New research findings pave the way to more accurate interpretation of brain imaging data

August 28, 2009

Functional magnetic resonance imaging (fMRI) is a technique widely used in studying the human brain. However, it has long been unclear exactly how fMRI signals are generated at brain cell level. This information is crucially important to interpreting these imaging signals. Scientists from the Academy of Finland's Neuroscience Research Programme (NEURO) have discovered that astrocytes, support cells in brain tissue, play a key role in the generation of fMRI signals.

Functional magnetic imaging has become a highly popular method in basic neurobiological research, psychology, medicine as well as in areas of study that interface with the social sciences and economics, such as neuroeconomics. fMRI imaging does not directly measure the activity of nerve cells or neural networks, but local changes in cerebrovascular circulation during the execution of certain functions. Interpretation of the measurement data obtained with this method therefore requires a close knowledge of the cell-level mechanisms that are responsible for these local changes in cerebrovascular circulation.

Studies conducted by Canadian and Finnish scientists in the NEURO programme have shown that astrocytes in play a key role in generating the fMRI signal. Astrocytes are not nerve cells, but neuronal support or glial cells that are present in the brain in greater abundance than nerve cells. Their signals change with changes in nerve cell activity in a manner that depends on the brain's metabolic state, and the astrocyte signals thus created regulate the diameter of blood vessels in the brain thereby affecting local circulation.

Professor Kai Kaila, who is in charge of the Finnish contribution to the research programme, says the results shed valuable light on the basic mechanisms behind fMRI signals. They also make it clear that interpretation of the fMRI results is not as straightforward as is assumed.

"For example, it is generally believed that changes in fMRI signals associated with different diseases reflect changes in the function of and neural networks, even though the explanation might lie in a pathological change in the characteristics and function of astrocytes. Likewise, the distinctive characteristics seen in fMRI signals measured from premature newborns is probably in large part based on the immaturity of astrocyte and blood vessel function," Kaila explains.

Source: Academy of Finland

Related Stories

Recommended for you

Study finds graspable objects grab attention more than images of objects do

December 15, 2017
Does having the potential to act upon an object have a unique influence on behavior and brain responses to the object? That is the question Jacqueline Snow, assistant professor of psychology at the University of Nevada, Reno, ...

Little understood cell helps mice see color

December 14, 2017
Researchers at the University of Colorado Anschutz Medical Campus have discovered that color vision in mice is far more complex than originally thought, opening the door to experiments that could potentially lead to new treatments ...

Scientists chart how brain signals connect to neurons

December 14, 2017
Scientists at Johns Hopkins have used supercomputers to create an atomic scale map that tracks how the signaling chemical glutamate binds to a neuron in the brain. The findings, say the scientists, shed light on the dynamic ...

Journaling inspires altruism through an attitude of gratitude

December 14, 2017
Gratitude does more than help maintain good health. New research at the University of Oregon finds that regularly noting feelings of gratitude in a journal leads to increased altruism.

Activating MSc glutamatergic neurons found to cause mice to eat less

December 13, 2017
(Medical Xpress)—A trio of researchers working at the State University of New York has found that artificially stimulating neurons that exist in the medial septal complex in mouse brains caused test mice to eat less. In ...

Gene mutation causes low sensitivity to pain

December 13, 2017
A UCL-led research team has identified a rare mutation that causes one family to have unusually low sensitivity to pain.

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.