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Abstract #3554

Conditional Granger Causality Analysis of fMRI Data Shows a Direct Connection from LGN to HMT+ Bypassing V1

Anna Gaglianese1, Mauro Costagli2, Giulio Bernardi1, Lorenzo Sani1, Emiliano Ricciardi1, Pietro Pietrini1

1Laboratory of Clinical Biochemistry & Molecular Biology, Pisa, Italy, Italy; 2Laboratory for Cognitive Brain Mapping, RIKEN - Brain Science Institute, Wako, Japan

The human middle temporal complex (hMT+) is devoted to motion perception. To determine whether motion-related neural information may reach hMT+ directly from the thalamus, by-passing the primary visual cortex (V1), we measured effective connectivity in an optic flow fMRI experiment in humans. Conditional Granger Causality analysis was employed to measure direct influences between the lateral geniculate nucleus (LGN) and hMT+, discarding indirect effects mediated by V1. Results indicated the existence of a bilateral alternative pathway for visual motion processing that allows for a direct flow of information from LGN to hMT+. This direct link may play a role in blindsight.