Saccades and scanpaths: models of cognitive processing

C. Kennard

Division of Neuroscience and Psychological Medicine, Imperial College School of Medicine, Charing Cross Campus, London W6 8RF, United Kingdom (

Several cognitive processes, which include attention, spatial working memory and response inhibition, are involved in the generation of a saccade. Appropriate manipulation of the behavioural paradigm in which an isolated saccade is required allows analysis of these individual processes. Applying these paradigms to subjects with focal structural or neurochemical lesions and during brain imaging, has made it possible to develop a provisional functional neuro-anatomical brain network for saccadic generation, which will be described.

The analysis of sequences of saccades, called scanpaths, undertaken during the performance of specific behavioural tasks can also provide valuable insights into the cognitive processes involved, and their disturbance in patients with neurological disease. Analysis of the scanpaths made during the performance of standard neuropsychological tasks, such as cancellation and the Tower of London planning task in patients with parietal lobe lesions and Parkinson's disease, can be used to provide evidence for specific cognitive deficits. As an example, recent studies of these patients will be described which have revealed impairments in spatial working memory.