Prof Frank Sengpiel
Orientation map in the primary visual cortex.
Developmental plasticity of the visual cortex, and the role of visual experience in common disorders of vision
The primary visual cortex (V1) is one of the most extensively studied areas of the mammalian brain.
For a long time, the issue of "nature versus nurture" has been of particular interest: to what extent is the way we see the world determined by intrinsic factors such as our genes, and how far are our visual abilities shaped by the environment, that is by our own visual experience during the so-called critical period?
We visualize cortical activity by means of "optical imaging of intrinsic signals", a functional brain imaging technique. We can thus obtain cortical maps that reveal responses to contour lines of different orientations (“orientation maps”, above)
We study the mechanisms of normal development of V1 and the physiological and molecular basis of common developmental disorders of vision such as strabismus (squint) and amblyopia (lazy eye). Our work aims at gaining a better understanding of how the brain in general and the visual cortex in particular integrates normal and abnormal experience. Specifically, we examine how the risk of amblyopia developing from patching of one eye may be counterbalanced by just brief periods of daily vision with both eyes. This knowledge will also be of benefit to the management of patients, especially children, who have to wear an eye patch.
Second, we plan to investigate the molecular basis of what makes the visual cortex susceptible to developing abnormally in the face of abnormal experience. A prime candidate for mediating a range of learning processes in the brain at the cellular level is the NMDA receptor. Changes to this molecule or to one of a number of other molecules that associate with it in a large complex are thought to be related to learning and plasticity at the synaptic level. We want to find out exactly which molecules within this complex change as the visual cortex adapts to changes in visual experience.
Ocular dominance maps reveal differences in responses through the two eyes.
Ocular dominance maps reveal differences in responses through the two eyes.
Finally, while much has been learned from animal experiments about the conditions leading to amblyopia, and the accompanying changes in the brain, there is no treatment available as yet. Very recent research suggests that the fine mesh of molecules surrounding the neurons, called extracellular matrix, is an impediment to improvement of vision through an amblyopic eye. We attempt to “loosen” this extracellular matrix in amblyopic animals and test whether normal vision can be restored. If successful, these experiments could lead to a cure for amblyopia.
Active Grants
MRC Project Grant
Treating amblyopia by digestion of the extracellular matrix and stimulation of axonal growth in the visual cortex
MRC Project Grant
Normal vs. abnormal vision during development of the primary visual cortex: functional outcomes and molecular substrates
Wellcome Trust Project Grant
Investigation into the pathogenesis of ischaemic brain damage, by live imaging of peri-lesion spreading depression (SD) in stroke models
Collaborations
Peter Kind , University of Edinburgh , Scotland
Donald Mitchell , Dalhousie University, Halifax, Canada
Kathryn Murphy , McMaster University, Hamilton, Canada
Tiho Obrenovitch , University of Bradford
James Fawcett , University of Cambridge
Research Group Members
Sajjida Jaffer
David Neil Price
Vasily Vorobyov
Adam Ranson