Introducing the brain: higher energy costs in human brain (Introduction)

by David Turell , Thursday, December 14, 2023, 15:56 (135 days ago) @ David Turell

Creates our marked degree of intelligence:

https://www.science.org/doi/10.1126/sciadv.adi7632?utm_source=sfmc&utm_medium=email...

"Abstract
In comparison to other species, the human brain exhibits one of the highest energy demands relative to body metabolism. It remains unclear whether this heightened energy demand uniformly supports an enlarged brain or if specific signaling mechanisms necessitate greater energy. We hypothesized that the regional distribution of energy demands will reveal signaling strategies that have contributed to human cognitive development. We measured the energy distribution within the brain functional connectome using multimodal brain imaging and found that signaling pathways in evolutionarily expanded regions have up to 67% higher energetic costs than those in sensory-motor regions. Additionally, histology, transcriptomic data, and molecular imaging independently reveal an up-regulation of signaling at G-protein-coupled receptors in energy-demanding regions. Our findings indicate that neuromodulator activity is predominantly involved in cognitive functions, such as reading or memory processing. This study suggests that an up-regulation of neuromodulator activity, alongside increased brain size, is a crucial aspect of human brain evolution." (my bold)

***

A lay explanation: https://mail.google.com/mail/u/0/#inbox/FMfcgzGwJJVnFxbtNGtSXZVwmbGHhZdM

"The cost of a complex brain

"The human brain is a voracious organ. Despite only weighing about three pounds, it consumes a whopping 20% of the body’s metabolic energy, or around 500 calories per day—a much larger portion than the brain of any other species. Now, a new study in Science Advances reveals that some parts of the brain are hungrier than others—a fact that could shed light on how our species came to be so smart.

"Using scans from 30 people, researchers analyzed the distribution of energy usage across brain regions. They found that the frontoparietal network, a collection of brain structures that has expanded the most throughout human evolution and plays a major role in memory and decision-making, has a higher energy cost than networks responsible for movement and sensation. Slow-acting circuits regulated by neurotransmitters like dopamine and serotonin also demand a lot of energy.

"Scientists have long hypothesized that increased brain size is what allowed humans to develop extraordinary cognitive abilities. But some mammals have larger brains, higher brain-to-body-mass ratios, and more neurons than we do, casting doubt on this idea. These new findings provide a different perspective, supporting the idea that it wasn’t just growth in size overall but rather the expansion of specific networks that contributed to the evolution of human smarts." (my bold)

Comment: note the bolds. High energy use in cognitive areas is what makes us so intelligent. A different way to measure brain cognitive capacity.