1 5310 73 PSYCHOBIOLOGY AND MOLECULAR GENETICS OF RESILIENCE. EVERY INDIVIDUAL EXPERIENCES STRESSFUL LIFE EVENTS. IN SOME CASES ACUTE OR CHRONIC STRESS LEADS TO DEPRESSION AND OTHER PSYCHIATRIC DISORDERS, BUT MOST PEOPLE ARE RESILIENT TO SUCH EFFECTS. RECENT RESEARCH HAS BEGUN TO IDENTIFY THE ENVIRONMENTAL, GENETIC, EPIGENETIC AND NEURAL MECHANISMS THAT UNDERLIE RESILIENCE, AND HAS SHOWN THAT RESILIENCE IS MEDIATED BY ADAPTIVE CHANGES IN SEVERAL NEURAL CIRCUITS INVOLVING NUMEROUS NEUROTRANSMITTER AND MOLECULAR PATHWAYS. THESE CHANGES SHAPE THE FUNCTIONING OF THE NEURAL CIRCUITS THAT REGULATE REWARD, FEAR, EMOTION REACTIVITY AND SOCIAL BEHAVIOUR, WHICH TOGETHER ARE THOUGHT TO MEDIATE SUCCESSFUL COPING WITH STRESS. 2009 2 3092 24 GENOMIC AND EPIGENOMIC MECHANISMS OF GLUCOCORTICOIDS IN THE BRAIN. FOLLOWING THE DISCOVERY OF GLUCOCORTICOID RECEPTORS IN THE HIPPOCAMPUS AND OTHER BRAIN REGIONS, RESEARCH HAS FOCUSED ON UNDERSTANDING THE EFFECTS OF GLUCOCORTICOIDS IN THE BRAIN AND THEIR ROLE IN REGULATING EMOTION AND COGNITION. GLUCOCORTICOIDS ARE ESSENTIAL FOR ADAPTATION TO STRESSORS (ALLOSTASIS) AND IN MALADAPTATION RESULTING FROM ALLOSTATIC LOAD AND OVERLOAD. ALLOSTATIC OVERLOAD, WHICH CAN OCCUR DURING CHRONIC STRESS, CAN RESHAPE THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS THROUGH EPIGENETIC MODIFICATION OF GENES IN THE HIPPOCAMPUS, HYPOTHALAMUS AND OTHER STRESS-RESPONSIVE BRAIN REGIONS. GLUCOCORTICOIDS EXERT THEIR EFFECTS ON THE BRAIN THROUGH GENOMIC MECHANISMS THAT INVOLVE BOTH GLUCOCORTICOID RECEPTORS AND MINERALOCORTICOID RECEPTORS DIRECTLY BINDING TO DNA, AS WELL AS BY NON-GENOMIC MECHANISMS. FURTHERMORE, GLUCOCORTICOIDS SYNERGIZE BOTH GENOMICALLY AND NON-GENOMICALLY WITH NEUROTRANSMITTERS, NEUROTROPHIC FACTORS, SEX HORMONES AND OTHER STRESS MEDIATORS TO SHAPE AN ORGANISM'S PRESENT AND FUTURE RESPONSES TO A STRESSFUL ENVIRONMENT. HERE, WE DISCUSS THE MECHANISMS OF GLUCOCORTICOID ACTION IN THE BRAIN AND REVIEW HOW GLUCOCORTICOIDS INTERACT WITH STRESS MEDIATORS IN THE CONTEXT OF ALLOSTASIS, ALLOSTATIC LOAD AND STRESS-INDUCED NEUROPLASTICITY. 2017 3 23 33 60 YEARS OF NEUROENDOCRINOLOGY: REDEFINING NEUROENDOCRINOLOGY: STRESS, SEX AND COGNITIVE AND EMOTIONAL REGULATION. THE DISCOVERY OF STEROID HORMONE RECEPTORS IN BRAIN REGIONS THAT MEDIATE EVERY ASPECT OF BRAIN FUNCTION HAS BROADENED THE DEFINITION OF 'NEUROENDOCRINOLOGY' TO INCLUDE THE RECIPROCAL COMMUNICATION BETWEEN THE BRAIN AND THE BODY VIA HORMONAL AND NEURAL PATHWAYS. THE BRAIN IS THE CENTRAL ORGAN OF STRESS AND ADAPTATION TO STRESS BECAUSE IT PERCEIVES AND DETERMINES WHAT IS THREATENING, AS WELL AS THE BEHAVIORAL AND PHYSIOLOGICAL RESPONSES TO THE STRESSOR. THE ADULT AND DEVELOPING BRAIN POSSESS REMARKABLE STRUCTURAL AND FUNCTIONAL PLASTICITY IN RESPONSE TO STRESS, INCLUDING NEURONAL REPLACEMENT, DENDRITIC REMODELING, AND SYNAPSE TURNOVER. STRESS CAUSES AN IMBALANCE OF NEURAL CIRCUITRY SUBSERVING COGNITION, DECISION-MAKING, ANXIETY AND MOOD THAT CAN ALTER EXPRESSION OF THOSE BEHAVIORS AND BEHAVIORAL STATES. THIS IMBALANCE, IN TURN, AFFECTS SYSTEMIC PHYSIOLOGY VIA NEUROENDOCRINE, AUTONOMIC, IMMUNE AND METABOLIC MEDIATORS. IN THE SHORT TERM, AS FOR INCREASED FEARFUL VIGILANCE AND ANXIETY IN A THREATENING ENVIRONMENT, THESE CHANGES MAY BE ADAPTIVE. BUT, IF THE DANGER PASSES AND THE BEHAVIORAL STATE PERSISTS ALONG WITH THE CHANGES IN NEURAL CIRCUITRY, SUCH MALADAPTATION MAY NEED INTERVENTION WITH A COMBINATION OF PHARMACOLOGICAL AND BEHAVIORAL THERAPIES, AS IS THE CASE FOR CHRONIC ANXIETY AND DEPRESSION. THERE ARE IMPORTANT SEX DIFFERENCES IN THE BRAIN RESPONSES TO STRESSORS THAT ARE IN URGENT NEED OF FURTHER EXPLORATION. MOREOVER, ADVERSE EARLY-LIFE EXPERIENCE, INTERACTING WITH ALLELES OF CERTAIN GENES, PRODUCE LASTING EFFECTS ON BRAIN AND BODY OVER THE LIFE-COURSE VIA EPIGENETIC MECHANISMS. WHILE PREVENTION IS MOST IMPORTANT, THE PLASTICITY OF THE BRAIN GIVES HOPE FOR THERAPIES THAT TAKE INTO CONSIDERATION BRAIN-BODY INTERACTIONS. 2015 4 235 21 ADDING FUEL TO THE FIRE: THE IMPACT OF STRESS ON THE AGEING BRAIN. BOTH AGEING AND CHRONIC STRESS ARE ASSOCIATED WITH ALTERED BRAIN PLASTICITY, DYSREGULATION OF THE IMMUNE SYSTEM, AND AN INCREASED RISK OF DEVELOPING BRAIN DISORDERS; ALL OF WHICH HAVE CONSEQUENCES FOR COGNITIVE AND EMOTIONAL PROCESSING. HERE WE EXAMINE THE SIMILARITIES BETWEEN BEHAVIOURAL CHANGES DURING AGEING AND STRESS ALTERED BEHAVIOURS (ANXIETY, DEPRESSIVE-LIKE BEHAVIOUR, COGNITION, AND SOCIABILITY) IN RODENTS AND HUMANS. THE MOLECULAR MECHANISMS HYPOTHESISED TO MEDIATE AGE-RELATED CHANGES IN BRAIN FUNCTION INCLUDING DYSFUNCTION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS, DYSREGULATION OF NEUROTRANSMISSION AND NEUROTROPHIC FACTOR SIGNALLING, INCREASED INFLAMMATORY STATE, GENETIC AND EPIGENETIC CHANGES, OXIDATIVE STRESS, METABOLIC CHANGES, AND CHANGES IN THE MICROBIOTA-GUT-BRAIN AXIS ARE DISCUSSED. FINALLY, WE EXPLORE HOW THE ALREADY STRESSED AGED BRAIN PSYCHOLOGICALLY AND PHYSIOLOGICALLY RESPONDS TO EXTERNAL STRESSORS. 2015 5 4621 30 NEUROBIOLOGICAL AND SYSTEMIC EFFECTS OF CHRONIC STRESS. THE BRAIN IS THE CENTRAL ORGAN OF STRESS AND ADAPTATION TO STRESS BECAUSE IT PERCEIVES AND DETERMINES WHAT IS THREATENING, AS WELL AS THE BEHAVIORAL AND PHYSIOLOGICAL RESPONSES TO THE STRESSOR, WHICH PROMOTE ADAPTATION ("ALLOSTASIS") BUT ALSO CONTRIBUTE TO PATHOPHYSIOLOGY ("ALLOSTATIC LOAD/OVERLOAD") WHEN OVERUSED AND DYSREGULATED. THE ADULT AS WELL AS DEVELOPING BRAIN POSSESSES A REMARKABLE ABILITY TO SHOW STRUCTURAL AND FUNCTIONAL PLASTICITY IN RESPONSE TO STRESSFUL AND OTHER EXPERIENCES, INCLUDING NEURONAL REPLACEMENT, DENDRITIC REMODELING AND SYNAPSE TURNOVER. STRESS CAN CAUSE AN IMBALANCE OF NEURAL CIRCUITRY SUBSERVING COGNITION, DECISION MAKING, ANXIETY AND MOOD THAT CAN INCREASE OR DECREASE EXPRESSION OF THOSE BEHAVIORS AND BEHAVIORAL STATES. THIS IMBALANCE, IN TURN, AFFECTS SYSTEMIC PHYSIOLOGY VIA NEUROENDOCRINE, AUTONOMIC, IMMUNE AND METABOLIC MEDIATORS. IN THE SHORT TERM, THESE CHANGES MAY BE ADAPTIVE; BUT, IF THE THREAT PASSES AND THE BEHAVIORAL STATE PERSISTS ALONG WITH THE CHANGES IN NEURAL CIRCUITRY, SUCH MALADAPTATION REQUIRES INTERVENTION WITH A COMBINATION OF PHARMACOLOGICAL AND BEHAVIORAL THERAPIES. THERE ARE IMPORTANT SEX DIFFERENCES IN HOW THE BRAIN RESPONDS TO STRESSORS. MOREOVER, ADVERSE EARLY LIFE EXPERIENCE, INTERACTING WITH ALLELES OF CERTAIN GENES, PRODUCES LASTING EFFECTS ON BRAIN AND BODY VIA EPIGENETIC MECHANISMS. WHILE PREVENTION IS KEY, THE PLASTICITY OF THE BRAIN GIVES HOPE FOR THERAPIES THAT UTILIZE BRAIN-BODY INTERACTIONS. POLICIES OF GOVERNMENT AND THE PRIVATE SECTOR ARE IMPORTANT TO PROMOTE HEALTH AND INCREASE "HEALTHSPAN." 2017 6 5812 36 STRESS AND ANXIETY: STRUCTURAL PLASTICITY AND EPIGENETIC REGULATION AS A CONSEQUENCE OF STRESS. THE BRAIN IS THE CENTRAL ORGAN OF STRESS AND ADAPTATION TO STRESS BECAUSE IT PERCEIVES AND DETERMINES WHAT IS THREATENING, AS WELL AS THE BEHAVIORAL AND PHYSIOLOGICAL RESPONSES TO THE STRESSOR. THE ADULT, AS WELL AS DEVELOPING BRAIN, POSSESS A REMARKABLE ABILITY TO SHOW REVERSIBLE STRUCTURAL AND FUNCTIONAL PLASTICITY IN RESPONSE TO STRESSFUL AND OTHER EXPERIENCES, INCLUDING NEURONAL REPLACEMENT, DENDRITIC REMODELING, AND SYNAPSE TURNOVER. THIS IS PARTICULARLY EVIDENT IN THE HIPPOCAMPUS, WHERE ALL THREE TYPES OF STRUCTURAL PLASTICITY HAVE BEEN RECOGNIZED AND INVESTIGATED, USING A COMBINATION OF MORPHOLOGICAL, MOLECULAR, PHARMACOLOGICAL, ELECTROPHYSIOLOGICAL AND BEHAVIORAL APPROACHES. THE AMYGDALA AND THE PREFRONTAL CORTEX, BRAIN REGIONS INVOLVED IN ANXIETY AND FEAR, MOOD, COGNITIVE FUNCTION AND BEHAVIORAL CONTROL, ALSO SHOW STRUCTURAL PLASTICITY. ACUTE AND CHRONIC STRESS CAUSE AN IMBALANCE OF NEURAL CIRCUITRY SUBSERVING COGNITION, DECISION MAKING, ANXIETY AND MOOD THAT CAN INCREASE OR DECREASE EXPRESSION OF THOSE BEHAVIORS AND BEHAVIORAL STATES. IN THE SHORT TERM, SUCH AS FOR INCREASED FEARFUL VIGILANCE AND ANXIETY IN A THREATENING ENVIRONMENT, THESE CHANGES MAY BE ADAPTIVE; BUT, IF THE DANGER PASSES AND THE BEHAVIORAL STATE PERSISTS ALONG WITH THE CHANGES IN NEURAL CIRCUITRY, SUCH MALADAPTATION MAY NEED INTERVENTION WITH A COMBINATION OF PHARMACOLOGICAL AND BEHAVIORAL THERAPIES, AS IS THE CASE FOR CHRONIC OR MOOD ANXIETY DISORDERS. WE SHALL REVIEW CELLULAR AND MOLECULAR MECHANISMS, AS WELL AS RECENT WORK ON INDIVIDUAL DIFFERENCES IN ANXIETY-LIKE BEHAVIOR AND ALSO DEVELOPMENTAL INFLUENCES THAT BIAS HOW THE BRAIN RESPONDS TO STRESSORS. FINALLY, WE SUGGEST THAT SUCH AN APPROACH NEEDS TO BE EXTENDED TO OTHER BRAIN AREAS THAT ARE ALSO INVOLVED IN ANXIETY AND MOOD. THIS ARTICLE IS PART OF A SPECIAL ISSUE ENTITLED 'ANXIETY AND DEPRESSION'. 2012 7 6912 25 [UNDERSTANDING OF THE PSYCHIATRY IN PALLIATIVE CARE: DYSFUNCTION OF THE REWARDING SYSTEM UNDER THE PAIN STATE ASSOCIATED WITH EXACERBATING PAIN]. RECENT HUMAN BRAIN IMAGING STUDIES HAVE EXAMINED DIFFERENCES IN ACTIVITY IN THE NUCLEUS ACCUMBENS (N.ACC.) IN RESPONSE TO HEAT STIMULI BETWEEN CONTROLS AND PATIENTS WITH CHRONIC PAIN, AND HAVE REVEALED THAT THE N.ACC. PLAYS A ROLE IN PREDICTING THE VALUE OF A NOXIOUS STIMULUS AND ITS OFFSET, AND IN THE CONSEQUENT CHANGES IN THE MOTIVATIONAL STATE. NEVERTHELESS, THE MOLECULAR MECHANISMS OF CHANGE IN THE CIRCUITRY INVOLVED IN EMOTION AND MOTIVATION IN RESPONSE TO CHRONIC PAIN STIMULI WERE NOT FULLY EXPLORED. ON THE OTHER HAND, IT HAS BEEN CONSIDERED THAT MICRO RNAS (MIRNAS) PLAY IMPORTANT ROLES AS KEY MODULATORS OF POST-TRANSCRIPTIONAL GENE EXPRESSION. WE HAVE REPORTED THAT CHANGES IN MIRNAS ARE ASSOCIATED WITH PREDICTED CHANGES IN GENE EXPRESSION OF CANDIDATE TARGETS IN THE N.ACC. UNDER NEUROPATHIC PAIN. THEREFORE, WE HAVE INTRODUCED A NEW INSIGHT INTO AN EPIGENETIC DYSFUNCTION OF "MESOLIMBIC MOTIVATION/VALUATION CIRCUITRY" UNDER A NEUROPATHIC PAIN-LIKE STATE. THESE FINDINGS RAISE INTRIGUING POSSIBILITIES THAT MIRNA-MODULATING CELLULAR EVENTS ALONG WITH EPIGENETIC MODIFICATIONS MAY BE ASSOCIATED WITH NEURAL PLASTICITY AND NEURONAL ADAPTIVE RESPONSES IN MESOLIMBIC MOTIVATION/VALUATION CIRCUITRY UNDER WHICH THE NEUROPATHIC PAIN MAY INDUCE NEGATIVE EMOTIONS, EXACERBATING PAIN. 2013 8 2770 27 EXTENDING INJURY- AND DISEASE-RESISTANT CNS PHENOTYPES BY REPETITIVE EPIGENETIC CONDITIONING. SIGNIFICANT REDUCTIONS IN THE EXTENT OF ACUTE INJURY IN THE CNS CAN BE ACHIEVED BY EXPOSURE TO DIFFERENT PRECONDITIONING STIMULI, BUT THE DURATION OF THE INDUCED PROTECTIVE PHENOTYPE IS TYPICALLY SHORT-LASTING, AND THUS IS DEEMED AS LIMITING ITS CLINICAL APPLICABILITY. EXTENDING THE PERIOD OVER WHICH SUCH ADAPTIVE EPIGENETIC CHANGES PERSIST - IN EFFECT, EXPANDING CONDITIONING'S "THERAPEUTIC WINDOW" - WOULD SIGNIFICANTLY BROADEN THE POTENTIAL APPLICATIONS OF SUCH A TREATMENT APPROACH IN PATIENTS. THE FREQUENCY OF THE CONDITIONING STIMULUS MAY HOLD THE KEY. WHILE TRANSIENT (1-3 DAYS) PROTECTION AGAINST CNS ISCHEMIC INJURY IS WELL ESTABLISHED PRECLINICALLY FOLLOWING A SINGLE PRECONDITIONING STIMULUS, REPETITIVELY PRESENTING PRECONDITIONING STIMULI EXTENDS THE DURATION OF ISCHEMIC TOLERANCE BY MANY WEEKS. MOREOVER, REPETITIVE INTERMITTENT POSTCONDITIONING ENHANCES POST-ISCHEMIC RECOVERY METRICS AND IMPROVES LONG-TERM SURVIVAL. INTERMITTENT CONDITIONING IS ALSO EFFICACIOUS FOR PREVENTING OR DELAYING INJURY IN PRECLINICAL MODELS OF CHRONIC NEURODEGENERATIVE DISEASE, AND FOR PROMOTING LONG-LASTING FUNCTIONAL IMPROVEMENTS IN A NUMBER OF OTHER PATHOLOGIES AS WELL. ALTHOUGH THE DETAILED MECHANISMS UNDERLYING THESE PROTRACTED KINDS OF NEUROPLASTICITY REMAIN LARGELY UNSTUDIED, ACCUMULATING EMPIRICAL EVIDENCE SUPPORTS THE CONTENTION THAT ALL OF THESE ADAPTIVE PHENOTYPES ARE EPIGENETICALLY MEDIATED. GOING FORWARD, ADDITIONAL PRECLINICAL DEMONSTRATIONS OF THE ABILITY TO INDUCE SUSTAINED BENEFICIAL PHENOTYPES THAT REDUCE THE BURDEN OF ACUTE AND CHRONIC NEURODEGENERATION, AND EXPERIMENTAL INTERROGATIONS OF THE REGULATORY CONSTRUCTS RESPONSIBLE FOR THESE EPIGENETIC RESPONSES, WILL ACCELERATE THE IDENTIFICATION OF NOT ONLY EFFICACIOUS BUT ALSO PRACTICAL, ADAPTIVE EPIGENETICS-BASED TREATMENTS FOR INDIVIDUALS WITH NEUROLOGICAL DISEASE. 2015 9 1877 18 EMERGING ROLES OF EPIGENETIC MECHANISMS IN THE ENDURING EFFECTS OF EARLY-LIFE STRESS AND EXPERIENCE ON LEARNING AND MEMORY. EPIGENETIC MECHANISMS ARE INVOLVED IN PROGRAMMING GENE EXPRESSION THROUGHOUT DEVELOPMENT. IN ADDITION, THEY ARE KEY CONTRIBUTORS TO THE PROCESSES BY WHICH EARLY-LIFE EXPERIENCE FINE-TUNES THE EXPRESSION LEVELS OF KEY NEURONAL GENES, GOVERNING LEARNING AND MEMORY THROUGHOUT LIFE. HERE WE DESCRIBE THE LONG-LASTING, BI-DIRECTIONAL EFFECTS OF EARLY-LIFE EXPERIENCE ON LEARNING AND MEMORY. WE DISCUSS HOW ENRICHED POSTNATAL EXPERIENCE ENDURINGLY AUGMENTS SPATIAL LEARNING, AND HOW CHRONIC EARLY-LIFE STRESS RESULTS IN PERSISTENT AND PROGRESSIVE DEFICITS IN THE STRUCTURE AND FUNCTION OF HIPPOCAMPAL NEURONS. THE EXISTING AND EMERGING ROLES OF EPIGENETIC MECHANISMS IN THESE FUNDAMENTAL NEUROPLASTICITY PHENOMENA ARE ILLUSTRATED. 2011 10 3463 26 HYPOTHALAMIC-PITUITARY-ADRENAL AND HYPOTHALAMIC-PITUITARY-GONADAL AXES: SEX DIFFERENCES IN REGULATION OF STRESS RESPONSIVITY. GONADAL HORMONES PLAY A KEY ROLE IN THE ESTABLISHMENT, ACTIVATION, AND REGULATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS. BY INFLUENCING THE RESPONSE AND SENSITIVITY TO RELEASING FACTORS, NEUROTRANSMITTERS, AND HORMONES, GONADAL STEROIDS HELP ORCHESTRATE THE GAIN OF THE HPA AXIS TO FINE-TUNE THE LEVELS OF STRESS HORMONES IN THE GENERAL CIRCULATION. FROM EARLY LIFE TO ADULTHOOD, GONADAL STEROIDS CAN DIFFERENTIALLY AFFECT THE HPA AXIS, RESULTING IN SEX DIFFERENCES IN THE RESPONSIVITY OF THIS AXIS. THE HPA AXIS INFLUENCES MANY PHYSIOLOGICAL FUNCTIONS MAKING AN ORGANISM'S RESPONSE TO CHANGES IN THE ENVIRONMENT APPROPRIATE FOR ITS REPRODUCTIVE STATUS. ALTHOUGH THE ACUTE HPA RESPONSE TO STRESSORS IS A BENEFICIAL RESPONSE, CONSTANT ACTIVATION OF THIS CIRCUITRY BY CHRONIC OR TRAUMATIC STRESSFUL EPISODES MAY LEAD TO A DYSREGULATION OF THE HPA AXIS AND CAUSE PATHOLOGY. COMPARED TO MALES, FEMALE MICE AND RATS SHOW A MORE ROBUST HPA AXIS RESPONSE, AS A RESULT OF CIRCULATING ESTRADIOL LEVELS WHICH ELEVATE STRESS HORMONE LEVELS DURING NON-THREATENING SITUATIONS, AND DURING AND AFTER STRESSORS. FLUCTUATING LEVELS OF GONADAL STEROIDS IN FEMALES ACROSS THE ESTROUS CYCLE ARE A MAJOR FACTOR CONTRIBUTING TO SEX DIFFERENCES IN THE ROBUSTNESS OF HPA ACTIVITY IN FEMALES COMPARED TO MALES. MOREOVER, GONADAL STEROIDS MAY ALSO CONTRIBUTE TO EPIGENETIC AND ORGANIZATIONAL INFLUENCES ON THE HPA AXIS EVEN BEFORE PUBERTY. CORRESPONDINGLY, CROSSTALK BETWEEN THE HYPOTHALAMIC-PITUITARY-GONADAL (HPG) AND HPA AXES COULD LEAD TO ABNORMALITIES OF STRESS RESPONSES. IN HUMANS, A DYSREGULATED STRESS RESPONSE IS ONE OF THE MOST COMMON SYMPTOMS SEEN ACROSS MANY NEUROPSYCHIATRIC DISORDERS, AND AS A RESULT, SUCH INTERACTIONS MAY EXACERBATE PERIPHERAL PATHOLOGIES. IN THIS REVIEW, WE DISCUSS THE HPA AND HPG AXES AND REVIEW HOW GONADAL STEROIDS INTERACT WITH THE HPA AXIS TO REGULATE THE STRESS CIRCUITRY DURING ALL STAGES IN LIFE. 2017 11 1774 22 EARLY-LIFE STRESS: FROM NEUROENDOCRINE MECHANISMS TO STRESS-RELATED DISORDERS. STRESS EXPOSURE IS HIGHLY PREVALENT IN THE GENERAL POPULATION; HOWEVER, THE EXPERIENCE OF STRESS DURING VULNERABLE PERIODS OF DEVELOPMENT HAS SUBSTANTIAL AND PERMANENT EFFECTS ON BRAIN STRUCTURE AND FUNCTION AND PHYSICAL HEALTH IN ADULTHOOD. STRESS, THE STATE OF THREATENED HOMEOSTASIS, IS GENERALLY ASSOCIATED WITH A TIME-LIMITED ACTIVATION OF THE STRESS SYSTEM, I.E., THE HYPOTHALAMIC-PITUITARY-ADRENAL AXIS AND THE AROUSAL/SYMPATHETIC NERVOUS SYSTEM, TAILORED TO THE STRESSFUL STIMULUS ALSO KNOWN AS THE STRESSOR. ON THE OTHER HAND, CHRONIC STRESS MAY BE ASSOCIATED WITH LINGERING HYPER- OR HYPOSECRETION OF MEDIATORS OF THE STRESS SYSTEM. THIS CHRONIC CONDITION IS CALLED DYSHOMEOSTASIS, ALLOSTASIS, OR CACOSTASIS AND IS ASSOCIATED WITH INCREASED MENTAL AND PHYSICAL MORBIDITY IN THE LONG TERM. STRESSFUL OR TRAUMATIC EXPERIENCES DURING FETAL LIFE, EARLY CHILDHOOD, AND ADOLESCENCE HAVE BEEN RELATED TO PERSISTENT NEUROENDOCRINE AND EPIGENETIC CHANGES. FURTHER, BRAIN STRUCTURES INVOLVED IN THE STRESS RESPONSE, SUCH AS THOSE OF THE STRESS SYSTEM, THE HIPPOCAMPUS, AND THE AMYGDALA, MAY BE PROGRAMMED EARLY ON FOR A LIFE OF ADVERSITY. 2018 12 800 21 CELLULAR, MOLECULAR, AND EPIGENETIC MECHANISMS IN NON-ASSOCIATIVE CONDITIONING: IMPLICATIONS FOR PAIN AND MEMORY. SENSITIZATION IS A FORM OF NON-ASSOCIATIVE CONDITIONING IN WHICH AMPLIFICATION OF BEHAVIORAL RESPONSES CAN OCCUR FOLLOWING PRESENTATION OF AN AVERSIVE OR NOXIOUS STIMULUS. UNDERSTANDING THE CELLULAR AND MOLECULAR UNDERPINNINGS OF SENSITIZATION HAS BEEN AN OVERARCHING THEME SPANNING THE FIELD OF LEARNING AND MEMORY AS WELL AS THAT OF PAIN RESEARCH. IN THIS REVIEW WE EXAMINE HOW SENSITIZATION, BOTH IN THE CONTEXT OF LEARNING AS WELL AS PAIN PROCESSING, SHARES EVOLUTIONARILY CONSERVED BEHAVIORAL, CELLULAR/SYNAPTIC, AND EPIGENETIC MECHANISMS ACROSS PHYLA. FIRST, WE CHARACTERIZE THE BEHAVIORAL PHENOMENON OF SENSITIZATION BOTH IN INVERTEBRATES AND VERTEBRATES. PARTICULAR EMPHASIS IS PLACED ON LONG-TERM SENSITIZATION (LTS) OF WITHDRAWAL REFLEXES IN APLYSIA FOLLOWING AVERSIVE STIMULATION OR INJURY, ALTHOUGH ADDITIONAL INVERTEBRATE MODELS ARE ALSO COVERED. IN THE CONTEXT OF VERTEBRATES, SENSITIZATION OF MAMMALIAN HYPERAROUSAL IN A MODEL OF POST-TRAUMATIC STRESS DISORDER (PTSD), AS WELL AS MAMMALIAN MODELS OF INFLAMMATORY AND NEUROPATHIC PAIN IS CHARACTERIZED. SECOND, WE INVESTIGATE THE CELLULAR AND SYNAPTIC MECHANISMS UNDERLYING THESE BEHAVIORS. WE FOCUS OUR DISCUSSION ON SEROTONIN-MEDIATED LONG-TERM FACILITATION (LTF) AND AXOTOMY-MEDIATED LONG-TERM HYPEREXCITABILITY (LTH) IN REDUCED APLYSIA SYSTEMS, AS WELL AS MAMMALIAN SPINAL PLASTICITY MECHANISMS OF CENTRAL SENSITIZATION. THIRD, WE EXPLORE RECENT EVIDENCE IMPLICATING EPIGENETIC MECHANISMS IN LEARNING- AND PAIN-RELATED SENSITIZATION. THIS REVIEW ILLUSTRATES THE FUNDAMENTAL AND FUNCTIONAL OVERLAY OF THE LEARNING AND MEMORY FIELD WITH THE PAIN FIELD WHICH ARGUES FOR HOMOLOGOUS PERSISTENT PLASTICITY MECHANISMS IN RESPONSE TO SENSITIZING STIMULI OR INJURY ACROSS PHYLA. 2013 13 6626 33 UNDERSTANDING RESILIENCE. RESILIENCE IS THE ABILITY TO ADAPT SUCCESSFULLY IN THE FACE OF STRESS AND ADVERSITY. STRESSFUL LIFE EVENTS, TRAUMA, AND CHRONIC ADVERSITY CAN HAVE A SUBSTANTIAL IMPACT ON BRAIN FUNCTION AND STRUCTURE, AND CAN RESULT IN THE DEVELOPMENT OF POSTTRAUMATIC STRESS DISORDER (PTSD), DEPRESSION AND OTHER PSYCHIATRIC DISORDERS. HOWEVER, MOST INDIVIDUALS DO NOT DEVELOP SUCH ILLNESSES AFTER EXPERIENCING STRESSFUL LIFE EVENTS, AND ARE THUS THOUGHT TO BE RESILIENT. RESILIENCE AS SUCCESSFUL ADAPTATION RELIES ON EFFECTIVE RESPONSES TO ENVIRONMENTAL CHALLENGES AND ULTIMATE RESISTANCE TO THE DELETERIOUS EFFECTS OF STRESS, THEREFORE A GREATER UNDERSTANDING OF THE FACTORS THAT PROMOTE SUCH EFFECTS IS OF GREAT RELEVANCE. THIS REVIEW FOCUSES ON RECENT FINDINGS REGARDING GENETIC, EPIGENETIC, DEVELOPMENTAL, PSYCHOSOCIAL, AND NEUROCHEMICAL FACTORS THAT ARE CONSIDERED ESSENTIAL CONTRIBUTORS TO THE DEVELOPMENT OF RESILIENCE. NEURAL CIRCUITS AND PATHWAYS INVOLVED IN MEDIATING RESILIENCE ARE ALSO DISCUSSED. THE GROWING UNDERSTANDING OF RESILIENCE FACTORS WILL HOPEFULLY LEAD TO THE DEVELOPMENT OF NEW PHARMACOLOGICAL AND PSYCHOLOGICAL INTERVENTIONS FOR ENHANCING RESILIENCE AND MITIGATING THE UNTOWARD CONSEQUENCES. 2013 14 4633 28 NEUROIMMUNE ACTIVATION DRIVES MULTIPLE BRAIN STATES. NEUROIMMUNE SIGNALING IS INCREASINGLY IDENTIFIED AS A CRITICAL COMPONENT OF NEURONAL PROCESSES UNDERLYING MEMORY, EMOTION AND COGNITION. THE INTERACTIONS OF MICROGLIA AND ASTROCYTES WITH NEURONS AND SYNAPSES, AND THE INDIVIDUAL CYTOKINES AND IMMUNE SIGNALING MOLECULES THAT MEDIATE THESE INTERACTIONS ARE A CURRENT FOCUS OF MUCH RESEARCH. HERE, WE DISCUSS NEUROIMMUNE ACTIVATION AS A MECHANISM TRIGGERING DIFFERENT STATES THAT MODULATE COGNITIVE AND AFFECTIVE PROCESSES TO ALLOW FOR APPROPRIATE BEHAVIOR DURING AND AFTER ILLNESS OR INJURY. WE PROPOSE THAT THESE STATES LIE ON A CONTINUUM FROM A NAIVE HOMEOSTATIC BASELINE STATE IN THE ABSENCE OF STIMULATION, TO ACUTE NEUROIMMUNE ACTIVITY AND CHRONIC ACTIVATION. IMPORTANTLY, CONSEQUENCES OF ILLNESS OR INJURY INCLUDING COGNITIVE DEFICITS AND MOOD IMPAIRMENTS CAN PERSIST LONG AFTER RESOLUTION OF IMMUNE SIGNALING. THIS SUGGESTS THAT NEUROIMMUNE ACTIVATION ALSO RESULTS IN AN ENDURING SHIFT IN THE HOMEOSTATIC BASELINE STATE WITH LONG LASTING CONSEQUENCES FOR NEURAL FUNCTION AND BEHAVIOR. SUCH DIFFERENT STATES CAN BE IDENTIFIED IN A MULTIDIMENSIONAL WAY, USING PATTERNS OF CYTOKINE AND GLIAL ACTIVATION, BEHAVIORAL AND COGNITIVE CHANGES, AND EPIGENETIC SIGNATURES. IDENTIFYING DISTINCT NEUROIMMUNE STATES AND THEIR CONSEQUENCES FOR NEURAL FUNCTION WILL PROVIDE A FRAMEWORK FOR PREDICTING VULNERABILITY TO DISORDERS OF MEMORY, COGNITION AND EMOTION BOTH DURING AND LONG AFTER RECOVERY FROM ILLNESS. 2018 15 2269 29 EPIGENETIC PROGRAMMING OF THE NEUROENDOCRINE STRESS RESPONSE BY ADULT LIFE STRESS. THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS IS CRITICALLY INVOLVED IN THE NEUROENDOCRINE REGULATION OF STRESS ADAPTATION, AND THE RESTORATION OF HOMEOSTASIS FOLLOWING STRESS EXPOSURE. DYSREGULATION OF THIS AXIS IS ASSOCIATED WITH STRESS-RELATED PATHOLOGIES LIKE MAJOR DEPRESSIVE DISORDER, POST-TRAUMATIC STRESS DISORDER, PANIC DISORDER AND CHRONIC ANXIETY. IT HAS LONG BEEN UNDERSTOOD THAT STRESS DURING EARLY LIFE CAN HAVE A SIGNIFICANT LASTING INFLUENCE ON THE DEVELOPMENT OF THE NEUROENDOCRINE SYSTEM AND ITS NEURAL REGULATORS, PARTIALLY BY MODIFYING EPIGENETIC REGULATION OF GENE EXPRESSION, WITH IMPLICATIONS FOR HEALTH AND WELL-BEING IN LATER LIFE. EVIDENCE IS ACCUMULATING THAT EPIGENETIC PLASTICITY ALSO EXTENDS TO ADULTHOOD, PROPOSING IT AS A MECHANISM BY WHICH PSYCHOLOGICAL TRAUMA LATER IN LIFE CAN LONG-LASTINGLY AFFECT HPA AXIS FUNCTION, BRAIN PLASTICITY, NEURONAL FUNCTION AND BEHAVIOURAL ADAPTATION TO NEUROPSYCHOLOGICAL STRESS. FURTHER CORROBORATING THIS CLAIM IS THE PHENOMENON THAT THESE EPIGENETIC CHANGES CORRELATE WITH THE BEHAVIOURAL CONSEQUENCES OF TRAUMA EXPOSURE. THEREBY, EPIGENETIC MODIFICATIONS PROVIDE A PUTATIVE MOLECULAR MECHANISM BY WHICH THE BEHAVIOURAL PHENOTYPE AND TRANSCRIPTIONAL/TRANSLATIONAL POTENTIAL OF GENES INVOLVED IN HPA AXIS REGULATION CAN CHANGE DRASTICALLY IN RESPONSE TO ENVIRONMENTAL CHALLENGES, AND APPEAR AN IMPORTANT TARGET FOR TREATMENT OF STRESS-RELATED DISORDERS. HOWEVER, IMPROVED INSIGHT IS REQUIRED TO INCREASE THEIR THERAPEUTIC (DRUG) POTENTIAL. HERE, WE PROVIDE AN OVERVIEW OF THE GROWING BODY OF LITERATURE DESCRIBING THE EPIGENETIC MODULATION OF THE (PRIMARILY NEUROENDOCRINE) STRESS RESPONSE AS A CONSEQUENCE OF ADULT LIFE STRESS AND INTERPRET THE IMPLICATIONS FOR, AND THE CHALLENGES INVOLVED IN APPLYING THIS KNOWLEDGE TO, THE IDENTIFICATION AND TREATMENT OF STRESS-RELATED PSYCHIATRIC DISORDERS. 2017 16 248 31 ADVANCE IN STRESS FOR DEPRESSIVE DISORDER. STRESS IS AN ADAPTIVE RESPONSE TO ENVIRONMENT AVERSIVE STIMULI AND A COMMON LIFE EXPERIENCE OF ONE'S DAILY LIFE. CHRONIC OR EXCESSIVE STRESS ESPECIALLY THAT HAPPENED IN EARLY LIFE IS FOUND TO BE DELETERIOUS TO INDIVIDUAL'S PHYSICAL AND MENTAL HEALTH, WHICH IS HIGHLY RELATED TO DEPRESSIVE DISORDERS ONSET. STRESSFUL LIFE EVENTS ARE CONSISTENTLY CONSIDERED TO BE THE HIGH-RISK FACTORS OF ENVIRONMENT FOR PREDISPOSING DEPRESSIVE DISORDERS. IN LINKING STRESSFUL LIFE EVENTS WITH DEPRESSIVE DISORDER ONSET, DYSREGULATED HPA AXIS ACTIVITY IS SUPPOSED TO PLAY AN IMPORTANT ROLE IN MEDIATING AVERSIVE IMPACTS OF LIFE STRESS ON BRAIN STRUCTURE AND FUNCTION. INCREASING EVIDENCE HAVE INDICATED THE STRONG ASSOCIATION OF STRESS, ESPECIALLY THE CHRONIC STRESS AND EARLY LIFE STRESS, WITH DEPRESSIVE DISORDERS DEVELOPMENT, WHILE THE ASSOCIATION OF STRESS WITH DEPRESSION IS MODERATED BY GENETIC RISK FACTORS, INCLUDING POLYMORPHISM OF SERT, BDNF, GR, FKBP5, MR, AND CRHR1. MEANWHILE, STRESSFUL LIFE EXPERIENCE PARTICULARLY EARLY LIFE STRESS WILL EXERT EPIGENETIC MODIFICATION IN THESE RISK GENES VIA DNA METHYLATION AND MIRNA REGULATION TO GENERATE LONG-LASTING EFFECTS ON THESE GENES EXPRESSION, WHICH IN TURN CAUSE BRAIN STRUCTURAL AND FUNCTIONAL ALTERATION, AND FINALLY INCREASE THE VULNERABILITY TO DEPRESSIVE DISORDERS. THEREFORE, THE INTERACTION OF ENVIRONMENT WITH GENE, IN WHICH STRESSFUL LIFE EXPOSURE INTERPLAY WITH GENETIC RISK FACTORS AND EPIGENETIC MODIFICATION, IS ESSENTIAL IN PREDICTING DEPRESSIVE DISORDERS DEVELOPMENT. AS THE MEDIATOR OF ENVIRONMENTAL RISK FACTORS, STRESS WILL FUNCTION TOGETHER WITH GENETIC AND EPIGENETIC MECHANISM TO INFLUENCE BRAIN STRUCTURE AND FUNCTION, PHYSIOLOGY AND PSYCHOLOGY, AND FINALLY THE VULNERABILITY TO DEPRESSIVE DISORDERS. 2019 17 375 20 AN ENERGETIC VIEW OF STRESS: FOCUS ON MITOCHONDRIA. ENERGY IS REQUIRED TO SUSTAIN LIFE AND ENABLE STRESS ADAPTATION. AT THE CELLULAR LEVEL, ENERGY IS LARGELY DERIVED FROM MITOCHONDRIA - UNIQUE MULTIFUNCTIONAL ORGANELLES WITH THEIR OWN GENOME. FOUR MAIN ELEMENTS CONNECT MITOCHONDRIA TO STRESS: (1) ENERGY IS REQUIRED AT THE MOLECULAR, (EPI)GENETIC, CELLULAR, ORGANELLAR, AND SYSTEMIC LEVELS TO SUSTAIN COMPONENTS OF STRESS RESPONSES; (2) GLUCOCORTICOIDS AND OTHER STEROID HORMONES ARE PRODUCED AND METABOLIZED BY MITOCHONDRIA; (3) RECIPROCALLY, MITOCHONDRIA RESPOND TO NEUROENDOCRINE AND METABOLIC STRESS MEDIATORS; AND (4) EXPERIMENTALLY MANIPULATING MITOCHONDRIAL FUNCTIONS ALTERS PHYSIOLOGICAL AND BEHAVIORAL RESPONSES TO PSYCHOLOGICAL STRESS. THUS, MITOCHONDRIA ARE ENDOCRINE ORGANELLES THAT PROVIDE BOTH THE ENERGY AND SIGNALS THAT ENABLE AND DIRECT STRESS ADAPTATION. NEURAL CIRCUITS REGULATING SOCIAL BEHAVIOR - AS WELL AS PSYCHOPATHOLOGICAL PROCESSES - ARE ALSO INFLUENCED BY MITOCHONDRIAL ENERGETICS. AN INTEGRATIVE VIEW OF STRESS AS AN ENERGY-DRIVEN PROCESS OPENS NEW OPPORTUNITIES TO STUDY MECHANISMS OF ADAPTATION AND REGULATION ACROSS THE LIFESPAN. 2018 18 2386 26 EPIGENETIC REGULATORY MECHANISMS IN STRESS-INDUCED BEHAVIOR. STRESS RESPONSE IS CONSIDERED TO HAVE ADAPTIVE VALUE FOR ORGANISMS FACED WITH STRESSFUL CONDITION. CHRONIC STRESS HOWEVER ADVERSELY AFFECTS THE PHYSIOLOGY AND MAY LEAD TO NEUROPSYCHIATRIC DISORDERS. REPEATED STRESSFUL EVENTS IN ANIMAL MODELS HAVE BEEN SHOWN TO CAUSE LONG-LASTING CHANGES IN NEURAL CIRCUITRIES AT MOLECULAR, CELLULAR, AND PHYSIOLOGICAL LEVEL, LEADING TO DISORDERS OF MOOD AS WELL AS COGNITION. MOLECULAR STUDIES IN RECENT YEARS HAVE IMPLICATED DIVERSE EPIGENETIC MECHANISMS, INCLUDING HISTONE MODIFICATIONS, DNA METHYLATION, AND NONCODING RNAS, THAT UNDERLIE DYSREGULATION OF GENES IN THE AFFECTED NEURAL CIRCUITRIES IN CHRONIC STRESS-INDUCED PATHOPHYSIOLOGY. A REVIEW OF THE MYRIAD EPIGENETIC REGULATORY MECHANISMS ASSOCIATED WITH NEURAL AND BEHAVIORAL RESPONSES IN ANIMAL MODELS OF STRESS-INDUCED NEUROPSYCHIATRIC DISORDERS IS PRESENTED HERE. THE REVIEW ALSO DEALS WITH CLINICAL EVIDENCE OF THE EPIGENETIC DYSREGULATION OF GENES IN PSYCHIATRIC DISORDERS WHERE CHRONIC STRESS APPEARS TO UNDERLIE THE ETIOPATHOLOGY. 2014 19 5831 32 STRESS-INDUCED CHRONIC VISCERAL PAIN OF GASTROINTESTINAL ORIGIN. VISCERAL PAIN IS GENERALLY POORLY LOCALIZED AND CHARACTERIZED BY HYPERSENSITIVITY TO A STIMULUS SUCH AS ORGAN DISTENSION. IN CONCERT WITH CHRONIC VISCERAL PAIN, THERE IS A HIGH COMORBIDITY WITH STRESS-RELATED PSYCHIATRIC DISORDERS INCLUDING ANXIETY AND DEPRESSION. THE MECHANISMS LINKING VISCERAL PAIN WITH THESE OVERLAPPING COMORBIDITIES REMAIN TO BE ELUCIDATED. EVIDENCE SUGGESTS THAT LONG TERM STRESS FACILITATES PAIN PERCEPTION AND SENSITIZES PAIN PATHWAYS, LEADING TO A FEED-FORWARD CYCLE PROMOTING CHRONIC VISCERAL PAIN DISORDERS SUCH AS IRRITABLE BOWEL SYNDROME (IBS). EARLY LIFE STRESS (ELS) IS A RISK-FACTOR FOR THE DEVELOPMENT OF IBS, HOWEVER THE MECHANISMS RESPONSIBLE FOR THE PERSISTENT EFFECTS OF ELS ON VISCERAL PERCEPTION IN ADULTHOOD REMAIN INCOMPLETELY UNDERSTOOD. IN RODENT MODELS, STRESS IN ADULT ANIMALS INDUCED BY RESTRAINT AND WATER AVOIDANCE HAS BEEN EMPLOYED TO INVESTIGATE THE MECHANISMS OF STRESS-INDUCE PAIN. ELS MODELS SUCH AS MATERNAL SEPARATION, LIMITED NESTING, OR ODOR-SHOCK CONDITIONING, WHICH ATTEMPT TO MODEL EARLY CHILDHOOD EXPERIENCES SUCH AS NEGLECT, POVERTY, OR AN ABUSIVE CAREGIVER, CAN PRODUCE CHRONIC, SEXUALLY DIMORPHIC INCREASES IN VISCERAL SENSITIVITY IN ADULTHOOD. CHRONIC VISCERAL PAIN IS A CLASSIC EXAMPLE OF GENE X ENVIRONMENT INTERACTION WHICH RESULTS FROM MALADAPTIVE CHANGES IN NEURONAL CIRCUITRY LEADING TO NEUROPLASTICITY AND ABERRANT NEURONAL ACTIVITY-INDUCED SIGNALING. ONE POTENTIAL MECHANISM UNDERLYING THE PERSISTENT EFFECTS OF STRESS ON VISCERAL SENSITIVITY COULD BE EPIGENETIC MODULATION OF GENE EXPRESSION. WHILE THERE ARE RELATIVELY FEW STUDIES EXAMINING EPIGENETICALLY MEDIATED MECHANISMS INVOLVED IN VISCERAL NOCICEPTION, STRESS-INDUCED VISCERAL PAIN HAS BEEN LINKED TO ALTERATIONS IN DNA METHYLATION AND HISTONE ACETYLATION PATTERNS WITHIN THE BRAIN, LEADING TO INCREASED EXPRESSION OF PRO-NOCICEPTIVE NEUROTRANSMITTERS. THIS REVIEW WILL DISCUSS THE POTENTIAL NEURONAL PATHWAYS AND MECHANISMS RESPONSIBLE FOR STRESS-INDUCED EXACERBATION OF CHRONIC VISCERAL PAIN. ADDITIONALLY, WE WILL REVIEW THE IMPORTANCE OF SPECIFIC EXPERIMENTAL MODELS OF ADULT STRESS AND ELS IN ENHANCING OUR UNDERSTANDING OF THE BASIC MOLECULAR MECHANISMS OF PAIN PROCESSING. 2017 20 4622 19 NEUROBIOLOGICAL DEVELOPMENT IN THE CONTEXT OF CHILDHOOD TRAUMA. NEUROBIOLOGICAL SYSTEMS MAY BE PARTICULARLY SUSCEPTIBLE TO DELETERIOUS IMPACT OF CHILDHOOD TRAUMA, AND THE IMPACT OF CHILDHOOD TRAUMA ON DEVELOPMENT AND SUBSEQUENT FUNCTIONAL OUTCOMES ACROSS THE LIFESPAN HAS BEEN WELL-DOCUMENTED. THE CURRENT REVIEW ADDRESSES THE NEUROBIOLOGICAL IMPACT OF EXPOSURE TO INTERPERSONAL TRAUMA IN CHILDHOOD IN THE CONTEXT OF EXECUTIVE FUNCTION, EMOTION REGULATION, AND DISSOCIATION/INTEROCEPTIVE AWARENESS. SUBSEQUENT RISK FOR PTSD AND DEPRESSION IS ALSO DISCUSSED. THE PATHWAY OF RISK FROM CHILDHOOD TRAUMA TO THESE COGNITIVE, EMOTIONAL, AND PSYCHIATRIC OUTCOMES IS ADDRESSED IN TERMS OF POTENTIAL STRUCTURAL AND FUNCTIONAL ALTERATIONS WITHIN THE HIPPOCAMPUS, PREFRONTAL CORTEX, AND AMYGDALA RESULTING FROM CHRONIC OR REPEATED ACTIVATION OF THE HYPOTHALAMIC-PITUITARY-ADRENAL (HPA) AXIS AND ITS INTERACTION WITH AND INFLUENCE ON GENETIC AND EPIGENETIC PROCESSES DURING SENSITIVE PERIODS OF DEVELOPMENT. IMPLICATIONS FOR PRACTICE ARE DISCUSSED. 2017