Dopamine Sensor Enhances Brain-Imaging Procedures

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By responding to the neurotransmitter dopamine, new MRI sensors could improve imaging in future brain imaging platforms. Image: Patrick Gillooly/MIT

An innovative dopamine sensor developed by neuroscientists at MIT (Cambridge, MA) could allow for a method of noninvasively measuring brain activity that is more precise than current functional magnetic resonance imaging (fMRI) techniques. By providing in vivo imaging of neural signal processes, the protein engineering technology has the potential to enhance specificity and resolution in future brain-imaging procedures.Currently, fMRI detects brain activity via elevated levels of iron in hemoglobin that occur when activity causes increased blood flow to a region of the brain. Measuring blood flow, however, produces a slow and indirect readout of neural activity, according to the researchers. By directly responding to such neurotransmitters as dopamine instead, the researchers' sensors yield more-precise analysis and enable molecular-level functional MRI."We have designed an artificial molecular probe that changes its magnetic properties in response to the neurotransmitter dopamine," says Alan Jasanoff, an associate professor of biological engineering at MIT and senior author of a related Nature Biotechnology paper. "This new tool connects molecular phenomena in the nervous system with whole-brain imaging techniques, allowing us to probe very precise processes and relate them to the overall function of the brain and of the organism. With molecular fMRI, we can say something much more specific about the brain's activity and circuitry than we could using conventional blood-related fMRI."Visit MIT's Web site to view a video on the technology or to find out how the group developed the sensors, or read the abstract for the journal Nature Biotechnology.