Functional neuroanatomy of visual object naming: a PET study.
BACKGROUND
The ability to name objects depends partly on visual perception. We used positron emission tomography (PET) to measure activity-related changes in regional cerebral blood flow (r-CBF) in order to identify regions of the brain activated during visual object naming.


METHODS
Four right-handed volunteers were recruited. Following an intravenous injection of 15O-labeled water, r-CBF was measured during visual object naming, counting numbers, and resting. PET and MRI images were coregistered, the size of the brain was proportionally adjusted in each axis to Talairach's and Tournoux's atlas, and the comparison of stimulated versus resting blood flow images revealed activated brain regions.


RESULTS
In the subtraction of resting from naming, activation was observed in the bilateral primary visual cortex, bilateral fusiform gyrus, left lingual gyrus, bilateral inferotemporal cortex, bilateral inferior frontal gyrus, bilateral precentral gyrus, anterior cingulate gyrus, left parietal operculum, and left putamen. In the subtraction of counting from naming, most of the those areas were activated, but no significant activity was observed in the left lingual gyrus, left parietal operculum, or bilateral precentral gyrus (motor cortex). The areas activated with the paradigm included those dedicated to visual perception (primary and associate visual cortex), visual recognition (inferior temporal cortex), and phonological output (Broca's area).


CONCLUSIONS
Our results indicated that the major neural network from occipital lobe to frontal cortex, which is mainly involved in the ventral visual pathway, demonstrated activation in these tasks. Result of this study will serve as base line data for analyzing the findings in patients with impaired visual perception.
Kiyosawa
M
M
Department of Ophthalmology, Tokyo Medical and Dental University, School of Medicine, Japan.
Inoue
C
C
Kawasaki
T
T
Tokoro
T
T
Ishii
K
K
Ohyama
M
M
Senda
M
M
Soma
Y
Y
D000328:Adult; D000368:Aged; D001921:Brain / Q000098:blood supply / Q000000981:diagnostic imaging / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D003071:Cognition / Q000502:physiology; D004292:Dominance, Cerebral; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009445:Neuroanatomy; D010104:Oxygen Radioisotopes; D014055:Tomography, Emission-Computed / Q000379:methods*; D014795:Visual Pathways / Q000502:physiology; D014796:Visual Perception / Q000502:physiology*
D010104:Oxygen Radioisotopes