Neuroplasticity in songbirds: how changing behaviour and experience affect learning and the brain

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Over the course of a year, animals must change their behaviour in response to their changing environment. For example, birds use changes in day length or availability of resources as a cue to tell them when to breed or when not to breed. Animals must also adapt their behaviour to different situations on a daily basis: females may hear and evaluate a potential mate and learn to respond to that male's vocalizations. In order to change behaviour, the brain must have the potential and capacity to change as well. It is therefore important to measure how environmental change affects the brain. My research program aims to understand the neuroplasticity that occurs in response to the environment resulting in appropriate behavioural response. To do this, I study how both breeding condition (the physiological state of animal as ready to breed or not) and learning affect the brain of two species of songbirds: black-capped chickadees and zebra finches. Black-capped chickadees are seasonal breeders they respond to changes in day length, and in turn their behaviour and brains change with the season. In spring when in breeding condition, they sing more songs and regions in their brain important for song are larger than when they are in non-breeding condition. In winter, when in non-breeding condition, they spend a lot of time hiding and retrieving seeds (a task requiring spatial learning memory for “where”) and the hippocampus, a brain region critical for spatial memory, has more new neurons (neurogenesis) than at other times of year. One study I will perform will be to determine whether performing a task appropriate to the season (discriminating among songs when in breeding condition, remembering where seeds are hidden when in non-breeding condition) helps more new neurons live longer than when performing a task not appropriate to the season. This will tell us whether breeding condition, learning, or both affect neuroplasticity. Zebra finches are opportunistic breeders they respond to changes in resource availability, however much less is known about how their brains change depending on breeding condition. I will study how neural activity and neurogenesis (cell birth and survival) are affected by breeding condition in zebra finches by exposing some birds to resources such as a mate and nesting materials and comparing their brains to those without resources. I will also study whether exposure to a difficult learning task promotes neurogenesis compared to birds that do not perform a cognitively enriching task, to determine whether active learning helps more new neurons live longer. I will integrate the results of my experiments to achieve my long-term goal of determining how behavioural change in response to internal (breeding condition) and external factors (experience) affect neuroplasticity. My results have the potential to impact understanding of behavioural and neuroplasticity in songbirds and other organisms.