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Dec - Todd Woodward

Speaker: Todd Woodward

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Talk Title: Constrained Principal Component Analysis for fMRI Data: Relating fMRI Signal to Experimental Conditions.

Event Details


Thursday, December 9, 2010, 6:00 pm

Affiliation: Assistant Professor, Department of Psychiatry, University of British Columbia

URL: Todd Woodward


Functional magnetic resonance imaging (fMRI) data from one subject

typically involves measurement of blood-oxygen level dependent (BOLD)

changes in the whole brain, measured every two seconds, over a period

of about 12 minutes, at 65,000 brain regions. Over this 12 minute

period, participants are asked to repeatedly carry out some cognitive

task, for example, to remember 8 numbers for a short period of time

(e.g., 4 seconds). Researchers using this technology need to determine

which brain networks are invoked in response to the task (and not some

other aspect of thinking, like “this scanner is uncomfortable!”), but

also (and importantly), which are differentially involved in the

experimental conditions that are built into the task. The method that

our laboratory has developed for this purpose is named constrained

principal component analysis (fMRI-CPCA), and combines multivariate

multiple regression with principal component analysis (i.e., singular

value decomposition). Multivariate multiple regression is used to

separate the BOLD signal variance into what is predictable from the

task and what is not, and singular value decomposition is used to

determine the dominant patterns of intercorrelation between the brain

regions for each source of BOLD signal variance, thereby forming brain

networks. Changes over time in these brain networks can be correlated

with the timing of the task to determine their relative involvement in

the experimental conditions. fMRI-CPCA is available for download free

of charge (

Please note:

Trainees are invited to meet with the VanBUG speaker for open discussion

of both science and career paths. This takes place 4:30-5:30pm in either

the Boardroom or Lunchroom on the ground floor of the BCCRC

Recommended Readings

FIR-CPCA analysis

Introductory Speaker: Raymond Lim, MSc Candidate, Pavlidis Lab, Centre for High Throughput Biology, University of British Columbia

Title: Wide Scale Comparison of Transcriptome Profiles

Presentation: Download Presentation