From local to global: Cortical dynamics of contour integration. 2008

Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
Helsinki University of Technology, Espoo, Finland. topi.tanskanen@tkk.fi

Processing of global contours requires integration of local visual information. To study the involvement of different cortical areas and the temporal characteristics of their activity in such integration, we recorded neuromagnetic responses to arrays of Gabor patches in which a proportion of the patches was oriented either tangentially or radially with respect to a global circular contour; arrays with random patch orientations served as control stimuli. The first responses at 60-80 ms around the calcarine sulcus were similar to all stimuli. Starting from 130 ms, responses to the tangential contours differed significantly from responses to control stimuli, and the difference reached its maximum at 275 ms. The most pronounced differences emerged around the parieto-occipital sulcus, precuneus, cuneus, and superior and middle occipital gyri. This pattern of cortical activity was similar irrespective of whether the local elements were radial or tangential to the circle; however, the differences were smaller for the radial contours and tended to start 20-30 ms later. Correspondingly, discrimination reaction times were shortest for the contours consisting of tangential elements. These results demonstrate two spatially and temporally distinct stages of visual cortical processing, the first one limited to local features and the second one integrating information at a more global level.

UI MeSH Term Description Entries
D008297 Male Males
D010364 Pattern Recognition, Visual Mental process to visually perceive a critical number of facts (the pattern), such as characters, shapes, displays, or designs. Recognition, Visual Pattern,Visual Pattern Recognition
D010775 Photic Stimulation Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity. Stimulation, Photic,Visual Stimulation,Photic Stimulations,Stimulation, Visual,Stimulations, Photic,Stimulations, Visual,Visual Stimulations
D011930 Reaction Time The time from the onset of a stimulus until a response is observed. Response Latency,Response Speed,Response Time,Latency, Response,Reaction Times,Response Latencies,Response Times,Speed, Response,Speeds, Response
D005260 Female Females
D005556 Form Perception The sensory discrimination of a pattern, shape, or outline. Contour Perception,Contour Perceptions,Form Perceptions,Perception, Contour,Perception, Form,Perceptions, Contour,Perceptions, Form
D006801 Humans Members of the species Homo sapiens. Homo sapiens,Man (Taxonomy),Human,Man, Modern,Modern Man
D000328 Adult A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available. Adults
D014793 Visual Cortex Area of the OCCIPITAL LOBE concerned with the processing of visual information relayed via VISUAL PATHWAYS. Area V2,Area V3,Area V4,Area V5,Associative Visual Cortex,Brodmann Area 18,Brodmann Area 19,Brodmann's Area 18,Brodmann's Area 19,Cortical Area V2,Cortical Area V3,Cortical Area V4,Cortical Area V5,Secondary Visual Cortex,Visual Cortex Secondary,Visual Cortex V2,Visual Cortex V3,Visual Cortex V3, V4, V5,Visual Cortex V4,Visual Cortex V5,Visual Cortex, Associative,Visual Motion Area,Extrastriate Cortex,Area 18, Brodmann,Area 18, Brodmann's,Area 19, Brodmann,Area 19, Brodmann's,Area V2, Cortical,Area V3, Cortical,Area V4, Cortical,Area V5, Cortical,Area, Visual Motion,Associative Visual Cortices,Brodmanns Area 18,Brodmanns Area 19,Cortex Secondary, Visual,Cortex V2, Visual,Cortex V3, Visual,Cortex, Associative Visual,Cortex, Extrastriate,Cortex, Secondary Visual,Cortex, Visual,Cortical Area V3s,Extrastriate Cortices,Secondary Visual Cortices,V3, Cortical Area,V3, Visual Cortex,V4, Area,V4, Cortical Area,V5, Area,V5, Cortical Area,V5, Visual Cortex,Visual Cortex Secondaries,Visual Cortex, Secondary,Visual Motion Areas
D015225 Magnetoencephalography The measurement of magnetic fields over the head generated by electric currents in the brain. As in any electrical conductor, electric fields in the brain are accompanied by orthogonal magnetic fields. The measurement of these fields provides information about the localization of brain activity which is complementary to that provided by ELECTROENCEPHALOGRAPHY. Magnetoencephalography may be used alone or together with electroencephalography, for measurement of spontaneous or evoked activity, and for research or clinical purposes. Magnetoencephalogram,Magnetoencephalograms

Related Publications

Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
April 1997, Vision research,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
April 2001, Vision research,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
January 2003, Journal of physiology, Paris,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
August 2015, Neuropsychologia,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
March 2015, Journal of experimental child psychology,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
May 2013, NeuroImage,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
June 2009, Vision research,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
November 2002, Journal of neurophysiology,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
November 2008, Physical review letters,
Topi Tanskanen, and Jussi Saarinen, and Lauri Parkkonen, and Riitta Hari
July 2019, Neuron,
Copied contents to your clipboard!