Does exercise augment operant and Pavlovian extinction: A meta-analysis. Roquet Rheall F,Monfils Marie-H Journal of psychiatric research BACKGROUND:Exposure therapy, a behavioral approach to reduce symptomology in fear, anxiety, and drug-related psychiatric disorders, is based on learning and memory principles of extinction, and is subject to relapse. As such, it is important to find ways to enhance outcomes. One such way is through exercise. OBJECTIVES:Identify if exercise augments extinction behavior, and whether this depends on the experimental paradigm used (i.e. operant or Pavlovian) and/or stimulus (i.e. appetitive or aversive). Additionally, determine which moderating variables influence the effects of exercise on extinction learning. METHODS:A literature search was conducted and a Hedges' g calculation was employed to conduct a meta-analysis (metaSEM) using a structural equation modeling approach. This approach was chosen because of its ability to account for dependencies in effect sizes. RESULTS:We found a significant effect of exercise as an augmentation over extinction alone (g = 0.37, p < 0.001), with extinction paradigm (but not stimulus) producing a moderating effect (B = 0.43, p = 0.030). Data were then split by extinction paradigm, with operant extinction models having a significant effect (g = 0.55, p < 0.001), and number of extinction sessions moderating aggregate effects. Pavlovian models did not have significant overall effects (g = 0.11, p = 0.3976), but were moderated by the number of animals housed together and exercise after extinction. CONCLUSIONS:The effects of exercise on extinction learning are differentially modulated by the type of paradigm used, the number of extinction sessions, the timing of when exercise treatment was applied (after extinction), and the housing conditions. 10.1016/j.jpsychires.2017.09.018
    Running from fear: Exercise modulation of fear extinction. Tanner Margaret K,Hake Holly S,Bouchet Courtney A,Greenwood Benjamin N Neurobiology of learning and memory Extinction-based exposure therapy is the most common behavioral therapy for anxiety and trauma-related disorders, but fear tends to resurface even after successful extinction. Identification of novel strategies to enhance fear extinction and reduce fear relapse is of paramount importance to mental health. Exercise can enhance cognitive function, but it is not yet well understood whether exercise can be an effective augmentation strategy for fear extinction. In the current review, we present the current state of knowledge on the effects of exercise on fear extinction. Effects of exercise duration, explanations for conflicting results, and potential mechanisms, focusing on a hypothesized role for dopamine, are all discussed. We also provide new data suggesting that the timing in which acute exercise occurs relative to fear extinction, is a crucial variable in determining whether exercise can enhance fear extinction. Clinical implications and ideas to guide future research endeavors in this area are provided. 10.1016/j.nlm.2018.03.021
    Hippocampal neurogenesis regulates forgetting during adulthood and infancy. Akers Katherine G,Martinez-Canabal Alonso,Restivo Leonardo,Yiu Adelaide P,De Cristofaro Antonietta,Hsiang Hwa-Lin Liz,Wheeler Anne L,Guskjolen Axel,Niibori Yosuke,Shoji Hirotaka,Ohira Koji,Richards Blake A,Miyakawa Tsuyoshi,Josselyn Sheena A,Frankland Paul W Science (New York, N.Y.) Throughout life, new neurons are continuously added to the dentate gyrus. As this continuous addition remodels hippocampal circuits, computational models predict that neurogenesis leads to degradation or forgetting of established memories. Consistent with this, increasing neurogenesis after the formation of a memory was sufficient to induce forgetting in adult mice. By contrast, during infancy, when hippocampal neurogenesis levels are high and freshly generated memories tend to be rapidly forgotten (infantile amnesia), decreasing neurogenesis after memory formation mitigated forgetting. In precocial species, including guinea pigs and degus, most granule cells are generated prenatally. Consistent with reduced levels of postnatal hippocampal neurogenesis, infant guinea pigs and degus did not exhibit forgetting. However, increasing neurogenesis after memory formation induced infantile amnesia in these species. 10.1126/science.1248903
    Association between posttraumatic stress disorder and lack of exercise, poor diet, obesity, and co-occuring smoking: A systematic review and meta-analysis. van den Berk-Clark Carissa,Secrest Scott,Walls Jesse,Hallberg Ellen,Lustman Patrick J,Schneider F David,Scherrer Jeffrey F Health psychology : official journal of the Division of Health Psychology, American Psychological Association OBJECTIVES:Research has shown that posttraumatic stress disorder (PTSD) increases the risk of development of cardiometabolic disease (CMD) including cardiovascular disease and diabetes. Whether PTSD is also associated with behavioral risk factors (e.g., diet, exercise, smoking and obesity) for CMD, is less clear. METHODS:PubMed, Web of Science, and Scopus databases were searched to obtain papers published between 1980-2016. Studies were reviewed for quality using the Quality of Cohort screen. Significance values, odds ratios (OR), 95% confidence intervals (CI), and tests of homogeneity of variance were calculated. PRINCIPAL FINDINGS:A total of 1,349 studies were identified from our search and 29 studies met all eligibility criteria. Individuals with PTSD were 5% less likely to have healthy diets (pooled adjusted OR = 0.95; 95% CI: 0.92, 0.98), 9% less likely to engage in physical activity (pooled adjusted OR = 0.91; 95% CI: 0.88, 0.93), 31% more likely to be obese (pooled adjusted OR = 1.31; 95% CI:1.25, 1.38), and about 22% more likely to be current smokers (pooled adjusted OR = 1.22; 95% CI: 1.19, 1.26), than individuals without PTSD. CONCLUSIONS:Evidence shows PTSD is associated with reduced healthy eating and physical activity, and increased obesity and smoking. The well-established association between PTSD and metabolic and cardiovascular disease may be partly due to poor diet, sedentary lifestyle, high prevalence of obesity, and co-occurring smoking in this population. The well-established association of PTSD with CMD is likely due in part to poor health behaviors in this patient population. (PsycINFO Database Record 10.1037/hea0000593
    Exercise Intervention in PTSD: A Narrative Review and Rationale for Implementation. Hegberg Nicole J,Hayes Jasmeet P,Hayes Scott M Frontiers in psychiatry Posttraumatic stress disorder (PTSD) is a prominent mental health problem in veteran and community populations. There is accumulating evidence to suggest that aerobic exercise may serve as an effective treatment option for individuals with PTSD. The purpose of this review is to summarize the existing literature exploring aerobic exercise and PTSD and briefly discuss potential mechanisms of PTSD symptom reduction. A search of electronic databases and reference sections of relevant articles published through October 1, 2018 revealed 19 relevant studies that examined aerobic exercise and PTSD symptomatology. A narrative review of extant studies provides encouraging evidence that aerobic exercise interventions alone or as an adjunct to standard treatment may positively impact PTSD symptoms. Potential mechanisms by which aerobic exercise could exert a positive impact in PTSD include exposure and desensitization to internal arousal cues, enhanced cognitive function, exercise-induced neuroplasticity, normalization of hypothalamic pituitary axis (HPA) function, and reductions in inflammatory markers. Randomized clinical trials and translational neuroscience approaches are required to clarify the efficacy of exercise intervention for PTSD and elucidate potential mechanisms of exercise-induced PTSD symptom reduction. 10.3389/fpsyt.2019.00133
    Depression and Anxiety Disorders: Benefits of Exercise, Yoga, and Meditation. Saeed Sy Atezaz,Cunningham Karlene,Bloch Richard M American family physician Many people with depression or anxiety turn to nonpharmacologic and nonconventional interventions, including exercise, yoga, meditation, tai chi, or qi gong. Meta-analyses and systematic reviews have shown that these interventions can improve symptoms of depression and anxiety disorders. As an adjunctive treatment, exercise seems most helpful for treatment-resistant depression, unipolar depression, and posttraumatic stress disorder. Yoga as monotherapy or adjunctive therapy shows positive effects, particularly for depression. As an adjunctive therapy, it facilitates treatment of anxiety disorders, particularly panic disorder. Tai chi and qi gong may be helpful as adjunctive therapies for depression, but effects are inconsistent. As monotherapy or an adjunctive therapy, mindfulness-based meditation has positive effects on depression, and its effects can last for six months or more. Although positive findings are less common in people with anxiety disorders, the evidence supports adjunctive use. There are no apparent negative effects of mindfulness-based interventions, and their general health benefits justify their use as adjunctive therapy for patients with depression and anxiety disorders.
    Effects of swimming exercise on the extinction of fear memory in rats. Faria Rodolfo Souza,Bereta Álvaro Luiz Bianchim,Reis Guilherme Henrique Teixeira,Santos Lourdes Bethania Braga,Pereira Marcela Santos Gomes,Cortez Paulo José Oliveira,Dias Elayne Vieira,Moreira Dalmo Antônio Ribeiro,Trzesniak Clarissa,Sartori Cesar Renato Journal of neurophysiology We investigated the relation between swimming exercise and fear memory extinction. Rats that performed regular swimming exercise over 6 wk underwent fear conditioning. Twenty-eight days later, they were submitted to extinction tests. Swimming rats had enhanced extinction process throughout the 5 days of the extinction test compared with sedentary rats. This suggests that the swimming exercise accelerated the process of aversive memory extinction, reducing the expression of conditioned fear behavior. These results encourage further studies addressing the anxiolytic effects of exercise, with potential implications for anxiety disorders such as posttraumatic stress disorder. NEW & NOTEWORTHY We have shown that rats that performed regular swimming exercise over 6 wk had enhanced extinction process compared with sedentary animals. The swimming exercise may accelerate the process of aversive memory extinction, reducing the expression of conditioned fear behavior. 10.1152/jn.00586.2018
    The capacity for acute exercise to modulate emotional memories: A review of findings and mechanisms. Keyan Dharani,Bryant Richard A Neuroscience and biobehavioral reviews Anxiety disorders, such as posttraumatic stress disorder, are underpinned by fear learning mechanisms. This review outlines how acute bouts of exercise can moderate fear memory acquisition, consolidation, and extinction. These fear memory mechanisms are central to the development and treatment of anxiety disorders. We propose that the documented effects of acute exercise directly impact key neurobiological processes implicated in fear memory modulation. Central to the relationship between acute exercise and fear memory is brain derived neurotrophic factor (BDNF), which is augmented following acute exercise and is involved in synaptic plasticity and associative learning and memory. BDNF is a likely candidate for how acute exercise may moderate fear memories via key glucocorticoid and noradrenergic systems. Recent work has extended animal studies on acute exercise and fear memory to human populations, and has replicated the effects of exercise on emotional memories and extinction consolidation. This accumulative evidence suggests that the role of acute exercise in fear memory modulation may have significant potential benefits for how anxiety disorders are managed. 10.1016/j.neubiorev.2019.09.033