Visual feature-tolerance in the reading network.

A century of neurology and neuroscience shows that seeing words depends on ventral occipital-temporal (VOT) circuitry. Typically, reading is learned using high-contrast line-contour words. We explored whether a specific VOT region, the visual word form area (VWFA), learns to see only these words or recognizes words independent of the specific shape-defining visual features.

Spelling and reading: using visual sensitivity to explore shared or separate orthographic representations.

Do we use the same neurocognitive mechanisms to spell that we do to read? There is a considerable number of conflicting findings, such that evidence has been provided to support common mechanisms for reading and spelling, while other research supports the proposal that reading and spelling utilise unique neurocognitive resources. Sensitivity to visual spatial-frequency doubling (FD) has been demonstrated to correlate with and specifically predict orthographic processing when reading; therefore, if spelling and reading share some elements of orthographic representation, sensitivity to FD should similarly correlate with, and predict, spelling ability by virtue of this shared association. A double dissociation between reading and spelling was found such that sensitivity to the FD task, as mediated by the visual dorsal stream, predicted reading ability but not spelling, while the visual control task predicted spelling but not reading ability, in poor readers/spellers.

Predicting early reading skills from pre-reading measures of dorsal stream functioning.

It is well documented that good reading skills may be dependent upon adequate dorsal stream processing. However, the degree to which dorsal stream deficits play a causal role in reading failure has not been established. This study used coherent motion and visual frequency doubling to examine whether dorsal stream sensitivity measured before the commencement of formal reading instruction can predict emerging literacy skills in Grade 1.

Visual deficits in pre-readers at familial risk for dyslexia.

Visual processing deficits in dyslexic readers are argued to evolve as a consequence of reading failure. This study examines dorsal stream functioning of children before they commence formal reading instruction to determine whether visual deficits precede reading difficulties. Coherent motion and visual frequency doubling detection were measured in children at familial risk for dyslexia and in children unselected for family reading history.

Making the link between dorsal stream sensitivity and reading.

Different levels of dorsal stream functioning were teased apart to determine whether the observed deficits in dyslexic readers may exist as early as the retinal level, and to explore the relative contribution that the different aspects of dorsal processing may make to reading. The paradigm combining frequency doubled stimuli with endogenous cueing demonstrated that dyslexic readers possess a retinal level magnocellular deficit. Regression analyses provided evidence to suggest that different levels of dorsal processing relates to various aspects of reading skills, with low-level magnocellular M(y) processing relating to reading accuracy and irregular word reading, and dorsal stream functioning relating to all aspects of reading skills, including nonword reading.