Saccadic adaptation modulates inhibition of return
56.301, Tuesday, May 14, 2:45 - 6:45 pm, Royal Ballroom 6-8
Farahnaz Ahmed Wick1, Tyler Garaas2, Marc Pomplun1; 1University of Massachusetts Boston, Department of Computer Science, 2Mitsubishi Electric Research Laboratories
Saccadic adaptation, a form of motor learning responsible for maintaining saccadic accuracy to targets, has been shown to additionally affect the distribution of attention when it is shifted to a location selected for a subsequent saccadic eye movement. In this study, we investigated the effective relationship between the alteration of attention associated with saccadic adaptation and inhibition of return (IOR), an inhibitory mechanism associated with covert orienting of attentional resources. IOR refers to the finding that response times are typically slower for targets at previously (SOA > 300 ms) cued locations than for targets at uncued locations. Previous studies have examined relationships involving IOR and distribution of saccadic latencies, deviation and fixation times. However, the exact mechanism linking saccade amplitudes and both the attentional and oculomotor biases of IOR is currently unknown. We hypothesized that when saccade amplitudes were modified, covert attentional shifts (Doré-Mazars & Collins, 2005; McFadden et al., 2001), attentional resource distribution (Ahmed Wick et al., under review) and oculomotor programming (see Hopp & Fuchs, 2004) to the cued location would be modified correspondingly. As a result, attentional shifts would miss the cued location and, therefore, receive less inhibition. In this study, we used the classic double-step paradigm to effect an increase (forward adaptation) or decrease (backward adaptation) in saccade amplitudes. Afterwards, we examined changes in IOR to cued and uncued targets at 5o and 10o in the left and right hemifield against a control condition using a within-subjects design. We found no IOR effects after both forward and backward adaptation, while significant IOR was observed in the control condition. These results indicate that a change in the oculomotor programming of saccades through saccadic adaptation affects not only saccadic amplitude and shifts of attention but also behavioral qualities related to the distribution of attentional resources.