May 2008
Volume 8, Issue 6
Free
Vision Sciences Society Annual Meeting Abstract  |   May 2008
The balance between transient and sustained temporal response varies across the V1 visual field map
Author Affiliations
  • Hiroshi Horiguchi
    Department of Ophthalmology, Jikei University, School of Medicine, Tokyo, Japan, and Department of Psychology, Stanford University
  • Satoshi Nakadomari
    Department of Ophthalmology, Jikei University, School of Medicine, Tokyo, Japan, and Department of Ophthalmology, Kanagawa Rehabilitation Hospital, Atsugi, Japan
  • Ayumu Furuta
    Maeda Ophthalmic Clinic, Aizuwakamatsu, Japan
  • Yoichiro Masuda
    Department of Ophthalmology, Jikei University, School of Medicine, Tokyo, Japan, and Department of Psychology, Stanford University
  • Kunihiro Asakawa
    Department of Ophthalmology, Jikei University, School of Medicine, Tokyo, Japan, and Division of Sensory and Cognitive Information, Department of Information Physiology, National Institute for Physiological Sciences, Okazaki, Japan
  • Takahiko Koike
    National Institute of Information and Communications Technology, Kobe, Japan
  • Shigeyuki Kan
    National Institute of Information and Communications Technology, Kobe, Japan
  • Masaya Misaki
    National Institute of Information and Communications Technology, Kobe, Japan
  • Satoru Miyauchi
    National Institute of Information and Communications Technology, Kobe, Japan
  • Brian Wandell
    Department of Psychology, Stanford University
Journal of Vision May 2008, Vol.8, 294. doi:10.1167/8.6.294
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      Hiroshi Horiguchi, Satoshi Nakadomari, Ayumu Furuta, Yoichiro Masuda, Kunihiro Asakawa, Takahiko Koike, Shigeyuki Kan, Masaya Misaki, Satoru Miyauchi, Brian Wandell; The balance between transient and sustained temporal response varies across the V1 visual field map. Journal of Vision 2008;8(6):294. doi: 10.1167/8.6.294.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: The temporal impulse response in V1 reflects multiple neural and hemodynamic components. We analyze these components by modeling the temporal response as a mixture of several terms and comparing the relative contributions of these terms across the cortical surface.

Methods: Functional MRI measurements were made using a 3T scanner (Siemens, Trio, Erlangen, Germany). We dilated subjects' pupils with mydriatics and placed semi-transparent, hemisphere-shaped diffusers on their eyes to eliminate spatial contrast (Ganzfeld). Subjects viewed spatially uniform brightness that alternated between a low and high luminance every 24 seconds (square wave). We modeled the temporal response as the sum of two terms. One corresponds to a signal at the luminance step (transient) and a second that corresponds to the mean illumination (sustained). Both regressors were convolved with the hemodynamic response function. We also measured the visual field eccentricity maps.

Results: The temporal responses varied as we measured from posterior to anterior calcarine sulcus. The responses spread far above 14 degrees isoeccentricity line which we could precisely determine from the eccentricity map. The sustained response decreased with visual field eccentricity, while the transient responses increased with increasing eccentricity. In the central representation, the ratio of the transient reponse to the sustained was 0.52 ± 0.18; in the periphery the ratio was 2.39 ± 0.26.

Discussion: The responses in central visual field representation depend more on the absolute luminance level (sustained) while in the periphery responses are influenced more by instantaneous luminance changes. This difference might reflect the differential weighting of cell types in these regions of V1.

Horiguchi, H. Nakadomari, S. Furuta, A. Masuda, Y. Asakawa, K. Koike, T. Kan, S. Misaki, M. Miyauchi, S. Wandell, B. (2008). The balance between transient and sustained temporal response varies across the V1 visual field map [Abstract]. Journal of Vision, 8(6):294, 294a, http://journalofvision.org/8/6/294/, doi:10.1167/8.6.294. [CrossRef]
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