Jorge H. Daruna

Unilateral Temporal Lobe Lesions Alter P300 Scalp Topography

Event related potentials were recorded from patients with unilateral temporal lobe lesions and healthy volunteers. Subjects were required to silently count on infrequent target tone interspersed among presentations of a non-target tone, with an interval between tones that was relatively long and variable (6-10s). Under these task conditions, the patients were found to have P300 amplitudes that were smaller on the lesioned side relative to the non-lesioned side. This finding is interpreted as evidence that temporal lobe lesions affect the configuration of intracranial sources generating the P300 component of event-related potentials.

Event-Related Potential Correlates of Intelligence and Personality

Event-related potentials (ERPs) have been shown to be sensitive to the manipulation of cognitive processes by instructions to the subject, such as to ignore or to focus attention on a series of events (Naatanen and Michie, 1979). There has been comparatively little work examining the extent to which stable characteristics of the subject as an information processor affect specific ERP components, and their scalp distribution. Studies which have examined relations between ERP features and individual difference variables have generally been encouraging (Callaway, 1975), even though the cognitive demands on the subjects have been minimal, and ERP topography has been typically ignored. The present paper reports on the correlations of ERP measures, obtained during a stimulus guessing task, to measures of intelligence, impulsivity, and free-floating anxiety.

NEUROTICISM PREDICTS NORMAL VARIABILITY IN THE NUMBER OF CIRCULATING LEUCOCYTES

Abstract Exposure to Stressors and states of high negative affect have been associated with a variety of deviations in immune function, including a higher white blood cell (leucocyte) count in the peripheral circulation. Such a higher leucocyte count may be a consequence of increased sympathetic nervous system activity, since catecholamines have been shown to increase the leucocyte count. The present study explored this hypothesis by examining the relationship between neuroticism, an aspect of personality associated with sympathetic reactivity, and the number of circulating leucocytes in a sample of healthy volunteers. Neuroticism was found to be positively correlated with leucocyte count after controlling for the effect of gender, history of allergy, current use of medicines, alcohol consumption, and lifetime use of illicit drugs. Further analyses indicated that specific facets of neuroticism (e.g. irritability, anxiety, depression) appeared to be differentially related to counts of the various cell types that make up the leucocyte population. These findings are briefly discussed with respect to possible significance for immune response dynamics and health maintenance.

P3 amplitude in young children: Relation to anxiety

The late posiUve component (P3) of event related potentials (ERPs) has been established as a manifestation of neural activity ~dated to cognitive processes (Verleger 1988)• Efforts to ascertain the origins of P3 have implicated temporal and frontal lobe regions (Halgren et al 1986) which are known to mediate affect and cognition, and regulate behavior. Study of P3 variability in relation to normal atfecfive, cognitive, or behavioral t r~s has been limited, even though it seems central to efforts to delineate neurophysiological concomitants of psychopathology. Research on college students g~as shown that P3 amplitude and its topography are related to impulsivity (Daruna et al 1985) and anxiety (Daruna and Karrer 1986), respectively. This report presents further evidence of an association between P3 amplitude topography and anxiety in normal young children.

Chapter 11 – Immune Function Enhancement

Publisher Summary This chapter focuses on the evidence that a variety of personal beliefs and practices, including social activity, expression of emotion, relaxation habits, physical exercise, and nutritional choices, have beneficial effects on immune function. Beliefs are complex mental phenomena that serve as guiding principles in the process of human life. Hypnosis is fundamentally a process rooted in the willingness of one individual to participate with another in a relationship marked by the belief in the power of suggestion delivered by a qualified source. There is abundant evidence that suggestion under hypnosis can alter basic aspects of experience such as the sensation of pain. Analgesia induced via hypnosis has been repeatedly demonstrated. Under placebo effect approach, the belief by both the afflicted person and the healer that some potion or ritual has the power to cure could bring about such an outcome. The nocebo effect refers to the observation that expectation of sickness or even death may promote such an outcome—in effect that the power of belief operates also in negative outcomes. The importance of social engagement or more generally social interaction has been abundantly documented by epidemiological studies that demonstrate that those who have more social contact are more likely to retain health and live longer.

Chapter 9 – Cancer, Autoimmunity, and Psychosocial Stress

Publisher Summary This chapter examines diseases that arise when self-tissues become malignant or when immune activity is directed at healthy tissue. Genetic factors play a role in creating susceptibility to cancer and autoimmune disorders. In the case of cancer or neoplastic disease, the threat arises from within. The individuals own cells undergo transformation so they multiply uncontrollably and compete with healthy tissue for both space and resources. It is now understood that a cancer is an expanding clone. It begins when a single cell becomes transformed, through the accumulation of specific genetic mutations, so that it reproduces frequently and remains insensitive to signals for growth inhibition. The genes that appear mutated in cancer cells are typically those that are involved in some aspect of cell growth. The p53 gene is believed to be the most commonly mutated gene in human cancer. The p53 protein functions in the activation of cell death in response to deoxyribonucleic acid (DNA) damage. Females are at higher risk of autoimmune disorders. The phases of their reproductive function appear to modulate autoimmunity, probably because of hormonal effects on immune function.

Chapter 12 – Integration and Implications

Publisher Summary This chapter highlights the key insights derived from psychoneuroimmunology and draws implications for research and health care. Psychoneuroimmunology is a higher order scientific discipline that has emerged from reductionistic approaches that isolate bodily systems or their components to characterize aspects of their operation but that consequently fall short of elucidating how the systems operate in their natural context. The immune system operates at the boundary between the organism and other life forms. It is composed of elements that protect the integrity of the organism by blocking, neutralizing, or destroying microscopic predators or aberrant cells originating within the organism. The endocrine and immune systems intercommunicate to achieve balanced activity compatible with life, given specific contexts. Growth-oriented hormones that modulate the storage and use of nutrients have effects on immune function by how available resources are allocated. Psychoneuroimmunology underscores the notion that disease begins within microenvironments. A microenvironment can be defined at different levels, such as that immediately adjacent to a segment of deoxyribonucleic acid (DNA) containing a single gene or that surrounding a single cell or a small volume of tissue composed of a few interacting cells.

Chapter 4 – Endocrine-Immune Modulation

Publisher Summary This chapter focuses on the role of the endocrine system in the modulation of immune function, focusing on the major structures that compose the endocrine system and the major hormones released by the endocrine glands. The hypothalamus lies at the base of the brain. Neurons located within various hypothalamic nuclei are directly involved in the release of the pituitary hormones, which, in turn affect the activity of the other endocrine glands. It is important to emphasize that there is a high degree of interconnectivity among hypothalamic nuclei that have been implicated in endocrine regulation. The pituitary gland, or hypophysis, lies at the base of the brain, just behind the eyes, and it is directly connected to the hypothalamus by the pituitary stalk. The thyroid gland is located in the throat area. The adrenal glands are located above the kidneys. They are composed of a cortex (outer) and a medulla (inner) region. The release of GH (somatotropin) from the anterior pituitary cells, known as somatotrophs, is influenced by a wide range of factors. GH release is stimulated by thyroid hormones and testosterone. It is inhibited by estradiol. GH regulates its own release both at the hypothalamic level and at the level of the pituitary.

Chapter 6 – Stress, Contextual Change, and Disease

Publisher Summary This chapter focuses on the Hans Selyes concept of stress that is viewed as fundamentally denoting contextual change that demands a response. Selye regarded the stress response as relatively nonspecific. He documented a number of physiological and tissue changes that occur with stress. Selye noted three phases in the stress response. There was an initial alarm reaction, a mobilization of the bodys defenses. This phase had two components—an initial shock-reaction phase, from the offensive stimulation, soon followed by a systemic counter–shock-reaction phase. Human mobility has been regarded as a source of stress. However, it is not simply a matter of leaving behind familiar surroundings that are part of the nonliving world or social context. The nonliving environment encompasses features such as solar radiation, weather, altitude, chemical composition of the earth, and availability of water. The individual is an aspect of his or her own context. When one focuses on any particular bodily function or system, all else that transpires within the organism, including the psychological, provides the context for the function or system that is being examined.

Chapter 7 – Psychosocial Stress: Neuroendocrine and Immune Effects

Publisher Summary This chapter focuses on psychosocial stress and how it affects endocrine, neural, and immune activity, particularly in humans. The psychological characteristics of individuals are part of what determines how changes in social and nonsocial conditions affect the individuals psychological equilibrium. Activation of the pituitary—adrenal axis is a defining characteristic of stress, although individual differences in the extent of such activation exist. The research on primates illustrates the impact of social context. Subjects who have a lower rank in the social group have higher levels of adrenocorticotropic hormone (ACTH) and cortisol. The experience of individual animals can be drastically different even within a relatively stable hierarchy. For instance, an individual of intermediate rank that is subjected to frequent challenges by lower ranking individuals will tend to have a higher cortisol level than the lowest ranking individual. Stress causes changes in the activity of the autonomic nervous system (ANS) and more generally the peripheral nervous system (PNS).