Hierarchical visual processing is dependent on the oculomotor system

Neuroreport. 2000 Feb 7;11(2):241-7. doi: 10.1097/00001756-200002070-00004.

Abstract

Using functional MRI and eye movement recordings we studied the processing of hierarchical stimuli. In agreement with others, we found a minor left hemispheric dominance during local and right dominance during global processing. When attention was directed locally, well-known oculomotor cortical areas were activated, and saccades were elicited in 41% of the trials. Their latencies were similar to pro-saccades. During global processing virtually no saccades occurred. These results suggest two different operational modes of attention. Attending to local features induces a shift of attention, which simultaneously computes a saccade on any level above the brainstem with a computational burden equal to reflexive saccades. Conversely, attending to global features induces an expansion of the focus of attention, which reinforces fixation.

Publication types

  • Clinical Trial

MeSH terms

  • Attention / physiology*
  • Fixation, Ocular / physiology*
  • Functional Laterality / physiology
  • Humans
  • Magnetic Resonance Imaging
  • Male
  • Models, Neurological
  • Oculomotor Muscles / physiology
  • Parietal Lobe / physiology
  • Photic Stimulation
  • Reaction Time / physiology
  • Reference Values
  • Regression Analysis
  • Saccades / physiology*
  • Visual Cortex / physiology*
  • Visual Perception / physiology*