Energy consumption by the brain is 230-247 calories, based on 17
calories/gram and human brain sizes of 1,350-1,450 grams. During
periods of peak performance, adults increase that energy consumption
by up to 50%, according to psychology lecturer Mark Moss, of the
University of Northumbria.
While this may not seem an extraordinary amount of energy, the brain
may use 30% of a body's total energy, while being only 2?3% of total
body mass.
Moss cites the original 1986 work of Siebert, Gessner, and Klasser on
the energy supply of the central nervous system in his thesis. The
thesis, particularly the chapter 1 introduction, is a good and not
overly technical discussion of what we know about brain activity,
including descriptions of how PET scans are being used to monitor
glucose consumption in the brain. I've linked the first chapter:
University of Northumbria
"Oxygen Administration, Cognitive Performance and Physiological Responses," (Mark C. Moss, PhD Thesis 1999)
http://psychology.unn.ac.uk/mark/chapter1/chap1.htm
