Jeans, Rhiannon2015-02-252015-02-25b37574176http://hdl.handle.net/1885/12731In the brain, every cortical inter-area feedforward projection shares a reciprocal feedback connection. Despite its pervasive nature in the brain, our understanding of the functional role of neural feedback in form perception remains incomplete, particularly in behaving animals. This problem is addressed in humans with a novel form completion paradigm. Seven subjects (5 female) had their EEG waveforms analysed using three linear models showing non-significant differences between stimulus conditions designed to produce differences by manipulating neural feedback to V1. Two of these subjects (one female), in addition to EEG waveforms, had combined magnetic resonance imaging (MRI) and functional MRI (fMRI) cortical maps that allowed anatomically close areas such as V1 and V2 to have their signals decomposed and neural feedback inferred. Differences between stimulus conditions arose once signals had been divided into V1 and V2. Significant differences (p < .05) for one subject in V1 and V2 suggests cortical interactions at 100ms and 350ms. This suggests the form completion paradigm has utility at investigating the influence of the V2 far receptive field surround on V1, given future given signal to noise issues are resolved.94 pagesneural feedbackfeedbackV1V2visual cortexform perceptionEEGfMRIMRIelectroencephalographyfunctional magnetic resonance imagingmagnetic resonance imagingcontour integrationvisual evoked potentialERPVEPreceptive fieldextra-classical receptive fieldextraclassical receptive fieldfar surroundnear surroundform completion paradigmillusory contourillusory contourshorizontal fieldhorizontal connectionhorizontal neuronfeedback neuronorientation selectivityorientation sensitivityorientationlinesquaresource analysisrealistic head modelglobal field powerglobal field root mean squareGFPprincipal comonents analysisPCAsingle value decompositionSVDtexture perceptionGestaltvisual groupingvisionattentionretinotopiccollinearorthogonal201410.25911/5d723be5d88d1