Plans are underway in the Psychology Dept. to open a brain imaging center that will allow UCSB to join the ranks of six other UC campuses in brain research.
Professor of Psychology Greg Ashby is the director of the UCSB imaging center, which anticipates opening a magnetic resonance imaging (MRI) facility. The facility would feature a MRI scanner that would allow researchers to view brain activity in people while they perform simple mental tasks. The imaging center will be located in the new psychology building, for which a groundbreaking ceremony was held on March 1.
Ashby said that the building would have three stories above ground and a basement. The scanner would be in the basement and will operate at 3 tesla; a tesla is a measure of magnetic field strength that describes how powerful the scanner is. Three tesla is the highest common field strength used in human brain imaging. The machine will cost about $2 million.
The imaging center has not secured the funds to buy the scanner yet, which is built by Siemens and only allows imaging of the head. Because the center is only interested in brain imaging, the additional $700,000 cost for a full-body scanner was not justified.
Ashby has already started looking for sources of funding. He said the new psychology building should be done in less than 18 months, so he plans to be done with fund raising by that time.
“I wrote a grant proposal to the National Science Foundation that was submitted in January,” Ashby said. “The university is also looking for private donors.”
So far, the grant proposal has not been approved, and no private donations have been made, but Ashby said he feels the new imaging center will be a worthwhile asset to the university.
“Anytime you submit a federal grant, you’re worried about getting the grant money. It’s a long shot anytime you submit,” Ashby said. “But I am really confident we will have the money by the time the building is completed. It’s a strong proposal.”
Many brain imaging studies use a technique called functional magnetic resonance imaging (fMRI). This technique allows the scanner to detect which regions within the brain are active while the subject performs mental tasks such as adding numbers.
Conventional magnetic imaging is useful for visualizing tissue damage and cancer, but is unable to provide information about the activity of brain tissue. Functional MRI is able to detect brain activity by indirectly measuring the blood flow in regions of the brain.
When a part of the brain starts to do work – adding numbers, for example – that part of the brain needs more blood to perform the work. The increased blood flow means that more incoming oxygenated blood is being converted to deoxygenated blood, just like in an active muscle. The deoxygenated blood is darker in color, and it is also slightly more magnetic than its oxygenated counterpart.
The iron within hemoglobin, the oxygen-carrying component of blood, determines its magnetic properties. When the hemoglobin is deoxygenated, the iron atom has unpaired electrons, which give it its magnetism.
This difference between oxygenated and deoxygenated blood forms the basis for how the fMRI scanner detects which brain regions are active and using more oxygen from the blood.
A magnetic field formed by the scanner causes the hydrogen nuclei in water molecules to gyrate in a uniform direction. Normally, the nuclei gyrate in random directions. Once the nuclei are all gyrating in the assigned direction, the MRI scanner emits a short radio frequency pulse that disorients the gyrations. Following this, the scanner records the time it takes for the nuclei to return to their magnetic field-induced gyration.
The deoxygenated hemoglobin’s magnetism causes surrounding nuclei to return more slowly to their initial state. The scanner records the time blood in different regions of the brain takes to recover and thereby determines where in the brain the thinking is being done.
UCSB has already participated in brain imaging studies by working with Dartmouth College’s imaging facility.
“We have a collaborative arrangement with Dartmouth in New Hampshire,” Ashby said. “There have been, in the last six months, four or five projects run [at Dartmouth].”
Most of the planning for these imaging studies is completed here, and then a few team members fly to Dartmouth to use their scanner to collect the imaging data from human subjects, Ashby said.