1 / 47

STRESS DISSONANCE and DENIAL Subclinical Stress and Cognitive Deficits

STRESS DISSONANCE and DENIAL Subclinical Stress and Cognitive Deficits. Neil Greenberg -- A&O 2014. Neil Greenberg Department of Ecology and Evolutionary Biology The University of Tennessee, Knoxville. STRESS can be COMMUNICATIVE BEHAVIOR within and between organisms. CONNECTIONS.

Download Presentation

STRESS DISSONANCE and DENIAL Subclinical Stress and Cognitive Deficits

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. STRESSDISSONANCE and DENIAL Subclinical Stress and Cognitive Deficits Neil Greenberg -- A&O 2014

  2. Neil Greenberg Department of Ecology and Evolutionary Biology The University of Tennessee, Knoxville STRESS can be COMMUNICATIVE BEHAVIOR within and between organisms

  3. CONNECTIONS • The organism possesses a remarkable sense of biological priorities (needs met by activating/energizing MOTIVATIONAL SYSTEMS) • A reference point (safe stability, the status quo) is ALWAYS being challenged by developmental or environmental CHANGE • Challenges to meeting real or perceived NEEDS = stressors

  4. CONNECTIONS • Stressors evoke diverse COPING MECHANISMS: • Physiological and behavioral mechanisms that respond to deviations from set points to restore HOMEOSTASIS • The AUTONOMIC branch of the nervous system is the principal response, energizing the organism, including specific motivational systems • COLLATERAL effects of autonomic activities can communicate internal status and be RITUALIZED into effective signals (“bricolage”)

  5. AUTONOMIC

  6. Real or perceived NEEDS that must be met: • Physiology( Homeostasis) (Food comes first, then morals. -Bertolt Brecht) • Safety(security, order, protection) • Sociality( acceptance, “acceptance”) • Esteem(better reproductive opportunities status, prestige;) • Self-Actualization(reproduction; direct or indirect fitness; “personal fulfillment”) -apologies to Maslow

  7. Coping . . . • STRESSORS are internal or external changes which by challenging an organism’s ability to meet its needs evokes a coordinated coping response • ECOLOGICAL sources of stress –if sufficiently severe-- can constitute SELECTION PRESSURE • SUBCLINCAL STRESSORS – stretch towards the set-point – depending on PRIORITIES of NEEDS • . . . constrained by a neurobehavioral threshold for detectionof the change, for attentionbased on real or perceived relevance, andcapacity to respond at any particular level once the challenge is detected.

  8. COPING RESPONSES: constraints of the system • Input (stress can change the sensitivity of sense organs (e.g., Gandelman 1983); resolve competitive parallel afferent pathways,) • Integration(receptive field modulation; stress can affect arousal, selective attention (e.g., Archer 1973, R.J. Andrew 1972); differential regional sensitivity to hormones or neurotransmitters (e.g., Amy Arnsten 2000); control of microcirculation (e.g., Palmer 1986) • Output (resolve competitive parallel efferent paths to action; energetic reserves and the ability to mobilize them)

  9. COPING RESPONSES: stress sensitive hormones • Sympathoadrenomedullary (SAMS) response (adrenal medullary /chromaffin response to sympathetic activation: EPI & NOREPI) • Hypothalamic-pituitary-adrenal (HPA) axis activation(CRF, ACTH, adrenal glucocorticoids) • Opioids(endorphin, enkephalin; affects perception of pain and reproductive axis) • Prolactin (affects reproductive axis) • Angiotensin, Melanotropin?

  10. AUTONOMIC

  11. COPING RESPONSES: problems of interpretation • Bi-phasic (“paradoxical”) responses(responses can be diametrically opposed depending on absolute levels of hormone (e.g., Gandelman 1983) or presence of facilitating hormones (e.g., stress can facilitate classical conditioning [Shors et al. 1992] in males but not in females [Wood & Shors 1998]) • Extra-trophic effects(e.g., CRF canenhances effects of novelty, affect learning,(see Koob 1991); ACTH can suppress aggression (see Brain et al 1971); MSH affects motivation, attention (Stratton & Kastin 1973; Kastin et al. 1971)

  12. COPING RESPONSES: hierarchically arrayed • The most ancient (evolutionarily conservative) responses are invoked first (adrenal medullary /chromaffin response to sympathetic activation) (fear –subcortical limbic areas; pleasure --cortical limbic) • As each response’s adaptive scope is exceeded, successive mechanisms deploy (local, neuroendocrine [CRF, ACTH, glucocorticoids], behavior) • Behavior is the final option (invoked when “lower” responses capacity is exceeded or they would be would be too “expensive”)

  13. COPING RESPONSES: not only emergencies ! • Elements of the stress response can be invoked whenever there is a mismatch (unmet expectations, cognitive dissonance; (Goldstein 1990)) • Stressors can be cumulative(acute, sequential, episodic, or sustained stressors all make demands on the system) • The level of response is related to perceived prospects for success (e.g., learned helplessness; active versus passive coping identified with specific columns within the periaquaductal gray (Paradiso et al. 1999))

  14. COPING RESPONSES:delicately balanced alternatives ! • “Fight or flight” (the classic stress alternatives to imminent aggressive threat –not only in animals with a cerebral cortex! -- Cannon) • “Flee or freeze”(lizards can apparently calculate prospects for survival based on external threat , internal resources, and environmental possibilities -- Rand) • “Green or brown” (the Anolis carolinensis dermal chromatophore –the “chromomotor model” --Greenberg) • “Tend and Befriend”(nurturing children or seeking social contact: oxytocin in conjunction with other stress hormones and opioids – SE Taylor 2002)

  15. SURVEY: stress-sensitive behavior • Detection, Arousal and Attention(steroids affect sensory thresholds, EPI intensifies; acute CS enhances salience) • Activity(CRF facilitates in familiar habitat, inhibits in unfamiliar habitat) • Exploration(CRF and ACTH enhances effects of novelty, CS facilitates) • Learning and memory( EPI, CRF, MSH facilitate acquisition) • Cognition( catecholamine modulation; taking prefrontal cortex “offline” (Arnsten))

  16. SURVEY: stress-sensitive behavior • Feeding( CS stimulates or inhibits depending on circulating levels) • Aggression(ACTH suppresses, CS increases or decreases depending on circulating levels) • Social Dominance(CS increases submissiveness) • Reproduction( ACTH, CS, opiods, and prolactin impair HPG axis) • Dysfunctional behavior(stereotypies, neuroses, psychoses)

  17. The Anolis Model • Small, easily maintained, • displays focal behavioral patterns easily in laboratory • Dermal chromatophore responds only to circulating hormones

  18. Chromomotor model for the stress response • Acute, repetitive, or sustained stressors are integrated in the CNS • Autonomic neurons activate the adrenal medullary response • H-P-A axis integrates the adrenal cortical response • The Anolis body color thus reflects underlying neuroendocrine coping activities • Body color reflects autonomic tone

  19. IMMEDIATE PHYSIOLOGICAL CONSEQUENCES OF LOSING • CATECHOLAMINE SURGES (body color, nuchal crest erection, Greenberg et al. 1984) • NE LOWER RELATIVE TO WINNER (Summers & Greenberg 1994) • CORTICOSTERONE INCREASED (Greenberg et al. 1984) • MSH INCREASED (relative to winners, Greenberg, Chen, and Vaughan 1986) • SEROTONIN ACTIVITY INCREASED IN THE MIDBRAIN, HIND BRAIN (Summers & Greenberg 1995), HIPPOCAMPUS, AND NUCLEUS ACCUMBENS (Summers et al. 1998)

  20. LONG-TERM PHYSIOLOGICAL CONSEQUENCES OF LOSING • ANDROGEN REDUCED (Greenberg & Crews 1990) • CORTICOSTERONE ELEVATED (Greenberg et al. 1984) • MSH INCREASED (relative to dominants, Greenberg, Chen, and Vaughan 1986) • DOPAMINE ACTIVITY DIMINISHED, ADRENERGIC ACTIVITY ENHANCED IN THE MID AND HIND BRAIN (but back to control values by one month) (Summers & Greenberg 1995)

  21. EFFECTS of CORTICOSTERONE • CS-implanted A sagrei: reduced approach and aggression (Tokarz 1987) • CS-implanted Uta: reduced aggression even if implanted with testosterone(DeNardo & Licht 1993) • CS-implanted A carolinensis: initial agonistic responses vigorous but rapidly manifest submissiveness when adversary answers display (Greenberg unpubl pilot study)

  22. LIFE AS A SUBORDINATE • Many dominant/subordinate pairs stabilize and can maintain long-term relationship • Subordinates do not typically succumb to “diseases of adaptation” • Contribution from trophic MSH effects? • Contribution from androgen reduction?

  23. STRESS and the EVOLUTION of BEHAVIOR “In animals, almost invariably, a change in behavior is the crucial factor initiating evolutionary innovation” (Ernst Mayr 1988). Behavior creates new selective pressures (Mark Baldwin via Deacon 1998)

  24. Gradualism in Mental Powers • If no organic being excepting man had possessed any mental power, or if his powers had been of a wholly different nature from those of the lower animals, then we should never have been able to convince ourselves that our high faculties had been gradually developed. But it can be shewn that there is no fundamental difference of this kind. We must also admit that there is a much wider interval in mental power between one of the lowest fishes, as a lamprey or lancelet, and one of the higher apes, than between an ape and a man; yet this interval is filled up by numberless gradations. (Charles Darwin, 1871, p. 445)

  25. The Peacock’s Tail • raised by feather pilomotor muscles • an ancient autonomic theromregulatory mechanism • Ordinarily hidden • displayed when aroused

  26. The Lizard’s Flag • Effected by the hyoid apparatus • An ancient mechanism activated by stress • Ordinarily hidden • displayed when aroused

  27. STRESS and the EVOLUTION of BEHAVIOR The “Ritualization” of signals a model: fragments of motor patterns or autonomoic reflexesbecome temporally or spatially associated as an ensemble (Morris 1956, Hinde and Tinbergen 1958) The “Central Adaptation Syndrome”(Huether 1996). Controllable stressors lead to a “go and specialize” strategy (e.g., earlier recognition and avoidance, improved fighting strategies, refined submission behavior) Uncontrollable stressors lead to a “wait and reorganize” strategy (e.g., CS reorganization of neural circuits; tuning of learning, motivation, and emotional states)

  28. STRESS and the EVOLUTION of BEHAVIOR Stress-sensitive intersections of motivation, affect, and cognition are candidates for evolutionary change. Valence of affect : positive, cortical-limbic areas; negative, subcortical-limbic areas(Paradiso et al. 1999) note: male anoles with subcortical lesions act like castrates- they attend stimuli but are not motivated to respond aggressively (“social agnosia,” recalling autistic failure to recognize signals) Active versus passive copingparallel autonomic strategies correlated with activity in discrete columns of periaquaductal gray(Bandler et al. 2000)

  29. AN ASIDE on ACUTE & CHRONIC responses • BRIEF episodes of high stress may be tolerated , but if sufficiently intense, the THRESHOLD for future effects on the responsiveness and integrative mechanisms of the nervous system may be LOWER ( effects of hormones on INPUT, INTEGRATION, OUTPUT of the brain ; effectiveness of nonspecific stress and sex steroids in arousal and attention ) • REPEATED episodes of stress and the recovery time between episodes may be more potent than sustained stress. • TRANSITION from physiological response to structural changes to enable more efficient future response

  30. ENVOI, POSTLUDE Effectiveness of nonspecific stress and sex steroids in arousal and attention An appreciation for close ethological description and temporal resolution A sensitivity to comparative approach A need for field and laboratory mutual respect and reciprocity An understanding of differential effects in the brain Awareness of the potential for the multiple input, integration, and output options and pathways for evolutionary bricolage

  31. NERVOUS SYSTEM

  32. OVERVIEW: STRESS SUBCLINICAL STRESS Evoked by real or perceived challenge to meeting real or perceived needs Fine-tunes physiological and behavioral coping responses without evoking clinically challenging syndrome • BASAL GANGLIA Stereotyped behavior Social Agnosia

  33. An aside on subclincal stress

  34. OVERVIEW: DENIAL DENIAL • “Vital Lies” (Golman) • Freudian denial (to preserve ego) • Resolves cognitive dissonance (Festinger) • Phantom function: signals from motor cortex go to parietal monitoring area AND to muscles (that no longer exist). In the absence of feedback from muscles parietal area prevails • Right hemisphere impairment could mute emotionality, flatten affect, and lead to apparent indifference • Anososognosia

  35. AGNOSIA Agnosia: a loss of ability to recognize objects, persons, sounds, shapes, or smells; no sensory deficit, no memory loss. • Simultanagnosia: inability to recognize more than one object or detail in their visual field at a time (common symptom of Balint's syndrome) • Prosopagnosia: (aka facial agnosia; TMWMWH)) • Anosognosia: denial or unawareness of handicap (assoc w/ damage to nondominant (usually rt) cerebral hemisphere ( “disorder of belief”)

  36. SOCIAL AGNOSIA SOCIAL-EMOTIONAL AGNOSIA • right cerebral, or bilateral temporal and amygdala injury. An inability to correctly perceive or comprehend social-emotional nuances conveyed through voice, gesture, or facial expression (Joseph, 2000).

  37. ANOSOGNOSIA • from the Greek: A+nosos (disease) + gnosis (knowledge) --Described by Babinski in 1914 • “Unaware” of dysfunction • Diminished “insight” • “Ignorance or denial of the presence of disease Most famously of paralysis in patients with non-dominant (usually right) parietal lobe damage -- patients deny their hemiparesis, & confabulate rationalizations • Impaired right hemisphere appears unable to detect discrepancies between internal model and sensory feedback requiring patient to improvise, “hallucinate,” or confabulate left-side function.

  38. An aside on confabulation

  39. HOW IS BELIEF ESTABLISHED? • Empiricism and Reality-Testing • data-based, induction-driven • PERCEPT CORRESPONDS to reality • Rationalism and Story-Telling • theory-based, deduction-driven • PERCEPTS COHERE with each other

  40. BELIEF Belief is the psychological state in which an individual is more-or-less confident in the validity of a proposition. (confidence can translate into biological fitness) Validity can be more-or-less • internal (limited generalizability; eg, individual) or • external(broad generalizablity; eg, population)

  41. BELIEF

  42. LEFT - RIGHT HEMISPHERE LATERALITY • When separated, EACH hemisphere is UNAWARE of the ipsilateral world • Yet neither is aware of being incomplete • Each functions as best it can with the information available

  43. LEFT HEMISPHERE Coherence: creates a consistent belief system – works to “save appearances” (Ramachandran 1998) Probabilistic reasoning (Osherson et al 1998) Abstract object recognition (Marsolek 1999) Activated by familiar percepts (Goldberg 2001) RIGHT HEMISPHERE Correspondence: “skeptical,” tests reality and if damaged, confabulation runs rampant (Ramachandran 1998) Deductive reasoning (Osherson et al 1998) Specific object recognition (Marsolek 1999) Activated by unfamiliar percepts (Goldberg 2001)

  44. DEEP TRUTH STRESS RESPONSES are evoked by REAL or PERCEIVED challenges to an organism’s ability to meet its needs SUBCLINCAL STRESSis evoked by modest challenges to homeostasis, including COGNITIVE DISSONANCE, an apparent mismatch between internal perceptions and external reality; challenges to the narrative that confers biologically valuable confidence.

  45. DISORDERS of BELIEF? Acceptance of experience that doesn’t correspond to external reality:kinds of hallucinations, Bonnet’s Syndrome(filling in scotoma),dismorphic body (False positive (confident match with memories); Type I Error)) Denial of experience that corresponds to external reality: agnosias: eg, visual(left occip), associative, anasognosia(denial of dysfunction / right cerebral cortices), prosopagnosia(faces) (False negative (failure to match with memories); Type II Error))

  46. THE EVOLUTIONARY BIOLOGY of BELIEFtesting and organizing percepts The philosophical constructs of correspondence and coherence may have cerebral representation: there are neurobehavioral mechanisms to establish the validity of an experience by means of: REALITY TESTING confirming validity of a percept and ORGANIZING validated percepts into a narrative (“theorizing”) The mechanisms are emphasized in the RIGHT and LEFT hemispheres, respectively, and must work together to derive the fullest possible understanding.

  47. OVERVIEW • BASAL GANGLIA • Stereotyped behavior • Social Agnosia • AGNOSIA • Paths to knowledge: Correspondence and coherence components of knowledge • Anosognosia (acquired “lack of insight” can lead to denial) • BELIEF • How do we know? Disorders of belief

More Related