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Imaging of Brain Activity using fMRI

In this demonstrator project MOVIII collaborates with the Center for Medical Image Science and Visualization (CMIV). The project will target the area of Functional Magnetic Resonance Imaging (fMRI), i.e. detection of brain activation using the MRI signal. fMRI is one of the major advances in neuroscience during the last decades and an important tool for neurological research. The fMRI group at CMIV has developed a new technique (based on Restricted Canonical Correlation Analysis) which is considered the best of all presently available methods for analyzing fMRI data. The visualization of fMRI data is challenging in view of the large data sets obtained as well as the need for simultaneous display of functional and anatomical information. New software for this purpose, combining volume rendering of both functional and anatomical data, has recently been implemented within CMIV as an add-on to the existing 3D Slicer software from Harvard. The project is currently being extended to use Mixed Reality techniques, which fuse MRI data with direct visual information in an operating theater. Other areas of fMRI related research at CMIV include the development of examination paradigms for neuroscience, new data acquisition methods, and clinical use of the fMRI method. Through CMIV we will also have access to equipment such as an fMRI Philips Achieva system with state-of-the-art hardware and software.

fMRI scanner.
Figure: MRI scanner.

The combined MOVIII-CMIV competence puts us in a position to develop new important applications of techniques used in information modeling and integration to biomedical systems. A rather visionary idea is analysis and ”control” of brain activity. We believe this approach has the potential to open up a whole new field in brain research. One of the consequences of the projects would be that the activation state of the brain could be steered towards a goal pattern by producing a sequence of stimuli that is dependent on the estimated activation pattern sequence. A parallel view is that a person can be told to try to make the stimuli produced move towards a target stimulus by will. In the future it may, in this way even be possible to analyze brain function in terms of brain state transition probability matrices. It should be noted that a fundamental challenge in this application will be the slow sampling rate for fMRI. A time span of at least one minute will most likely be required to make any statistically reasonable estimate of the current state. This project involves fundamental technical research in several of the MOVIII focus areas. Aspects of information modeling such as hybrid models involving reasoning functionality will play a key role. Information integration will also be an important component in obtaining consistent representations of fMRI and human sensory input signals. Interaction through visual interfaces with the obtained models and the underlying data will pose interesting challenges in areas such as hybrid rendering techniques for volumetric data and automated selection of regions of interest.

Brain activity.
Figure: Brain activity.
  • A poster describing the project used at the MOViii workshop 2007 can be viewed here.
  • See also the youtube clip of one of the fMRI based BCI realizations. The human brain and a computer were here linked by fMRI and worked together as a controller of a dynamical system. The dynamical system was made up of a cart with an inverted pendulum mounted on top of it. The subject had the ability to induce a force by evoking brain activity in the motor cortex. A force was applied from the left if the subject activated the left hand and from the right if the subject activated the right hand. If the subject was resting no force was applied. A neural network was trained to separate between rest, activity induced by activating the left and right hand. The subject was able to balance the inverted pendulum during a 7 minute test run.

Participants:

Anders Ynnerman (project manager), Lennart Ljung, Henrik Ohlsson, Jacob Roll, Hans Knutsson, Joakim Rydell, Anders Brun, Anders Eklund and Mats Andersson.