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UMass Chan Affiliations
Department of PsychiatryDocument Type
Journal ArticlePublication Date
2009-07-15Keywords
AdultBrain
*Brain Mapping
*Electroencephalography
Evoked Potentials, Visual
Female
Humans
*Magnetic Resonance Imaging
Male
Visual Perception
Psychiatry
Metadata
Show full item recordAbstract
In the human visual system, the internal representation of the left and right visual hemifields is split at the midline of the two cerebral hemispheres. The present study aims to address the questions of when and where the lateralized cortical visual representations are merged to form an intact percept by using a multimodal neuroimaging approach. Visual evoked potential (VEP) and functional magnetic resonance imaging (fMRI) data were acquired from a group of healthy subjects presented with unilateral versus bilateral visual stimuli. Cortical activities involved in processing bilateral visual information are expected to be equally responsive to ipsilateral and contralateral stimuli, and demonstrate spatial nonlinearity in the response to bilateral stimuli. Utilizing these features, we performed integrative as well as separate analyses for both VEP and fMRI data. The present results suggest that i) the majority of cortical activity that integrates visual information across hemifields takes place at extrastriate areas during late visual processing, and that ii) the lateral occipito-temporal (LOT) regions (likely the MT+ complex) and the medial occipital cortex (i.e. V1) may contribute to bilateral visual integration during early visual processing. Our findings are generally in agreement with the bottom-up visual hierarchy, with the exception of the evidence suggesting an early activation of the higher-tier LOT areas and the influence from ipsilateral visual inputs upon the V1 response.Source
Neuroimage. 2009 Jul 15;46(4):989-97. Epub 2009 Mar 20. Link to article on publisher's siteDOI
10.1016/j.neuroimage.2009.03.028Permanent Link to this Item
http://hdl.handle.net/20.500.14038/45979PubMed ID
19306933Related Resources
Link to Article in PubMedae974a485f413a2113503eed53cd6c53
10.1016/j.neuroimage.2009.03.028