[NiHaoMike]

Originally Posted by jamesqf

I think what "they say" is usually wrong. There's really not that much difference in the brain's energy consumption when thinking hard and when "not thinking". There' are several reasons for this. For one, a lot of the energy the brain consumes is used just to keep all the neurons alive. They're constantly producing electrochemical signals (action potentials). Thinking is more about changing the signal patterns than increasing the number of signals.

Then there's the ongoing stream of consciousness thinking that really isn't active problem solving. There's also a lot of non-thinking activity going on all the time, for instance the visual cortex constantly processes input regardless of whether you're thinking about what you see.

One thing that does use more energy, though, is long-term learning, since that is actively changing the structure of the brain.

I always thought that thinking uses more energy because it takes more energy to change states than it does to remain in one state. From my understanding, the brain is not "hard clocked" like a CPU is, but really more comparable to a FPGA. But I'm not sure if it operates similarly to CMOS logic as far as power dissipation is concerned.