Christopher Conroy¹, Abe Leite², Hossein Adeli³, Gregory J. Zelinsky², Robert M. McPeek¹; ¹SUNY College of Optometry, ²Stony Brook University, ³Columbia University

Natural visual scenes are composed of spatially extended visual objects, and objects are often the targets of saccades. However, little is known about how such objects are represented by the saccadic system or selected as the targets of saccades. Recently, we discovered that when a saccade is made to one part of an extended object, superior colliculus (SC) spiking activity is enhanced throughout the object. Here, we examined local field potentials (LFPs) in the SC to better understand the population neuronal activity underlying this object-based saccadic enhancement. Rhesus monkeys fixated a central point and made saccades to peripheral target locations that were either part of an extended object (connected condition) or separated from the object by a small gap (disconnected condition). LFPs were recorded from SC sites with response fields (RFs) that overlapped the extended object. Crucially, however, the RFs of those sites were spatially remote from the saccade target locations. We found that peri-saccadic LFPs differed in the connected and disconnected conditions, despite the fact that the saccades made in the two conditions were identical. Because LFPs, unlike spiking activity, are thought to reflect primarily synaptic activity associated with the input to neurons, this suggests that the object-based saccadic enhancement of SC spiking activity that we previously demonstrated is mediated by upstream neural structures and/or by intra-collicular interactions.

Acknowledgements: NIH-NEI R01-EY030669