September 2024
Volume 24, Issue 10
Open Access
Vision Sciences Society Annual Meeting Abstract  |   September 2024
The Hidden Details: Effects of Partial Occlusion on Response Dynamics in the Primate Inferotemporal Cortex
Author Affiliations & Notes
  • Anna Bognar
    KU Leuven
  • Ghazaleh Ghamkhari Nejad
    KU Leuven
  • Rufin Vogels
    KU Leuven
  • Footnotes
    Acknowledgements  This research was supported by the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement 856495).
Journal of Vision September 2024, Vol.24, 571. doi:https://doi.org/10.1167/jov.24.10.571
  • Views
  • Share
  • Tools
    • Alerts
      ×
      This feature is available to authenticated users only.
      Sign In or Create an Account ×
    • Get Citation

      Anna Bognar, Ghazaleh Ghamkhari Nejad, Rufin Vogels; The Hidden Details: Effects of Partial Occlusion on Response Dynamics in the Primate Inferotemporal Cortex. Journal of Vision 2024;24(10):571. https://doi.org/10.1167/jov.24.10.571.

      Download citation file:


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

      ×
  • Supplements
Abstract

The primate brain can recognize objects even when partially concealed by occluders. To investigate the effect of occlusion on temporal dynamics of neuronal responses, we conducted experiments in two male macaques, recording single units in body-responsive regions in the posterior and anterior inferotemporal cortex (PIT & AIT) during fixation. Seven levels of occlusion were applied to static bodies, ranging from 5 to 60 percent occlusion. In both monkeys and regions, three key findings emerged: 1) average response strength decreased and 2) response onset and peak latency gradually increased by ~70 ms with degree of occlusion, PIT responses consistently preceding AIT. 3) The first response peak was followed by a trough and a stronger second peak under occlusion. To examine the role of visual information loss in the latency shifts, reduced responses, and response peaks, we presented, in addition to the partially occluded bodies, the same stimuli on top of the occluding pattern, and with an invisible occluding pattern, creating bodies with cut-outs. Interestingly, onset latency only shifted ~20 ms for the highest cut-out levels and remained unaffected by the background occluding pattern. Thus, onset latency shifts with occlusion may result from bottom-up occluder-related processing. Despite cut-out-induced response weakening, cut-outs with 60% information loss maintained selectivity similar to that observed during occlusion. However, the trough formation was pronounced when bodies were presented on top of the occluder. Intriguingly, the second peak did not align with response onset shifts but maintained latency differences between regions, occurring earlier in PIT. Thus, the second response peak in PIT is unlikely to arise from recurrent processing within the region or feedback from AIT. If generated by top-down feedback, one would expect it to appear earlier in AIT and may expect better body selectivity. Yet, it never surpassed early response selectivity based on neural decoding.

×
×

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.

×