Does the deaf auditory cortex have a role in cognition?

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When a sound is made in the environment, neurons fire in the auditory cortex of the brain, giving us the subjective experience of hearing. In congenitally deaf people, following a process known as crossmodal plasticity, this hearing machinery, rather than being redundant, is known to be used for functions such as vision and touch. However, my work suggests that the story may be more complicated. I have shown that the auditory cortex of the deaf is involved in working memory, the cognitive capacity that we use to keep and manipulate information in our mind. This finding suggests that the deaf auditory cortex may not only serve sensory functions, but also reorganise to become part of a cognitive control network. How is it that activity in the same cortex results in different perceptual experiences in deaf and hearing individuals? Moreover, how does a cortex that evolved to respond to sounds change its function to respond not only to vision and touch, but also to take on higher cognitive functions such as working memory? Proving these to be true would represent a profound change in our understanding of behaviour, cognition and the brain: namely that, as a consequence of sensory loss and neural reorganisation, parts of the brain that usually have sensory functions can change their role to primarily cognitive functions, and potentially modify our behaviour.Using functional magnetic resonance imaging (fMRI) to measure neural function in deaf and hearing individuals, and machine learning techniques, I aim to address the following questions: Is the deaf auditory cortex involved in multiple cognitive functions? Can it represent abstract task rules across sensory modalities? Furthermore, can deaf individuals strategically allocate cognitive resources to the auditory cortex?Over 5% of the world's population has a significant hearing loss, and results from this project will contribute evidence that can guide the development of better (re)habilitation and educational options to these individuals. Moreover, principles derived from this project can be applied to other types of sensory losses, and to the design of electronic devices that can restore missing brain functions (neural prostheses). Thus, this project will not only address a fundamental scientific question, but also has the potential of important benefits for society.