Using the P300 and ERN brain potentials to understand the effects of prism adaptation on attention.

Abstract

During prism adaptation (PA) a participant is asked to reach to targets while wearing glasses that shift their vision in one direction. Initially, the participant misses in the direction of the prism shift. However, after a number of reaches the participant recalibrates their movements in the opposite direction to compensate for the visual shift. Rightward PA has been used for many years as a method of rehabilitating patients with left visuospatial neglect (VSN), a leftward spatial attentional disorder, by shifting the patient's egocentric reference frame leftward, towards their neglect field. Similarly, left prisms, which result in a rightward shift in the egocentric reference frame, can be used to induce neglect-like behavior in healthy adults. Prior research involving event-related potentials (ERPs) has shown that, during PA, there are two brain potentials that are elicited: the P300, and the error-related negativity (ERN). The P300 is thought to index the role of the posterior parietal cortex (PPC) in context updating and learning, whereas the ERN is suggested to occur as part of an error processing system in the medial-frontal cortex (MFC). In the proposed study we will examine the roles of these brain potentials in creating the beneficial effects of PA on attention through recording ERPs while healthy adults adapt to varying degrees of leftward shifting prisms. The magnitude of these ERPs will then be correlated with behavioural changes on attention tasks that are induced following leftward PA. Ultimately, these findings may help us better understand how PA influences patients with VSN.

Discipline: Psychology Honours

Faculty Mentor: Dr. Christopher Striemer