The Neural Processes Underpinning Visual Associative Memory: A Comparison of Young Grapheme- Colour Synaesthetes, Older Adults and Young Controls

Abstract

The traditional modular account of memory segregates visual associative memory and visual perception, with the former underpinned by the medial temporal lobes (MTL) and the latter by posterior visual regions. By contrast, the representational account of memory envisages visual associative memory as a perceptual-mnemonic continuum that can be traced from early visual cortex to anterior MTL structures. In this thesis, we tested these fundamentally different memory models by using a novel between-group design with young grapheme-colour synaesthetes, older adults and young controls, each of whom have their respective strengths and weaknesses in memory and perception. Specifically, grapheme-colour synaesthetes possess enhanced perceptual mechanisms, allowing them to experience black letters, words or digits as inherently coloured. They also show enhanced early visual cortex sensitivity in response to non-synaesthesia inducing stimuli (Barnett et al., 2008) as well as enhanced memory for verbal and visual stimuli. Using psychophysical techniques and functional magnetic resonance imaging (fMRI), we compared these three groups on a range of cognitive processes involved in visual associative memory: encoding, working memory, associative retrieval and recognition.

Date of Award	Mar 2015
Original language	English
Awarding Institution	University of Brighton