Thesis

Interactions between the pre-fontal cortex and temporal lobe in visual working memory : an EEG study

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Awarding institution
  • University of Strathclyde
Date of award
  • 2012
Thesis identifier
  • T13268
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Department, School or Faculty
Abstract
  • This study considered visual working memory and the brain's ability to encode and store an internal representation of an external visual stimulus for comparison to other visual stimuli. Visual working memory relies on interactions between the visual association area of the pre-frontal cortex and the inferior temporal lobe. The primary focus of this research was to collect electrophysiological evidence of communication between these regions whilst determining the upload and download mechanisms involved in temporo-frontal interactions. The experimental protocol utilised a modified sequential matching task, whereby a subject was asked to attend to a series of view-invariant fractal images, each followed by a fixation cross, the colour of which signalled the subject to either 'store' or 'ignore' the image. The participant then had to determine if subsequent images matched the stored image. This method forced the subject to give each image the same level of concentration. It was proposed that the 'store' and 'match' processes would require temporo-frontal interactions with information flowing in opposite directions, whilst the 'ignore' process would be restricted to the temporal lobe. Using the standard 10/20 setup, a 64-channel electroencephalographic (EEG) system was used to record brain activity whilst the subject was engaged in the task. A classification algorithm was developed to select an optimal distribution of electrodes across the scalp. Time domain event-related potentials (ERPs) associated with the 'store', 'ignore' and 'match' processes were then calculated and compared. Results confirmed the original hypothesis in that interaction between the temporal lobe and pre-frontal cortex was identified. A statistical analysis revealed differential activity within the temporal lobe indicative of the temporary storage of visual information. Synchronous activity between the temporal lobe and pre-frontal cortex was observed during image recall and match recognition processes. Finally, an ERP analysis revealed further evidence of transient activity associated with visual working memory processes.
Resource Type
DOI
Date Created
  • 2012
Former identifier
  • 948604

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