CHICAGO: The quest to understand ourselves by modelling the human brain continues this week with news from Germany, where a team of researchers discovered a way to combine two different brain-imaging modalities in order to confer directionality onto the connectome, or the connectivity map of the human brain.
Information about the function of living human brains has historically been difficult to obtain, even with sophisticated medical imaging techniques. fMRIs produce a set of image slices which can be reassembled into a 3D model with fine spatial resolution. But MRI scans have a low temporal resolution — below a sampling interval of about one to two seconds, faster scanning doesn’t yield additional detail.
That means that it’s impossible for an fMRI to keep up with the speed of the brain, so even though we know a lot about the structural connectivity of the brain, we don’t know much about the functional connectivity. When both sensory and cognitive areas light up in response to a stimulus, it’s hard to tell which way the river of information flows. But not impossible — it just takes some collaboration.