Neurogenic plasticity and brain development

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The production of new neurons in the brain, a process called neurogenesis, continues throughout life. This is made possible by the existence of small populations of stem cells that persist in defined regions of the brain (called stem cell niches) that undergo cell division to produce new neurons functionally integrating into existing neural circuits. Research over the last 20 years has shown that neurogenesis in the mature brain is not a passive process, but instead can be modified with respect to the rate of stem cell division, the type of new neurons produced, or the extent to which new neurons survive. This form of structural plasticity, referred to here as ‘neurogenic plasticity,' is thought to depend on mechanisms that are intrinsic to the brain interacting with the animal's environment. However, our understanding of this interaction is quite limited and this represents a topic of intense interest in the field. Our research investigates how an animal's external environment influences neurogenesis in the brain and whether this affects behaviour.***The long-term objective of our NSERC-funded research is to use zebrafish to gain novel insight into the molecular and cellular basis of environment-induced neurogenic plasticity in the brain. To accomplish this objective, we have developed a research proposal that will address three experimental aims. First, we will explore how altering visual cues can modify neurogenesis in distinct stem cell niches in the brain. By utilizing genetic methods, we can trace when new neurons are born, what part of the brain they originate from, and identify the type of neuron they become. We will perform these experiments under standard environmental conditions as well as visually altered environments to determine how sensory input affects neurogenesis. Second, we will examine the impact that a change in sensory environment has on behaviour and whether neurogenesis itself is necessary for these effects. A digital tracking system will be used to see if vision-dependent movement is affected as animals experience an altered visual environment, and genetic methods will be used to specifically block neurogenesis to see if this has the same effect on behaviour. Finally, using both genetic and genomic technologies, we will investigate the extent to which different molecular signalling pathways serve as mechanistic links that modify neurogenesis output in response to a changing visual environment.***Our research will elucidate mechanisms of experience induced neurogenic plasticity for a deeper understanding of the fundamental relationship between the environment, brain structure, and behaviour. Beyond developmental neuroscience, our work will have broad implications for other fields of research with a focus on animal-environment interactions, such as behavioural ecology, cognitive neuroscience, and neural repair and rehabilitation.**