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Latest News

Two new papers are out! :
Kimura R, Ohzawa I (2009) "Time course of cross-orientation suppression in the early visual cortex"

Tanaka H, Ohzawa I (2009) "Surround suppression of V1 neurons mediates orientation-based representation of high-order visual features"

» See our Publication List...

 



Visual Neuroscience Laboratory
(Ohzawa Laboratory)

Graduate School of Frontier Biosciences and
School of Engineering Science, Osaka University

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LabTourMovieTitlePage
A Video Tour of Ohzawa Visual Neuroscience Lab. (Click the image)
(English, 274MB, 9min, 960x540, MP4/H.264, Needs QuickTime/ iTunes/ VLC to view on Windows) (transcript)


Priority Messages
  Izumi Ohzawa's Google Scholar Citations
  October 25, 2011: Personal Radiation Diclosure to our Friends and Colleagues Visiting Western Japan (PDF) -- Izumi Ohzawa
  Old Videos from Berkeley have been digitized and are available for download here. They may still be usefull for educational purposes.

Activities of Vision, Neuroscience Groups at Osaka Univ.
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Recent Research Results
  Tanaka H, Ohzawa I (2009)
J. Neurophysiol. 101: 1444-1462

Surround suppression of V1 neurons mediates orientation-based representation of high-order visual features
The classical receptive field (CRF) and suppressive surround areas should be viewed as a whole as a new kind of receptive field for sensing high-order visual features, such as texture boundaries and 2-nd order variations of contrast. We have devised a method to measure these center-surround receptive fields and show that V1 neurons with surround suppression are able to represent the high-order visual features via orientation-spatial frequency-based encoding scheme.
  Kimura R, Ohzawa I (2009)
J. Neurophysiol. 101: 1463-1479.

Time course of cross-orientation suppression in the early visual cortex
Plaid stimuli as well as the optimal and orthogonal mask stimuli were presented in rapid sequeces, and correlated with the generated spike sequence to study spatio-temporal dynamics of cross-orientation suppression of neurons in the early visual cortex.
  Sasaki KS, Ohzawa I (2007)
J. Neurophysiol. 98: 1194-1212

Internal spatial organization of receptive fields of complex cells in the early visual cortex
Detailed internal structure of complex cells are measured by studying two-dot interactions in responses to dense dynamic random-dot stimuli via reverse-correlation. This is a definitive extension of two-bar interaction results in V1 complex cells by Movshon et al. 1978.
  Tanaka H, Ohzawa I (2006)
J. Neurosci. 26: 4370-4382.

Stereopsis from 2-nd order contrast cues
Even when luminance or color cues are absent, the visual system is capable of using contrast envelopes for identifying object borders and depths. We show evidence for a neual basis for this perceptual ability.
  Nishimoto S, Ishida T, Ohzawa I (2006)
J. Neurosci. 26: 3269-3280.

Local Spectral Reverse Correlation (LSRC)
We have developed a novel method for studying response properties of many visual neurons simultaneously.
  Sanada TM , Ohzawa I (2006)
J Neurophysiol. 95: 2768-2786.

Neurons encoding 3-D surface slant information
Information about slants of surfaces in 3 dimensions may already be encoded by neurons of the early visual cortex.

 

 

Address for postal mail or courier:

Izumi Ohzawa
Graduate School of Frontier Biosciences
CiNet Bulding Rm. 2B1-1
Osaka University
1-4 Yamadaoka, Suita 565-0871 Japan
Telephone: 06-6879-4434

Please also visit our old site: Visual Neuroscience Lab (Ohzawa Lab).

 

 


Taka Sanada presenting a poster at the Neuroscience 2004 meeting in San Diego (travel support from COE21).


Shinji Nishimoto talking research with Dr. B.C. Cumming of NIH, also in San Diego (travel support from COE21).

 
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