How Reliable Are Visual Context Effects in the Parahippocampal Place Area?

• Published in: Cerebral cortex (New York, N.Y. 1991) Vol. 20; no. 2; pp. 294 - 303
• Main Authors: Epstein, Russell A., Ward, Emily J.
• Format: Journal Article
• Language: English
• Published: United States Oxford University Press 01-02-2010
• Subjects: Adult; Brain Mapping; context effects; Dominance, Cerebral - physiology; Face; Female; fMRI; Functional Laterality - physiology; Humans; Magnetic Resonance Imaging; Male; Neuropsychological Tests; Parahippocampal Gyrus - anatomy & histology; Parahippocampal Gyrus - physiology; parahippocampal place area; Pattern Recognition, Visual - physiology; Photic Stimulation; Reaction Time - physiology; Recognition, Psychology - physiology; spatial layout; Temporal Lobe - anatomy & histology; Temporal Lobe - physiology; Visual Cortex - anatomy & histology; Visual Cortex - physiology; Visual Pathways - anatomy & histology; Visual Pathways - physiology; Visual Perception - physiology; visual recognition; visual scenes; Young Adult; context effects; fMRI; parahippocampal place area; visual recognition; visual scenes; spatial layout
• ISSN: 1047-3211; 1460-2199
• DOI: 10.1093/cercor/bhp099

The parahippocampal place area (PPA) is a region of human cortex that responds more strongly to visual scenes (e.g., landscapes or cityscapes) than to other visual stimuli. It has been proposed that the primary function of the PPA is encoding of contextual information about object co-occurrence. Supporting this context hypothesis are reports that the PPA responds more strongly to strong-context than to weak-context objects and more strongly to famous faces (for which contextual associations are available) than to nonfamous faces. We reexamined the reliability of these 2 effects by scanning subjects with functional magnetic resonance imaging while they viewed strong- and weak-context objects, scrambled versions of these objects, and famous and nonfamous faces. “Contextual” effects for objects were observed to be reliable in the PPA at slow presentation rates but not at faster presentation rates intended to discourage scene imagery. We were unable to replicate the earlier finding of preferential PPA response to famous versus nonfamous faces. These results are difficult to reconcile with the hypothesis that the PPA encodes contextual associations but are consistent with a competing hypothesis that the PPA encodes scenic layout.