Functional anatomy of a common semantic system for words and pictures.
The relationship between the semantic processing of words and of pictures is a matter of debate among cognitive scientists. We studied the functional anatomy of such processing by using positron-emission tomography (PET). We contrasted activity during two semantic tasks (probing knowledge of associations between concepts, and knowledge of the visual attributes of these concepts) and a baseline task (discrimination of physical stimulus size), performed either with words or with pictures. Modality-specific activations unrelated to semantic processing occurred in the left inferior parietal lobule for words, and the right middle occipital gyrus for pictures. A semantic network common to both words and pictures extended from the left superior occipital gyrus through the middle and inferior temporal cortex to the inferior frontal gyrus. A picture-specific activation related to semantic tasks occurred in the left posterior inferior temporal sulcus, and word-specific activations related to semantic tasks were localized to the left superior temporal sulcus, left anterior middle temporal gyrus, and left inferior frontal sulcus. Thus semantic tasks activate a distributed semantic processing system shared by both words and pictures, with a few specific areas differentially active for either words or pictures.
Vandenberghe
R
R
Wellcome Department of Cognitive Neurology, Institute of Neurology, London, UK.
Price
C
C
Wise
R
R
Josephs
O
O
Frackowiak
R S
RS
D000328:Adult; D000368:Aged; D000377:Agnosia / Q000503:physiopathology; D001307:Auditory Perception / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D001931:Brain Mapping; D006801:Humans; D008297:Male; D008875:Middle Aged; D009778:Occipital Lobe / Q000502:physiology; D010296:Parietal Lobe / Q000502:physiology; D012660:Semantics; D013067:Speech Perception / Q000502:physiology*; D014055:Tomography, Emission-Computed; D014796:Visual Perception / Q000502:physiology*