Blog 8: K-Core Decomposition and Density Mapping of the Cerebral Cortex.

Drawing on my neuroscience background, I chose a study that operationalized k-core decomposition and density to understand the structure of the human cerebral cortex.   Their research question: how can the cerebral cortex be mapped quantitatively to help us understand process and function.  Prior research has looked at connectivity within the cerebral cortex, but they were unable to map out the structural core, network modules and hubs objectively.  By applying k-core decomposition and density analysis neural pathways more at the periphery could be removed in a controlled fashion to provide a distillate of the structures involved in information processing.

The data was collected using diffusion spectrum imaging which allows for a detailed representation of pathways within the human brain.  As it is evident in the picture below, it allows for the obtainment of quantifiable data.

The sample size consisted of 5 participants whose diffusion spectrum images were averaged to increase generalizability.

The nodes represent neural structures involved in information processing and integration.

Image result for neural structure of the brain frontal parietal occipital

The links are axonal pathways that interconnect the brain.

The results indicate the presence of large structural networks within the brain.  Structural cores were revealed in the posterior medial and parietal cortex.  Network modules were present in the temporal and frontal cortex.   Structural cores had high degree and betweenness centrality values and served as connector hubs that linked significant neural structural modules.

While the images and the study may appear simple.  This represents research that could hardly be imagined during my undergraduate studies at Berkeley.  Back then, people were injecting dyes into each axon and following its path to understand interconnections (image below).  Now they are not only able to visualize these connections but obtain quantifiable data directly from the human brains.

Image result for axonal dye

This level of understanding of the human brain is startling and scary.  If the processing power of the brain is fully leveraged in technology,  it can have many unforeseen consequences that cannot be controlled.

It reminds me of what Facebook ran into when developing artificial intelligence (AI).  What they found was that their AI created its own programming language that could not be deciphered by leading computer scientists.  Once this happened the AI was shut down but under less controlled settings it could have resulted in disaster.

References

Hagmann, P., Cammoun, L., Gigandet, X., Meuli, R., Honey, C. J., Van Wedeen, J., & Sporns, O. (2008). Mapping the structural core of human cerebral cortex. PLoS Biology. https://doi.org/10.1371/journal.pbio.0060159

Omatu, S., Malluhi, Q. M., González, S. R., Bocewicz, G., Bucciarelli, E., Giulioni, G., & Iqbal, F. (2015). Distributed computing and artificial intelligence, 12th international conference. In Advances in Intelligent Systems and Computing. https://doi.org/10.1007/978-3-319-19638-1

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