No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

No description available.

Infant vocalisations are uniquely salient sounds in the environment. They universally attract attention and compel the listener to respond with speed and care. They provide a wealth of information to parents about their infant’s needs and affective state. There is a scientific consensus that early parenting has a profound impact on child development. In particular, the sensitivity with which parents respond to their infant’s communicative cues has been shown to affect cognitive and socio-emotional outcomes. The mechanisms underlying such sensitivity are not well understood. In this thesis, adults’ sensitivity to infant cues will be considered in terms of two components, the ‘promptness’ and ‘appropriateness’ of responses, as originally conceptualised by Bell and Ainsworth (1972). Promptness of responses is considered in terms of adults’ ability to move with speed and effort after listening to infant vocalisations. Appropriateness, on the other hand, is considered in terms of adults’ ability to differentiate between functionally significant parameters in infant vocalisations. The effect of modifiable environmental factors on the promptness and appropriateness of responses is also investigated. Finally, a focused investigation of the brain basis of responses to infant vocalisations is presented. Overall, findings demonstrated that infant vocalisations undergo privileged, specialised processing in the adult brain. After hearing an infant cry, adults with and without depression were found to move with greater coordination and effort. Adults were also found to be attuned to subtle parameters in infant cries. This sensitivity was shown to be affected by two participant-level factors, depression and previous musical training. Furthermore, this sensitivity could be enhanced through intervention, as evidenced by findings from short-term, perceptual discrimination training. The notion of privileged processing of infant vocalisations is further supported by evidence of early discrimination of infant sounds in a survival-related subcortical brain structure. Future directions for this work include directly relating current experimental measures of adults’ responses to infant cues with parental sensitivity to infant communication during dynamic interactions. Translating current findings into applied settings would require an investigation of the effects of factors such as musical and perceptual training on sensitivity to infant cues in at-risk populations, such as mothers and fathers with depression. Lastly, an increased understanding of the brain basis of adults’ sensitivity to infant cues will provide insight into our greatest challenge: parenting our young.

Introduction: Exploring the brain for optimal locations for deep brain stimulation (DBS) therapy is a challenging task, which can be facilitated by analysis of DBS efficacy in a large number of patients with Parkinson’s disease (PD). The Unified Parkinson's Disease Rating Scale (UPDRS) scores indicate the DBS efficacy of the corresponding stimulation location in a particular patient. The spatial distribution of these clinical scores can be used to construct a functional model which closely models the expected efficacy of stimulation in the region. Designs and Methods: In this study, different interpolation techniques were investigated that can appropriately model the DBS efficacy for Parkinson’s disease patients. These techniques are linear triangulation based interpolation, ‘roving window’ interpolation and ‘Monopolar inverse weighted distance’ (MIDW) interpolation. The MIDW interpolation technique is developed on the basis of electric field geometry of the monopolar DBS stimulation electrodes, based on the DBS model of monopolar cathodic stimulation of brain tissues. Each of these models was evaluated for their predictability, interpolation accuracy, as well as other benefits and limitations. The bootstrapping based optimization method was proposed to minimize the observational and patient variability in the collected database. A simulation study was performed to validate that the statistically optimized interpolated models were capable to produce reliable efficacy contour plots and reduced false effect due to outliers. Some additional visualization and analysis tools including a graphic user interface (GUI) were also developed for better understanding of the scenario. Results: The interpolation performance of the MIDW interpolation, the linear triangulation method and Roving window method was evaluated as interpolation error as 0.0903, 0.1219 and0.3006 respectively. Degree of prediction for the above methods was found to be 0.0822, 0.2986 and 0.0367 respectively. The simulation study demonstrate that the mean improvement in outlier handling and increased reliability after bootstrapping based optimization (performed on Linear triangulation interpolation method) is 6.192% and 12.8775% respectively. The different interpolation techniques used to model monopolar and bipolar stimulation data is found to be useful to study the corresponding efficacy distribution. A user friendly GUI (PDRP_GUI) and other utility tools are developed. Conclusion: Our investigation demonstrated that the MIDW and linear triangulation methods provided better degree of prediction, whereas the MIDW interpolation with appropriate configuration provided better interpolation accuracy. The simulation study suggests that the bootstrapping-based optimization can be used as an efficient tool to reduce outlier effects and increase interpolated reliability of the functional model of DBS efficacy. Additionally, the differential interpolation techniques used for monopolar and bipolar stimulation modeling facilitate study of overall DBS efficacy using the entire dataset.