QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

HOME  |   SEARCH  |   ARCHIVE  |   SUBSCRIBE  |   CONTACT  |   HELP

The Journal of Neuroscience, November 11, 2009, 29(45):14342-14351; doi:10.1523/JNEUROSCI.3136-09.2009

This Article Full Text Full Text (PDF) Supplemental Data Submit an eLetter Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Google Scholar Articles by Henriksson, L. Articles by Vanni, S. PubMed PubMed Citation Articles by Henriksson, L. Articles by Vanni, S.

 Previous Article  |  Next Article 

Behavioral/Systems/Cognitive
Representation of Cross-Frequency Spatial Phase Relationships in Human Visual Cortex

Linda Henriksson,^1,2 Aapo Hyvärinen,^3,4,5,6 and Simo Vanni^1,2

¹Brain Research Unit, Low Temperature Laboratory, and ²Advanced Magnetic Imaging Centre, Helsinki University of Technology, FI-02015 TKK, Espoo, Finland, and Departments of ³Computer Science and ⁴Mathematics and Statistics, Faculty of Science, ⁵Department of Psychology, Faculty of Behavioural Sciences, and ⁶Helsinki Institute for Information Technology, University of Helsinki, FI-00014 University of Helsinki, Helsinki, Finland

Correspondence should be addressed to Linda Henriksson, Low Temperature Laboratory and Advanced Magnetic Imaging Centre, Helsinki University of Technology, P.O. Box 3000, FI-02015 TKK, Espoo, Finland. Email: henriksson{at}neuro.hut.fi

An image patch can be locally decomposed into sinusoidal waves of different orientations, spatial frequencies, amplitudes, and phases. The local phase information is essential for perception, because important visual features like edges emerge at locations of maximal local phase coherence. Detection of phase coherence requires integration of spatial frequency information across multiple spatial scales. Models of early visual processing suggest that the visual system should implement phase-sensitive pooling of spatial frequency information in the identification of broadband edges. We used functional magnetic resonance imaging (fMRI) adaptation to look for phase-sensitive neural responses in the human visual cortex. We found sensitivity to the phase difference between spatial frequency components in all studied visual areas, including the primary visual cortex (V1). Control experiments demonstrated that these results were not explained by differences in contrast or position. Next, we compared fMRI responses for broadband compound grating stimuli with congruent and random phase structures. All studied visual areas showed stronger responses for the stimuli with congruent phase structure. In addition, selectivity to phase congruency increased from V1 to higher-level visual areas along both the ventral and dorsal streams. We conclude that human V1 already shows phase-sensitive pooling of spatial frequencies, but only higher-level visual areas might be capable of pooling spatial frequency information across spatial scales typical for broadband natural images.

---

Received July 2, 2009; revised Sept. 17, 2009; accepted Oct. 10, 2009.

Correspondence should be addressed to Linda Henriksson, Low Temperature Laboratory and Advanced Magnetic Imaging Centre, Helsinki University of Technology, P.O. Box 3000, FI-02015 TKK, Espoo, Finland. Email: henriksson{at}neuro.hut.fi

Home  |   Search  |   Archive  |   Subscribe  |   Contact  |   Help