Central Motive States Feedforward Neuroendocrine Systems in the Brain

Motivational states are generated by the brain. As my deceased colleague Alan Epstein would say when discussing central motive states and drinking behavior, Thirst is a state of the brain (Epstein et al., 1973). However, the acceptance of concepts such as motivation has declined in some intellectual traditions. They warrant resurrection, particularly in the context of the hormonal regulation of behavior, and in the context of allostatic regulation of behavioral and physiological events. This...

Rethinking Homeostasis

Allostatic Regulation in Physiology and Pathophysiology A Bradford Book The MIT Press Cambridge, Massachusetts London, England 2003 Massachusetts Institute of Technology AH rights reserved. No part of this book may be reproduced in any form by any electronic or mechanical means (including photocopying, recording, or information storage and retrieval) without permission in writing from the publisher. This book was set in Palatino by Achorn Graphic Services, Inc., on the Miles 33 system, and was...

Ptsd

Cerebrospinal fluid (CSF) corticotropin releasing hormone levels in posttraumatic stress disorder (PTSD) patients and control subjects (adapted from Bremner et al., 1997). This finding of low basal cortisol in PTSD patients stands out in contrast to the cortisol levels of people with melancholic depression or excessively shy children. It is important to note that there is some evidence that patients with PTSD have elevated levels of CRH in their cerebrospinal fluid (figure 3.11 Darnell et al.,...

Chronic Angst Allostasis and Pathology

McEwen and his colleagues (McEwen and Stellar, 1993 McEwen, 1998a, b, 1999 McEwen and Seeman, 1999) formulated and developed the terms allostasis and allostatic overload in an attempt to account for preserving physiological stability amid changing circumstances. For example, when uncertainty persists for long periods or is perceived as going beyond one's control, it results in negative consequences that my colleagues and I called anticipatory angst in an earlier paper (Schulkin et al., 1994)....

Addiction to Drugs Allostatic Regulation under Duress

There are several features of addiction that are relevant to allo-stasis. The first is the simple elevation in use of a number of neural systems during addiction, both in the appetitive and in the consummatory phases of the central motive state. The second is the dysregulation of the reward system associated with the chronic use of drugs (Koob and Le Moal, 2001). There are indications (for example, in animal models) that drug consumption can have long-term potentiation in specific neurons from...

Positive to sweet

Facial expressions to infusions of bitter and sweet tasting substances (from Berridge, 2000 Steiner et al., 2001). Facial expressions to infusions of bitter and sweet tasting substances (from Berridge, 2000 Steiner et al., 2001). substance or the sensory characteristics (Berridge and Grill, 1983 Berridge and Schulkin, 1989). Allesthesia is a more physiological term that has been used (Cabanac, 1971, 1979) to depict the regulatory role of hedonics in behavior. Like the example above with regard...

Conclusion Adaptation Allostasis and Anticipation

Both homeostasis and allostasis, whole body regulatory concepts, function in our lexicon as integrative terms for understanding physiological behavioral systems. They reflect our need to understand how internal viability is maintained in a changing environment (see also Mrosovsky, 1990 Bauman, 2000). Allostasis is tied to the central nervous system as it supervenes in the assessment and regulation of bodily states (Sterling and Eyer, 1988 Schulkin et al., 1994). One impetus for the idea of...

Anticipation Angst Allostatic Regulation Adrenal Steroid Regulation of Corticotropin Releasing Hormone

The emotion of fear is regulated by neuroendocrine events in neural circuits that underlie fear-related behavioral and autonomic responses. One brain region critical in the regulation of fear is the amygdala. I suggest that one function of glucocorti-coid hormones is to facilitate the synthesis of the neuropeptide CRH in this nucleus (along with the lateral bed nucleus of the stria terminalis). CRH aids in maintaining and coping with events that are perceived as frightening. Elevated levels of...

Allostasis The Emergence of a Concept

The logic of this chapter is to begin with a brief discussion of the evolution of thinking about homeostatic systems that is, historical and contemporary perspectives on maintaining internal physiological stability, and its breakdown during duress. One outcome of thinking about homeostatic systems has been the recognition that a concept was needed to explain how the animal anticipates and or reacts to unpredictable change as a function of internal regulation of physiological events. Finally, I...

Stress

The fetopolacental corticotropin-releasing hormone and glucocorticoid positive feedback hypothesis. Corticotropin-releasing hormone, secreted by the placental trophoblasts (T), enters the fetal circulation via the umbilical cord vein and stimulates (+) fetal ACTH release from the fetal pituitary (PIT). Fetal ACTH stimulates secretion of fetal adrenal cortisol sulfate, which enters the placental sulfatase, and cortisol stimulates further placental corticotropin-releasing hormone secretion,...

C0

Concentrations of immunoreactive corticotropin-releasing hormone (CRH) in placental tissue at various stages of human gestation (adapted from Frim et al., 1988). several species, including humans (Frim et al., 1988 Riley et al., 1991), gorillas (Robinson et al., 1989), chimpanzees (Smith et al., 1999), and rhesus monkeys (Wu et al., 1995), although there appear to be primate species (Goland et al., 1992a, b Smith et al., 1993). It is possible that CRH levels, although low in early gestation,...

Normal and Pathological Facilitation of Parturition by a Feedforward Endocrine Mechanism

The emergence of mammals is tied to evolved brains, evolving placental function, and lactation (Easteal, 1999). The placenta is unique in its vast storehouse of biochemical information molecules that are vital to the developing fetus. Nature conserved, extended, and utilized the diverse myriad of information molecules that are well represented in the brain and the placenta and that are fundamental for normal development (Petraglia et al., 1990). Moreover, nature selected a number of endocrine...