Task load modulation of tDCS effects on behavioural and neural correlates of phonological processing: a brain-state-dependent stimulation approach

Rodrigues de Almeida, Lílian (2019). Task load modulation of tDCS effects on behavioural and neural correlates of phonological processing: a brain-state-dependent stimulation approach. University of Birmingham. Ph.D.

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Abstract

This thesis investigates the task load modulation of transcranial direct current stimulation (tDCS) effects on the behavioural and neural correlates of phonological processing in the healthy, dyslexic and aphasic brain. Tasks selected from a range of speech perception to speech production were assumed to engage the two main regions of the dorsal pathway of phonological processing, the targets left inferior frontal gyrus (LIFG) and left superior temporal gyrus (LSTG), differently: increasing engagement for the LIFG and decreasing engagement for the LSTG across the range. Anodal tDCS (facilitatory) and cathodal tDCS (inhibitory) were expected to have an effect as a direct function of target engagement with the task. Cathodal tDCS was also expected to induce indirect facilitation via network compensation negatively related to target engagement. These effects should be weaker in dyslexia and aphasia, and consistent with their altered pattern of brain activity. The findings suggest that task load modulation of tDCS effects occurred. Outcomes such as improved performance in a speech perception task caused by cathodal tDCS would suggest that cathodal tDCS induced network compensation. Results in dyslexia and aphasia were consistent with their altered pattern of brain activity, indicating that tDCS shows promise as both diagnosis and treatment tool.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):