A new paper in the open access journal PLoS Biology describes a new way to model the human brain using diffusion spectrum imaging. Since we’re in the omics age of science, you shouldn’t be surprised that this map is dubbed the connectome. The semantics of the connectome is similar to genome, proteome, metabalome, transcriptome — etc. in that it is a matrix of nearly all the neuronal connections of the human brain. The image to your right is from the new PLoS Biology study, the larger the dot represented the more neurons are in that area in 4 or more individuals.
The current map of the brain has largely been made by functional magnetic resonance imaging (fMRI) technology, which measures the activity of the brain. fMRI has been used to locate which parts of the brain become active during some stimulus. Several months ago, our very own Alex told us of an example of how fMRI was used on musicians to track their improvisational abilities.
But there has been one major shortcoming with fMRI studies, they provide little to no information on the role of the underlying anatomy that generates the activity picked up by the resonance detector. Furthermore, the fMRI images give us general areas of activity in the brain, and anyone out there who has seen neurons from a slice of brain under a microscope — you’d know there’s general areas can be composed of millions of neurons.
In this new study, titled, “Mapping the Structural Core of Human Cerebral Cortex,” the authors use a similar magnetic resonance imaging technology called diffusion spectrum imaging (DSI) along with fMRI for comparison. The study examined the brains of five human participants. The DSI technique estimates connections of neuronal fiber trajectories by mapping the gradient of the diffusion of water molecules through brain tissue, which is much more specific than fMRI.
Olaf Sporns, one of the co-authors, took these images, and
“carried out a computational analysis trying to identify regions of the brain that played a more central role in the connectivity, serving as hubs in the cortical network… these analyses revealed a single highly and densely connected structural core in the brain of all participants.”
Sporns said that the fMRI and DSI imagery are closely related and that this new technique can measure a significant correlation between brain anatomy and brain dynamics. I highly recommend you check out this paper, and also the synopsis PLoS Biology published, “From Structure to Function: Mapping the Connection Matrix of the Human Brain.”
- Hagmann, P., Cammoun, L., Gigandet, X., Meuli, R., Honey, C.J., Wedeen, V.J., Sporns, O., Friston, K.J. (2008). Mapping the Structural Core of Human Cerebral Cortex. PLoS Biology, 6(7), e159. DOI: 10.1371/journal.pbio.0060159
- Gross, L. (2008). From Structure to Function: Mapping the Connection Matrix of the Human Brain. PLoS Biology, 6(7), e164. DOI: 10.1371/journal.pbio.0060164
- Sporns, O., Tononi, G., KÃ¶tter, R. (2005). The Human Connectome: A Structural Description of the Human Brain. PLoS Computational Biology, 1(4), e42. DOI: 10.1371/journal.pcbi.0010042
- Lichtman, J.W., Livet, J., Sanes, J.R. (2008). A technicolour approach to the connectome. Nature Reviews Neuroscience, 9(6), 417-422. DOI: 10.1038/nrn2391