The Brain

1. The Brain

2. Brain MisconceptionsComputers (1) Is the brain like the CPU of a computer? Not really. Computers are made of metal and use electricity to process information. Brains are made of organic cells and use a mix of electrical signals and chemicals to process information. If one part of a computer breaks it can do almost nothing. If one part of your brain gets damaged only certain things are hard to do and it can sometimes gradually repair itself.

3. Brain MisconceptionsComputers (2) Are humans smarter than computers or computers smarter than people? Neither, they work in different ways. Computers are currently all programmed to do a specific task by people who give them specific instructions about how to do it. Computers are much faster at doing many of these things. Currently, computers are not able to do things they are not specifically told how to do. This is changing as people figure out ways to make computers learn to do new tasks on their own. Humans, however, are very good at figuring out creative ways to do things on their own.

4. The Early Human Brain • Embryonic Brain The Brain at Birth

5. Brain Development Embryonic to 6 Mos.

6. Brain Facts The adult human brain is about 4 to 5 pounds. A baby’s brain weighs about 1.5 pounds. However, a baby’s body weighs about 15-30 times smaller than an adult’s body. So a baby’s brain is 6 times bigger compared to its body weight!!! (that is why babies have huge heads compared to their bodies) Human brain has over 100 billion! neurons (a type of brain cell); that’s about 20 times the total number of people in the world. Neurons require a lot of energy: Your brain uses over half of all the energy in your body.

7. Fissures (deep grooves) divide the cerebrum into lobes The Brain Frontal lobe Parietal lobe Motor cortex Somatosensory cortex Somatosensory association area Frontal association area Taste Reading Visual association area Hearing Speech Auditory association area Smell Vision Occipital lobe Temporal lobe

8. If Christopher is in a car accident and due to brain damage loses his sight, which lobe of the brain were probably damaged? Occipital When you go to the refrigerator and reach for a carton of milk, which lobes of the brain are you using? Frontal & Occipital When you are listening to music on earphones, which lobe of the brain are you using? Temporal When an Olympic gymnast does a flip on the balance beam, which lobes of the brain is she using? Frontal, Occipital, Parietal, & Temporal

10. Regions of the Brain • Brain stem • Cerebellum • Cerebral hemispheres • Diencephalon Surface is made of ridges (gyri) and grooves (sulci) purpose: to increase surface area Figure 7.12b

11. Brain MisconceptionsWrinkles Why are there wrinkles in the brain? Do more wrinkles appear when you learn something new? No. Your cerebral cortex is essentially a flat sheet (like a large sheet of paper) that it has to fit in your skull (which is like a cup)… A crumpled up sheet of paper fits in a cup easier than an unfolded one. Most scientists think that new learning is changed connections between neurons (brain cells; similar to different wiring in a computer).

12. Specialized Areas of the Cerebrum Somatic sensory area – receives impulses from the body’s sensory receptors (audio, visual, olfactory, and taste) • Interpretation areas of the cerebrum • Speech/language region Broca’s area – involved in our ability to speak Figure 7.13c

13. Motor Areas of the Cerebral Cortex Primary motor area – sends impulses to skeletal muscles Figure 7.14

14. Layers of the Cerebrum • Gray matter • Outer layer • Composed mostly of neuron cell bodies White matter • Fiber tracts inside the gray matter • Example: corpus callosum connects hemispheres Figure 7.13a

15. Diencephalon • Sits on top of the brain stem • Enclosed by the cerebral hemispheres • Thalamus • Hypothalamus • Epithalamus

16. Thalamus • Surrounds the third ventricle • The relay station for sensory impulses • Transfers impulses to the correct part of the cortex for localization and interpretation

17. Hypothalamus • Under the thalamus • Important autonomic nervous system center • Helps regulate body temperature • Controls water balance • Regulates metabolism • An important part of the limbic system (emotions) • The pituitary gland is attached to the hypothalamus

18. Epithalamus • Forms the roof of the third ventricle • Houses the pineal body (an endocrine gland) • Includes the choroid plexus – forms cerebrospinal fluid

19. Brain Stem • Attaches to the spinal cord • Parts of the brain stem • Midbrain • Pons • Medulla oblongata

20. Midbrain • Mostly composed of tracts of nerve fibers • Has two bulging fiber tracts – cerebral peduncles • Has four rounded protrusions – corpora quadrigemina • Reflex centers for vision and hearing

21. Pons • The bulging center part of the brain stem • Mostly composed of fiber tracts • Includes nuclei involved in the control of breathing

22. Medulla Oblongata • The lowest part of the brain stem • Merges into the spinal cord • Contains important control centers • Heart rate control • Blood pressure regulation • Breathing • Swallowing • Vomiting

23. What does the brain do?

24. Random Brain Facts

25. BRAIN FACTS • Let’s do some myth-busting.

26. Myths – TRUE OR FALSE? • We use 10% of brain

27. FALSE! • We use all of our brain. Under PET scans and CAT scans, different areas of the brain are used, but we use our whole brain.

28. The effect of extreme deprivation in infancy: This child suffers from emotional and cognitive problems.

29. Brain Misconceptions10% Do people only use 10% of their brain? No. Different parts of your brain do different things. So not all of your brain needs to be doing something all of the time. However, using modern technology we have shown almost every area of the brain active during some task. For many hard tasks, a large percentage of your brain may be active at one time.

30. Myth? • As we age, we lose our brain cells.

31. FALSE! • The brain can continue to learn and “make connections” until death.

32. Myth ? • Every drink kills 10,000 cells

33. FALSE • Every drink does not kill 10,000 cells. • Scare tactic. • Drinking does affect development – especially fetus and teenagers.

34. Brain MisconceptionsDrug Addiction (1) If you are careful you won’t get addicted to drugs, right? Examples of addictive Drugs – all types of Cocaine (crack); Heroin; Opium; Ecstasy; … Mostly affect the parts of your brain that process reward (pleasure) information or help you manage pain: when they work normally, they help you in emergencies or to encourage you to become addicted to good behavior (like eating nutritious food) to make you want to do it again and again The problem: these drugs either overuse or kill off cells in these systems so they work too strongly or eventually not enough… Some brain areas cause a little addiction even when working correctly; drugs cause these areas to work way too much…

35. Brain MisconceptionsDrug Addiction (2) Do drugs really hurt you long-term? Yes. Long-term overuse of the systems of reward through drugs: Strong addiction to the drugs. Leads to less sense of reward for other activities that are actually good for you so you stop doing them. As cells die from overuse (or become habituated), you need more and more drugs to get the same high. Then when you are not doing drugs you feel worse than you did before you started. In other words: Drugs damage your brain more the longer and more you do them (much of which will never recover). They trick your brain into thinking life is great when you are on them and much worse when you are not (even compared to before you started) so they are harder to stop.

36. Does Size Matter? What is the biggest organ in the body?

37. The Skin • Skin – 6 lbs • Brain, 2.75-3 lbs There is no correlation between brain size and ability.

38. Brain MisconceptionsGender and Brain Size Do boys have bigger brains and are they smarter than girls or the opposite? (1) Men on average actually do have larger brains than women (just like they have bigger bodies on average). But, elephants have much bigger brains than humans (4 times as heavy) and cats are about 45 times smaller. (2) A bigger brain does not mean you are smarter. Men and women have the same intelligence level on average (although there is some evidence that each may be slightly better at specific tasks). Two people with the biggest and one of the smallest brains ever found both belong to professional writers!

39. Random Brain Facts • We’ve learned more about the brain in last 20 yrs than all time previous to that • No two brains are identical • Brain is mostly water (78%), fat (10%), and protein (8%) • Living brain is so soft it can be cut w/ butter knife

40. Random Brain Facts • The adult human brain weighs about 3 pounds (1,300-1,400 gm) • Elephant brains = 6,000gm • Cat brains = 30 gm • Brain is ~2% of body weight, but consumes ~20% of body’s energy • Total surface area of cerebral cortex = ~2.5 sq ft • Bigger brains are not necessarily better • Einstein’s was average size

41. Random Brain Facts • Human brain has ~100,000,000,000 neurons • If all neurons were stretched end to end, would reach to moon and back • Every second, brain receives 100 million messages from the senses • ¾ of body’s neurons are in brain • On day you are born, all brain cells are in place • They’re just immature – still developing • Explains why don’t have memories until ~3-4 y.o. • Will not regenerate – this is all you get • (Recent research is challenging this idea…)

42. Random Brain Facts • ~10 trillion pieces of information in the brain • There are 1,000 – 10,000 synapses for a typical neuron • Human brain is capable of processing 10,000,000,000,000,000,000,000,000,000 bits of data per second • Intelligence has nothing to do with number of neurons – it has everything to do with number of dendrite connections

43. Random Brain Facts • World record for time w/o sleep: • 264 hours (11 days) – Randy Gardner, 1963 • Unconsciousness occurs 8-10 sec after loss of blood supply to brain

44. Random Brain Facts • Changing brain: • 525 billion neurons in brain at 26 wks gestation • 200 billion on day born • 100 billion today • Brain is ultimate “use it or lose it” machine • “neural sculpting” happens during REM sleep • Computer/TV has huge impact on brain • Recommend no TV/internet 0-2 yrs • Sesame Street?

45. Random Brain Facts • Humans can process 400-600 words/min • Talk about 100-125 words/min • Speaker needs to fill in gaps to avoid boredom, mind wandering • Older people take longer to learn, but retain information as well as younger ppl • Before age 5, brain is very plastic – can simultaneously adapt after injury • After age 5, severe, permanent damage more likely • Ex – 5 y.o. boy w/ severe seizures had entire left hemisphere removed – paralyzed on right side, but scored above avg on intelligence tests, finished college & grad school – today an executive

46. Random Brain Facts • Brain disorders cost Americans more than $600 billion a year • Alcohol use in teens devastating to the pre-frontal cortex • Mature neuron has myelin sheath protection, young adolescent brain does not • MN in top 5 for alcohol consumption • Also top 5 for FAS cases

47. In the beginning … • In the early years, the brain nearly triples in size and weight.  • There is a huge buildup of neural connections. • This is followed by a massive reorganization at the terrible two’s.

48. The Neuron

49. Neuron Migration Neuronal Cell Migration - “Brain Density" Newborn 3 Months Two Years Rethinking the Brain, Families and Work Institute, Rima Shore, 1997.

50. Neuron Migration Neuronal Cell Migration - “Brain Density"