Overview

Visual perceptual abilities develop rapidly in infants, but considerable maturation occurs in preschool and elementary school-aged children. Several things can go wrong during the course of this development and a child may be left with visual deficits that interfere with different aspects of life. Of particular interest are motion and depth perception. The goal of our research is to understand the normal development of the underlying brain structures that control these perceptual abilities and to discover the changes in the brain that result in deficits. We focus specifically on a developmental visual disorder called amblyopia, or lazy eye, and a developmental reading disorder called dyslexia.

Publications

Neural Correlates of Speed-Tuned Motion Perception in Healthy Adults
Perception
Kimberly Meier, Marita Partanen, Deborah Giaschi
DOI: 10.1177/0301006618771463
06/2018

Disparity configuration influences depth discrimination in naïve adults, but not in children
Vision Research
Wilcox, L.M. and Hartle, B. and Solski, A. and Mackenzie, K.J. and Giaschi, D.
DOI: 10.1016/j.visres.2016.12.010
2017

Effect of spatial and temporal stimulus parameters on the maturation of global motion perception
Vision Research
Meier, K. and Giaschi, D.
DOI: 10.1016/j.visres.2017.04.004
2017

Unilateral amblyopia affects two eyes: Fellow eye deficits in amblyopia
Investigative Ophthalmology and Visual Science
Meier, K. and Giaschi, D.
DOI: 10.1167/iovs.16-20964
2017

Global motion perception in children with amblyopia as a function of spatial and temporal stimulus parameters
Vision Research
Meier, K. and Sum, B. and Giaschi, D.
DOI: 10.1016/j.visres.2016.06.011
2016

A case of Bilateral Perisylvian Syndrome with reading disability
Cortex
Eckert, M.A. and Berninger, V.W. and Hoeft, F. and Vaden, K.I. and Beaulieu, C. and Berninger, V. and Castellanos, X. and Chiarello, C. and Conway, T. and Cutting, L. and Dehaene-Lambertz, G. and Eden, G. and Frye, R. and Giaschi, D. and Gilger, J. and Hoeft, F. and Kibby, M. and van Krigstein, K. and Kronbichler, M. and Leonard, C. and Milham, M. and Odegard, T. and Poldrack, R. and Pugh, K. and Richards, T. and Rollins, N. and Schneider, K. and Talcott, J. and Wandell, B.
DOI: 10.1016/j.cortex.2016.01.004
2016

The effect of occlusion therapy on motion perception deficits in amblyopia
Vision Research
Giaschi, D. and Chapman, C. and Meier, K. and Narasimhan, S. and Regan, D.
DOI: 10.1016/j.visres.2015.05.015
2015

Flicker adaptation or superimposition raises the apparent spatial frequency of coarse test gratings
Vision Research
Kaneko, S. and Giaschi, D. and Anstis, S.
DOI: 10.1016/j.visres.2015.01.005
2015

Using Colors to Assess Pain in Toddlers: Validation of “The Rainbow Pain Scale”—A Proof-of-Principle Study
Journal of Pediatric Oncology Nursing
Mahon, P. and Holsti, L. and Siden, H. and Strahlendorf, C. and Turnham, L. and Giaschi, D.
DOI: 10.1177/1043454214555197
2015

The maturation of global motion perception depends on the spatial and temporal offsets of the stimulus
Vision Research
Meier, K. and Giaschi, D.
DOI: 10.1016/j.visres.2013.12.007
2014

On the typical development of stereopsis: Fine and coarse processing
Vision Research
Giaschi, D. and Narasimhan, S. and Solski, A. and Harrison, E. and Wilcox, L.M.
DOI: 10.1016/j.visres.2013.07.011
2013

Sparing of coarse stereopsis in stereodeficient children with a history of amblyopia
Journal of Vision
Giaschi, D. and Lo, R. and Narasimhan, S. and Lyons, C. and Wilcox, L.M.
DOI: 10.1167/13.10.17
2013

Cortical basis for dichotic pitch perception in developmental dyslexia
Brain and Language
Partanen, M., Fitzpatrick, K., Mädler, B., Edgell, D., Bjornson, B., Giaschi, D.E.
DOI: 10.1016/j.bandl.2012.09.002
2012

The Processing of Motion-Defined Form
Seeing Spatial Form
Giaschi, D.
DOI: 10.1093/acprof:oso/9780195172881.003.0008
2012

The effect of dot speed and density on the development of global motion perception
Vision Research
Narasimhan, S. and Giaschi, D.
DOI: 10.1016/j.visres.2012.02.016
2012

Quantitative measurement of interocular suppression in children with amblyopia
Vision Research
Narasimhan, S. and Harrison, E.R. and Giaschi, D.E.
DOI: 10.1016/j.visres.2012.06.007
2012

Neural correlates of the multiple-object tracking deficit in amblyopia
Vision Research
Secen, J. and Culham, J. and Ho, C. and Giaschi, D.
DOI: 10.1016/j.visres.2011.10.011
2011

Effects of speed, age, and amblyopia on the perception of motion-defined form
Vision Research
Hayward, J. and Truong, G. and Partanen, M. and Giaschi, D.
DOI: 10.1016/j.visres.2011.08.023
2011

Combined functional MRI and diffusion tensor imaging analysis of visual motion pathways
Journal of Neuro-Ophthalmology
Lanyon, L.J. and Giaschi, D. and Young, S.A. and Fitzpatrick, K. and Diao, L. and Bjornson, B.H. and Barton, J.J.S.
DOI: 10.1097/WNO.0b013e3181a58ef8
2009

Low- and high-level first-order random-dot kinematograms: Evidence from fMRI
Vision Research
Ho, C.S. and Giaschi, D.E.
DOI: 10.1016/j.visres.2009.04.018
2009

Low- and high-level motion perception deficits in anisometropic and strabismic amblyopia: Evidence from fMRI
Vision Research
Ho, C.S. and Giaschi, D.E.
DOI: 10.1016/j.visres.2009.07.012
2009

The role of low-spatial frequencies in lexical decision and masked priming
Brain and Cognition
Boden, C. and Giaschi, D.
DOI: 10.1016/j.bandc.2008.12.002
2009

Navigational skills correlate with hippocampal fractional anisotropy in humans
Hippocampus
Iaria, G. and Lanyon, L.J. and Fox, C.J. and Giaschi, D. and Barton, J.J.S.
DOI: 10.1002/hipo.20400
2008

Deficient motion-defined and texture-defined figure-ground segregation in amblyopic children
Journal of Pediatric Ophthalmology and Strabismus
Wang, J. and Ho, C.S. and Giaschi, D.E.
2007

Stereopsis-dependent deficits in maximum motion displacement in strabismic and anisometropic amblyopia
Vision Research
Ho, C.S. and Giaschi, D.E.
DOI: 10.1016/j.visres.2007.07.008
2007

The role of cortical area V5/MT+ in speed-tuned directional anisotropies in global motion perception
Vision Research
Giaschi, D. and Zwicker, A. and Young, S.A. and Bjornson, B.
DOI: 10.1016/j.visres.2006.12.017
2007

M-stream deficits and reading-related visual processes in developmental dyslexia
Psychological Bulletin
Boden, C. and Giaschi, D.
DOI: 10.1037/0033-2909.133.2.346
2007

Deficient maximum motion displacement in amblyopia
Vision Research
Ho, C.S. and Giaschi, D.E.
DOI: 10.1016/j.visres.2006.09.025
2006

The effects of optical blur on motion and texture perception
Optometry and Vision Science
Zwicker, A.E. and Hoag, R.A. and Edwards, V.T. and Boden, C. and Giaschi, D.E.
DOI: 10.1097/01.opx.0000222919.21909.1e
2006

Abnormal spatial selection and tracking in children with amblyopia
Vision Research
Ho, C.S. and Paul, P.S. and Asirvatham, A. and Cavanagh, P. and Cline, R. and Giaschi, D.E.
DOI: 10.1016/j.visres.2006.03.029
2006

Sensory and nonsensory influences on children's performance of dichotic pitch perception tasks
Journal of the Acoustical Society of America
Edwards, V.T. and Giaschi, D.E. and Low, P. and Edgell, D.
DOI: 10.1121/1.1861599
2005

Deficient motion perception in the fellow eye of amblyopic children
Vision Research
Ho, C.S. and Giaschi, D.E. and Boden, C. and Dougherty, R. and Cline, R. and Lyons, C.
DOI: 10.1016/j.visres.2004.12.009
2005

The maturation of form and motion perception in school age children
Vision Research
Parrish, E.E. and Giaschi, D.E. and Boden, C. and Dougherty, R.
DOI: 10.1016/j.visres.2004.10.005
2005

The effect of disrupting the human magnocellular pathway on global motion perception
Vision Research
Chapman, C. and Hoag, R. and Giaschi, D.
DOI: 10.1016/j.visres.2004.06.003
2004

Psychophysical indexes of temporal processing abnormalities in children with developmental dyslexia
Developmental Neuropsychology
Edwards, V.T. and Giaschi, D.E. and Dougherty, R.F. and Edgell, D. and Bjornson, B.H. and Lyons, C. and Douglas, R.M.
DOI: 10.1207/s15326942dn2503_5
2004

Children with dyslexia: Evidence for visual attention deficits in perception of rapid sequences of objects
Vision Research
Visser, T.A.W. and Boden, C. and Giaschi, D.E.
DOI: 10.1016/j.visres.2004.05.010
2004

Warning: Attending to a mask may be hazardous to your perception
Psychonomic Bulletin and Review
Tata, M.S. and Giaschi, D.E.
2004

Motion coherence thresholds can be elevated by flicker adaptation or red background
Journal of Vision
Hoag, R.A. and Chapman, C.S. and Giaschi, D.E.
DOI: 10.1167/3.9.274
2003

Conscious visual abilities in a patient with early bilateral occipital damage
Developmental Medicine and Child Neurology
Giaschi, D. and Jan, J.E. and Bjorson, B. and Young, S.A. and Tata, M. and Lyons, C.J. and Good, W.V. and Wong, P.K.H.
DOI: 10.1017/S0012162203001439
2003

Conscious visual abilities in a patient with early bilateral occipital damage
Journal of Vision
Giaschi, D. and Bjornson, B. and Jan, J. and Tata, M. and Young, S.A. and Lyons, C.J. and Good, W.V. and Wong, P.K.H.
DOI: 10.1167/2.7.428
2002

Attention deficits in children with anisometropic amblyopia
Journal of Vision
Paul, P.S. and Giaschi, D. and Cavanagh, P. and Cline, R.
DOI: 10.1167/1.3.80
2001

Cortical mechanisms of central pitch processing revealed by dichotic pitch stimuli
NeuroImage
Giaschi, D. and Bjornson, B. and Dougherty, R. and Young, S.A.
2000

Non-invasive mapping of sensorimotor cortex in a child with a cavernous angioma: FMRI and high-resolution EEG compared with surgical mapping
NeuroImage
Bjornson, B. and Giaschi, D. and Cochrane, D. and Au Young, S. and Rootman, D. and Boden, C. and Connolly, M. and Poskitt, K. and Boyle, C. and Smith, S. and Akagemi, R. and Wong, P.K.H.
1999

High resolution EEG & seizure localization
NeuroImage
Wong, P.K.H. and Bjornson, B. and Connolly, M. and Steinbok, P. and Young, S.A. and Giaschi, D. and Gregory, D. and Smith, S. and Lee, R. and Man, A. and Cochrane, D.
1999

Dichotic pitch: A new stimulus distinguishes normal and dyslexic auditory function
NeuroReport
Dougherty, R.F. and Cynader, M.S. and Bjornson, B.H. and Edgell, D. and Giaschi, D.E.
1998

Comparison of visual activation measured by fMRI and high resolution EEC
NeuroImage
Dougherty, R.F. and Au Young, S.M.W. and Giaschi, D.E. and Bjornson, B.H. and Wong, P.K.H.
1998

Development of motion-defined figure-ground segregation in preschool and older children, using a letter-identification task
Optometry and Vision Science
Giaschi, D. and Regan, D.
DOI: 10.1097/00006324-199709000-00024
1997

The effect of stationary noise on global motion perception
Investigative Ophthalmology and Visual Science
Giaschi, D.E. and Simpson, W.A. and Ferdinandi, A.K. and Tata, M.S.
1997

In search of the best psychophysical indicator of an M-stream deficit in developmental dyslexia
Investigative Ophthalmology and Visual Science
Dougherty, R.F. and Giaschi, D.E. and Bjornson, B.H. and Chamul, S.L. and Edgcll, D. and Lyons, C.J.
1997

Reversible dissociation of sensitivity to dynamic stimuli in Parkinson's disease: Is magnocellular function essential to reading motion-defined letters
Vision Research
Giaschi, D. and Lang, A. and Regan, D.
DOI: 10.1016/S0042-6989(96)00316-1
1997

Loss of sensitivity to motion-defined form in patients with primary open-angle glaucoma and ocular hypertension
Journal of the Optical Society of America A: Optics and Image Science, and Vision
Giaschi, D.E. and Trope, G.E. and Kothe, A.C. and Hong, X.-H.
1996

Measurement of glare susceptibility using low-contrast letter charts
Optometry and Vision Science
Regan, D. and Giaschi, D.E. and Fresco, B.B.
1993

The time course of direction-selective adaptation in simple and complex cells in cat striate cortex
Journal of Neurophysiology
Giaschi, D. and Douglas, R. and Marlin, S. and Cynader, M.
1993

Measurement of glare sensitivity in cataract patients using low-contrast letter charts
Ophthalmic and Physiological Optics
Regan, D. and Giaschi, D.E. and Fresco, B.B.
1993

Crowding and contrast in amblyopia
Optometry and Vision Science
Giaschi, D.E. and Regan, D. and Kraft, S.P. and Kothe, A.C.
1993

Visual processing of motion-defined form: Selective failure in patients with parietotemporal lesions
Journal of Neuroscience
Regan, D. and Giaschi, D. and Sharpe, J.A. and Hong, X.H.
1992

Defective processing of motion-defined form in the fellow eye of patients with unilateral amblyopia
Investigative Ophthalmology and Visual Science
Giaschi, D.E. and Regan, D. and Kraft, S.P. and Hong, X.-H.
1992

Motion-defined letter detection and recognition in patients with multiple sclerosis
Annals of Neurology
Giaschi, D. and Regan, D. and Kothe, A. and Hong, X.H. and Sharpe, J.A.
1992

Method for identifying amblyopes whose reduced line acuity is caused by defective selection and/or control of gaze
Ophthalmic and Physiological Optics
Regan, D. and Giaschi, D.E. and Kraft, S.P. and Kothe, A.C.
1992

The less you see it, the faster it moves: Shortening the "on-time" speeds up apparent motion
Vision Research
Giaschi, D. and Anstis, S.
DOI: 10.1016/0042-6989(89)90082-5
1989

Suppression of OKN and VOR by afterimages and imaginary objects
Experimental Brain Research
Howard, I.P. and Giaschi, D. and Murasugi, C.M.
DOI: 10.1007/BF00248537
1989

Adaptation to apparent motion
Vision Research
Anstis, S. and Giaschi, D. and Cogan, A.I.
DOI: 10.1016/0042-6989(85)90093-8
1985

Research

Predicting patching treatment success in children with amblyopia
Amblyopia (lazy eye) is a common developmental disorder in which vision is impaired in one eye and cannot be corrected with glasses. An eye turn or an optical problem can cause amblyopia to develop in an otherwise healthy eye. If these problems are detected and treated when a child is young enough, amblyopia can often be prevented or reversed by patching the unaffected fellow eye; however, not all children respond well to this patching therapy. Treatment failures may occur because patching treats only some of the problems in amblyopia. Most amblyopia treatment and research focuses on problems with form perception, such as visual acuity (the smallest character that can be seen on an eye chart). In contrast, our research focuses on problems with motion perception and eye gaze control. We are using customized computer games to identify visual problems that predict treatment success by testing children (age 4 to 7 years) who are about to start patching therapy and children with normal vision.

Motion perception in children
It is rare for a person to totally lack the ability to perceive motion, but certain developmental disorders affect the ability to perceive specific types of motion. In addition, the development of motion perception in children differs for different types of motion. The age at which performance on different visual tasks reaches adult levels may be an indicator of the brain structures and the amount of processing involved. We use computer ‘games’ to obtain information about the typical maturation of motion perception and about the changes in motion perception caused by lazy eye, dyslexia or preterm birth. We are also using functional MRI to study the brain regions involved in these developmental disorders.

Evaluation of reading improvement and brain changes following treatment for dyslexia
There are some children who have difficulty learning to read. This disability is called developmental dyslexia. Children with dyslexia have poor school performance, but they may also develop mental health problems. Therefore, increasing reading skills in childhood is very important to their overall health as adults. The purpose of our research is to evaluate an intensive reading intervention program using behavioural and neuroimaging techniques, and whether these measures can predict success with the intervention program. We are also examining the brain networks associated with reading and reading difficulty.

Honours & Awards

BC Research Institute for Children’s & Women’s Health Investigatorship Award – 1999-2002

Research Group Members

Kimberly Meier
Steffany Ellingham, Operations Manager MRI Research Facility
Kevin Moon, Research Staff
Kevin Chang
Laveniya Kugathasan
Ari Chakraborty, Brain Canada - Kids Brain Health Fellow
Jane Gardiner, pediatric ophthalmologist
Katherine Paton, Ophthalmologist