November 2002
Volume 2, Issue 7
Vision Sciences Society Annual Meeting Abstract  |   November 2002
Separated processing of local motion signal depending on its polarity in MDM detection
Author Affiliations
  • K. Maruya
    University of Tokyo, Japan
Journal of Vision November 2002, Vol.2, 390. doi:10.1167/2.7.390
  • Views
  • Share
  • Tools
    • Alerts
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      K. Maruya, T. Sato; Separated processing of local motion signal depending on its polarity in MDM detection. Journal of Vision 2002;2(7):390. doi: 10.1167/2.7.390.

      Download citation file:

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

  • Supplements

Purpose: We have already reported that reversed-phi was perceived with Motion Defined Motion (MDM) stimulus (ARVO2001). This suggests that polarity-dependent detector function for MDM (Maruya & Sato, 2000; 2001: cf. Zanker, 1993). In this study, we further investigated the role of polarities by comparing perception characteristics for the stimuli with the same modulation waveform but containing only a single motion direction (uni-directional) and those with two opposite directions (bi-directional). The uni-directional motion was created by raising the modulation waveform for bi-directional motion by half of its amplitude. Methods: The stimulus was 10 (V) × 4 (H) deg horizontal motion-defined patterns consisted of dynamic random dots. Dot density was uniform over the whole field, and dots were moving horizontally (right or left). The dot speed was modulated along V-axis either by sinusoidal (Exp. 1) or missing fundamental (Exp. 2) function (spatial frequency: 0.2 c/d). In bi-directional condition, the speed was modulated either −100 to 100 or −200 to 200 min/sec (both to the right and left around 0). In uni-directional condition, the speed of the dots was modulated between 0 and 200 min/sec, i.e. by plus/minus 100 min/sec function raised by 100 min/sec DC level. A 5-frame apparent motion was presented with a 1/4-cycle shift between frames. SOA was fixed at 320 ms. Subject was asked to report the perceived direction by 2AFC. Results: We found the motion was perceived stronger under the uni-directional condition than under the bi-directional condition. This suggests, in the MDM detection, signals after local motion detection-level are processed separately depending on its polarity. If this is the case, in the bi-directional stimuli, the signals were processed by separate detectors depending on their polarities, so the waveform of local motion flow-field was rectified and the detection supposedly is less efficient than in coincident condition.

Maruya, K., Sato, T.(2002). Separated processing of local motion signal depending on its polarity in MDM detection [Abstract]. Journal of Vision, 2( 7): 390, 390a,, doi:10.1167/2.7.390. [CrossRef]
 Supported by JSPS, HFSP

This PDF is available to Subscribers Only

Sign in or purchase a subscription to access this content. ×

You must be signed into an individual account to use this feature.