ISSN 1671-3710
CN 11-4766/R

### Ghost in the Machine: Trans-saccadic Modulation of Figure–ground Segmentation in the Thalamus

Ian Max Andolina; Wei Wang; Stewart Shipp

1. Institute of Neuroscience, State Key Laboratory of Neuroscience and Key Laboratory of Primate Neurobiology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, P. R. China
UCL Inst. of Ophthalmology, 11-43 Bath Street, London, UK
• Online:2016-12-31 Published:2016-12-31

Abstract:

PURPOSE: Figure–ground segmentation is a fundamental task for biological and artificial visual systems. The visual figure is many multiples greater in size than the receptive fields/filters of early visual areas. Computing figure-ground must therefore involve a cascade of bottom–up & top–down processes across multiple visual areas and spatial scales. We previously observed figure–ground enhancement at long latency (~100ms) at the earliest stage of central vision, the lateral geniculate nucleus (dLGN). Here we ask how large saccadic eye movements affect figure-ground modulation in dLGN. Critically, we wished to evaluate how figure-ground representations were affected across the saccade.
METHODS: We performed tetrode recordings of spiking and local field potentials (LFP) in behaving macaque dLGN. We used speeded reaction–time where the subject had to find, and then saccade to a moving-dot defined visual figure against a background. Spiking and LFP responses were analysed by aligned them to either the stimulus onset, or the target–saccade onset.
RESULTS: We found strong and robust saccadic modulation of neural responses in macaque dLGN across all locations analysed. Saccadic modulation was seen for parvo–, magno– and konio–cellular streams. Time-frequency analysis showed that saccadic modulation is largely driven in the α-band. In the trials where a figure stimulus was in the receptive field, a continued figure-ground specific enhancement was maintained even after the saccade terminated.
CONCLUSIONS: We found figure-ground selective enhancement is amplified across saccades (i.e. even after the stimulus has left the receptive field), showing that trans-saccadic continuity of representation may have significant implications for the stability of visual perception.