The Role of the Immune System in Psychology and Neuroscience

Abstract

The immune system and the nervous system are connected in a dynamic network that has important implications for psychology. First, if analyzed in functional terms, the immune system and the nervous system are not distinctly separated: The immune system can take part in neuronal signaling through the production of an array of transmitters and hormones, and brain cells can process and present antigen and produce immune proteins. Moreover, synapses seem to be formed between immune and neural cells in lymphoid tissue. The basis of this phenomenon may be a common evolutionary background of physiological systems that by tradition have been viewed as discrete rather than overlapping. Second, the immune system is actively involved in homeostatic regulation. Signals from immune cells can profoundly change the physiological state of the organism, with changes observed in metabolism, stress axes activity, behavior, motivation and cognition. Many of these changes have probably evolved to ease recuperation. Third, the activity in the immune system is dependent of homeostatic regulation by the neuroendocrine system in a biologically important network that is also capable of mediating psychological impact on immunity. In this review, it is argued that immunology should be ecological in nature and thereby related to psychological and neural science. Hypothetically, an ecological immunology will show cross-fertilizing properties, increasing the explanatory power of the seemingly disparate scientific disciplines involved.