The Influence of Social Hierarchy on Primate Health

Sapolsky, R. M. (2005). The influence of social hierarchy on primate health. Science308(5722), 648-652.


Dominance hierarchies occur in numerous social species, and rank within them can greatly influence the quality of life of an animal. In this review, I consider how rank can also influence physiology and health. I first consider whether it is high- or low-ranking animals that are most stressed in a dominance hierarchy; this turns out to vary as a function of the social organization in different species and populations. I then review how the stressful characteristics of social rank have adverse adrenocortical, cardiovascular, reproductive, immunological, and neurobiological consequences. Finally, I consider how these findings apply to the human realm of health, disease, and socioeconomic status.


The reactive scope model—a new model integrating homeostasis, allostasis, and stress

Romero, L. M., Dickens, M. J., & Cyr, N. E. (2009). The reactive scope model—a new model integrating homeostasis, allostasis, and stress. Hormones and behavior55(3), 375-389.


Allostasis, the concept of maintaining stability through change, has been proposed as a term and a model to replace the ambiguous term of stress, the concept of adequately or inadequately coping with threatening or unpredictable environmental stimuli. However, both the term allostasis and its underlying model have generated criticism. Here we propose the Reactive Scope Model, an alternate graphical model that builds on the strengths of allostasis and traditional concepts of stress yet addresses many of the criticisms. The basic model proposes divergent effects in four ranges for the concentrations or levels of various physiological mediators involved in responding to stress. (1) Predictive Homeostasis is the range encompassing circadian and seasonal variation — the concentrations/levels needed to respond to predictable environmental changes. (2) Reactive Homeostasis is the range of the mediator needed to respond to unpredictable or threatening environmental changes. Together, Predictive and Reactive Homeostasis comprise the normal reactive scope of the mediator for that individual. Concentrations/levels above the Reactive Homeostasis range is (3) Homeostatic Overload, and concentrations/levels below the Predictive Homeostasis range is (4) Homeostatic Failure. These two ranges represent concentrations/levels with pathological effects and are not compatible with long-term (Homeostatic Overload) or short-term (Homeostatic Failure) health. Wear and tear is the concept that there is a cost to maintaining physiological systems in the Reactive Homeostasis range, so that over time these systems gradually lose their ability to counteract threatening and unpredictable stimuli. Wear and tear can be modeled by a decrease in the threshold between Reactive Homeostasis and Homeostatic Overload, i.e. a decrease in reactive scope. This basic model can then be modified by altering the threshold between Reactive Homeostasis and Homeostatic Overload to help understand how an individual’s response to environmental stressors can differ depending upon factors such as prior stressors, dominance status, and early life experience. We illustrate the benefits of the Reactive Scope Model and contrast it with the traditional model and with allostasis in the context of chronic malnutrition, changes in social status, and changes in stress responses due to early life experiences. The Reactive Scope Model, as an extension of allostasis, should be useful to both biomedical researchers studying laboratory animals and humans, as well as ecologists studying stress in free-living animals.

Vividness, Consciousness, and Mental Imagery: Making the Missing Links across Disciplines and Methods

Guest Editor: Amedeo D’Angiulli

All articles can be accessed freely online.

Marks, D.F. I Am Conscious, Therefore, I Am: Imagery, Affect, Action, and a
General Theory of Behavior. Brain Sci. 2019, 9(5), 107;
Views: 2082, Downloads: 1277, Citations: 2, Altmetrics: 2

Lefebvre, E.; D’Angiulli, A. Imagery-Mediated Verbal Learning Depends on
Vividness–Familiarity Interactions: The Possible Role of Dualistic Resting
State Network Activity Interference. Brain Sci. 2019, 9(6), 143;
Views: 1537, Downloads: 645, Citations: 0, Altmetrics: 5

Pinna, B.; Conti, L. The Limiting Case of Amodal Completion: The Phenomenal
Salience and the Role of Contrast Polarity. Brain Sci. 2019, 9(6), 149;
Views: 1307, Downloads: 701, Citations: 2, Altmetrics: 1

Craver-Lemley, C.; Reeves, A. Taste Modulator Influences Rare Case of
Color-Gustatory Synesthesia. Brain Sci. 2019, 9(8), 186;
Views: 1041, Downloads: 907, Citations: 0, Altmetrics: 0

Haustein, S.; Vellino, A.; D’Angiulli, A. Insights from a Bibliometric
Analysis of Vividness and Its Links with Consciousness and Mental Imagery.
Brain Sci. 2020, 10(1), 41;
Views: 810, Downloads: 300, Citations: 0, Altmetrics: 1

van der Helm, P.A. Dubious Claims about Simplicity and Likelihood: Comment on
Pinna and Conti (2019). Brain Sci. 2020, 10(1), 50;
Views: 699, Downloads: 234, Citations: 1, Altmetrics: 0

Pinna, B.; Conti, L. On the Role of Contrast Polarity: In Response to van der
Helm’s Comments. Brain Sci. 2020, 10(1), 54;
Views: 657, Downloads: 243, Citations: 0, Altmetrics: 0

Thorudottir, S.; Sigurdardottir, H.M.; Rice, G.E.; Kerry, S.J.; Robotham,
R.J.; Leff, A.P.; Starrfelt, R. The Architect Who Lost the Ability to
Imagine: The Cerebral Basis of Visual Imagery. Brain Sci. 2020, 10(2), 59;
Views: 2817, Downloads: 972, Citations: 0, Altmetrics: 56

Brain Sciences (ISSN 2076-3425) is a journal published by MDPI AG, Basel,


Homeostasis, behavioral adjustment and the concept of health and disease

G L Engel’s (1953) theory of homeostasis


The psychiatrist G L Engel is famous for his concept of the‘biopsychosocial model’(BPSM), which has been cited, to date, 14109 times: 

Engel, G. L. (1977). The need for a new medical model: a challenge for biomedicine. Science196(4286), 129-136.

Much less cited but, arguably, a more interesting and significant contribution is Engel’s earlier paper about homeostasis, behavioral adjustment and the concept of health and disease. See details below:


Engel, G. L. (1953). Homeostasis, behavioral adjustment and the concept of health and disease. In R. R. Grinker (Ed.), Mid-century psychiatry: an overview (p. 33–59). C. C. Thomas. 


All the phenomena of disease can be derived from interference with attempts at satisfaction of instinctual needs; inner perception of a disturbed equilibrium or unsatisfied need, with the concept of a danger signal; chemical, physiological, psychological and social adaptive devices coping with the stress; and structural or functional damage resulting from the stress and from attempts at adaptation which are inappropriate or unsuccessful.

Role of Exosomes in the Regulation of T-Cell Mediated Immune Responses and in Autoimmune Disease

Anel, A., Gallego-Lleyda, A., de Miguel, D., Naval, J., & Martínez-Lostao, L. (2019). Role of exosomes in the regulation of T-cell mediated immune responses and in autoimmune disease. Cells8(2), 154.


T-cell mediated immune responses should be regulated to avoid the development of autoimmune or chronic inflammatory diseases. Several mechanisms have been described to regulate this process, namely death of overactivated T cells by cytokine deprivation, suppression by T regulatory cells (Treg), induction of expression of immune checkpoint molecules such as CTLA-4 and PD-1, or activation-induced cell death (AICD). In addition, activated T cells release membrane microvesicles called exosomes during these regulatory processes. In this review, we revise the role of exosome secretion in the different pathways of immune regulation described to date and its importance in the prevention or development of autoimmune disease. The expression of membrane-bound death ligands on the surface of exosomes during AICD or the more recently described transfer of miRNA or even DNA inside T-cell exosomes is a molecular mechanism that will be analyzed.

Keywords: exosomes; extracellular vesicles; immune regulation; autoimmunity.


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Homeostasis and Self-Tolerance in the Immune System: Turning Lymphocytes off

Van Parijs, L., & Abbas, A. K. (1998). Homeostasis and self-tolerance in the immune system: turning lymphocytes off. Science280(5361), 243-248.


The immune system responds in a regulated fashion to microbes and eliminates them, but it does not respond to self-antigens. Several regulatory mechanisms function to terminate responses to foreign antigens, returning the immune system to a basal state after the antigen has been cleared, and to maintain unresponsiveness, or tolerance, to self-antigens. Here, recent advances in understanding of the molecular bases and physiologic roles of the mechanisms of immune homeostasis are examined.

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Homeostasis and consumer behavior across cultures

Parker, P. M., & Tavassoli, N. T. (2000). Homeostasis and consumer behavior across cultures. International Journal of Research in Marketing, 17(1), 33-53.


The focus of this paper is the process of homeostasis by which the body seeks to regulate its internal environment. In particular, we present a global model for a set of consumer behaviors that may vary across cultures as a direct response to the intensity and duration of sunlight and experienced temperature. This process creates physical and psychological needs, so that changes in sunlight and temperature may be reflected in various behaviors. We integrate research findings from the neural sciences and psychology to generate testable predictions of relevance to the marketing literature. These hypotheses predict how the physical environment motivates variations in the consumption of different types of products, and how mood, expressed affect, and related affective behaviors may vary across cultures. We also consider how variations in sunlight and temperature may affect consumer behaviors related to consumers’ optimal stimulation levels. We conclude by discussing the implications of a physiological model on the debate of global convergence in consumer behavior.

Climate, Psychological Homeostasis…Across Cultures

Tavassoli, N. T. (2009). 11 Climate, Psychological Homeostasis, and Individual Behaviors Across Cultures. Understanding culture: Theory, research, and application, 211.

Sleep function and synaptic homeostasis

Tononi, G., & Cirelli, C. (2006). Sleep function and synaptic homeostasis. Sleep medicine reviews10(1), 49-62.


This paper reviews a novel hypothesis about the functions of slow wave sleep—the synaptic homeostasis hypothesis. According to the hypothesis, plastic processes occurring during wakefulness result in a net increase in synaptic strength in many brain circuits. The role of sleep is to downscale synaptic strength to a baseline level that is energetically sustainable, makes efficient use of gray matter space, and is beneficial for learning and memory. Thus, sleep is the price we have to pay for plasticity, and its goal is the homeostatic regulation of the total synaptic weight impinging on neurons. The hypothesis accounts for a large number of experimental facts, makes several specific predictions, and has implications for both sleep and mood disorders

Consciousness without a cerebral cortex

Merker, B. (2007). Consciousness without a cerebral cortex: A challenge for neuroscience and medicine. Behavioral and brain sciences30(1), 63-81.


A broad range of evidence regarding the functional organization of the vertebrate brain – spanning from comparative neurology to experimental psychology and neurophysiology to clinical data – is reviewed for its bearing on conceptions of the neural organization of consciousness. A novel principle relating target selection, action selection, and motivation to one another, as a means to optimize integration for action in real time, is introduced. With its help, the principal macrosystems of the vertebrate brain can be seen to form a centralized functional design in which an upper brain stem system organized for conscious function performs a penultimate step in action control. This upper brain stem system retained a key role throughout the evolutionary process by which an expanding forebrain – culminating in the cerebral cortex of mammals – came to serve as a medium for the elaboration of conscious contents. This highly conserved upper brainstem system, which extends from the roof of the midbrain to the basal diencephalon, integrates the massively parallel and distributed information capacity of the cerebral hemispheres into the limited-capacity, sequential mode of operation required for coherent behavior. It maintains special connective relations with cortical territories implicated in attentional and conscious functions, but is not rendered nonfunctional in the absence of cortical input. This helps explain the purposive, goal-directed behavior exhibited by mammals after experimental decortication, as well as the evidence that children born without a cortex are conscious. Taken together these circumstances suggest that brainstem mechanisms are integral to the constitution of the conscious state, and that an adequate account of neural mechanisms of conscious function cannot be confined to the thalamocortical complex alone.

Keywords: action selection; anencephaly; central decision making; consciousness; control architectures; hydranencephaly; macrosystems; motivation; target selection; zona incerta

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