Semantic Control of Feature Extraction from Natural Scenes

Peter Neri*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

29 Citations (Scopus)

Abstract

In the early stages of image analysis, visual cortex represents scenes as spatially organized maps of locally defined features (e.g., edge orientation). As image reconstruction unfolds and features are assembled into larger constructs, cortex attempts to recover semantic content for object recognition. It is conceivable that higher level representations may feed back onto early processes and retune their properties to align with the semantic structure projected by the scene; however, there is no clear evidence to either support or discard the applicability of this notion to the human visual system. Obtaining such evidence is challenging because low and higher level processes must be probed simultaneously within the same experimental paradigm.
We developed a methodology that targets both levels of analysis by embedding low-level probes within natural scenes. Human observers were required to discriminate probe orientation while semantic interpretation of the scene was selectively disrupted via stimulus inversion or reversed playback.
We characterized the orientation tuning properties of the perceptual process supporting probe discrimination; tuning was substantially reshaped by semantic manipulation, demonstrating that low-level feature detectors operate under partial control from higher level modules. The manner in which such control was exerted may be interpreted as a top-down predictive strategy whereby global semantic content guides and refines local image reconstruction.
We exploit the novel information gained from data to develop mechanistic accounts of unexplained phenomena such as the classic face inversion effect
Original languageEnglish
Pages (from-to)2374-2388
Number of pages15
JournalJournal of Neuroscience
Volume34
Issue number6
DOIs
Publication statusPublished - 5 Feb 2014

Keywords

  • inversion effect
  • natural statistics
  • noise image classification
  • orientation tuning
  • reverse correlation

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