Identifying objects seen from different viewpoints. A PET investigation.
Positron emission tomography scans were acquired when subjects performed three tasks, each in a separate block of trials. They decided whether words named pictures of objects viewed from a canonical perspective, decided whether words named pictures of objects viewed from a non-canonical (unusual) perspective or saw random patterns of lines and pressed a pedal when they heard the word (this was a baseline condition). The dorsolateral prefrontal region was activated when subjects identified objects seen from non-canonical perspectives, as expected if the frontal lobes are involved in top-down perceptual processing. In addition, several areas in the occipital, temporal and parietal lobes were selectively activated when subjects identified objects seen from non-canonical perspectives, as specifically predicted by a recent theory. Overall, the pattern of results supported the view that the human brain identifies objects by using a system of areas similar to that suggested by studies of other primates.
Department of Psychology, Harvard University, Cambridge, MA 02138.
S M
SM
Kosslyn
N M
NM
Alpert
W L
WL
Thompson
C F
CF
Chabris
S L
SL
Rauch
A K
AK
Anderson
D000293:Adolescent; D000328:Adult; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008568:Memory; D008606:Mental Processes; D014055:Tomography, Emission-Computed; D014796:Visual Perception / Q000502:physiology*