Cognitive Neuroscience And NeuropsychologyUnseen stimuli modulate conscious visual experience: evidence from inter-hemispheric summationde Gelder, Beatrice1,2, CA; Pourtois, Gilles1,2; van Raamsdonk, Monique1; Vroomen, Jean1; Weiskrantz, Lawrence3Author Information 1Cognitive Neuroscience Laboratory, Tilburg University, PO Box 90153, 5000 LE Tilburg, The Netherlands; 2Neurophysiology Laboratory, Faculty of Medicine, Louvain University, Brussels, Belgium; 3Department of Experimental Psychology, Oxford University, Oxford, UK CACorresponding Author Received 9 October 2000; accepted 23 November 2000 Neuroreport: February 12, 2001 - Volume 12 - Issue 2 - p 385-391 Buy Abstract Emotional facial expression can be discriminated despite extensive lesions of striate cortex. Here we report differential performance with recognition of facial stimuli in the intact visual field depending on simultaneous presentation of congruent or incongruent stimuli in the blind field. Three experiments were based on inter-hemispheric summation. Redundant stimulation in the blind field led to shorter latencies for stimulus detection in the intact field. Recognition of the expression of a half-face expression in the intact field was faster when the other half of the face presented to the blind field had a congruent expression. Finally, responses to the expression of whole faces to the intact field were delayed for incongruent facial expressions presented in the blind field. These results indicate that the neuro-anatomical pathways (extra-striate cortical and sub-cortical) sustaining inter-hemispheric summation can operate in the absence of striate cortex. © 2001 Lippincott Williams & Wilkins, Inc.