Pain, Affect, Nonlinear Dynamical Systems, and Chronic Pain: Bringing Order to Disorder

Chronic pain and narcotics: a dilemma for primary care.

Creativity and nonlinear dynamical systems

This chapter introduces the basic concepts of dynamical systems theory and several basic mathematical methods for controlling chaos. The main goal of this chapter is to provide an introduction to and a summary of the theory of dynamical systems, with particular emphasis on fractal theory, chaos theory, and chaos control. We first define what is meant by a dynamical system, then we define an attractor, and then the concept of the fractal dimension of a geometrical object. We also define the Lyapunov exponents as a measure of the chaotic behavior of a dynamical system. On the other hand, the fractal dimension can be used to classify geometrical objects because it measures the complexity of an object. The chapter also describes mathematical methods for controlling chaos in dynamic systems. These methods can be used to control a real dynamic system; however, due to efficiency and accuracy requirements we were forced to use fuzzy logic to model the uncertainty, which is present when numerical simulations are performed. We also describe in this chapter a new theory of chaos using fuzzy logic techniques. Chaotic behavior in nonlinear dynamical systems is very difficult to detect and control. Part of the problem is that mathematical results for chaos are difficult to use in many cases, and even if one could use them there is an underlying uncertainty in the accuracy of the numerical simulations of the dynamical systems. For this reason, we can model the uncertainty of detecting the range of values where chaos occurs, using fuzzy set theory. Using fuzzy sets, we can build a theory of fuzzy chaos, where we can use fuzzy sets to describe the behaviors of a system. We illustrate our approach with two cases: Chua’s circuit and Duffing’s oscillator.

Years ago, many researchers proposed that chaos theory could provide a kind of universal theory of the qualitative behavior of all dynamical systems. Thus it could provide a solid mathematical foundation for unifying efforts to address the three really fundamental questions of basic science: (1) what is life?; (2) what is mind or intelligence?; (3) what are the underlying physical laws of the universe? Chaos theory is essentially a recent extension of a larger field of mathematics which it is part of: nonlinear system dynamics (NSD). It mainly addresses systems governed by Ordinary Differential Equations (ODE) or their discrete-time cousins. Because the vast bulk of models now used in computational neuroscience are ODE models, it is only natural that neuroscience has developed great interest in the use of NSD as a tool for analyzing and designing neural network models. Walter Freeman, in particular, has played a seminal role in describing how chaos theory can be used in computational neuroscience, in his classical models of the olfactory system, described in articles in Scientific American and many scientific journals and IJCNN proceedings. His colleague Morris Hirsch in mathematics has helped provide a solid foundation for this work. This work has helped to inspire many efforts throughout the world to use chaos as a design principle in computer systems and in artificial neural network (ANN) design. Recently, however, several issues or questions have begun to emerge, some at Berkeley and some in other places. The author discusses these questions and their implications.

Chaos theory moots that consequences can be predicted in a system of deterministic thinking. Moreover, in general, chaotic systems can be accepted as random as they are predicted. Of course, the prediction depends on how the dimensions are clear. As chaos theory is applied for social sciences, many related studies were done on business management and to its functions. However both the studies on chaos theory and human resources management are satisfactory in numbers, studies on the relationship between these two are scarce. This paper provides a review of literature that underlines the basic principles of chaos and complexity theory, and the functions of human recourses management. In addition to this common practices of human resource management functions will be discussed in the context of chaos and complexity theory. During the text, the question of how HRM can be explained with chaos theory will be answered. It is aimed to fill the gap in the area with showing the connections between two levels of reality. Then, the study was designed to serve the daily business life with is discussions.

RETRACTED: The Effect of Cyclooxygenase-2 Inhibition on Acute and Chronic Donor-Site Pain after Spinal-Fusion Surgery

The article discusses the application of the theory of dynamic chaos to the study of social phenomena. Appeal to the origins of the creation of the theory of dynamic chaos in natural science (A. Poincaré, I. Prigogine, E. Lorenz, and others) revealed nonlinear dynamic systems in the natural environment (turbulent flows, atmosphere, biological populations, etc.). The category of “chaos” is now firmly established in the arsenal of the social sciences and humanities, although only recently it referred exclusively to natural science knowledge (the theory of chaos in mathematics, physics, biology, etc.). In synergetics, for the first time, the description of self-organization processes as a mutual transition of order and chaos was proposed by I.R. Prigogine.But in the social sciences such systems are society, its economic, political and other spheres, which have the properties of non-closure, instability and non-linear development. In Ukrainian philosophical thought, one of the first works in which the problem of the development of nonlinear self-developing systems was highlighted was the work of I.S. Dobronravova (1991). Scientific monograph I.V. Yershova-Babenko (1992) also had a significant impact on the development of studies of complex non-linear systems, since for the first time the system of the human psyche was considered as a non-linear self-organized system. The psycho-synergetic model of social reality is based on the fact that social reality is a psychomeric environment, i.e. a complex nonlinear system consisting of other complex nonlinear integrity, which are determined by phase transitions between different states of chaos and order. The application of chaos theory is also possible at the micro and macro levels of social research, which is presented by Ukrainian researchers in synergetics (I. S. Dobronravova, L. Finkel) and in psychosynergetics (I.V. Yershova-Babenko), L. Bevzenko and others.

Knee osteoarthritis (KOA) can be associated with local and central sensitization. As an indicator of the central gain, facilitated temporal summation of pain (TSP) has been found in KOA patients. This facilitation is predictive of the development of chronic postoperative pain after total knee arthroplasty (TKA). Other studies have suggested hypoesthesia/hypoalgesia to thermal stimuli as a feature in KOA. This study investigated associations between preoperative TSP, thermal sensitivity, and radiologic severity for the development of chronic postoperative pain after TKA. Radiologic KOA (Kellgren and Lawrence), TSP, and thermal stimuli were collected, preoperatively. Clinical knee pain intensity (VAS 0-10) was assessed before and 12 months following TKA. Patients were categorized into a chronic postoperative pain group if they experienced <30% pain reduction of the initial pain after 12 months. In total, 19% of the patients were categorized as chronic pain patients and presented facilitated preoperative TSP (P<0.05) and a trend towards increased heat pain threshold (P=0.077) compared with patients with normal recovery. Pearson correlations found that preoperative TSP (R=0.193; P=0.013), Kellgren and Lawrence (R=-0.168; P=0.027), warm detection threshold (R=0.195; P=0.012), and heat pain threshold (R=0.196; P=0.012) were associated with pain intensity 12 months after TKA where TSP was identified as an independent factor. This study showed that preoperatively facilitated TSP in KOA patients was predictive of the development of chronic postoperative pain following TKA. Furthermore, this study is the first to find an association between preoperative hypoalgesia to heat and the development of chronic postoperative pain following TKA.

Driving functions in a video simulator in chronic non-malignant pain patients using and not using codeine

IntroductionWhy some people develop chronic pain following an acute episode of low back pain is unknown. Recent cross-sectional studies have suggested a relationship between aberrant sensorimotor cortex activity and pain...

Chronic pain is associated with anhedonia and decreased motivation. These behavioral alterations have been linked to alterations in the limbic brain and could explain the increased risk for obesity in pain patients. The mechanism of these behavioral changes and how they set in in relation to the development of chronic pain remain however poorly understood. Here we asked how eating behavior was affected in low-back pain patients before and after they transitioned to chronic pain, compared to patients whose pain subsided. Additionally, we assessed how the hedonic perception of fat-rich food, which is altered in chronic pain patients, related to the properties of the nucleus accumbens in this patients' population. We hypothesized that the accumbens would be directly implicated in the hedonic processing of fat-rich food in pain patients because of its well-established role in hedonic feeding and fat ingestion, and its emerging role in chronic pain. Accordingly, we used behavioral assays and structural brain imaging to test sub-acute back pain patients (SBP) and healthy control subjects at baseline and at approximately one-year follow-up. We also studied a sample of chronic low-back pain patients (CLBP) at one time point only. We found that SBP patients who recovered at follow-up (SBPr) and CLBP patients showed disrupted eating behaviors. In contrast, SBP patients who persisted in having pain at follow-up (SBPp) showed intact eating behavior. From a neurological standpoint, only SBPp and CLBP patients showed a strong and direct relationship between hedonic perception of fat-rich food and nucleus accumbens volume. This suggests that accumbens alterations observed in SBPp patients in previous works might protect them from hedonic eating disruptions during the early course of the illness. We conclude that disrupted eating behavior specifically sets in after pain chronification and is accompanied by structural changes in the nucleus accumbens.

Behavioral scientists are regularly summoned by the legal system to make predictions about the likelihood of future dangerous behavior (i.e., violence prediction/risk assessment). In recent years, such efforts have been subjected to considerable scrutiny as, despite the evolution of risk assessment instruments, social scientists have yet to demonstrate the ability to predict violence with a reasonable degree of accuracy. Yet concerns with predictive efficacy may be rooted in the limitations of prediction itself. Nonlinear dynamical systems theory (i.e., chaos theory) and quantum physics jointly paint a picture of human behavior as fundamentally unpredictable; in their light, we are asked to question whether future violence can ever be predicted with a tolerable level of error. In this article, I provisionally explore this very issue, particularly as it appears in the context of decisions concerning the disposition of criminal sexual offenders.

Differential diagnosis of facial pain and guidelines for management

Pain is an important warning signal that normally disappears when the stimuli that caused it disappear. However, pain often persists for months or even years after the original rigger has disappeared. This chronic pain is debilitating and affects ~20% of the world population. Chronic inflammatory and bone pain are common causes of chronic pain and affect millions of people worldwide. These types of pain are caused by diseases such as osteoarthritis, rheumatoid arthritis, lupus, psoriasis, ankylosing spondylitis, bone cancer or fibrous dysplasia. Existing therapies are not effective in treating chronic inflammatory and bone pain, and often cause severe side effects. Recent evidence shows that immune cells and neuronal mitochondrial disturbances play an important role in chronic pain. Nevertheless, there is still an incomplete understanding of how these aspects contribute to the development of chronic inflammatory and bone pain. Therefore, in this thesis, we examined the role of mitochondrial regulation and neuroimmune interactions in chronic pain, with a particular focus on the transition between acute and chronic inflammatory pain and chronic bone pain. In this thesis, we show that inflammation-induced mitochondrial and metabolic disturbances in sensory neurons predispose to failing pain resolution pathways. Moreover, targeting specific elements of these disturbances such as the redox balance and or the mitochondrial protein ATPSc-KMT in sensory neurons were sufficient to restore resolution of inflammatory pain and prevent chronic pain. We identified that the increased oxidative stress associated with the observed disturbed redox balance results in the activation of the NLRP3 inflammasome pathway in sensory neurons. Inhibiting the NLRP3 inflammasome pathway prevents not only the transition from acute to chronic inflammatory pain, but also reduces osteoarthritis pain. Interestingly, in male mice with osteoarthritis pain, NLPR3 inflammasome inhibition had longer-lasting analgesic effects than in females. Moreover, NLPR3 inflammasome inhibition decreased the population of inflammatory macrophages in the dorsal root ganglia (DRG) only in males. These data indicate that NLRP3 inflammasome activation contributes to osteoarthritis pain in a sex dependent manner, while also highlighting the importance of neuro-immune interactions in chronic pain. We further add to the evidence that the immune system plays a key role in pain regulation, by showing that macrophages contribute to the development of cancer bone pain, another type of bone pain which etiology is not fully understood. However, in contrast to osteoarthritis pain, DRG and spinal cord macrophages do not contribute to the maintenance of cancer bone pain. Future research has to identify in which tissues these macrophages contribute to bone cancer pain. Lastly, we showed that the inhibitory immune receptor LAIR-1 is required to resolve from inflammatory pain, likely through T cells mediated regulation Thus, we identified a previously unknown role for LAIR-1 in the regulation of inflammatory pain. Overall, the studies described in the thesis unveil how mitochondrial regulation and neuro-immune interactions contribute to chronic pain development.

Developed in the paper is a probabilistic theory for nonlinear dynamical systems. The theory is based on discretizing the state space into a cell structure and using the cell probability functions to describe the state of a system. Although the dynamical system may be highly nonlinear the probabilistic formulation always leads to a set of linear ordinary differential equations. The evolution of the probability distribution among the cells can then be studied by applying the theory of Markov processes to this set of equations. It is believed that this development possibly offers a new approach to the global analysis of nonlinear systems.