Most of human brain research has focused on the cerebral cortex, but the subcortical structures such as the thalamus play important roles in controlling the flow of information in the brain.
Larissa McKetton, a PhD student in the Department of Biology, Faculty of Graduate Studies, used this observation as a basis for her master’s thesis project titled, Abnormal visual system development in human albinism: a review of developmental mechanisms and measurement of the lateral geniculate nucleus and optic chiasm using high resolution mri. On Friday, Feb. 15, she was awarded the inaugural Marian Regan Prize for Best Master’s Thesis in a vision-related topic.
Larissa McKetton (centre) was awarded the first Marian Regan Prize for Best Master’s Thesis. Fran Wilkinson (left), professor of psychology in the Faculty of Health, chaired the award committee and the prize was presented by Professor Laurence Harris (right), director of the Centre for Vision Research.
McKetton examined the development of the subcortical visual system in human albinism using high-resolution magnetic resonance imaging (MRI), specifically in individuals with albinism.
The results of McKetton’s award-winning master’s research project will not only help create an understanding of the specific visual deficits that occur in people with albinism, but also by studying how the thalamus develops and adapts to abnormal input, vision researchers will be better able to understand the functioning of the brain in general.
“Albinism is a genetic condition that results in hypopigmentation of the skin and also alters retinal development and affects the rest of the visual system,” said McKetton. “People with albinism have a number of difficulties with their vision. One of the most striking changes in the brain in albinism is that a large fraction of the nerve fibres in the optic nerve from the eye cross to the wrong side of the brain.
“These abnormally crossed fibres connect to the lateral geniculate nucleus (LGN) in the thalamus and alter its development and structure. The LGN is a small visual nucleus that is the main relay and control structure of visual information between the eye and the rest of the brain,” she said. "I made unprecedented measurements in living humans with albinism and found statistically smaller LGN, optic chiasm, optic tract and optic nerve sizes in subjects with albinism compared to individuals without albinism.
“The measurements are the first steps in investigating the structural changes in the brain caused by albinism,” she said. “In addition, I performed experimental high-resolution scans to try to resolve the eye-specific layers in the LGN.”
McKetton’s project was supervised by York biology Professor Keith Schneider in the Faculty of Science. The committee awarding the prize was chaired by Fran Wilkinson, professor of psychology in the Faculty of Health. It was presented to McKetton by Professor Laurence Harris, director of the Centre for Vision Research.
More about Marian Regan
The prize is named for Prof. Marian P. Regan (1937-2010), who was a beloved member of the Centre for Vision Research and the wife of professor emeritus David Martin Regan. Marian was born in Folkstone in England but her family soon moved to London. Marian Regan was evacuated to a farm in Wales with her brother and sister during the Second World War. She read mathematics at London University, where she met her future husband in 1956. Mrs. Regan taught mathematics in a girl’s grammar school in London. After moving to Newcastle-under-
Lyme in 1965, where her husband was employed at Keele University, she continued teaching mathematics.
Marian Regan
In 1975, the Regans moved to Dalhousie University. It was there that Marian Regan completed a master’s degree in mathematics while her two sons were at school. In 1986, David and Marian Regan moved to York University, where Marian Regan developed a novel mathematical technique for modelling nonlinear systems, such as the human visual and auditory systems. She was awarded a PhD under the supervision of Professor Ralph Nichols, then Chair of the Department of Physics, and went on to use her technique to model human steady-state electrical and magnetic brain responses to visual and auditory stimulation. She published papers in numerous journals, including Vision Research, Auditory Research, Brain Research, Experimental Brain Research, Biological Cybernetic, and the Canadian Journal of Neuroscience. Marian Regan died on April 17, 2010.