Human behavior is fundamentally predictive. One way to see this fact is by considering our ability to make fast and accurate movements that anticipate upcoming changes or events in the environment. A tractable domain in which to study predictive behavior is eye movements. Saccades are rapid eye movements that everyone uses throughout their waking lives to scan their visual environments in order to maintain and update perceptual representations. Saccades are known to be ballistic, which means that once a saccade is initiated, its course cannot be altered. Therefore saccades must typically predict the near future location of visual stimuli so that the eyes land on their intended targets. In previous studies it was found that the nervous system holds information about the sequential history of eye movements in order to time future predictive eye movements. Intriguingly, the statistical nature of this memory is long-range correlated, and long-range correlations are mysteriously ubiquitous to many biological and complex systems found throughout nature.
With support of the National Science Foundation, Dr. Shelhamer will study nature of these long-range correlations in eye movements. In particular, he will examine the pattern of endpoint locations of saccades, and the characteristics of their spatial correlations. The experiments are designed to determine how far the correlations extend in time and space, how they differ between predictive and reactive saccades, and how they change with learning. An important aspect of the latter issue is that stronger correlations may be related to better adaptive capabilities. Motor adaptation is common to many neuromuscular systems, and the lessons learned in this study may help to increase the effectiveness of motor training and rehabilitation programs.
