June 2020
Volume 61, Issue 7
Free
ARVO Annual Meeting Abstract  |   June 2020
Role of Superior Colliculus in fixation preference during a delayed saccade task in strabismic non-human primates
Author Affiliations & Notes
  • Santoshi Ramachandran
    College of Optometry, University of Houston, Houston, Texas, United States
  • Vallabh E Das
    College of Optometry, University of Houston, Houston, Texas, United States
  • Footnotes
    Commercial Relationships   Santoshi Ramachandran, None; Vallabh Das, None
  • Footnotes
    Support  NIH Grant EY026568; NIH Grant P30 EY07551
Investigative Ophthalmology & Visual Science June 2020, Vol.61, 5082. doi:
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Santoshi Ramachandran, Vallabh E Das; Role of Superior Colliculus in fixation preference during a delayed saccade task in strabismic non-human primates. Invest. Ophthalmol. Vis. Sci. 2020;61(7):5082.

      Download citation file:


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

      ×
  • Supplements
Abstract

Purpose : Strabismic patients and non-human primates often develop the ability to saccade to and fixate on a target with either eye depending on the targets’ spatial location. Spatial fixation preference in strabismus could possibly be accounted for in a competitive decision framework wherein the brain chooses between two retinal errors (since eyes are pointing in different directions) to prepare a saccade. We tested this framework by recording from visuo-motor neurons in the superior colliculus (SC), a structure critical in target selection and saccade generation, during spatial fixation preference behavior.

Methods : Single cell neural recordings from the intermediate/deep SC were obtained while a head-fixed strabismic [M1, ~30° XT] monkey performed a delayed saccade task under binocular viewing conditions. Once the neuronal receptive field was localized, visual targets were presented at one of two locations corresponding to the receptive field location of either the viewing or deviated eye, and resulted in fixation-switch or no fixation-switch saccades. Amplitude and direction were matched (Exp 1 – two target condition). For certain target locations, fixation-switch and no fixation-switch saccades were in opposite directions (different colliculi) (Exp 2 – single target condition). Paired t-tests were performed to compare firing rates of visual, buildup and saccade related response in fixation-switch and no fixation-switch trials.

Results : Exp 1 (n=10): Robust visual sensory responses were observed when targets were presented to either the viewing or deviated eye with evidence of only small interocular suppression. As expected, motor responses for fixation-switch and no-fixation switch trials were not significantly different since the saccade parameters are matched. Additionally, the mean build-up responses showed no difference in these trials since the cell corresponds to the ‘winning’ saccade. Exp 2 (n=11): For the single target condition, both visual and mean build-up responses were reduced for trials in which the cell did not correspond to the ‘winning’ eye, suggesting that the build-up activity may be used to facilitate eye choice. Analysis of more cells from M1 and data acquisition from a second animal is ongoing.

Conclusions : Analysis of neural data from SC visuo-motor cells suggests that this structure plays an important role in eye choice for visual stimuli in strabismus.

This is a 2020 ARVO Annual Meeting abstract.

×
×

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.

×