Brain Activation Due to Various Visual Stimuli: A Pilot Study using Fixed-effects Analysis on Healthy Participants
- Author:
N.H. Nasaruddin
;
A.N. Yusoff
;
Sharanjeet Kaur
;
N.F. Nasrudin
;
S. Muda
- Publication Type:Journal Article
- Keywords:
fMRI;
SPM;
visual stimulus;
occipital gyrus;
middle temporal gyrus
- MeSH:
Photic Stimulation
- From:Malaysian Journal of Health Sciences
2015;13(1):57-68
- CountryMalaysia
- Language:English
-
Abstract:
Ocular abnormalities have apparent effects on brain activation. However, neuroimaging data about the ocular
characteristics of healthy participants are still lacking to be compared with data for patients with ocular pathology. The
objective of this multiple participants’ functional magnetic resonance imaging (fMRI) studies was to investigate the brain
activation characteristics of healthy participants when they view stimuli of various shapes, pattern and size. During the
fMRI scans, the participants view the growing ring, rotating wedge, fl ipping hour glass/bow tie, quadrant arc and full
checker board stimuli. All stimuli have elements of black-and-white checkerboard pattern. Statistical parametric mapping
(SPM) was used in generating brain activation via fi xed-effects (FFX) and conjunction analyses. The stimuli of various
shapes, pattern and size produce different brain activation with more activation concentrated in the left hemisphere.
These results are supported by the conjunction analysis which indicated that the left pre-central, post-central, superior
temporal and occipital gyrus as well as the left cingulate cortices were involved when the participants viewed each given
stimulus. Differential activation analysis showed activation with high specifi city in the occipital region due to the stimuli of
various shapes, pattern and size. The activation in the right middle temporal gyrus was found to be signifi cantly higher in
response to moving stimuli as compared to stationary stimuli. This confi rms the involvement of the right middle temporal
gyrus in the observation of movements. The black-and-white checkerboard stimuli of various shapes, pattern and size,
stationary and moving was found to 1) activate visual as well as other cortices in temporal and parietal lobes, 2) cause
asymmetry in brain function and 3) exhibit functional integration characteristics in several brain areas.
- Full text:W020150624353662431277.pdf
