By the numbers
86 billionneurons
~100 trillionconnections (synapses)
3 lbabout 2% of body weight
20%of the body's energy
Neurons signal with tiny electrical pulses and chemical messengers.
Who does what
| Part | Main job |
|---|---|
| Frontal lobe | Planning, decisions, personality |
| Hippocampus | Forming new memories |
| Cerebellum | Balance and coordination |
| Brainstem | Breathing and heartbeat |
| Occipital lobe | Vision |
Most tasks use many regions working together.
What we know and don't
Known
- The brain rewires itself as you learn
- Sleep helps lock in memories
- Exercise and learning help keep it healthy
Still a mystery
- How brain activity becomes conscious experience
- Exactly how memories are stored
- Why we dream
Sources: National Institutes of Health; Society for Neuroscience
Remember
The brain keeps changing all your life; how its activity becomes your experience is still unsolved.
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Answer key
- About how many neurons does the brain have?86 billionAbout 86 billion.
- How much of the body's energy does the brain use?About 20%Roughly 20% despite being 2% of body weight.
- Which part helps form new memories?HippocampusThe hippocampus is key for new memories.
- What is neuroplasticity?The brain's ability to rewire itselfThe brain changes its connections as you learn.
- Which question remains unsolved?How brain activity produces conscious experienceConsciousness remains a deep open question.