Title:
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Examining functional plasticity in the human brain
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The ability to quickly learn and adapt behaviour is critical to animal survival. Recent evidence has shown that short-term training can induce widespread changes in the neural activity across the brain. In this thesis, I conducted a series of studies that examined the behavioural and neural consequences of short-term training in humans. In Chapter 3, I showed that resting-state functional connectivity could detect task- specific changes. However, I also observed changes that were not task-specific, and even occurred when participants had no training. This experiment demonstrates that resting-state functional connectivity is an appropriate tool for studying plasticity and also highlights the importance of experimental controls in plasticity research. In Chapter 4 and 5, I investigated the impact of reward and punishment on performance during skill learning. In Chapter 4, I focused on how task-demands interact with skill the learning, and in Chapter 5, I focused on whether the learner's intention to learn modifies the impact of reward and punishment. In Chapter 6, I used resting-state fMRI to elucidate the impact of reward and punishment on the neural activity evoked by training on two different tasks. I determined that reward and punishment evoked different neural patterns after training, but that the precise regions affected by feedback processing depended on the task being trained. In Chapter 7, I conducted a preliminary investigation into the neurochemical basis of resting-state functional connectivity using a novel MRSI technique. I found a preliminary link between the distribution of the inhibitory neurotransmitter GABA and network-level functional connectivity. I also found that the interaction between GABA concentration and network-level functional connectivity may be associated with sensorimotor performance. Collectively, these studies demonstrate the short-term training induces wide- spread changes throughout the brain. These changes are influenced by the task being trained as well as contextual influences. In addition, these findings raise new questions into the physiological basis of network level plasticity that can be addressed in the future.
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