Clinical Neuro-ophthalmology
Summary of Research
The neuro-ophthalmology research group is primarily interested in the neural control of eye movements in health and disease. We are currently focusing on several areas including:
• In our current Wellcome Trust Programme Grant we aim to identify the roles of the different fronto-striatal pathways in the cognitive control of movement using saccadic (fast conjugate) eye movements as the exemplar. We will test the hypotheses that the medial system plays a major role in self-initiated action, the control of action when we suddenly have to stop or change our movements, learning sequences of actions without being aware (implicit), and how the control of movement is changed by the rewards achieved by our actions. By contrast, we predict that the dorsolateral system has a far greater contribution to short-term memory and selecting where we direct our eyes. We will test our hypotheses using functional brain scanning (fMRI) and repetitive transcranial magnetic stimulation in healthy volunteers, examining the performance of patients with small brain lesions on our tasks and electrical recordings from the subthalamic nucleus (STN) in the basal ganglia in patients undergoing surgery for STN stimulator implantation to treat their medical condition.
• An investigation of the utility of saccadic eye movements as a biomarker the recogition of early neuronal dysfunction in presymptomatic patients with the genetic mutation for Huntington's disease.
• Working with Dr Patrick Degenaar (neurobionics) on methods to augment vision in visually impaired patients with for example macular degeneration and on the development of novel optoelectronic visual prostheses.
• fMRI studies of imaginative perception.
• The use of magnets for the treatment of oscillopsia.
• The value of visual search tasks in the rehabilitation of patients with homonymous hemianopia due to stroke.
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Current Laboratory Members
Dr Stephen Hicks
Dr Siobhan Keenan
Dr Sabira Mannan
Dr Parashkev Nachev
Dr Clive Rosenthal
Dr Charlotte Winn
PhD students
Rebecca Graham
Jocelyn Cammock (Royal College of Art)
Nir Grossman (IBME - joint Dr P Degenaar)
Walid al Alabany (IBME - joint Dr P Degenaar)
External Collaborations
Professor Masud Husain (Institute of Neurology, UCL)
Professor Sarah Tabrizi (Institute of Neurology, UCL)
Professor Quentin Pankhurst (UCL/ICL)
Mr Geoffrey Rose (Moorfields Eye Hospital)
External Funding
Wellcome Trust
HighQ Foundation
National Institute of Health Research (NEAT Programme)
Key publications
2000 M. Husain, J.B. Mattingley, J. Driver, C. Rorden, C. Kennard. Distinguishing sensory and motor biases in parietal and frontal neglect. Brain, 123, 1643-1659
2000 T. Hodgson, A Bajwa,A.M. Owen, C. Kennard. The Strategic Control of Gaze direction in the Tower of London Task. J. Cognit.Neurosci. 12:5, 894-907.
2001 M Husain, S Mannan, T Hodgson, J Driver, C Kennard. Impaired spatial working memory across saccades contributes to abnormal search in parietal neglect. Brain 124, 941-952.
2003 DJ Mort, P Malhotra, SK Mannan, S. K, C Rorden, A Pambakian, C Kennard, M Husain. The anatomy of visual neglect. Brain, 126:9, 1986-1997.
2003 DJ Mort, RJ Perry, SK Mannan, TL Hodgeson, E Anderson, R Quest, D McRobbie, A McBridge, M. Husain, C Kennard. Differential cortical activation during voluntary and reflexive saccades in man. Neuroimage 18:2,231-46.
2004 RJ Leigh, C Kennard. Using saccades as a research tool in the clinical neurosciences. Brain, 127; 1 - 18.
2004 TL Hodgson, C Golding, D Molyva, CR Rosenthal, C Kennard. Reflexive, symbolic and affective contributions to eye movements during task switching: response selection. Journal of Cognitive Neuroscience, 16, 318-330.
2004 P Sumner, P Nachev, N Vora, M Husain, C Kennard. Distinct cortical and collicular mechanisms of inhibition of return revealed by using S cone stimuli. Current Biology 14, 2259-2263
2005 S Mannan, DJ Mort, TL Hodgson, J Driver, C Kennard, M Husain. Revisiting previously searched location in visual neglect; role of right parietal and frontal lesions in misjudging old locations as new. Journal of Cognitive Neuroscience, 17, 340-354.
2005 A Pambakian, J Currie, C Kennard. Rehabilitation strategies for patients with homonymous visual field defects. Journal of Neuro-ophthalmology, 25, 136-142.
2005 Nachev, G Rees, A Parton, C Kennard, M Husain. Volition and conflict in human medial frontal cortex. Current Biology 15, 122-128.
2006 CVP Golding, C Danchaivijitr, TL Hodgson, S Tabrizi, C Kennard. Identification of an oculomotor biomarker of preclinical Huntington's disease. Neurology, 67, 485-7.
2006 P Sumner, P Nachev, S Castor-Perry, H Isenman, C Kennard. Which visual pathways cause fixation-related inhibition? Journal of Neurophysiology, 95, 1527-1536.
2007 P Nachev, H Wydell, K O'Neill, M Husain, C Kennard. The role of the pre-supplementary motor area in the control of action. Neuroimage 36 Suppl 2;T155-163..
2007 E Anderson, S Mannan, M Husain, G Rees, P Sumner, DJ Mort, D McRobbie, C Kennard. Involvement of prefrontal cortex in visual search. Experimental Brain Research 180, 289-302.
2007 T Hodgson, M Chamberlain, B Parris, M James, N Gutowski, M Husain, C Kennard. The role of the ventro-lateral frontal cortex in inhibitory oculomotor control. Brain 130,1527-1537.
2007 P Sumner, P Nachev, P Morris, AM Peters, SR Jackson, C Kennard, M Husain. Human medial frontal cortex mediates unconscious inhibition of voluntary action. Neuron 54, 697-711.
