Direction of magnetoencephalography sources associated with feedback and feedforward contributions in a visual object recognition task. (12th January 2015)

• Record Type: Journal Article
• Authors: Ahlfors, Seppo P.; Jones, Stephanie R.; Ahveninen, Jyrki; Hämäläinen, Matti S.; Belliveau, John W.; Bar, Moshe
• Is Part Of: Neuroscience letters. Volume 585(2015)
• Page Start: 149
• Page End: 154
• Publication Date: 2015-01-12
• Subjects: Magnetoencephalography -- Cerebral cortex -- Current dipole -- Top–down -- Bottom–up; Neurology -- Periodicals; Neurology -- Periodicals; Research -- Periodicals; Neurologie -- Périodiques; Neuroanatomie -- Périodiques; Neuropharmacologie -- Périodiques; Neurophysiologie -- Périodiques; Neurology; Periodicals; Electronic journals; 617.48
• DOI: 10.1016/j.neulet.2014.11.029
• Languages: English
• ISSNs: 0304-3940

Abstract

Highlights: Fusiform sources in a visual object recognition MEG experiment were examined. Directions of source currents were opposite for expected feedforward and feedback inputs. MEG and EEG source direction may depend on hierarchical organization. Abstract: Identifying inter-area communication in terms of the hierarchical organization of functional brain areas is of considerable interest in human neuroimaging. Previous studies have suggested that the direction of magneto- and electroencephalography (MEG, EEG) source currents depend on the layer-specific input patterns into a cortical area. We examined the direction in MEG source currents in a visual object recognition experiment in which there were specific expectations of activation in the fusiform region being driven by either feedforward or feedback inputs. The source for the early non-specific visual evoked response, presumably corresponding to feedforward driven activity, pointed outward, i.e., away from the white matter. In contrast, the source for the later, object-recognition related signals, expected to be driven by feedback inputs, pointed inward, toward the white matter. Associating specific features of the MEG/EEG source waveforms to feedforward and feedback inputs could provide unique information about the activation patterns within hierarchically organized cortical areas.