Psychoneuroendocrine immunology: site of recognition, learning and memory in the immune system and the brain

• Published in: International journal of neuroscience 1997-01, Vol.92 (3-4), p.259-286
• Main Authors: Hiramoto, Raymond N., Rogers, Carolyn F., Demissie, Sossiena, Hsueh, Chi-Mei, Hiramoto, Nancy S., Lorden, Joan F., Ghanta, Vithal K.
• Format: Article
• Language: English
• Subjects: Anatomical correlates of behavior; Behavioral psychophysiology; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Humans; Hypothalamus - immunology; Immunologic Memory; Memory - physiology; Neuroimmunomodulation - physiology; Neurosecretory Systems - immunology; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology
• ISSN: 0020-7454; 1563-5279; 1543-5245
• DOI: 10.3109/00207459708986405

How the interaction between the brain and immune system takes place has not been clearly defined. Because multiple changes are occurring simultaneously in all organ systems (e.g., cardiovascular, gastrointestinal, reproductive, renal, respiratory, immune, CNS), how many single systems interacts with the brain becomes extraordinarily difficult to understand. The problem boils down to developing an approach that not only allows one to study the whole organism and define the mediators of the interacting systems, but also permit one to establish the connection and physiologic relevance of the responses that are being evaluated. Conditioning, a phenomenon made popular by the work of Pavlov (1906, 1927), may provide insight into the pathways of communication between the brain and possibly any organ system of the body. Conditioning allows one to separate the afferent from the efferent circuits. That is, signals from the immune system to the CNS (IS→CNS) can be effectively separated from signals from the CNS to immune system (CNS → IS). This permits one to study each pathway individually. Simple, single association trial models to condition fever, natural killer (NK) cell and cytotoxic lymphocyte (CTL) activities have been developed to evaluate the pathways. Single trial learning is not new. Pavlov has observed that "The electric buzzer set going before administration of food established a conditioned alimentary reflex after only a single combination," whereas the reverse order of presentation failed to condition the animal (Pavlov 1927 p. 27). Thus, conditioning can be used to train the brain to activate the immune system and other organ systems participating in the response. During the course of the conditioned response, presumably the CNS via the hypothalamus integrates in a cohesive orderly fashion all input and output signals and coordinates the responses made by the brain to the organ systems. The odor of camphor, the conditioned stimulus (CS) can be associated with the response produced by an unconditioned stimulus (US). The unconditioned stimuli used are poly I:C to raise fever and nonimmunospecific NK cell activity or alloantigens to raise immunospecific CTL activity. The unconditioned stimulus serves only as a means to activate the immune system and unbalance the homeostasis so that a transient but new bidirectional communication loop can be established between the immune system and the CNS (IS↔CNS). The expression of the conditioned response (i.e., elev