fMRI subject preparation: a participant, ready to be entered in the scanner, is equipped with MRI-compatible sound transmitters and a 45°-tilted mirror above the eyes for visual stimulation via projection on a screen at the back of the scanner.
fMRI acquisition and analysis: a series of T2* cerebral images is acquired at regular intervals, while the participant is placed in different cognitive conditions. Analysis consists of measuring BOLD signal changes between the different conditions for each cerebral voxel. The resulting information can be viewed as a statistical map showing cortical regions in which activity is significantly different during the different conditions (courtesy of J. Culham).
CCNi includes a ultra-high field scanner (3 Tesla) and state-of-the-art equipment for sensory stimulation, measure of eye movements and physiological signals such as heart rate, skin conductance, etc. An fMRI-compatible EEG system will also allow joint recording of fMRI and EEG signals. Experiments, conducted in normal adult volunteers, will investigate issues related to ongoing research within the Department such as auditory cognition, high-level vision and cognition, perception and action.
|Example of auditory fMRI experiment: contrasting conditions of auditory stimulation with vocal vs. non-vocal sounds (above) highlights "voice-selective" regions in human auditory cortex.|
|Example of visual fMRI experiment: Cortical activity in primary visual cortex (V1) representing the illusory motion trace (green) of an apparent motion illusion.|
Belin P, Zatorre RJ, Lafaille P, Ahad P, Pike B. Voice-selective areas in human auditory cortex. (2000) Nature, 403:309-12.
Belliveau J, Kennedy D, McKinstry R, Buchbinder B, Weisskoff R, Cohen M, Vevea J, Brady T, Rosen B (1991). Functional mapping of the human visual cortex by magnetic resonance imaging Science, 254: 716-719.
Culham, J. fMRI for dummies ttp://defiant.ssc.uwo.ca/Jody_web/fmri4dummies.htm
Grosbras MH, PausT. (2005) Brain Networks Involved in Viewing Angry Hands or Faces Cerebral Cortex.
Huettel, SA, Song, AW, McCarthy, G. (2004) Functional Magnetic Resonance Imaging Sinauer Associates, Inc., Sunderland, Massachussets, USA.
Muckli, L., A. Kohler, N. Kriegeskorte & W. Singer. Primary visual cortex activity along the apparent-motion trace reflects illusory perception (2005). PLoS Biol. Jul 19;3(8):e265-275