Connectivity and cost

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Chapter 13 endnote 4, from How Emotions are Made: The Secret Life of the Brain by Lisa Feldman Barrett.
Some context is:

Neurotransmitters empower a single brain with a single set of networks to construct diverse mental events, creating something greater than the sum of the parts.

As cognitive demands increase (during performance of a effortful task), networks configure to reduce modularity and increase long-distance connectivity.[1] Dynamic changes in information flow is called functional connectivity. Increased functional connectivity can be metabolically expensive. For example, when processing prediction errors (i.e., during an effortful task), neurons with long axons fire more; their axons are usually thicker and cost more to run.[2][3] (with most of the energy costs going to signaling between neurons, particularly in post-synaptic processes[4][5][6][7]). So, increased connectivity is a more efficient configuration for neural communication but more expensive metabolically.

Notes on the Notes

  1. Kitzbichler, Manfred G., Richard NA Henson, Marie L. Smith, Pradeep J. Nathan, and Edward T. Bullmore. 2011. "Cognitive effort drives workspace configuration of human brain functional networks." The Journal of Neuroscience 31 (22): 8259-8270.
  2. Bullmore, Ed, and Olaf Sporns. 2012. "The economy of brain network organization." Nature Reviews Neuroscience 13 (5): 336-349.
  3. Sterling, Peter, and Simon Laughlin. 2015. Principles of Neural Design. Cambridge, MA: MIT Press.
  4. Attwell, David, and Simon B. Laughlin. 2001. "An energy budget for signaling in the grey matter of the brain." Journal of Cerebral Blood Flow & Metabolism 21 (10): 1133-1145.
  5. Attwell, David, and Costantino Iadecola. 2002. "The neural basis of functional brain imaging signals." Trends in Neurosciences 25 (12): 621-625.
  6. Alle et al., 2009
  7. Harris et al 2012 [full reference to be provided]