Physical skill training increases the number of surviving new cells in the adult hippocampus

Aerobic exercise training and neurocognitive function in cognitively normal older adults: A one-year randomized controlled trial

BACKGROUND

Current evidence is inconsistent on the benefits of aerobic exercise training for preventing or attenuating age-related cognitive decline in older adults.

OBJECTIVE

To investigate the effects of a 1-year progressive, moderate-to-high intensity aerobic exercise intervention on cognitive function, brain volume, and cortical thickness in sedentary but otherwise healthy older adults.

METHODS

We randomized 73 older adults to a 1-year aerobic exercise or stretching-and-toning (active control) program. The primary outcome was a cognitive composite score calculated from eight neuropsychological tests encompassing inductive reasoning, long-term and working memory, executive function, and processing speed. Secondary outcomes were brain volume and cortical thickness assessed by MRI, and cardiorespiratory fitness measured by peak oxygen uptake (VO2 ).

RESULTS

One-year aerobic exercise increased peak VO2 by ∼10% (p < 0.001) while it did not change with stretching (p = 0.241). Cognitive composite scores increased in both the aerobic and stretching groups (p < 0.001 for time effect), although no group difference was observed. Total brain volume (p < 0.001) and mean cortical thickness (p = 0.001) decreased in both groups over time, while the reduction in hippocampal volume was smaller in the stretching group compared with the aerobic group (p = 0.040 for interaction). Across all participants, improvement in peak VO2 was positively correlated with increases in cognitive composite score (r = 0.282, p = 0.042) and regional cortical thickness at the inferior parietal lobe (p = 0.016).

CONCLUSIONS

One-year aerobic exercise and stretching interventions improved cognitive performance but did not prevent age-related brain volume loss in sedentary healthy older adults. Cardiorespiratory fitness gain was positively correlated with cognitive performance and regional cortical thickness.

Hippocampal Egr1-Dependent Neuronal Ensembles Negatively Regulate Motor Learning

Motor skills learning is classically associated with brain regions including cerebral and cerebellar cortices and basal ganglia nuclei. Less is known about the role of the hippocampus in the acquisition and storage of motor skills. Here, we show that mice receiving a long-term training in the accelerating rotarod display marked hippocampal transcriptional changes and reduced pyramidal neurons activity in the CA1 region when compared with naive mice. Then, we use mice in which neural ensembles are permanently labeled in an Egr1 activity-dependent fashion. Using these mice, we identify a subpopulation of Egr1-expressing pyramidal neurons in CA1 activated in short-term (STT) and long-term (LTT) trained mice in the rotarod task. When Egr1 is downregulated in the CA1 or these neuronal ensembles are depleted, motor learning is improved whereas their chemogenetic stimulation impairs motor learning performance. Thus, Egr1 organizes specific CA1 neuronal ensembles during the accelerating rotarod task that limit motor learning. These evidences highlight the role of the hippocampus in the control of this type of learning and we provide a possible underlying mechanism.SIGNIFICANCE STATEMENT It is a major topic in neurosciences the deciphering of the specific circuits underlying memory systems during the encoding of new information. However, the potential role of the hippocampus in the control of motor learning and the underlying mechanisms has been poorly addressed. In the present work we show how the hippocampus responds to motor learning and how the Egr1 molecule is one of the major responsible for such phenomenon controlling the rate of motor coordination performances.

Unexpected Consequences of Noise-Induced Hearing Loss: Impaired Hippocampal Neurogenesis, Memory, and Stress

Noise-induced hearing loss (NIHL), caused by direct damage to the cochlea, reduces the flow of auditory information to the central nervous system, depriving higher order structures, such as the hippocampus with vital sensory information needed to carry out complex, higher order functions. Although the hippocampus lies outside the classical auditory pathway, it nevertheless receives acoustic information that influence its activity. Here we review recent results that illustrate how NIHL and other types of cochlear hearing loss disrupt hippocampal function. The hippocampus, which continues to generate new neurons (neurogenesis) in adulthood, plays an important role in spatial navigation, memory, and emotion. The hippocampus, which contains place cells that respond when a subject enters a specific location in the environment, integrates information from multiple sensory systems, including the auditory system, to develop cognitive spatial maps to aid in navigation. Acute exposure to intense noise disrupts the place-specific firing patterns of hippocampal neurons, “spatially disorienting” the cells for days. More traumatic sound exposures that result in permanent NIHL chronically suppresses cell proliferation and neurogenesis in the hippocampus; these structural changes are associated with long-term spatial memory deficits. Hippocampal neurons, which contain numerous glucocorticoid hormone receptors, are part of a complex feedback network connected to the hypothalamic-pituitary (HPA) axis. Chronic exposure to intense intermittent noise results in prolonged stress which can cause a persistent increase in corticosterone, a rodent stress hormone known to suppress neurogenesis. In contrast, a single intense noise exposure sufficient to cause permanent hearing loss produces only a transient increase in corticosterone hormone. Although basal corticosterone levels return to normal after the noise exposure, glucocorticoid receptors (GRs) in the hippocampus remain chronically elevated. Thus, NIHL disrupts negative feedback from the hippocampus to the HPA axis which regulates the release of corticosterone. Preclinical studies suggest that the noise-induced changes in hippocampal place cells, neurogenesis, spatial memory, and glucocorticoid receptors may be ameliorated by therapeutic interventions that reduce oxidative stress and inflammation. These experimental results may provide new insights on why hearing loss is a risk factor for cognitive decline and suggest methods for preventing this decline.

GABAergic deficits in absence of LPA1 receptor, associated anxiety-like and coping behaviors, and amelioration by interneuron precursor transplants into the dorsal hippocampus

Defects in GABAergic function can cause anxiety- and depression-like behaviors among other neuropsychiatric disorders. Therapeutic strategies using the transplantation of GABAergic interneuron progenitors derived from the medial ganglionic eminence (MGE) into the adult hippocampus reversed the symptomatology in multiple rodent models of interneuron-related pathologies. In turn, the lysophosphatidic acid receptor LPA₁ has been reported to be essential for hippocampal function. Converging evidence suggests that deficits in LPA₁ receptor signaling represent a core feature underlying comparable hippocampal dysfunction and behaviors manifested in common neuropsychiatric conditions. Here, we first analyzed the GABAergic interneurons in the hippocampus of wild-type and maLPA₁-null mice, lacking the LPA₁ receptor. Our data revealed a reduction in the number of neurons expressing GABA, calcium-binding proteins, and neuropeptides such as somatostatin and neuropeptide Y in the hippocampus of maLPA₁-null mice. Then, we used interneuron precursor transplants to test links between hippocampal GABAergic interneuron deficit, cell-based therapy, and LPA₁ receptor-dependent psychiatric disease-like phenotypes. For this purpose, we transplanted MGE-derived interneuron precursors into the adult hippocampus of maLPA₁-null mice, to test their effects on GABAergic deficit and behavioral symptoms associated with the absence of the LPA₁ receptor. Transplant studies in maLPA₁-null mice showed that grafted cells were able to restore the hippocampal host environment, decrease the anxiety-like behaviors and neutralize passive coping, with no abnormal effects on motor activity. Furthermore, grafted MGE-derived cells maintained their normal differentiation program. These findings reinforce the use of cell-based strategies for brain disorders and suggest that the LPA₁ receptor represents a potential target for interneuron-related neuropsychiatric disorders.

Differences in inhibitory control and motor fitness in children practicing open and closed skill sports

The aim of the present study was to investigate the differences between types of sport (i.e., closed vs. open skills sport) on inhibitory control and motor fitness in children. Forty-nine children were allocated into three groups based on their sports participation, which comprised an open skill sport group, a closed skill sport group, and a sedentary group. Participants were tested on cognitive performance (inhibitory control by the Flanker task) and motor fitness (reaction time, speed, agility, power, balance). Open skill sport group appeared to display higher inhibitory control (response time and accuracy of incongruent condition of the Flanker task) and motor fitness performance (reaction time, speed, agility, power) than sedentary group, whereas its superiority over closed skill sport group was found only in speed and agility. Moreover, closed skill sport group had only a better reaction time than sedentary group. Our data supports the framework according to which cognitive demands in complex motor actions may contribute to explain the beneficial effects of exercise on inhibitory control. This might suggest that the complexity of the environment (typical in open skill sports) in which sport training is performed plays a key role for both cognitive and motor development in children.

Taking neurogenesis out of the lab and into the world with MAP Train My Brain™

Neurogenesis in the adult hippocampus was rediscovered in the 1990's after being reported in the 1960's. Since then, thousands upon thousands of laboratories have reported on the characteristics and presumed functional significance of new neurons in the adult brain. In 1999, we reported that mental training with effortful learning could extend the survival of these new cells and in the same year, others reported that physical training with exercise could increase their proliferation. Based on these studies and others, we developed MAP Train My Brain™, which is a brain fitness program for humans. The program combines mental and physical (MAP) training through 30-min of effortful meditation followed by 30-min of aerobic exercise. This program, when practiced twice a week for eight weeks reduced depressive symptoms and ruminative thoughts in men and women with major depressive disorder (MDD) while increasing synchronized brain activity during cognitive control. It also reduced anxiety and depression and increased oxygen consumption in young mothers who had been homeless. Moreover, engaging in the program reduced trauma-related cognitions and ruminative thoughts while increasing self-worth in adult women with a history of sexual trauma. And finally, the combination of mental and physical training together was more effective than either activity alone. Albeit effortful, this program does not require inordinate amounts of time or money to practice and can be easily adopted into everyday life. MAP Training exemplifies how we as neuroscientists can take discoveries made in the laboratory out into the world for the benefit of others.

Voluntary exercise or systemic propranolol ameliorates stress-related maladaptive behaviors in female rats

Many people will experience at least one traumatic event in their lifetime, with up to 20% developing Post-Traumatic Stress Disorder (PTSD) or PTSD-like symptoms. In addition, the likelihood that females will develop PTSD after trauma is more than twice that of males. Despite its prevalence, current treatment strategies for trauma victims are limited and substantial portions of affected individuals remain resistant to treatment, suggesting that additional interventions are necessary. Using an animal model of traumatic stress, the present studies tested the hypothesis that either voluntary exercise and/or administration of the adrenergic beta-receptor antagonist propranolol, would ameliorate stress-related maladaptive behaviors. In Study 1 four groups of female rats were exposed to a sequence of stressors that included anesthesia, restraint, forced swim, exposure to predator scent and fear conditioning. Rats then underwent re-exposure sessions in which stress-related conditioned stimuli were presented. In addition to re-exposure, stressed rats were treated with propranolol (10 mg/kg) and/or given the opportunity to engage in voluntary wheel running intermittently for 4 weeks. Stress-associated maladaptive behavior was assessed using the elevated plus and open field mazes and fear memory tests. Cognitive ability was assessed using a novel odor recognition task. A main effect of exercise on behaviors related to anxiety and resilience was observed, but neither a main effect of propranolol nor a synergistic effect of propranolol and exercise were observed. Neither stress induction nor treatment influenced recognition memory. In contrast, in Study 2 in which the timing and dosage of propranolol (0.25-2.0 mg/kg), and the number and timing of re-exposure sessions were adjusted, propranolol produced both a reduction in anxiety-like behaviors as well as resilience to a subsequent stressor. These results are consistent with the notion that combining re-exposure therapy with additional interventions is beneficial for female trauma victims. Furthermore, the findings support the view that in pre-clinical models, voluntary exercise, which bolsters hippocampal function and propranolol, which affects amygdala-dependent memory reconsolidation and peripheral noradrenergic signaling, can ameliorate stress-related symptoms.

Impact of 1-day and 4-day MWM training techniques on oxidative and neurochemical profile in rat brain: A comparative study on learning and memory functions

Among multiple behavioral tasks used to assess memory performance, Morris water maze (MWM) is a well-known and reliable conventional behavioral task to monitor spatial memory performance in rodents. Although multiple procedures are employed by researchers for spatial learning training in MWM, but less is known about impact of these training protocol variations on oxidative and neurochemical systems. Therefore, this study aimed to examine whether variations in training protocol will influence spatial memory performance and induce changes in oxidative status and cholinergic and aminergic neurotransmission in rat brain. For this, rats were assigned to four groups; control (unexposed), 1-trial (exposed to single training trial), 1-day (exposed to four training trials for a single day) and 4-day (exposed to four training trials for four days). After conducting training, spatial reference memory performance was determined by performing retention and consolidation probe trials. Rats were then decapitated and their brain and plasma samples were collected for biochemical, oxidative and neurochemical analysis. It was found that spatial reference memory was improved following both 1-day and 4-day training protocols, however, corticosterone levels were raised extensively following 4-day training exposure compared to 1-day training protocol. Similarly, a significant improvement in redox profile and cholinergic and aminergic neurotransmitters was also observed following 1-day training procedure. Thus, 1-day training procedure can be suggested as a better procedure for assessing the spatial memory performance in rats as it has a profound impact on antioxidant status and cholinergic and aminergic neurotransmission in brain. Moreover, use of single-day training procedure can provide a rapid and effective tool for assessing spatial memory in rats compared to prolonged and complicated 4-day training protocol.

Exercise-induced neuroplasticity: Balance training increases cortical thickness in visual and vestibular cortical regions

Physical exercise has been shown to induce structural plasticity in the human brain and to enhance cognitive functions. While previous studies focused on aerobic exercise, suggesting a link between increased cardiorespiratory fitness and exercise-induced neuroplasticity, recent findings have suggested that whole-body exercise with minor metabolic demands elicits beneficial effects on brain structure as well. In the present study, we tested if balance training, challenging the sensory-motor system and vestibular self-motion perception, induces structural plasticity. Thirty-seven healthy adults aged 19-65 years were randomly assigned to either a balance training or a relaxation training group. All participants exercised twice a week for 12 weeks. Assessments before and after the training included a balance test and the acquisition of high-resolution T1-weighted images to analyze morphological brain changes. Only the balance group significantly improved balance performance after training. Cortical thickness was increased in the superior temporal cortex, in visual association cortices, in the posterior cingulate cortex, in the superior frontal sulcus, and in the precentral gyri in the balance group, compared to the relaxation group. Moreover, there was evidence that the balance training resulted in decreased putamen volume. Improved balance performance correlated with the increase of precentral cortical thickness and the decrease in putamen volume. The results suggest that balance training elicits neuroplasticity in brain regions associated with visual and vestibular self-motion perception. As these regions are known for their role in spatial orienting and memory, stimulating visual-vestibular pathways during self-motion might mediate beneficial effects of physical exercise on cognition.

MAP Training My Brain™: Meditation Plus Aerobic Exercise Lessens Trauma of Sexual Violence More Than Either Activity Alone

Sexual violence against women often leads to post-traumatic stress disorder (PTSD), a mental illness characterized by intrusive thoughts and memories about the traumatic event (Shors and Millon, 2016). These mental processes are obviously generated by the brain but often felt in the body. MAP Training My Brain™ is a novel clinical intervention that combines mental training of the brain with physical training of the body (Curlik and Shors, 2013; Shors et al., 2014). Each training session begins with 20-min of sitting meditation, followed by 10-min of slow-walking meditation, and ending with 30-min of aerobic exercise at 60-80% of the maximum heart rate (see maptrainmybrain.com). In previous studies, the combination of mental and physical (MAP) training together significantly reduced symptoms of depression and ruminative thoughts, while reducing anxiety (Shors et al., 2014, 2017; Alderman et al., 2016). We also documented positive changes in brain activity during cognitive control and whole-body oxygen consumption in various populations. In the present pilot study, we asked whether the combination of meditation and aerobic exercise during MAP Training would reduce trauma-related thoughts, ruminations, and memories in women and if so, whether the combination would be more effective than either activity alone. To test this hypothesis, interventions were provided to a group of women (n = 105), many of whom had a history of sexual violence (n = 32). Groups were trained with (1) MAP Training, (2) meditation alone, (3) aerobic exercise alone, or (4) not trained. Individuals in training groups completed two sessions a week for at least 6 weeks. MAP Training My Brain™ significantly reduced post-traumatic cognitions and ruminative thoughts in women with a history of sexual violence, whereas meditation alone, and exercise alone did not. MAP Training significantly enhanced a measure of self-worth, whereas meditation and exercise alone did not. Similar positive effects were observed for all participants, although meditation alone was also effective in reducing trauma-related thoughts. Overall, these data indicate the combination of meditation and exercise is synergistic. As a consequence, MAP Training is preferable and especially so for women who have experienced sexual violence in their past. Simply put, the whole is greater than the sum of its parts.

Behavioral and structural adaptations to stress

Unpredictable aversive experiences, or stressors, lead to changes in depression- and anxiety-related behavior and to changes in hippocampal structure including decreases in adult neurogenesis, granule cell and pyramidal cell dendritic morphology, and volume. Here we review the relationship between these behavioral and structural changes and discuss the possibility that these changes may be largely adaptive. Specifically, we suggest that new neurons in the dentate gyrus enhance behavioral adaptability to changes in the environment, biasing behavior in novel situations based on previous experience with stress. Conversely, atrophy-like changes in the hippocampus and decreased adult neurogenesis following chronic stress may serve to limit stress responses and stabilize behavior during chronic stress.

Do sex differences in rumination explain sex differences in depression?

It is generally accepted that women tend to ruminate more than men do and these thought patterns are often associated with depressive symptoms (Nolen-Hoeksema et al., ). Based on these findings, we considered whether the relationship between rumination and depression is stronger in women than in men and if so, whether this might explain the higher prevalence of major depressive disorder (MDD) in women and finally, whether the association can be disrupted through a mind/body intervention. Adult men and women, most of whom were clinically depressed, participated in an intervention known as MAP Training, which combines "mental" training with silent meditation and "physical" training with aerobic exercise (Shors et al., ). After eight weeks of training, both men and women reported significantly fewer symptoms of depression and fewer ruminative thoughts (Alderman et al., ). Statistical correlations between depressive symptoms and ruminative thoughts were strong and significant (rho > 0.50; p < 0.05) for both men and women before and after MAP Training. However, only in women did depressive symptoms relate to "reflective" ruminations, which involve analyses of past events, feelings, and behaviors. This is also the only relationship that dissipated after the intervention. In general, these analyses suggest that the strength of the relationship between depressive symptoms and rumination does not necessarily explain sex differences in depression; but because the relationship is strong, targeting rumination through intervention can reduce the incidence of MDD, which is more prevalent among women. © 2016 Wiley Periodicals, Inc.

Balance training improves memory and spatial cognition in healthy adults

Physical exercise has been shown to improve cognitive functions. However, it is still unknown which type of exercise affects cognition. In the present study, we tested the hypothesis that a demanding balance training program improves memory and spatial cognition. Forty healthy participants aged 19–65 years were randomly assigned to either a balance or relaxation training intervention. Each group exercised twice a week for a total of 12 weeks. Pre- and posttests assessed balance performance, cardiorespiratory fitness, memory, spatial cognition, and executive functions. Only the balance group significantly increased in balance performance from pre- to posttest, while cardiorespiratory fitness remained unchanged in both groups. Moreover, the balance group significantly improved in memory and spatial cognition. Effects on executive functions were not observed. These results suggest that balance training is capable of improving particularly memory and spatial cognition. Therefore, an increase in cardiorespiratory fitness does not seem to be necessary to induce beneficial effects of physical exercise on cognition. It might be speculated that stimulating the vestibular system during balance training induces changes of the hippocampus and parietal cortex possibly via direct pathways between the vestibular system and these brain regions.

Rehabilitation training in neural restitution

Over the last decade, neural transplantation has emerged as one of the more promising, albeit highly experimental, potential therapeutics in neurodegenerative disease. Preclinical studies in rat lesion models of Huntington's disease (HD) and Parkinson's disease (PD) have shown that transplanted precursor neuronal tissue from a fetus into the lesioned striatum can survive, integrate, and reconnect circuitry. Importantly, specific training on behavioral tasks that target striatal function is required to encourage functional integration of the graft to the host tissue. Indeed, "learning to use the graft" is a concept recently adopted in preclinical studies to account for unpredicted profiles of recovery posttransplantation and is an emerging strategy for improving graft functionality. Clinical transplant studies in HD and PD have resulted in mixed outcomes. Small sample sizes and nonstandardized experimental procedures from trial to trial may explain some of this variability. However, it is becoming increasingly apparent that simply replacing the lost neurons may not be sufficient to ensure the optimal graft effects. The knowledge gained from preclinical grafting and training studies suggests that lifestyle factors, including physical activity and specific cognitive and/or motor training, may be required to drive the functional integration of grafted cells and to facilitate the development of compensatory neural networks. The clear implications of preclinical studies are that physical activity and cognitive training strategies are likely to be crucial components of clinical cell replacement therapies in the future. In this chapter, we evaluate the role of general activity in mediating the physical ability of cells to survive, sprout, and extend processes following transplantation in the adult mammalian brain, and we consider the impact of general and specific activity at the behavioral level on functional integration at the cellular and physiological level. We then highlight specific research questions related to timing, intensity, and specificity of training in preclinical models and synthesize the current state of knowledge in clinical populations to inform the development of a strategy for neural transplantation rehabilitation training.

Enriched Environment Increases PCNA and PARP1 Levels in Octopus vulgaris Central Nervous System: First Evidence of Adult Neurogenesis in Lophotrochozoa

Organisms showing a complex and centralized nervous system, such as teleosts, amphibians, reptiles, birds and mammals, and among invertebrates, crustaceans and insects, can adjust their behavior according to the environmental challenges. Proliferation, differentiation, migration, and axonal and dendritic development of newborn neurons take place in brain areas where structural plasticity, involved in learning, memory, and sensory stimuli integration, occurs. Octopus vulgaris has a complex and centralized nervous system, located between the eyes, with a hierarchical organization. It is considered the most "intelligent" invertebrate for its advanced cognitive capabilities, as learning and memory, and its sophisticated behaviors. The experimental data obtained by immunohistochemistry and western blot assay using proliferating cell nuclear antigen and poli (ADP-ribose) polymerase 1 as marker of cell proliferation and synaptogenesis, respectively, reviled cell proliferation in areas of brain involved in learning, memory, and sensory stimuli integration. Furthermore, we showed how enriched environmental conditions affect adult neurogenesis.

Adult Neurogenesis in the Songbird: Region-Specific Contributions of New Neurons to Behavioral Plasticity and Stability

Our understanding of the role of new neurons in learning and encoding new information has been largely based on studies of new neurons in the mammalian dentate gyrus and olfactory bulb - brain regions that may be specialized for learning. Thus the role of new neurons in regions that serve other functions has yet to be fully explored. The song system provides a model for studying new neuron function in brain regions that contribute differently to song learning, song auditory discrimination, and song motor production. These regions subserve learning as well as long-term storage of previously learned information. This review examines the differences between learning-based and activity-based retention of new neurons and explores the potential contributions of new neurons to behavioral stability in the song motor production pathway.

Mental and physical skill training increases neurogenesis via cell survival in the adolescent hippocampus

The adolescent hippocampus produces thousands more new neurons daily than the adult, yet many die within weeks of their generation (Cameron and McCay, 2001; Curlik, DiFeo & Shors, 2014; Shors et al., 2016). Learning new skills can increase their survival. The present study tested the effects of physical skill training on the survival of these newly generated cells in males and female rodents during puberty. Newly generated cells were labeled with BrdU, a marker of cell mitosis, and training began one week later, just as the new cells begin to die. Significantly more BrdU-labeled cells were present in the hippocampus of both sexes after engaging in the physical training experiences. The young animals were able to maintain their balance on a modified rotarod task throughout most trials of training and as a consequence expended considerable energy and endurance during each training trial. These data suggest that a combination of both exercise and skill training can increase brain plasticity through increases in neurogenesis in the adolescent hippocampus. This finding supports the premise behind a clinical intervention known as MAP Training, which combines mental and physical training to enhance brain health in humans (Shors et al., 2014; Alderman et al., 2016). Although theoretical at this stage, the positive consequences of MAP Training for brain function may be mediated through neurogenesis. This article is part of a Special Issue entitled SI: Adolescent plasticity.

Sexual trauma and the female brain

Sexual aggression and violence against women (VAM) are not only social problems; they are mental health problems. Women who experience sexual trauma often express disruptions in emotional and cognitive processes, some of which lead to depression and post-traumatic stress disorder (PTSD). Animal models of neurogenesis and learning suggest that social yet aggressive interactions between a pubescent female and an adult male can disrupt processes of learning related to maternal care, which in turn reduce survival of new neurons in the female hippocampus. Mental and Physical (MAP) Training is a novel clinical intervention that was translated from neurogenesis research. The intervention, which combines meditation and aerobic exercise, is currently being used to help women learn to recover from traumatic life experiences, especially those related to sexual violence and abuse.

Noise induced hearing loss impairs spatial learning/memory and hippocampal neurogenesis in mice

Hearing loss has been associated with cognitive decline in the elderly and is considered to be an independent risk factor for dementia. One of the most common causes for acquired sensorineural hearing loss is exposure to excessive noise, which has been found to impair learning ability and cognitive performance in human subjects and animal models. Noise exposure has also been found to depress neurogenesis in the hippocampus. However, the effect is mainly attributed to the oxidant stress of noise on the cognitive brain. In the present study, young adult CBA/CAJ mice (between 1.5 and 2 months of age) were briefly exposed a high sound level to produce moderate-to-severe hearing loss. In both the blood and hippocampus, only transient oxidative stress was observed after noise exposure. However, a deficit in spatial learning/memory was revealed 3 months after noise exposure. Moreover, the deficit was correlated with the degree of hearing loss and was associated with a decrease in neurogenesis in the hippocampus. We believe that the observed effects were likely due to hearing loss rather than the initial oxidant stress, which only lasted for a short period of time.

MAP training: combining meditation and aerobic exercise reduces depression and rumination while enhancing synchronized brain activity

Mental and physical (MAP) training is a novel clinical intervention that combines mental training through meditation and physical training through aerobic exercise. The intervention was translated from neuroscientific studies indicating that MAP training increases neurogenesis in the adult brain. Each session consisted of 30 min of focused-attention (FA) meditation and 30 min of moderate-intensity aerobic exercise. Fifty-two participants completed the 8-week intervention, which consisted of two sessions per week. Following the intervention, individuals with major depressive disorder (MDD; n=22) reported significantly less depressive symptoms and ruminative thoughts. Typical healthy individuals (n=30) also reported less depressive symptoms at follow-up. Behavioral and event-related potential indices of cognitive control were collected at baseline and follow-up during a modified flanker task. Following MAP training, N2 and P3 component amplitudes increased relative to baseline, especially among individuals with MDD. These data indicate enhanced neural responses during the detection and resolution of conflicting stimuli. Although previous research has supported the individual beneficial effects of aerobic exercise and meditation for depression, these findings indicate that a combination of the two may be particularly effective in increasing cognitive control processes and decreasing ruminative thought patterns.

The Subjective Health Horizon Questionnaire (SHH-Q): Assessing Future Time Perspectives for Facets of an Active Lifestyle

BACKGROUND

A wider subjective time horizon is assumed to be positively associated with longevity and vitality. In particular, a lifestyle with exposure to novel and varied information is considered beneficial for healthy cognitive aging. At present, measures that specifically assess individuals' perceived temporal extension to engage in active lifestyles in the future are not available.

OBJECTIVES

We introduce and validate a new self-report measure, the Subjective Health Horizon Questionnaire (SHH-Q). The SHH-Q assesses individuals' future time perspectives in relation to four interrelated but distinct lifestyle dimensions: (1) novelty-oriented exploration (Novelty), (2) bodily fitness (Body), (3) work goals (Work), and (4) goals in life (Life Goals). The present study aims at: (a) validating the hypothesized factor structure of the SHH-Q, according to which the SHH-Q consists of four interrelated but distinct subscales, and (b) testing the hypothesis that the Novelty and Body subscales of the SHH-Q show positive and selective associations with markers of cognition and somatic health, respectively.

METHODS

Using structural equation modeling, we analyzed data from 1,371 healthy individuals (51% women) with a mean age of 70.1 years (SD = 3.6) who participated in the Berlin Aging Study II (BASE-II) and completed the SHH-Q.

RESULTS

As predicted, the SHH-Q formed four correlated but distinct subscales: (1) Novelty, (2) Body, (3) Work, and (4) Life Goals. Greater self-reported future novelty orientation was associated with higher current memory performance, and greater future expectations regarding bodily fitness with better current metabolic status.

CONCLUSION

The SHH-Q reliably assesses individual differences in four distinct dimensions of future time perspective. Two of these dimensions, Novelty and Body, show differential associations with cognitive status and somatic health. The SHH-Q may serve as a tool to assess how different facets of future time perspective relate to somatic health, cognition, motivation, and affect, and may help to identify the socioeconomic and individual antecedents, correlates, and consequences of an active lifestyle.

Sexual Conspecific Aggressive Response (SCAR): A Model of Sexual Trauma that Disrupts Maternal Learning and Plasticity in the Female Brain

Sexual aggression can disrupt processes related to learning as females emerge from puberty into young adulthood. To model these experiences in laboratory studies, we developed SCAR, which stands for Sexual Conspecific Aggressive Response. During puberty, a rodent female is paired daily for 30-min with a sexually-experienced adult male. During the SCAR experience, the male tracks the anogenital region of the female as she escapes from pins. Concentrations of the stress hormone corticosterone were significantly elevated during and after the experience. Moreover, females that were exposed to the adult male throughout puberty did not perform well during training with an associative learning task nor did they learn well to express maternal behaviors during maternal sensitization. Most females that were exposed to the adult male did not learn to care for offspring over the course of 17 days. Finally, females that did not express maternal behaviors retained fewer newly-generated cells in their hippocampus whereas those that did express maternal behaviors retained more cells, most of which would differentiate into neurons within weeks. Together these data support SCAR as a useful laboratory model for studying the potential consequences of sexual aggression and trauma for the female brain during puberty and young adulthood.

Rethinking psychopharmacotherapy: The role of treatment context and brain plasticity in antidepressant and antipsychotic interventions

Emerging evidence indicates that treatment context profoundly affects psychopharmacological interventions. We review the evidence for the interaction between drug application and the context in which the drug is given both in human and animal research. We found evidence for this interaction in the placebo response in clinical trials, in our evolving knowledge of pharmacological and environmental effects on neural plasticity, and in animal studies analyzing environmental influences on psychotropic drug effects. Experimental placebo research has revealed neurobiological trajectories of mechanisms such as patients' treatment expectations and prior treatment experiences. Animal research confirmed that "enriched environments" support positive drug effects, while unfavorable environments (low sensory stimulation, low rates of social contacts) can even reverse the intended treatment outcome. Finally we provide recommendations for context conditions under which psychotropic drugs should be applied. Drug action should be steered by positive expectations, physical activity, and helpful social and physical environmental stimulation. Future drug trials should focus on fully controlling and optimizing such drug×environment interactions to improve trial sensitivity and treatment outcome.

Vascular hippocampal plasticity after aerobic exercise in older adults

Aerobic exercise in young adults can induce vascular plasticity in the hippocampus, a critical region for recall and recognition memory. In a mechanistic proof-of-concept intervention over 3 months, we investigated whether healthy older adults (60-77 years) also show such plasticity. Regional cerebral blood flow (rCBF) and volume (rCBV) were measured with gadolinium-based perfusion imaging (3 Tesla magnetic resonance image (MRI)). Hippocampal volumes were assessed by high-resolution 7 Tesla MRI. Fitness improvement correlated with changes in hippocampal perfusion and hippocampal head volume. Perfusion tended to increase in younger, but to decrease in older individuals. The changes in fitness, hippocampal perfusion and volume were positively related to changes in recognition memory and early recall for complex spatial objects. Path analyses indicated that fitness-related changes in complex object recognition were modulated by hippocampal perfusion. These findings indicate a preserved capacity of the aging human hippocampus for functionally relevant vascular plasticity, which decreases with progressing age.

Early Life in a Barren Environment Adversely Affects Spatial Cognition in Laying Hens (Gallus gallus domesticus)

Spatial cognition in vertebrates is adversely affected by a lack of environmental complexity during early life. However, to our knowledge, no previous studies have tested the effect of early exposure to varying degrees of environmental complexity on specific components of spatial cognition in chickens. There are two main rearing systems for laying hens in the EU: aviaries and cages. These two systems differ from one another in environmental complexity. The aim of the present study was to test the hypothesis that rearing in a barren cage environment relative to a complex aviary environment causes long-lasting deficits in the ability to perform spatial tasks. For this purpose, 24 white Dekalb laying hens, half of which had been reared in an aviary system and the other half in a conventional cage system, were tested in a holeboard task. Birds from both treatment groups learnt the task; however, the cage-reared hens required more time to locate rewards and had poorer levels of working memory. The latter finding supports the hypothesis that rearing in a barren environment causes long-term impairment of short-term memory in chickens.

The motirod: a novel physical skill task that enhances motivation to learn and thereby increases neurogenesis especially in the female hippocampus

Males and females perform differently on a variety of training tasks. In the present study we examined performance of male and female rats while they were trained with a gross motor skill in which they learn to maintain their balance on an accelerating rotating rod (the accelerating rotarod). During training, many animals simply step off the rod, thus terminating the training. This problem was addressed by placing cold water below the rod. We termed the new training procedure "motirod" training because the trained animals were apparently motivated to remain on the rod for longer periods of time. Groups of male and female adult Sprague-Dawley rats were trained on either the standard accelerating rotarod or the motirod for four trials per day on four consecutive days. Latency to fall from the rod (in seconds) was recorded. The motivating feature increased performance especially in females (p=.001). As a consequence of enhanced performance, females retained significantly more new cells in the dentate gyrus of the hippocampus than those trained on the accelerating rotarod or those that received no training. In addition, individuals that learned well retained more new cells, irrespective of sex or task conditions. Previous studies have established that new cells rescued from death by learning remain in the hippocampus for months and mature into neurons (Leuner et al., 2004a; Shors, 2014). These data suggest that sex differences in physical skill learning can arise from sex differences in motivation, which thereby influence how many new neurons survive in the adult brain. This article is part of a Special Issue entitled SI: Brain and Memory.

Mental and Physical (MAP) Training: a neurogenesis-inspired intervention that enhances health in humans

New neurons are generated in the hippocampus each day and their survival is greatly enhanced through effortful learning (Shors, 2014). The numbers of cells produced can be increased by physical exercise (van Praag, Kempermann, & Gage, 1999). These findings inspired us to develop a clinical intervention for humans known as Mental and Physical Training, or MAP Training. Each session consists of 30min of mental training with focused attention meditation (20min sitting and 10min walking). Meditation is an effortful training practice that involves learning about the transient nature of thoughts and thought patterns, and acquiring skills to recognize them without necessarily attaching meaning and/or emotions to them. The mental training component is followed by physical training with 30min of aerobic exercise performed at moderate intensity. During this component, participants learn choreographed dance routines while engaging in aerobic exercise. In a pilot "proof-of-concept" study, we provided supervised MAP Training (2 sessions per week for 8weeks) to a group of young mothers in the local community who were recently homeless, most of them having previously suffered from physical and sexual abuse, addiction, and depression. Preliminary data suggest that MAP Training improves dependent measures of aerobic fitness (as assessed by maximal rate of oxygen consumed) while decreasing symptoms of depression and anxiety. Similar changes were not observed in a group of recently homeless women who did not participate in MAP Training. It is not currently possible to determine whether new neurons in the human brain increase in number as a result of MAP Training. Rather these preliminary results of MAP Training illustrate how neuroscientific research can be translated into novel clinical interventions that benefit human health and wellness.

Not only cardiovascular, but also coordinative exercise increases hippocampal volume in older adults

Cardiovascular activity has been shown to be positively associated with gray and white matter volume of, amongst others, frontal and temporal brain regions in older adults. This is particularly true for the hippocampus, a brain structure that plays an important role in learning and memory, and whose decline has been related to the development of Alzheimer's disease. In the current study, we were interested in whether not only cardiovascular activity but also other types of physical activity, i.e., coordination training, were also positively associated with the volume of the hippocampus in older adults. For this purpose we first collected cross-sectional data on "metabolic fitness" (cardiovascular fitness and muscular strength) and "motor fitness" (e.g., balance, movement speed, fine coordination). Second, we performed a 12-month randomized controlled trial. Results revealed that motor fitness but not metabolic fitness was associated with hippocampal volume. After the 12-month intervention period, both, cardiovascular and coordination training led to increases in hippocampal volume. Our findings suggest that a high motor fitness level as well as different types of physical activity were beneficial to diminish age-related hippocampal volume shrinkage or even increase hippocampal volume.

Preparing for adulthood: thousands upon thousands of new cells are born in the hippocampus during puberty, and most survive with effortful learning

The dentate gyrus of the hippocampal formation generates new granule neurons throughout life. The number of neurons produced each day is inversely related to age, with thousands more produced during puberty than during adulthood, and many fewer produced during senescence. In adulthood, approximately half of these cells undergo apoptosis shortly after they are generated. Most of these cells can be rescued from death by effortful and successful learning experiences (Gould et al., 1999; Waddell and Shors, 2008; Curlik and Shors, 2011). Once rescued, the newly-generated cells differentiate into neurons, and remain in the hippocampus for at least several months (Leuner et al., 2004). Here, we report that many new hippocampal cells also undergo cell death during puberty. Because the juvenile brain is more plastic than during adulthood, and because many experiences are new, we hypothesized that a great number of cells would be rescued by learning during puberty. Indeed, adolescent rats that successfully acquired the trace eyeblink response retained thousands more cells than animals that were not trained, and those that failed to learn. Because the hippocampus generates thousands more cells during puberty than during adulthood, these results support the idea that the adolescent brain is especially responsive to learning. This enhanced response can have significant consequences for the functional integrity of the hippocampus. Such a massive increase in cell proliferation is likely an adaptive response as the young animal must emerge from the care of its mother to face the dangers, challenges, and opportunities of adulthood.

Impact of hippocampal neuronal ablation on neurogenesis and cognition in the aged brain

Neuronal loss is the most common and critical feature of a spectrum of brain traumas and neurodegenerative disorders such as Alzheimer's disease (AD). The capacity to generate new neurons in the central nervous system diminishes early during brain development and is restricted mainly to two brain areas in the mature brain: subventricular zone and subgranular zone. Extensive research on the impact of brain injury on endogenous neurogenesis and cognition has been conducted primarily using young animals, when neurogenesis is most active. However, a critical question remains to elucidate the effect of brain injury on endogenous neurogenesis and cognition in older animals, which is far more relevant for age-related neurodegenerative disorders such as AD. Therefore, we examined the impact of neuronal loss on endogenous neurogenesis in aged animals using CaM/Tet-DTA mice, a transgenic model of hippocampal cell loss. Additionally, we investigated whether the upregulation of adult neurogenesis could mitigate cognitive deficits following substantial hippocampal neuronal loss. Our findings demonstrate that aged CaM/Tet-DTA mice that sustain severe neuronal loss exhibit an upregulation of endogenous neurogenesis. However, despite this significant upregulation, neurogenesis alone is not able to mitigate the cognitive deficits observed. Our studies suggest that the aged brain has the capacity to stimulate neurogenesis post-injury; however, multiple therapeutic approaches, including upregulation of endogenous neurogenesis, will be necessary to recover brain function after severe neurodegeneration.