Brain Basics
How much does the human brain weigh?
About 3 pounds
Why do many people believe the myth that we only use 10% of our brains?
The myth may have come from early psychologists suggesting humans only use part of their mental resources, misunderstandings about neurons, and repeated mentions in books, TV, and movies.
What food is well known to be high in omega-3s and support brain function?
Oily fish such as salmon, mackerel, and tuna
True or False: Drinking alcohol kills brain cells.
False — moderate alcohol doesn’t directly kill brain cells, but long-term heavy drinking can damage connections between neurons and shrink certain brain regions, impairing cognitive function.
How much of a person’s body weight does the brain make up?
Answer: About 2%
How many neurons (information-carrying cells) are in the human brain?
About 100 billion neurons (at birth). By adulthood, about 85 billion.
Functional MRI scans show how much of the brain is active, even during simple tasks?
Most of the brain is active, even during simple tasks.
What types of foods are rich in vitamin E and promote brain health?
Fruits and vegetables with dark skins, such as spinach, broccoli, and blueberries.
What condition can occur in babies if their mothers drink too much alcohol during pregnancy, and how does it affect the brain?
Fetal alcohol syndrome; it can cause smaller brains with fewer neurons, leading to learning difficulties and behavioral problems. In the most severe cases, facial features may have unique differences.
The brain has gray matter (responsible for processing information, muscle control, sensory perception, decision-making) and white matter (crucial for learning, memory, and coordination). What substance is present in white matter that is not present in gray matter?
Myelin, which is a fatty coating around the axons of certain neurons.
What percentage of the brain's total weight is made up of water?
73%
People mistakenly think we only use 10% of our brain because of what slightly different fact involving the number 10%?
Because about 10% of the brain is made up of neuron cells; the other 90% are a different type of cell.
What type of physical activity helps lower the risk of dementia?
Cardiovascular or regular physical exercise; examples include walking, biking, swimming
True or False: People are either left-brained (logical) or right-brained (creative).
False — this is a myth. While some functions are more active in one hemisphere (left: language, analytical thinking, sequential processing; right: visual-spatial tasks, facial recognition, some emotional processing), both sides of the brain are used for nearly all tasks, including logic and creativity.
What does the brain use as its main source of energy?
Glucose (sugar)
About what percentage of the brain’s solid (non-water) material is made of fat, and why is cholesterol important?
About 60%; cholesterol helps brain cells survive, and about 25% of the body’s total cholesterol is found in the brain
Which self-help author popularized the 10% myth in his 1936 book How to Win Friends and Influence People?
Dale Carnegie
What type of non-physical exercise helps improve mental function and may lower dementia risk by 29%?
Brain-training exercises, such as meditation, visualization activities, and games designed for cognitive improvement.
What is the myth about brain wrinkles when you learn something new?
That you get a new wrinkle each time you learn something (this is false)
How does sleep help your brain stay healthy?
During sleep, the brain clears waste products, strengthens memories, and prepares for new learning
What is brain plasticity, and why is it important?
Brain plasticity is the brain’s ability to form new connections and reorganize itself in response to learning or experience; it allows us to adapt, learn new skills, and recover from injury
What type of cell makes up about 90% of the brain and supports, protects, and nourishes neurons?
Glial cells (Neuroglia)
What did the most effective brain training games in a 2017 study focus on improving?
The brain’s speed and ability to process complex information
What can subliminal messages actually do, according to research?
They can provoke emotional responses and help recall information learned earlier, but they can’t teach completely new information
Which parts of the brain are responsible for coordination, and involuntary functions?
cerebellum (balance and coordination)
brainstem (involuntary functions like heart rate and breathing)