Lateral visual field stimulation reveals extrastriate cortical activation in the contralateral hemisphere: an fMRI study.
We examined whether lateral visual field stimulation (LSTM) could activate contralateral extrastriate cortical areas as predicted by a large experimental literature. We asked seven unscreened, control subjects to wear glasses designed to allow vision out of either the left (LVF) or right lateral visual field (RVF) depending upon which side the subject looked toward. Each subject participated in a block design functional magnetic resonance imaging (fMRI) study with alternating 30-s epochs in which he was asked to look to one side and then the other for a total of five epochs. On each side of the bore of the scanner, we taped a photograph for the subject to view in the LVF and RVF. The data were analyzed with SPM99 using a fixed effect, box-car design with contrasts for the LVF and the RVF conditions. Both LVF and RVF conditions produced the strongest fMRI activation in the contralateral occipitotemporal and posterior parietal areas as well as the contralateral dorsolateral prefrontal cortex. LSTM appears to increase contralateral fMRI activation in striate and extrastriate cortical areas as predicted by earlier studies reporting differential cognitive and/or emotional effects from unilateral sensory or motor stimulation.
Schiffer
Fredric
F
Department of Psychiatry, Harvard Medical School, and the Developmental Biopsychiatry Research Program, McLean Hospital, 115 Mill Street, Belmont, MA 02478, USA. fschif@attbi.com
Mottaghy
Felix M
FM
Pandey Vimal
Ram Lakhan
RL
Renshaw
Perry F
PF
Cowan
Ronald
R
Pascual-Leone
Alvaro
A
Teicher
Martin
M
Valente
Elizabeth
E
Rohan
Michael
M
D000328:Adult; D001288:Attention / Q000502:physiology*; D001931:Brain Mapping; D002540:Cerebral Cortex / Q000502:physiology*; D004292:Dominance, Cerebral / Q000502:physiology*; D004644:Emotions / Q000502:physiology; D005260:Female; D005403:Fixation, Ocular / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D007089:Image Enhancement; D007091:Image Processing, Computer-Assisted; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood; D014793:Visual Cortex / Q000502:physiology*; D014794:Visual Fields / Q000502:physiology*; D014795:Visual Pathways / Q000502:physiology
D010100:Oxygen