All ETDs from UAB

Advisory Committee Chair

Rajesh K Kana

Advisory Committee Members

Sarah O'Kelley

Maria Hopkins

Adrian H Thurstin

Kristina Visscher

Document Type

Dissertation

Date of Award

2014

Degree Name by School

Doctor of Philosophy (PhD) College of Arts and Sciences

Abstract

Deficits in imitation have been widely reported in children and adolescents with autism spectrum disorders (ASD). A proposed dysfunction of the mirror neuron system (MNS), the neural network underlying imitation, has been the subject of recent debate in ASD literature. However, while some research has found evidence of MNS abnormalities in ASD, recent studies have cast doubt onto the mirror neuron hypothesis of ASD as it is currently depicted. There is also behavioral evidence that the imitation deficit is not unitary, and therefore may not have one-to-ne correspondence with a malfunction of all aspects of MNS. Since functional imitation involves more than mirroring actions, a more complete understanding of the imitation deficit in ASD requires the analysis of the MNS in the context of the component skills comprising imitation and the wider neural networks involved in these skills. The current set of studies examined the component skills required for imitation and the role of the MNS functioning in autism at focal as well as network levels. The three functional MRI experiments that are part of this project investigated the functional integrity of the MNS using tasks involving visuospatial rotation, mental imitation, and motor imitation. For each study, behavioral, brain activation, functional connectivity, and brain-behavior relationships were analyzed. Results indicated that the ASD participants in this showed intact ability, reflected by their performance, in all tasks. However, the neural route with which tasks were accomplished differed between the TD and ASD groups. Specifically, aberrant activation and functional connectivity patterns were found for ASD participants in each of the three studies. Neural responses emerging from these studies indicated alterations in the regulation of the MNS by other neural systems. Altered neural responses were also found to be correlated with autism symptomatology. The findings of this project provide important insights into the neural and cognitive mechanism underlying imitation in children and adolescents with autism. Implications of these findings for future research as well as clinical applications addressing imitation deficits in ASD are discussed.

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