Representing the forest before the trees: a global advantage effect in monkey inferotemporal cortex.
Hierarchical stimuli (large shapes composed of small shapes) have long been used to study how humans perceive the global and the local content of a scene--the forest and the trees. Studies using these stimuli have revealed a global advantage effect: humans consistently report global shape faster than local shape. The neuronal underpinnings of this effect remain unclear. Here we demonstrate a correlate and possible mechanism in monkey inferotemporal cortex (IT). Inferotemporal neurons signal the global content of a hierarchical display approximately 30 ms before they signal its local content. This is a specific expression of a general principle, related to spatial scale or spatial frequency rather than to hierarchical level, whereby the representation of a large shape develops in IT before that of a small shape. These findings provide support for a coarse-to-fine model of visual scene representation.
Sripati
Arun P
AP
Center for Neural Basis of Cognition, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA. sparun@cnbc.cmu.edu
Olson
Carl R
CR
D000200:Action Potentials / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D005260:Female; D006801:Humans; D008253:Macaca mulatta; D008297:Male; D009474:Neurons / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012858:Size Perception / Q000502:physiology*; D013223:Statistics as Topic; D013702:Temporal Lobe / Q000166:cytology / Q000502:physiology*; D013997:Time Factors; D014795:Visual Pathways / Q000502:physiology