1. Unit 3: Behaviour, Populations and environment Chapter 25: The Brain 20/08/2015Mrs Smith Ch25 The Brain1 Higher Human Biology

2. Learning Intentions To examine the workings of the brain and the nervous system. Success Criteria 1.Outline the structure of the human brain with reference to; a.Size b.The cerebrum and its convoluted surface c.Localisation of function in discrete areas of the cerebrum d.The relationship between size of a discrete are and the function carried out e.The importance of the corpus callosum in transferring information between two hemispheres 20/08/20152Mrs Smith Ch25 The Brain

3. VARIABL ES The brain is a very complex organ not fully understood by scientists 20/08/2015Mrs Smith Ch25 The Brain3

4. FYI: The Brain Weighs 1300 - 1400g Made up of about 100 billion neurons. “The most complex living structure on the universe” Society for Neuroscience Makes us who we are. 20/08/20154Mrs Smith Ch25 The Brain

5. “We are like chameleons, we take our hue and the colour of our moral character, from those who are around us.” 20/08/2015Mrs Smith Ch25 The Brain5 John Locke was an influential philosopher from the 17 th century. He has provided many important ideas and bases on philosophy, one of which was his theory of personal identity. Locke believed all true knowledge came from the senses and human experience. Basically each of us are a combinations of all the experiences we ever had and how we perceive these experiences. This can only happen with a brain to perceive, process, store, these experiences “No man's knowledge here can go beyond his experience”.

6. The brain & size of the brain The brain is a large organ composed of billions of nerve cells (neurones). Compared with other animals, the human brain is disproportionally large, relative to body size. 20/08/20156Mrs Smith Ch25 The Brain

7. Why is it appropriate to say the weight of the brain determines intelligence? Animal Wt. of Brain Brain/Body wt ratio Whale15 lbs1/10000 Elephant3 lbs1/1000 Human3 lbs1/50 The human brain is more developed and has a larger weight in proportion to total body weight. 20/08/20157Mrs Smith Ch25 The Brain

8. Evolution of the Brain: Fossil evidence 20/08/20158Mrs Smith Ch25 The Brain

9. Increase in Brain Size Fossil evidence has shown that the human brain has increased in capacity (volume of skull occupied by the brain) over a fairly rapid evolutionary timescale. 20/08/20159Mrs Smith Ch25 The Brain

10. Apes When compared with the brains of modern apes, the human is found to be approximately three times larger. Humans have much larger centres responsible for higher mental faculties such as intelligence, speech, hearing and sight. An apes area controlling speech is so small and poorly developed it is impossible to teach an ape to speak. 20/08/201510Mrs Smith Ch25 The Brain

11. Image source: http://www.nature.comhttp://www.nature.com Ape Brains Compared to the brain of modern apes the human brain is about 3 times larger. Humans have much larger centres responsible for higher mental faculties such as intelligence, speech, hearing and sight. An apes area controlling speech is so small and poorly developed it is impossible to teach an ape to speak.. 20/08/201511Mrs Smith Ch25 The Brain

12. Dominant Species Compared to other animals humans are physically weak. However humans have become a dominant species on earth because the human brain has: a larger size complex internal development complex organisation 20/08/201512Mrs Smith Ch25 The Brain

13. Brain Structure:~ Revision 20/08/201513Mrs Smith Ch25 The Brain

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15. Cerebrum Structure Controls conscientious thought, voluntary actions, determines personality etc 20/08/201515Mrs Smith Ch25 The Brain

16. The Cerebrum: localisation of function The cerebral hemisphere has several distinct regions each with a particular function. 20/08/201516Mrs Smith Ch25 The Brain

17. Cerebrum: Con’t Cerebrum: Con’t Largest part of human brain Split into 2 halves called cerebral hemispheres 2 sides of the brain are joined by the corpus callosum - a large bundle of nerve fibres. This allows information to be transferred from one side to the other. 20/08/201517Mrs Smith Ch25 The Brain

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19. Each side of the brain controls the other side of the body 20/08/201519Mrs Smith Ch25 The Brain

20. inner cerebrum made of nerve cell fibres surface of cerebrum made of nerve cell bodies Cerebrum: Grey and white matter 20/08/201520Mrs Smith Ch25 The Brain

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22. Cerebrum Cerebrum: Convolution The cerebrum’s surface is convoluted (folded) to give it a large surface area allowing many cell bodies to be close together. This maximises the potential for interconnections and the transmission of messages. 20/08/201522Mrs Smith Ch25 The Brain

23. Task: Torrance-TYK pg 206 Qu 1-4 20/08/201523Mrs Smith Ch25 The Brain

24. The cerebrum has 3 main types of functional area, which are all discrete (they have their own function): Sensory Association Motor View the Scholar animation: http://courses.scholar.hw.ac.uk/vle/sch olar/session.controller?action=viewCo ntent&contentGUID=2ba96ae7-1eff- e695-8b5d-5f08e2cc8533 http://courses.scholar.hw.ac.uk/vle/sch olar/session.controller?action=viewCo ntent&contentGUID=2ba96ae7-1eff- e695-8b5d-5f08e2cc8533 Discrete Functional Areas 20/08/201524Mrs Smith Ch25 The Brain

25. Roles of the 3 discrete functional areas Sensory areas Receive info as sensory impulses from body’s receptors e.g. touch receptors in skin and thermoreceptors in hypothalamus Motor areas Receive info from association areas & send motor impulses to the effectors e.g. muscles Association areas Analyse & Interpret sensory impulses e.g. Make decisions 20/08/201525Mrs Smith Ch25 The Brain

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27. Association areas Somatosensory association area Visual association area Premotor association area Auditory association area 20/08/201527Mrs Smith Ch25 The Brain

28. Speech Each region of the left cerebral hemisphere is duplicated on the right cerebral hemisphere except speech. Each person only has one speech area. In 90% of people this is in the left cerebral hemisphere. 20/08/201528Mrs Smith Ch25 The Brain

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30. Interconnections in the Brain Tiny nerve fibres interconnect the different areas of the brain. Messages constantly pass between them. Sensory area Association area Motor area This allows the human brain to cope with several sensory impulses at once (sophisticated perception) They then cause more exchange of impulses between cerebral areas allowing a sophisticated response e.g. channel flicking e.g. singing & dancing 20/08/201530Mrs Smith Ch25 The Brain

31. Motor Area The motor area is one of the largest regions of each cerebral hemisphere. Each motor area consists of motor neurons which sends out impulses to bring about voluntary movement of skeletal muscles However, the size of the part of the motor area is not in proportion to the actual size of the body part. The size of the motor area is in proportion to the number of nerve endings in the body part 20/08/201531Mrs Smith Ch25 The Brain

32. Discovery of the motor area In 1870, Hitzig and Fritsch electrically stimulated parts of a dog's motor cortex. Depending on what part of the cortex they stimulated, a different part of the body contracted. When they destroyed this same small area of the cortex, the corresponding part of the body became paralysed. They concluded that every part of the body has a particular region of the primary motor cortex that controls its movement. 20/08/201532Mrs Smith Ch25 The Brain

33. MOTOR OR SENSORY AREA ALLOCATED TO A PARTICULAR BODY PART IS FOUND TO BE IN RELATIVE PROPORTION TO ITS MOBILITY/SENSORY. E.G. THE MORE MOBILE A PART THE LARGER THE MOTOR AREA. 20/08/2015Mrs Smith Ch25 The Brain33

34. Who is Homunculus? Imaginary human whose body parts have been drawn in proportion to –Mobility and fine motor control –Sensory perception The more control needed of a task, the larger the area of the brain that is required 20/08/201534Mrs Smith Ch25 The Brain

35. The motor area of the left cerebral hemisphere MOTOR HOMUNCULUS Mrs Smith Ch25 The Brain 35 Motor homunculus—larger parts of the brain control larger parts of the body such as the hand and mouth, which require a lot of “motor” or motion “signals.” That is, if the human body were to be built in proportion to its motor significance because of the brain power needed to “motor” them, the hands and mouth would be proportionally bigger. "This model shows what a man's body would look like if each part grew in proportion to the area of the cortex of the brain concerned with its movement." View the Scholar animation: http://courses.scholar.hw.ac.uk/vle/scholar/session.con troller?action=viewContent&contentGUID=8af4bea2- 600b-deeb-baec-d7517d578e46 http://courses.scholar.hw.ac.uk/vle/scholar/session.con troller?action=viewContent&contentGUID=8af4bea2- 600b-deeb-baec-d7517d578e46 20/08/2015

36. SENSORY HOMUNCULUS The sensory area of the left cerebral hemisphere 20/08/201536 Sensory homunculus—Similar to motor homunculus but it tells the brain how much power is needed for sensory perception of different body parts. "This model shows what a man's body would look like if each part grew in proportion to the area of the cortex of the brain concerned with its movement." Mrs Smith Ch25 The Brain

37. Cerebellum Attached to underside of brain Unconscious fine control of voluntary muscle movement and balance 20/08/201537Mrs Smith Ch25 The Brain

38. Medulla Oblongata Connects brain to spinal cord Unconscious co- ordination of basic functions – breathing, heart rate, digestion, reflex actions Medulla oblongata 20/08/201538Mrs Smith Ch25 The Brain

39. Studying the Brain The evidence that there is localisation of brain functions (i.e. that different parts of the brain have different functions) include: A.Electroencephalograms (EEG’s) B. Brain Scans Cat Scan fMRI Scan 20/08/201539Mrs Smith Ch25 The Brain

40. Brain Scans Speech involves several specific regions of the brain. These show up in brain scans as areas of high metabolic activity. FYI: You DON’T need to know the names of these areas!! View the Scholar animation: http://courses.scholar.hw.ac.uk/vle/scholar/session.controller?action=viewContent&contentGUID=c622c31f-213c-2853-d6e0-e311a44d055f 20/08/201540Mrs Smith Ch25 The Brain

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42. A record of the cerebrum’s electrical activity. Electrodes are placed on the different regions of the scalp. They detect impulses which are displayed on a monitor. Different brain wave patterns show different levels of mental activity. Electroencephalograms Studying the Brain- EEG 20/08/201542Mrs Smith Ch25 The Brain

43. The more densely packed the spikes, the higher the level of electrical activity in the brain. EEGs can show abnormal patterns that indicate a problem (e.g. dense spikes are shown during epileptic attacks), but the EEG doesn’t show the area of the brain responsible. EEGs are not very precise because they reflect the activity of many brain cells. Epilepsy Infants, Sleeping adults Children, Sleeping adults EEG wave patterns 20/08/201543Mrs Smith Ch25 The Brain

44. This brain scan shows a tumour in pale blue. Image source: www.sciencemuseum.org.ukwww.sciencemuseum.org.uk Studying the Brain: Brain Scans CAT SCANS Often referred to as CAT (Computer Assisted Tomography) scans. These give a clear image of the brain without any surgery used mainly to diagnose abnormalities Can indicate areas of high metabolic activity – so can be used to determine which part of the brain is responsible for certain actions and emotions. 20/08/201544Mrs Smith Ch25 The Brain

45. Brain scans provide pictures of very active parts of the brain The parts of the brain which are active show up as brightly coloured areas The following diagrams show four fMRI (functional magnetic resonance imaging) brain scans obtained during a visual memory task. Studying the Brain: Brain Scans fMRI SCANS 20/08/201545Mrs Smith Ch25 The Brain

46. Scan 1 In scan 1, a subject is asked to remember a face. Areas at the rear of the brain that process visual information are active during this task, as is an area in the frontal lobe. 20/08/201546Mrs Smith Ch25 The Brain

47. Scan 2 In scan 2, the subject is asked to "think about this face." The hippocampus is activated. The hippocampus was already known to be important for memory, but these results show that this part of the brain is specifically active during the time when we are remembering new information. 20/08/201547Mrs Smith Ch25 The Brain

48. Scans 3 and 4 In scans 3 and 4, the subject was asked to compare another face to the remembered face. Some of the same visual areas are activated as during the initial memory task, but other areas, such as part of the frontal lobe, are involved in making a decision about the memory. 20/08/201548Mrs Smith Ch25 The Brain

49. Split-brain studies Split brain happens when a person’s corpus callosum has been cut. Because of this exchange of information between cerebral hemispheres doesn’t occur. Learn more............. http://www.nobelprize.org/educational/medicine/split- brain/background.htmlhttp://www.nobelprize.org/educational/medicine/split- brain/background.html Play the split brain game................. http://www.nobelprize.org/educational/medicine/split- brain/index.htmlhttp://www.nobelprize.org/educational/medicine/split- brain/index.html 20/08/201549Mrs Smith Ch25 The Brain

50. Split Brain Studies Visual Pathways – Normal situation Each cerebral hemisphere only receives half the information of the visual field. Everything to the left Is represented by the right cerebral hemisphere Everything to the right is represented by the left cerebral hemisphere. When the corpus callosum is intact both hemispheres perceive all information from both eyes as each hemisphere quickly communicates so the whole picture is in view 20/08/201550Mrs Smith Ch25 The Brain

51. Normal Visual Pathway Information passed across corpus callosum 20/08/201551Mrs Smith Ch25 The Brain

52. View the Scholar animation: http://courses.scholar.hw.ac.uk/vle/scholar/session.controller?action=v iewContent&contentGUID=a3d7028a-e33c-5447-e177-1457682f9206 Split Brain Studies Visual Pathways – Abnormal situation If the corpus callosum is cut (e.g. during surgery required due to intractable epilepsy), exchange of information is prevented because the corpus callosum does not connect the 2 cerebral hemispheres. So each hemisphere only perceives half of the information. The right hemisphere only gets information from the left eye & vice versa. 20/08/201552Mrs Smith Ch25 The Brain

53. Abnormal Visual Pathway 20/08/201553Mrs Smith Ch25 The Brain

54. Because the speech area is only found in the left hemisphere. If a person with a split-brain (severed corpus callosum) is…. a)shown an object with their right eye open and left eye closed, they will be able to say the name of the object b) shown an object with their left eye open and right eye closed they will be able to use the object (e.g. a spoon), write the name of the object, but NOT say the word! 20/08/201554Mrs Smith Ch25 The Brain

55. Watch this!!!! http://www.youtube.com/watch?v=ZMLzP1VCANo http://www.youtube.com/watch?v=ZMLzP1VCANo 20/08/201555Mrs Smith Ch25 The Brain

56. See Scholar – Split Brain Studies http://courses.scholar.hw.ac.uk/vle/scholar /session.controller?action=viewContent&c ontentGUID=a3d7028a-e33c-5447-e177- 1457682f9206 20/08/201556Mrs Smith Ch25 The Brain

57. Blind Spot Because each eye has an optic nerve at the back, there is an area of the retina which has no light sensitive neurones. This area is called the blind spot. To find out about your blind spot, go to: http://serendip.brynmawr.edu/bb/blindspot 1.html http://serendip.brynmawr.edu/bb/blindspot 1.html 20/08/201557Mrs Smith Ch25 The Brain

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59. Task: Look around. Do you see a blind spot anywhere? Maybe the blind spot for one eye is at a different place than the blind spot for the other (this is actually true), so you don't notice it because each eye sees what the other doesn't. Close one eye and look around again. Now do you see a blind spot? Hmm. Maybe its just a little TINY blind spot, so small that you (and your brain) just ignore it. Nope, its actually a pretty BIG blind spot.Close LET’S PROVE IT!!! 20/08/201559Mrs Smith Ch25 The Brain

60. Try this!! Close your left eye and stare at the cross mark in the diagram with your right eye. Off to the right you should be able to see the spot. Don't LOOK at it; just notice that it is there off to the right (if its not, move farther away from the computer screen; you should be able to see the dot if you're a couple of feet away). Now slowly move toward the computer screen. Keep looking at the cross mark while you move. At a particular distance (probably a foot or so), the spot will disappear (it will reappear again if you move even closer). The spot disappears because it falls on the optic nerve head, the hole in the photoreceptor sheet. So, as you can see, you have a pretty big blind spot, at least as big as the spot in the diagram. What's particularly interesting though is that you don't SEE it. When the spot disappears you still don't SEE a hole. What you see instead is a continuous white field (remember not to LOOK at it; if you do you'll see the spot instead). What you see is something the brain is making up, since the eye isn't actually telling the brain anything at all about that particular part of the picture. 20/08/201560Mrs Smith Ch25 The Brain

61. Brain Injury Studies Studies for brain injuries include: Phineas Gage – frontal lobe determines personality. A man with visual agnosia mistook his wife for a hat. Soldiers with shrapnel wounds People with brain lesions Stroke sufferers Brain damage is usually caused by: Tumours, disease or accidents Studying this damage has allowed experts to learn more about the way the brain works. 20/08/201561Mrs Smith Ch25 The Brain

62. Damaged frontal lobe In 1848 an accident happened to a railroad worker. A rod entered beneath his left eye and through the top of his head. He survived and eventually returned to work...... BUT.... He changed personality becoming ill- tempered, unreliable and could no longer stick to a plan. This is because our FRONTAL LOBES are required in planning, goal setting and personality. 20/08/201562Mrs Smith Ch25 The Brain

63. Wife or Hat? A musician of great ability developed a problem in later life. He no longer recognised people or objects and failed to remember the past visually. He would chat to furniture thinking it was a person. On one occasion he reached out, took hold of his wife’s head and tried to lift it to put it on, thinking it was a hat. HE HAD A PROBLEM WITH HIS VISUAL ASSOCIATION CENTERS 20/08/201563Mrs Smith Ch25 The Brain

64. Shrapnel wounds Experts studied soldiers blinded or paralysed be cause of shrapnel. There findings provided early evidence that the rear of the cerebrum is responsible for vision and the area we call the MOTOR AREA controls movement. 20/08/201564Mrs Smith Ch25 The Brain

65. The cost of war: Washington Post 04/10/2010 http://voices.washingtonpost.com/blog- post/2010/10/traumatic_brain_injuries_ 18000.htmlhttp://voices.washingtonpost.com/blog- post/2010/10/traumatic_brain_injuries_ 18000.html Robert Warren, three weeks after leaving Afghanistan, could not remember the name of the country he was just in. Shrapnel tore into his skull and a chunk of it had to be removed. "That country," he called Afghanistan, unable to grasp the right word.Robert Warren A piece of shrapnel pierced John Barnes's brain, tearing through his frontal lobe, the region in charge of decision making, reason and morality. As a result, Barnes exhibits impulsive behaviour and is unable to live on his ownJohn Barnes 20/08/201565Mrs Smith Ch25 The Brain

66. Lesions Lesions are small regions of damage. The location of the brains language centres is verified by the fact that lesions in these areas give rise to speech defects. 20/08/201566Mrs Smith Ch25 The Brain

67. Strokes Stroke suffers often loose the function of part of their brain (sometimes permanent), by matching the area of the brain affected to the lost bodily function experts can identify which parts of the brain are responsible for which bodily functions. 20/08/201567Mrs Smith Ch25 The Brain

68. Task: Torrance-TYK pg 211 Qu’s 1-4 20/08/201568Mrs Smith Ch25 The Brain

69. Task: Torrance AYK pg211/212 Qu’s 1-6 20/08/201569Mrs Smith Ch25 The Brain

70. Task: Can you answer these? 20/08/201570Mrs Smith Ch25 The Brain

71. Task: Can you answer these? 20/08/201571Mrs Smith Ch25 The Brain

72. More Questions 20/08/201572Mrs Smith Ch25 The Brain

73. Answers 20/08/201573Mrs Smith Ch25 The Brain

74. Even more Questions 20/08/201574Mrs Smith Ch25 The Brain

75. Answers 20/08/201575Mrs Smith Ch25 The Brain

76. And Again!! 20/08/201576Mrs Smith Ch25 The Brain

77. Answer Again!! 20/08/201577Mrs Smith Ch25 The Brain

78. Essay style Questions Scholar Describe the appearance of the human brain, commenting on localised structures and their functions (10) 20/08/2015Mrs Smith Ch25 The Brain78

79. ANSWER: Describe the appearance of the human brain, commenting on localised structures and their functions (10) 79 Each numbered point is worth 1 mark. The information in brackets is not a required part Correct facts (8 marks) The brain consists of a central core, including medulla and cerebellum. The medulla controls unconscious activities such as peristalsis and rates of breathing and heartbeat. The limbic system, including the hippocampus, is found in above the medulla. The outer layer of the brain is called the cerebrum or cerebral hemispheres. Conscious activities are co-ordinated by the cerebrum. The outer surface of the cerebrum (cortex) is folded to increase the numbers of connections possible between neurones.connections A visible cleft in the cerebrum is the location of the somatosensory area.cleft Sensory messages are received in the latter part of the cleft and motor responses are sent out by the frontal part. The areas allocated are directly proportional to the degree of sensation and control required.degree Large areas are devoted to the lips and hands, particularly the fingers. The right side of the brain controls the left side of the body and vice versa. The corpus callosum is a massive bundle of nerves that transfers information across the cerebral hemispheres. Coherence (1 mark) One mark is given if at least 5 relevant points provided. Relevance (1 mark) It causes glycogen to be (rapidly) converted to glucose (not 'converts') converted One mark is deducted if a detailed explanation of negative feedback control is given. 20/08/2015Mrs Smith Ch25 The Brain

80. Humour: Toddler brain 20/08/201580Mrs Smith Ch25 The Brain

81. Humour: Teenage brain 20/08/201581Mrs Smith Ch25 The Brain

82. Humour: Adult brain 20/08/201582Mrs Smith Ch25 The Brain

83. Humour: Canine brain 20/08/201583Mrs Smith Ch25 The Brain

84. Humour: Feline brain 20/08/201584Mrs Smith Ch25 The Brain