June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Adultlike Sensitivity to Curvatures of V2 Neurons in Infant Monkeys
Author Affiliations & Notes
  • Bin Zhang
    College of Optometry, Nova Southeastern University, Plantation, Florida, United States
  • Ye Wang
    College of Optometry, University of Houston, Houston, Texas, United States
  • Xiaofeng Tao
    College of Optometry, University of Houston, Houston, Texas, United States
  • Guofu Shen
    College of Optometry, University of Houston, Houston, Texas, United States
  • Earl L Smith
    College of Optometry, University of Houston, Houston, Texas, United States
  • Izumi Ohzawa
    Osaka University, Osaka, Japan
  • Yuzo M Chino
    College of Optometry, University of Houston, Houston, Texas, United States
  • Footnotes
    Commercial Relationships   Bin Zhang, None; Ye Wang, None; Xiaofeng Tao, None; Guofu Shen, None; Earl Smith, None; Izumi Ohzawa, None; Yuzo Chino, None
  • Footnotes
    Support  R01 EY-008128 (YC), R01 EY-003611 (ES), and P30 EY-007551 (CORE) MEXT grants: KAKENHI 22135006 and 15H05921 (IO)
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 3825. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to Subscribers Only
      Sign In or Create an Account ×
    • Get Citation

      Bin Zhang, Ye Wang, Xiaofeng Tao, Guofu Shen, Earl L Smith, Izumi Ohzawa, Yuzo M Chino; Adultlike Sensitivity to Curvatures of V2 Neurons in Infant Monkeys. Invest. Ophthalmol. Vis. Sci. 2017;58(8):3825.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose : Non-human primates can discriminate texture-defined form as early as 6–8 weeks of age despite their relatively low visual acuity. The neuronal mechanisms underlying this remarkable visual capacity have not been extensively studied. Based on the findings that the receptive-field subunits of V2 neurons is as complex as in adults and the ability of V2 neurons to compare local features of neighboring stimulus elements is nearly adult like, our previous study implied that V2 neurons in infant monkeys could encode angles or curvatures. In this study we tested this idea more directly by using two-dimensional dynamic noise stimuli and a new analytical method called “Transform Domain Reverse Correlation (TDRC)”.

Methods : Unit recordings were made in V2 of anesthetized infant macaque monkeys (4 and 8weeks) and adult monkeys. In TDRC analysis, two neighboring regions in the 2D noises are filtered by Gaussian windows and transformed into the spatial frequency domain. For each region, the amplitude spectra within certain frequency band was integrated along all orientations, and the joint distribution of orientations of the two regions were computed as the product the amplitudes for all pairs of orientations. A further coordinate transformation mapped the data from the double orientation domain into the curvature-direction domain. Finally, the spike-triggered analysis is performed between the spikes and transformed stimuli in curvature-direction domain. The resulting map reveals the stimulus selectivity of individual neurons for angled or curved contours.

Results : As early as 4 weeks of age, about 40% of V2 neurons in non-human primates were sensitive to angled or curved contours in image sub-regions. The percentage of neurons that were sensitive to curvatures was similar in infants and adults. Moreover, there was no bias in optimal curvature direction in any age groups. The optimal curvature tuning width, the signal strength, and reliability (Zmax) for infant neurons were not significantly different from that for adults. Only the variance of curvatures of subunits for infant monkeys was lower in infants than in adults.

Conclusions : Our results provide a physiological substrate for the aforementioned perceptual finding that infant monkeys are capable of discriminating texture-defined visual borders as early as 6 weeks of age.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

×
×

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.

×