loops is described. A clinical illustration is utilized to exemplify the theoretical model.

Cognition↗
PubMed2006

Order, disorder, death: lessons from a superorganism.

Animal models contribute to the understanding of molecular mechanism of cancer, revealing complex roles of altered cellular-signaling networks and deficient surveillance systems. Analogous pathologies are documented in an unconventional model organism that receives attention in research on systems theory, evolution, and aging. The honeybee (Apis mellifera) colony is an advanced integrative unit, a "superorganism" in which order is controlled via complex signaling cascades and surveillance schemes. A facultatively sterile caste, the workers, regulates patterns of growth, differentiation, homeostasis, and death. Workers differentiate into temporal phenotypes in response to dynamic social cues; chemosensory signals that can translate into dramatic physiological responses, including programmed cell death. Temporal worker forms function together, and effectively identify and terminate abnormal colony members ranging from embryos to adults. As long as this regulatory system is operational at a colony level, the unit survives and propagates. However, if the worker phenotypes that collectively govern order become too few or change into malignant forms that bypass control mechanisms to replicate aberrantly; order is replaced by disorder that ultimately leads to the destruction of the society. In this chapter we describe fundamental properties of honeybee social organization, and explore conditions that lead to states of disorder. Our hope is that this chapter will be an inspirational source for ongoing and future work in the field of cancer research.

Animals↗
PubMed2004

From plasticity to complexity: a new diagnostic method for psychiatry.

There is growing dissatisfaction regarding the available diagnostic systems for psychiatric disorders (DSM, ICD). Psychiatrists acknowledge that though mental disease reflects brain disorders, the descriptive and symptom based nature of psychiatric diagnosis bears no relation to brain functions. According to Helmut's article published in the October 2003 issue of Science, in the coming decade researchers and psychiatrists will be called upon to propose a basis for the psychiatric diagnostic system of the future. I propose a new etiology-oriented diagnostic system for psychiatry by integrating two recently emerging bodies of knowledge, one regarding plasticity and the other involving complex systems. Plasticity refers to all brain processes involved in dynamic alterations within communicating neuronal ensembles or networks, in the brain. Complexity refers to certain formulations from system theories relevant to brain dynamics and plasticity. It is proposed to divide plasticity processes into three types based on time domains: (1) "developmental plasticity", (2) "tuning plasticity" and (3) "fast stabilizing plasticity". Each type of plasticity is related to different complexity models achieved by the brain, developmental plasticity is life-long brain organization, it is related to state-space configurations molded into brain representations internalized via processes such as Hebbian learning. Tuning plasticity is related to "matching complexity" a measure of adaptability between internal configurations in the brain-system and externally originating event stimuli. Fast stabilizing plasticity is related to "neural complexity" a measure of neural network integration in the brain. Neural complexity meets the mental requirement to extract important features from different sensory inputs and to simultaneously generate coherent perceptual and cognitive states, thus balancing specialized segregated brain processes with coherent globally integrated whole brain activity. Mental disorders can be reconceptualized as disorders of plasticity resulting in disturbances of state-space brain configurations, matching and neural complexities. Personality disorders result from altered internal representations of the psychosocial environment. Depression and anxiety have been recently linked to alterations of adaptive neuronal plasticity thus reconceptualized as disorders of matching complexity. Finally, psychoses, including schizophrenia spectrum disorders, are reconceptualized as disturbances of neural complexity resulting in altered fast stabilizing plasticity. The new diagnostic system generates testable predictions regarding diagnosis and treatments of mental disorders which may be the future of psychiatry.

Cognition↗
PubMed1995

Specialists without spirit: limitations of the mechanistic biomedical model.

This paper examines the origin and the development of the mechanistic model of the human body and health in terms of Max Weber's theory of rationalization. It is argued that the development of Western scientific medicine is a part of the broad process of rationalization that began in sixteenth century Europe as a result of the Reformation. The development of the mechanistic view of the human body in Western medicine is consistent with the ideas of calculability, predictability, and control-the major tenets of the process of rationalization as described by Weber. In recent years, however, the limitations of the mechanistic model have been the topic of many discussions. George Engel, a leading advocate of general systems theory, is one of the leading proponents of a new medical model which includes the general quality of life, clean environment, and psychological, or spiritual stability of life. The paper concludes with consideration of the potential of Engel's proposed new model in the context of the current state of rationalization in modern industrialized society.

Europe↗
PubMed1988

Estimation of the rate constants in a data-sparse environment: comparison of a mathematical method and least squares analysis.

A new method is presented for estimating the rate constants for the one-compartment open model with first-order absorption in a data-sparse environment. It is based on the principles of matrix algebra and system theory and requires only three to four plasma samples drawn at equal time intervals (a minimum of at least one sample in the absorption phase and one sample in the elimination phase). The utility of the technique is illustrated by comparing the parameter estimates from the matrix method with the estimates from a nonlinear computer parameter estimation program. In the preliminary evaluation of the method with both perfect data and data with randomly distributed error, the parameter estimates from the matrix method proved to be as good as the computer estimation for data-sparse systems. In a more realistic comparison with published patient data, the matrix method resulted in 0 to 456% better estimates of kel and ka than the computer estimation. Since the matrix method is mathematically simple and requires only three to four blood samples, it should prove very useful in data-sparse systems (e.g., clinical or small animal situations) where a minimum amount of blood samples can be drawn.

Absorption↗
PubMedDate not supplied

Modeling the inhibitor activity and relative binding affinities in enzyme-inhibitor-protein systems: application to developmental regulation in a PG-PGIP system.

Within a number of classes of hydrolytic enzymes are certain enzymes whose activity is modulated by a specific inhibitor-protein that binds to the enzyme and forms an inactive complex. One unit of a specific inhibitor-protein activity is often defined as the amount necessary to inhibit one unit of its target enzyme by 50 %. No objective quantitative means is available to determine this point of 50 % inhibition in crude systems such as those encountered during purification. Two models were derived: the first model is based on an irreversible binding approximation, and the second, or equilibrium, model is based on reversible binding. The two models were validated using the inhibition data for the polygalacturonase-polygalacturonase-inhibiting protein (PG-PGIP) system. Theory and experimental results indicate that the first model can be used for inhibitor protein activity determination and the second model can be used for inhibitor protein activity determination as well as for comparison of association constants among enzymes and their inhibitor-proteins from multiple sources. The models were used to identify and further clarify the nature of a differential regulation of expression of polygalacturonase-inhibiting protein in developing cantaloupe fruit. These are the first relations that provide for an objective and quantitative determination of inhibitor-protein activity in both pure and crude systems. Application of these models should prove valuable in gaining insights into regulatory mechanisms and enzyme-inhibitor-protein interactions.

Computer Simulation↗
PubMed2006

Optimization of the matrix inversion tomosynthesis (MITS) impulse response and modulation transfer function characteristics for chest imaging.

Matrix inversion tomosynthesis (MITS) uses linear systems theory, along with a priori knowledge of the imaging geometry, to deterministically distinguish between true structure and overlying tomographic blur in a set of conventional tomosynthesis planes. In this paper we examine the effect of total scan angle (ANG), number of input projections (N), and plane separation/number of reconstructed planes (NP) on the MITS impulse response (IR) and modulation transfer function (MTF), with the purpose of optimizing MITS imaging of the chest. MITS IR and MTF data were generated by simulating the imaging of a very thin wire, using various combinations of ANG, N, and NP. Actual tomosynthesis data of an anthropomorphic chest phantom were acquired with a prototype experimental system, using the same imaging parameter combinations as those in the simulations. Thoracic projection data from two human subjects were collected for corroboration of the system response analysis in vivo. Results suggest that ANG=20 degrees, N=71, NP=69 is the optimal combination for MITS chest imaging given the inherent constraints of our prototype system. MITS chest data from human subjects demonstrates that the selected imaging strategy can effectively produce high-quality MITS thoracic images in vivo.

Algorithms↗
PubMed1988

Measurement of pitch by subharmonic summation.

In order to account for the phenomenon of virtual pitch, various theories assume implicitly or explicitly that each spectral component introduces a series of subharmonics. The spectral-compression method for pitch determination can be viewed as a direct implementation of this principle. The widespread application of this principle in pitch determination is, however, impeded by numerical problems with respect to accuracy and computational efficiency. A modified algorithm is described that solves these problems. Its performance is tested for normal speech and "telephone" speech, i.e., speech high-pass filtered at 300 Hz. The algorithm out-performs the harmonic-sieve method for pitch determination, while its computational requirements are about the same. The algorithm is described in terms of nonlinear system theory, i.c., subharmonic summation. It is argued that the favorable performance of the subharmonic-summation algorithm stems from its corresponding more closely with current pitch-perception theories than does the harmonic sieve.

Algorithms↗
PubMed1988

Coordinates transformation and learning control for visually-guided voluntary movement with iteration: a Newton-like method in a function space.

In order to control visually-guided voluntary movements, the central nervous system (CNS) must solve the following three computational problems at different levels: (1) determination of a desired trajectory in the visual coordinates, (2) transformation of the coordinates of the desired trajectory to the body coordinates and (3) generation of motor command. In this paper, the second and the third problems are treated at computational, representational and hardware levels of Marr. We first study the problems at the computational level, and then propose an iterative learning scheme as a possible algorithm. This is a trial and error type learning such as repetitive training of golf swing. The amount of motor command needed to coordinate activities of many muscles is not determined at once, but in a step-wise, trial and error fashion in the course of a set of repetitions. Actually, the motor command in the (n + 1)-th iteration is a sum of the motor command in the n-th iteration plus two modification terms which are, respectively, proportional to acceleration and speed errors between the desired trajectory and the realized trajectory in the n-th iteration. We mathematically formulate this iterative learning control as a Newton-like method in functional spaces and prove its convergence under appropriate mathematical conditions with use of dynamical system theory and functional analysis. Computer simulations of this iterative learning control of a robotic manipulator in the body or visual coordinates are shown. Finally, we propose that areas 2, 5, and 7 of the sensory association cortex are possible sites of this learning control. Further we propose neural network model which acquires transformation matrices from acceleration or velocity to motor command, which are used in these schemes.

Central Nervous System↗
PubMed2001

Utilizing a systems approach to implement pressure ulcer prediction and prevention.

Efficient, effective patient care is an objective shared by all healthcare settings and systems. It is generally accepted that using national clinical guidelines facilitates pursuit of this objective. However, implementation of a guideline, or any process improvement activity, requires a systematic, collaborative approach from which new processes can be purposefully designed. This article reviews systems theory, presents the steps for process improvement using the Plan/Do/Check/Act cycle, and references a recent statewide quality improvement study conducted by the authors in collaboration with Stratis Health, a Minnesota Medical Peer Review Organization.

Beds↗
PubMed2001

Walking while memorizing: age-related differences in compensatory behavior.

This study investigated predictions of the life-span theory of selection, optimization, and compensation, focusing on different patterns of task priority during dual-task performance in younger and older adults. Cognitive (memorizing) and sensorimotor (walking a narrow track) performance were measured singly, concurrently, and when task difficulty was manipulated. Use of external aids was measured to provide another index of task priority. Before dual-task testing, participants received extensive training with each component task and external aid. Age differences in dual-task costs were greater in memory performance than walking, suggesting that older adults prioritized walking over memory. Further, when given a choice of compensatory external aids to use, older adults optimized walking, whereas younger adults optimized memory performance. The results have broad implications for systemic theories of cognitive and sensorimotor aging, and the costs and benefits of assistive devices and environmental support for older populations.

Adult↗
PubMedDate not supplied

Self-deception predicts self-report and endurance of pain.

This study sought to test predictions made from disregulation and systems theories regarding self-deception and pain responsivity. Sixty-four subjects completed the L-scale of the Eysenck Personality Inventory and, based on their scores, were categorized as either High, Medium, or Low Deceptors. Both sensory threshold and three levels of affective pain judgments were determined using electrocutaneous nociceptive stimulation applied to the forearm. Results indicated that there were no differences among groups in their sensation thresholds. However, large differences in affective pain judgments emerged between High and Low Deceptors. High Deceptors differed significantly from Low Deceptors at the Tolerance (9.4 vs. 5.2 mA, p less than 0.001), Pain threshold (7.9 vs. 3.8 mA, p less than 0.001), and Discomfort (4.4 vs. 2.2 mA, p less than 0.01) judgment levels. These findings are consistent with a systems model of pain perception and are discussed in terms of the role of pain in mediating the relationship between cognitive coping patterns and recovery from illness and surgery. A possible opiate-peptide hypothesis of repressive coping & disregulation of pain is proposed.

Adaptation, Psychological↗
PubMed2003

Molecular diagnostics of injury and repair responses in critical illness: what is the future of "monitoring" in the intensive care unit?

OBJECTIVE: To identify potential future means of monitoring injury and repair in critical illness. DESIGN: Review of the literature. RESULTS: Critically ill patients are monitored extensively and intensively by such means as hemodynamics, laboratory values, and radiologic studies. In general, however, the goal of monitoring has been to measure the degree of injury and to prevent further injury, rather than to measure repair. Measures of repair have been limited to phenotypic end points such as return of organ function, as measured by blood chemistry. In this article, I examine how it may be possible in the future to monitor the progress of repair using genomic and proteomic biomarkers. These types of monitors would enable clinicians to control the healing environment using real time, rapid biomarkers, and sophisticated techniques to target therapy to the patient's current inflammatory state, taking into account the genetic makeup of the patient and his or her likely response to a given drug. CONCLUSIONS: The rapidly evolving sciences of genomics, proteomics, computational biology, and complex system theory can be used a) to model critical illness; b) to model adaptive and maladaptive responses to critical illness; c) to tailor treatments to create an ideal inflammatory environment for repair and regeneration, taking into account the individual genetic contribution; and d) to monitor the progress of repair. The major obstacles to reaching these goals are technological, and experience suggests that they will be overcome.

Adaptation, Physiological↗
PubMed1979

Intervening briefly in the family system.

A brief therapeutic intervention in a family is presented with the use of the Synallactic Collective Image Technique (S.C.I.T.). The technique proves to be a very useful tool for therapeutic intervention along General System Theory lines. The S.C.I.T. makes use of family paintings as a 2nd catalyst (the first one being the therapist) of transaction. Five sessions were held over a period of about one month. The family paintings reflect the successive phases through which the family transaction proceeded: From a dry, unsatisfying, mutually destructive relationship with no hope for co-operation and survival, through a phase of resistance during which each one was able to see his predicament, through a final phase after the 'storm' where the sun rises for the first time and co-operation for fruitful exploration begins. It has been observed that such a brief and intense intervention could lead, with proper handling, to the reactivation of self-leading processes, which generate more functional transaction within the family system.

Adolescent↗
PubMed1997

Temporolimbic or transcallosal connections: where is the primary lesion in schizophrenia and what is its nature?

A critique of the article by Bogerts on the temporolimbic system theory is presented. Schizophrenia is conceived as arising as a component of the diversity of interhemisphric (callosal) connectivity associated with the evolution of language, a process that occurred through a genetic change (the speciation event) that allowed the hemispheres to develop with a degree of independence. Language and psychosis thus have a common evolutionary origin. The anatomical changes can be considered as a boundary component of the anatomical variation that is characteristic of the species.

Biological Evolution↗
PubMed2000

Limit-cycle oscillations and tubuloglomerular feedback regulation of distal sodium delivery.

A mathematical model was used to evaluate the potential effects of limit-cycle oscillations (LCO) on tubuloglomerular feedback (TGF) regulation of fluid and sodium delivery to the distal tubule. In accordance with linear systems theory, simulations of steady-state responses to infinitesimal perturbations in single-nephron glomerular filtration rate (SNGFR) show that TGF regulatory ability (assessed as TGF compensation) increases with TGF gain magnitude gamma when gamma is less than the critical value gamma(c), the value at which LCO emerge in tubular fluid flow and NaCl concentration at the macula densa. When gamma > gamma(c) and LCO are present, TGF compensation is reduced for both infinitesimal and finite perturbations in SNGFR, relative to the compensation that could be achieved in the absence of LCO. Maximal TGF compensation occurs when gamma approximately gamma(c). Even in the absence of perturbations, LCO increase time-averaged sodium delivery to the distal tubule, while fluid delivery is little changed. These effects of LCO are consequences of nonlinear elements in the TGF system. Because increased distal sodium delivery may increase the rate of sodium excretion, these simulations suggest that LCO enhance sodium excretion.

Animals↗
PubMed1992

Implementing the Americans With Disabilities Act of 1990 in higher education.

The purpose of this paper is to provide educators and administrators in higher education with a greater understanding of how the Americans With Disabilities Act of 1990 (ADA) (Public Law 101-336) may affect institutions of higher education and to suggest ways that occupational therapists can assist institutions of higher education to comply with the ADA. When educators attempt to comply with the ADA in systems of higher education, the complexity of universities calls for a model reflective of that complexity. The systems approach to higher education, a model based on the general systems theory, is suggested as such a model. The three essential components of the model--input (i.e., applicants to a university), throughput (i.e., enrolled university student), and output (i.e., the student being graduated)--are acted on by many subsystems of the university. Some of those likely to be affected are application procedures, transportation, housing, dining facilities, and curricula. In planning ways to comply with the ADA, educators in higher education may find that many of these subsystems are required to adapt and make reasonable accommodations for the student with a disability. The model can be used to help identify those subsystems that will be affected by the law and to facilitate planning to comply with the law. Although occupational therapists most often work with persons to help them adapt to change in their lives, they can also work in systems of higher education and help the systems to plan and implement programs related to the ADA. The most effective programs are usually those that are well planned and designed from a holistic perspective, rather than those that are developed as a reaction to a specific situation or incident, that is, programs that are proactive rather than reactive. By using the systems approach to higher education, occupational therapists can focus on those components and subsystems within a university that may be affected by the ADA and meet the individual needs of a university.

Adolescent↗
PubMed2000

Précis of Neural organization: structure, function, and dynamics.

NEURAL ORGANIZATION: Structure, function, and dynamics shows how theory and experiment can supplement each other in an integrated, evolving account of the brain's structure, function, and dynamics. (1) STRUCTURE: Studies of brain function and dynamics build on and contribute to an understanding of many brain regions, the neural circuits that constitute them, and their spatial relations. We emphasize Szentágothai's modular architectonics principle, but also stress the importance of the microcomplexes of cerebellar circuitry and the lamellae of hippocampus. (2) FUNCTION: Control of eye movements, reaching and grasping, cognitive maps, and the roles of vision receive a functional decomposition in terms of schemas. Hypotheses as to how each schema is implemented through the interaction of specific brain regions provide the basis for modeling the overall function by neural networks constrained by neural data. Synthetic PET integrates modeling of primate circuitry with data from human brain imaging. (3) DYNAMICS: Dynamic system theory analyzes spatiotemporal neural phenomena, such as oscillatory and chaotic activity in both single neurons and (often synchronized) neural networks, the self-organizing development and plasticity of ordered neural structures, and learning and memory phenomena associated with synaptic modification. Rhythm generation involves multiple levels of analysis, from intrinsic cellular processes to loops involving multiple brain regions. A variety of rhythms are related to memory functions. The Précis presents a multifaceted case study of the hippocampus. We conclude with the claim that language and other cognitive processes can be fruitfully studied within the framework of neural organization that the authors have charted with John Szentágothai.

Brain↗