A Systematic Look at Environmental Modulation and Its Impact in Brain Development

Several experimental procedures are currently used to investigate the impact of the environment on brain plasticity under physiological and pathological conditions. The available methodologies are aimed at obtaining global or specific reductions or intensifications of the stimuli, with initial standardization in animal models being paralleled by translational applications to humans. More procedures can be combined together or applied in series to obtain powerful experimental paradigms, and the choice of a given setting should take into account the specific genetic background, age, and phenotypic vulnerabilities of the target subjects. Sophisticated use of environmental manipulations can increase our knowledge of the mechanisms underlying experience-dependent plasticity, opening the way for new therapies for neurodevelopmental disorders, dysfunctions of plasticity, and brain aging. A large number of experimental procedures are being used to investigate the impact of the environment on brain plasticity, calling for a standardization of the available possibilities. The most widely used interventions are aimed at either enhancing or reducing the intensity of stimuli, focusing either on specific sensory channels or acting in a multi-domain manner. Combining different environmental manipulations together can result in new powerful settings aimed at investigating neural plasticity and the underlying molecular mechanisms. The effects, positive or negative, elicited by one environmental manipulation can often be reversed by the successive application of a different procedure that has an effect in the opposite direction, offering windows for therapeutic applications. The outcome of a given set of environmental modulations can be highly age-dependent. Strong gene × environment interactions must be taken into account, with the impact of environmental procedures being influenced by the specific genetic background of the individual.