Mapping inter-subject and inter-regional brain connectivity during free viewing of novel natural scenes
Date of Award
Master of Science in Biomedical Engineering - (M.S.)
Tara L. Alvarez
Traditional functional magnetic resonance imaging (fMRI) studies have used controlled tasks such as finger tapping to isolate function in distinct cortical. Recent studies have examined the mechanisms involved during natural conditions by asking subjects to freely view the presentation of a movie. The objective of our study was to further observe the extent to which similarities are present between subjects during natural vision. It was hypothesized that there would be a linear relationship between the percentage of region-specific overlap, which is the percent of the anatomical region of interest which contains spatial activation exhibited by all six subjects, and corresponding temporal correlation values between subjects from those regions. In this study, a controlled experiment was conducted in which all the subjects viewed a movie clip from the 2005 thriller Redeye for the first time during the tMRI scan. Spatial and temporal correlations were examined during a forty minute movie clip in which subjects casually viewed the stimulus. Significant spatial overlap between the six scanned subjects was observed in many regions during the viewing of the forty minute stimulus and this overlap was considerably lower during the second ten minute viewing. Temporal correlation values as high as 0.8 were observed between subjects during the viewing of the forty minute clip. Interregional correlation was also examined within subjects. The use of a movie clip allowed for the activation of a numerous functional regions in a single duration to identify similarity in cortical activation during a complex stimulus both spatially and temporally.
Nagaraj, Sheela, "Mapping inter-subject and inter-regional brain connectivity during free viewing of novel natural scenes" (2008). Theses. 333.