Does the enriched environment alter memory capacity in malnourished rats by modulating BDNF expression?

Riding waves to improve functioning: a quantitative evaluation of a Surf Week in individuals with chronic phase brain injury with six months follow-up

PURPOSE

Environmental enrichment seems to enable people in the chronic phase of acquired brain injury (ABI) to experience new functional abilities and motor/coping strategies and consequently to become more adaptable which might prevent/reverse functional decline. This study describes the influence of a five-days Surf Week program on participants on physical function, self-efficacy, functional balance performance and self-perceived recovery.

MATERIALS AND METHODS

A multiple-baseline single-case design was used. Adults participating in the Surf Week in chronic phase of ABI were eligible to participate. Participants completed a battery of tests monitoring physical function, self-efficacy, functional balance performance and self-perceived recovery. This battery was repeated 5 times over a 1-year period, two times pre-Surf Week, three times post-Surf Week. Visual data inspection with two non-overlap methods were used to determine if patients showed sustained improvement in outcomes post-intervention.

RESULTS

A moderate to strong indication for improvements on physical function, functional balance performance and self-perceived recovery exists till six months follow-up. No indication was observed on self-efficacy till six months follow-up.

CONCLUSIONS

A five-days Surf Week is a physically, cognitively and socially intensive stimulating activity that can positively challenge individuals after ABI and seems to improve physical functioning, functional balance performance and self-perceived recovery.

Gestational environmental enrichment prevents chronic social stress induced anxiety- and ethanol-related behaviors in offspring

Epidemiological surveys have shown a strong relationship between maternal stress and offspring's mood disorders. Growing evidence suggested that environmental enrichment (EE) improves cognitive function in models of psychiatric and neurological disorders. However, the potential protective effects of gestational EE on social stress-elicited mood disorders in offspring have not been studied. Knowing that the undeveloped brain is more sensitive to gestational environmental stimuli, we hypothesized that initiating cognitive stimulation, during gestation, would protect against social stress-induced behavioral alterations in adulthood. Therefore, the present study aimed to investigate the effects of gestational EE on social stress-elicited anxiety- and ethanol-related behaviors in adult offspring. EE consisted of free access, of dams, to tubular devices of different shapes, colors, and sizes that were changed regularly. After birth and weaning, young adult offspring were exposed to 19 days of social stress and anxiety-like behavior was evaluated by elevated plus maze, open field, and marbles burying tests. The two-bottle choice (TBC) drinking paradigm was used to assess stress-induced ethanol intake. Results showed that gestational EE prevented social stress-elicited anxiogenic-like effects with no differences in spontaneous locomotor activity. Moreover, in the TBC paradigm, mice pre-exposed to EE consistently showed a significantly decreased consumption and preference for ethanol with no effects on tastants' intakes. Interestingly, gestational EE increased serum BDNF levels, which showed a correlation with measures of anxiety- and ethanol-related behaviors. These findings indicate that some neurodevelopmental changes associated with prenatal EE may counteract adult social stress-induced behavioral alterations through a BDNF mechanism. Therefore, we propose that gestational EE has significant protective and beneficial effects on social stress-induced cognitive impairment. It can also alleviate anxiety-like behavior and subsequent excessive alcohol consumption.

The effects of physical activity on glutamate neurotransmission in neuropsychiatric disorders

Physical activity (PA) is an effective way of increasing cognitive and emotional health and counteracting many psychiatric conditions. Numerous neurobiological models for depression have emerged in the past 30 years but many struggle to incorporate the effects of exercise. The hippocampus and pre-frontal cortex (PFC) containing predominantly glutamate neurotransmission, are the centres of changes seen in depression. There is therefore increasing interest in glutamatergic systems which offers new paradigms of understanding mechanisms connecting physical activity, stress, inflammation and depression, not explained by the serotonin theories of depression. Similar hippocampal glutamate dysfunction is observed in many other neuropsychiatric conditions. Excitatory glutamate neurones have high functionality, but also high ATP requirements and are therefore vulnerable to glucocorticoid or pro-inflammatory stress that causes mitochondrial dysfunction, with synaptic loss, culminating in depressed mood and cognition. Exercise improves mitochondrial function, angiogenesis and synaptogenesis. Within the glutamate hypothesis of depression, the mechanisms of stress and inflammation have been extensively researched, but PA as a mitigator is less understood. This review examines the glutamatergic mechanisms underlying depression and the evidence of physical activity interventions within this framework. A dynamic glutamate-based homeostatic model is suggested whereby stress, neuroinflammation and PA form counterbalancing influences on hippocampal cell functionality, which manifests as depression and other neuropsychiatric conditions when homeostasis is disrupted.