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1 PowerPoint® Presentation by Jim Foley
Chapter 2 The Biology of Mind PowerPoint® Presentation by Jim Foley © 2013 Worth Publishers

2 Surveying the Chapter: Overview What We Have in Mind
Building blocks of the mind: neurons and how they communicate (neurotransmitters) Systems that build the mind: functions of the parts of the nervous system Supporting player: the slower-communicating endocrine system (hormones) Star of the show: the brain and its structures Click to reveal all bullets.

3 Searching for the biology of “self”
Is our identity in the heart? In the brain? In the whole body? No animation. Lesson to bring out here: the brain is not a computer, or a mind, or identity which is separate from the rest of the body; it is all interconnected, as we soon shall see.

4 Searching for the self by studying the body Phrenology
(developed by Franz Gall in the early 1800’s): the study of bumps on the skull and their relationship to mental abilities and character traits Click to reveal additional text. Phrenology yielded one big idea-- that the brain might have different areas that do different things (localization of function).

5 Today’s search for the biology of the self: biological psychology
Biological psychology includes neuroscience, behavior genetics, neuropsychology, and evolutionary psychology. All of these subspecialties explore different aspects of: how the nature of mind and behavior is rooted in our biological heritage. Our study of the biology of the mind begins with the “atoms” of the mind: neurons. Click to reveal bullets.

6 Neurons and Neuronal Communication: The Structure of a Neuron
No animation. Most of the neurons are in the brain but there are motor and sensory neurons throughout the body. The message does not travel down the axon in the same way an electrical signal does down a wire; in fact electricity in a wire travels 3 million times faster. In the body, neural signals travel about 2 to 180 miles per hour. However, the chemical signal has an advantage; it does not decrease in intensity as it travels down the axon. No signal is lost. You could demonstrate speed of signal transmission by having it travel across all the students hand to brain to hand across the room (or hand to shoulder to possibly bypass the brain). Note the myelin sheath. Multiple sclerosis involves the degeneration of this layer, thus interfering with neural communication with muscles and other areas. There are billions of neurons (nerve cells) throughout the body.

7 Action potential: a neural impulse that travels down an axon like a wave
Just as “the wave” can flow to the right in a stadium even though the people only move up and down, a wave moves down an axon although it is only made up of ion exchanges moving in and out. Automatic animation. Note: with both the stadium example and the action potential example, no physical object actually flows in any direction when the wave flows. The action potential is the area that is briefly charged by the net intake of positive ions; this is the traveling “electrical charge” created when channels in the cell membrane quickly allow positive ions in, and then more slowly pump the ions out again as the wave moves on. The fans in the stadium create the wave by standing up briefly; the cell membrane creates a wave by pumping positive ions in briefly. This could be the subject of a demonstration in class.

8 When does the cell send the action potential
When does the cell send the action potential?... when it reaches a threshold How neurons communicate (with each other): The neuron receives signals from other neurons; some are telling it to fire and some are telling it not to fire. When the threshold is reached, the action potential starts moving. Like a gun, it either fires or it doesn’t; more stimulation does nothing. This is known as the “all-or-none” response. The action potential travels down the axon from the cell body to the terminal branches. The signal is transmitted to another cell. However, the message must find a way to cross a gap between cells. This gap is also called the synapse. Click to show each stage in the path. If signals only have one level of intensity, then why does a punch hurt more than a tap? Because in the case of the punch, more neurons are firing. The threshold is reached when excitatory (“Fire!”) signals outweigh the inhibitory (“Don’t fire!”) signals by a certain amount.

9 The Synapse The synapse is a junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron. No animation. The synapse is also known as the “synaptic junction” or “synaptic gap.”

10 Neurotransmitters Neurotransmitters are chemicals used to send a signal across the synaptic gap. No animation. Neurotransmitters are released from the sending neuron and stimulate receptor sites on the receiving neuron. These are the signals telling the receiving cell whether or not to fire the next action potential.

11 Reuptake: Recycling Neurotransmitters [NTs]
Reuptake: After the neurotransmitters stimulate the receptors on the receiving neuron, the chemicals are taken back up into the sending neuron to be used again. No animation. Reuptake ends the transmission of the signal. Medications which inhibit this reuptake process help ensure that the signal gets transmitted. SSRIs help reduce depression by increasing serotonin levels at the synapse this way, and most ADHD medications such as Ritalin work by blocking the transport of dopamine back into the sending neuron.

12 Seeing all the Steps Together
Neural Communication: Seeing all the Steps Together No animation.

13 Roles of Different Neurotransmitters
Some Neurotransmitters and Their Functions Neurotransmitter Function Problems Caused by Imbalances Serotonin Affects mood, hunger, sleep, and arousal Undersupply linked to depression; some antidepressant drugs raise serotonin levels Dopamine Influences movement, learning, attention, and emotion Oversupply linked to schizophrenia; undersupply linked to tremors and decreased mobility in Parkinson’s disease and ADHD Acetylcholine (ACh) Enables muscle action, learning, and memory ACh-producing neurons deteriorate as Alzheimer’s disease progresses Click to reveal row. There are some uses/functions that are not mentioned, such as the role of inadequate norepinephrine and dopamine in ADHD. Note: Some antidepressants, by blocking reuptake of serotonin, raise serotonin levels at the synapse; they don’t add more serotonin to the body. The problem in schizophrenia may actually be an overabundance of dopamine receptors, not just an oversupply of dopamine itself. Norepinephrine Helps control alertness and arousal Undersupply can depress mood and cause ADHD-like attention problems GABA (gamma-aminobutyric acid A major inhibitory neurotransmitter Undersupply linked to seizures, tremors, and insomnia Glutamate A major excitatory neurotransmitter; involved in memory Oversupply can overstimulate the brain, producing migraines or seizures; this is why some people avoid MSG (monosodium glutamate) in food

14 Serotonin pathways Dopamine pathways
Networks of neurons that communicate with dopamine are involved in focusing attention and controlling movement. Networks of neurons that communicate with serotonin help regulate mood. No animation.

15 Hearing the message How Neurotransmitters Activate Receptors
When the key fits, the site is opened. No animation.

16 Keys that almost fit: Agonist and Antagonist Molecules
No animation. Examples you can use to test your students: pausing for the blanks below so students can fill in the correct term: Opiate drugs stimulate the opiate receptors that are otherwise stimulated by endorphins to reduce pain. These drugs are opiate ______ (agonists). Curare causes paralysis by blocking the acetlycholine (ACh) receptors on motor neurons; curare is an ACh _______ (antagonist). An agonist molecule fills the receptor site and activates it, acting like the neurotransmitter. An antagonist molecule fills the lock so that the neurotransmitter cannot get in and activate the receptor site.

17 The Inner and Outer Parts of the Nervous System
The peripheral nervous system [PNS] consists of ‘the rest’ of the nervous system. The PNS gathers and sends information to and from the rest of the body. The central nervous system [CNS] consists of the brain and spinal cord. The CNS makes decisions for the body. No animation. The descriptive text is color-coded to go with the part of the nervous system referred to in the diagram. The image is from a previous version of the text.

18 Types of Neurons Sensory neurons carry messages IN from the body’s tissues and sensory receptors to the CNS for processing. Motor neurons carry instructions OUT from the CNS out to the body’s tissues. Interneurons (in the brain and spinal cord) process information between the sensory input and motor output. Automatic animation. There are millions of sensory neurons and millions of motor neurons, but BILLIONS of interneurons.

19 The “Nerves” are not the same as neurons.
Nerves consist of neural “cables” containing many axons. Nerves are part of the peripheral nervous system and connect muscles, glands, and sense organs to the central nervous system. Click to reveal two sentences.

20 More Parts of the Nervous System
No animation. Note that the autonomic, somatic, sympathetic, and parasympathetic branches of the nervous system are all part of the PNS.

21 The Peripheral Nervous System
No animation.

22 The Autonomic Nervous System:
The sympathetic NS arouses (fight-or-flight) The parasympathetic NS calms (rest and digest) No animation. 1. Question to ask students: Why not just stay aroused all the time? allow the body to repair itself and regain energy from food. 2. Comment to students: note the sympathetic nervous system’s effect on the stomach and bladder., This helps us understand why “I was so upset that I wet my pants” or “I was so upset I threw up.” Now you can take these reports as a sign of strong activation of the sympathetic part of the autonomic nervous system.

23 The Central Nervous System
The brain is a web of neural networks. The spinal cord is full of interneurons that sometimes have a “mind of their own.” Click to reveal bullets.

24 Neural Networks These complex webs of interconnected neurons form with experience. Remember: “Neurons that fire together, wire together.” No animation. These neural networks are activated when needed for action.

25 Interneurons in the Spine
Your spine’s interneurons trigger your hand to pull away from a fire before you can say OUCH! This is an example of a reflex action. No animation. You not only won’t have time to say “ouch,” you won’t even think it. This is because before the brain gets the pain message, the interneurons in the spinal cord are already sending a message back through motor neurons saying, “pull your hand away!”

26 The Endocrine System The endocrine system refers to a set of glands that produce chemical messengers called hormones. No animation. Instead of sending messages across the synapse, the endocrine system sends messages through the bloodstream. The nervous system and the endocrine systems are connected and influence each other. Endocrine system messages travel more slowly but also last longer.

27 The Body’s “Slow but Sure” Endocrine Message System
The endocrine system sends molecules as messages, just like the nervous system, but it sends them through the bloodstream instead of across synapses. These molecules, called hormones, are produced in various glands around the body. The messages go to the brain and other tissues. Click to reveal bullets. “Slow but sure” endocrine system messages take longer to get to their location, but then the molecules hang around for a bit, so the effect of the “message” lasts longer. In neural communication, reuptake of the neurotransmitters sometimes prevents effective communication. (This is the real “chemical imbalance” treated by some medication: slowing reuptake.)

28 Adrenal Glands produce hormones such as adrenaline/epinephrine, noradrenaline/norepinephrine, and cortisol. The sympathetic “fight or flight” nervous system responds to stress by sending a message to adrenal glands to release the hormones listed above. Effect: increased heart rate, blood pressure, and blood sugar. These provide ENERGY for the fight or flight! Adrenal Glands Pancreas Click to reveal bullets. The adrenal glands also produce cortisol; more about this when we talk about stress and health.

29 The Pituitary Gland The pituitary gland is the “master gland” of the endocrine system. It is controlled through the nervous system by the nearby brain area--the hypothalamus. The pituitary gland produces hormones that regulate other glands such as the thyroid. It also produces growth hormone (especially during sleep) and oxytocin, the “bonding” hormone. Pituitary gland Click to reveal bullets.

30 Is it possible to ‘understand’ the brain?
What we’ll discuss: how we learn about the brain the life-sustaining inner parts of the brain: the brainstem and limbic system the outer, wrinkled “bark”: the cortex left, right, and split brains Questions about parts of the brain: Do you think that the brain is the sum of its parts, or is the brain actually about the way they are connected? What do you think might happen if a particular area of the brain was stimulated? What do you think might happen if a particular area of the brain was damaged or not working well? Is it possible to ‘understand’ the brain? “If the human brain were so simple that we could understand it, we would be so simple that we couldn’t.” –Emerson M. Pugh …but we can try. Click to reveal bullets and questions in sidebar, then a quote.

31 Investigating the Brain and Mind:
Strategies for finding out what is different about the mind when part of the brain isn’t working normally: case studies of accidents (e.g. Phineas Gage) case studies of split-brain patients (corpus callosum cut to stop seizures) lesioning brain parts in animals to find out what happens chemically numbing, magnetically deactivating, or electrically stimulating parts of the brain Investigating the Brain and Mind: How did we move beyond phrenology? How did we get inside the skull and under the “bumps”? by finding what happens when part of the brain is damaged or otherwise unable to work properly by looking at the structure and activity of the brain: CAT, MRI, fMRI, and PET scans Click to reveal all bullets.

32 Studying cases of brain damage
When a stroke or injury damages part of the brain, we have a chance to see the impact on the mind. No animation. Instructor: Some examples of brain areas we learned about thanks to patients with brain damage: the frontal lobes (as with Phineas Gage, pictured here), Broca’s area, and Wernicke’s area. Broca’s area is named after French physician Pierre Paul Broca ( ) . Wernicke’s area was named after German physician Carl Wernicke ( ).

33 Intentional brain damage:
Lesions (surgical destruction of brain tissue) performed on animals has yielded some insights, especially about less complex brain structures no longer necessary, as we now can chemically or magnetically deactivate brain areas to get similar information Click to reveal bullets.

34 Split-Brain Patients “Split” = surgery in which the connection between the brain hemispheres is cut in order to end severe full-brain seizures Study of split-brain patients has yielded insights discussed at the end of the chapter Click to reveal bullets.

35 We can stimulate parts of the brain to see what happens
Parts of the brain, and even neurons, can be stimulated electrically, chemically, or magnetically. This can result in behaviors such as giggling, head turning, or simulated vivid recall. Researchers can see which neurons or neural networks fire in conjunction with certain mental experiences, and even specific concepts. Click to reveal bullets. Hopefully students will understand that brain stimulation is less dramatic than the use of a bolt of lighting; it involves only small electrodes. Although people feel like the stimulation of certain brain locations produces vivid memories, research has proven that this impression is false; the memories feel vivid, but are inaccurate.

36 Monitoring activity in the brain
Tools to read electrical, metabolic, and magnetic activity in the brain: EEG: electroencephalogram PET: positron emission tomography Click to show four bubbles. MRI: magnetic resonance imaging fMRI: functional MRI

37 EEG: electroencephalogram
An EEG (electroencephalogram) is a recording of the electrical waves sweeping across the brain’s surface. An EEG is useful in studying seizures and sleep. No animation. EEGs use electrodes placed on the scalp.

38 PET: positron emission tomography
The PET scan allows us to see what part of the brain is active by tracing where a radioactive form of glucose goes while the brain performs a given task. No animation.

39 MRI: magnetic resonance imaging
fMRI: functional MRI MRI (magnetic resonance imaging) makes images from signals produced by brain tissue after magnets align the spin of atoms. The arrows below show ventricular enlargement in a schizophrenic patient (right). Functional MRI reveals brain activity and function rather than structures. Functional MRI compares successive MRI images taken a split second apart, and shows changes in the level of oxygen in bloodflow in the brain. Click to reveal Functional MRI information.

40 Areas of the brain and their functions
The brainstem and cerebellum: coordinates the body The limbic (border) system: manages emotions, and connects thought to body The cortex (the outer covering): integrates information No animation.

41 The Brain: Less Complex Brain Structures
Our tour of the brain begins with parts of the human brain found also in simpler animals; these parts generally deal with less complex functions: Brainstem (Pons and Medulla) Thalamus Reticular Formation Automatic animation. Cerebellum Limbic System

42 The Brainstem: Pons and Medulla
Click to “grow” a subsection view of the brainstem. The brain’s innermost region begins where the spinal cord enters the skull.

43 The Base of the Brainstem: The Medulla
The medulla controls the most basic functions such as heartbeat and breathing. Someone with total brain damage above the medulla could still breathe independently, but someone with damage in this area could not. Click to reveal second bullet. Christopher Reeve ( ; an image of him here might work well), an actor in Superman movies and Smallville, couldn’t breathe on his own after a horse riding accident broke his spine at the level of the medulla.

44 The Brainstem: The Pons
The pons helps coordinate automatic and unconscious movements. No animation. Examples of what the pons controls: movements such as swallowing, posture, facial expression, and eye movement. The pons also has a role in suppressing body movement during REM sleep. The pons supports communication across the hemispheres and also communication from the frontal lobes to the cerebellum.

45 The Thalamus (“Inner Chamber”)
The thalamus is the “sensory switchboard” or “router.” All sensory messages, except smell, are routed through the thalamus on the way to the cortex (higher, outer brain). The thalamus also sends messages from the cortex to the medulla and cerebellum. Click to reveal bullets. The book says “switchboard,” but perhaps it’s time to upgrade the term to “router.” Damage to the thalamus can cause blindness and other loss of the senses, even if the sensory organ is fine. However, damage to the thalamus could not hurt your sense of smell, which bypasses the thalamus and goes straight to the olfactory bulb in the brain.

46 Reticular (“Netlike”) Formation
The reticular formation is a nerve network in the brainstem. It enables alertness, (arousal) from coma to wide awake (as demonstrated in the cat experiments). It also filters incoming sensory information. Click to reveal bullets. Additional information/lecture material: The structure of the reticular formation: this network of neurons branches from the spinal cord up into the thalamus. I have added two lines to the picture to indicate this. How do we know about arousal? In the cat experiments, researchers stimulated the reticular formation in order to make a sleeping cat pop awake. Similarly, cutting the reticular formation made a cat lapse into a permanent coma. About the filtering: it could be said that the reticular formation controls selective awareness; it ‘selects’ which incoming information to send to other brain areas. This enables us to follow a conversation in a crowd, i.e. to select a “signal” out of sensory “noise.”

47 Cerebellum (“little brain”)
The cerebellum helps coordinate voluntary movement such as playing a sport. Click to reveal bullets. The cerebellum is located in two parts, behind the pons and below the back of the brain. The cerebellum also is the area where implicit memories and conditioning are stored. It also helps us judge time, modulate emotions, and integrate multiple sources of sensory input. The cerebellum has many other functions, including enabling nonverbal learning and memory.

48 The Limbic (“Border”) System The limbic system coordinates:
emotions such as fear and aggression. basic drives such as hunger and sex. the formation of episodic memories. The hippocampus (“seahorse”) processes conscious, episodic memories. works with the amygdala to form emotionally charged memories. The Amygdala (“almond”) consists of two lima bean sized neural clusters. helps process emotions, especially fear and aggression. Click to reveal bullets. The limbic system is located on the “border”/limbus between the brainstem and cortex; it is between the least complex and most advanced brain structures and between the cerebral hemispheres. The hippocampus is one of the few places in the brain in which neurogenesis is known to take place. Stimulating different parts of the amygdala triggers different versions of the defensive, self-protective emotions; one part increases aggressive reactions, while another increases fearful withdrawal. Destruction of part of the amygdala can apparently eliminate both emotions. Note: aggression and fear reactions involve networks across the brain, and these reactions can be stimulated elsewhere. The pituitary gland is in the text image, but I faded and shrank the label because it is not really part of the limbic system; I’ll restore it when talking about the hypothalamus.

49 The Amygdala Electrical stimulation of a cat’s amygdala provokes aggressive reactions. If you move the electrode very slightly and cage the cat with a mouse, the cat will cower in terror. Click to reveal bullets.

50 The Hypothalamus: The Hypothalamus as a Reward Center
lies below (“hypo”) the thalamus. regulates body temperature and ensures adequate food and water intake (homeostasis), and is involved in sex drive. directs the endocrine system via messages to the pituitary gland. Thalamus The Hypothalamus as a Reward Center Riddle: Why did the rat cross the grid? Why did the rat want to get to the other side? Click to reveal bullets. If you lesion one part of the hypothalamus of a rat, it stops eating; lesion another part and it hardly stops eating. Click to reveal ‘Hypothalamus Reward Center’ riddle. Click again for answer. Instructor: After addressing the riddle on the slide, but before adding the additional lecture material below, consider throwing out a question, “So where on this screen is the reward center?. Is it here, (point to the cage), the place to go to get rewards? Oh, it’s up here? (point to the hypothalamus).” [This is where you could note, as below, that there are other reward centers…] Additional lecture material: There are other reward centers, including an area near the hypothalamus, the nucleus accumbens. Many of these areas rely on dopamine, which may be why people with low dopamine (ADHD) don’t learn well from rewards, and why people who crave dopamine (ADHD, addicts, young teens, and those with reward deficiency syndrome) are reckless in their search for it, maybe even crossing an electrified grid like the rat in the illustration. Pushing the pedal that stimulated the electrode placed in the hypothalamus was much more rewarding than food pellets.

51 Review of Brain Structures
No animation.

52 The Cerebral Cortex The lobes consist of:
outer grey “bark” structure that is wrinkled in order to create more surface area for 20+ billion neurons. inner white stuff—axons linking parts of the brain. 180+ billion glial cells, which feed and protect neurons and assist neural transmission. 300 billion synaptic connections Click to reveal bullets. The orange area is the cerebellum. The brain has left and right hemispheres

53 The Lobes of the Cerebral Cortex: Preview
involved in speaking and muscle movements and in making plans and judgments Frontal Lobes Parietal Lobes Occipital Lobes Temporal Lobes include the sensory cortex include the visual areas; they receive visual information from the opposite visual field Click to reveal bullets. include the auditory processing areas

54 Functions of the Brain: The Motor and Sensory Strips
Input: Sensory cortex (Left hemisphere section receives input from the body’s right side) Output: Motor cortex (Left hemisphere section controls the body’s right side) No animation. The body parts along each strip represent the amount of neural space devoted to movement or sensation of that body part. Parts needing more precise sensation or control take up more cortical space. These “strips” are located at the border of the frontal lobe and the parietal lobe.  Axons receiving motor signals FROM the cortex Axons sending sensory information TO the cortex

55 Using our knowledge of functions: Brain-computer interfaces and neural prosthetics
Here, a robotic arm is operated through controls embedded in the motor strip of the cortex. We may soon be able to use computers to translate neural inputs into more commands and words than simply grabbing food. Click to reveal bullets.

56 Sensory Functions of the Cortex
The sensory strip deals with information from touch stimuli. The occipital lobe deals with visual information. Auditory information is sent to the temporal lobe. Click to reveal bullets. Auditory areas are also active when someone in a psychotic state is experiencing “voices”/auditory hallucinations

57 The Visual Cortex This fMRI scan shows increased activity in the visual cortex when a person looks at a photograph. No animation.

58 Association function of the cortex
More complex animals have more cortical space devoted to integrating/associating information No animation. The relative proportion of the cortex devoted to taking in sensory information and sending out motor commands is smaller as the association areas are larger (a negative correlation).

59 Association Areas: Frontal Lobes
The frontal lobes are active in “executive functions” such as judgment, planning, and inhibition of impulses. The frontal lobes are also active in the use of working memory and the processing of new memories. Click to reveal bullets. There is a large set of association areas in front of the motor strip and behind the forehead.

60 Phineas Gage ( ) Case study: In a work accident, a metal rod shot up through Phineas Gage’s skull, destroying his eye and part of his frontal lobes. After healing, he was able to function in many ways, but his personality changed; he was rude, odd, irritable, and unpredictable. Possible explanation: Damage to the frontal lobes could result in loss of the ability to suppress impulses and to modulate emotions. The possible explanation appears with a click. See if students can guess at an explanation for Gage’s symptoms based on the area of brain damage.

61 Parietal Lobe Association Areas
This part of the brain has many functions in the association areas behind the sensory strip: managing input from multiple senses performing spatial and mathematical reasoning monitoring the sensation of movement Click to reveal bullets.

62 Temporal Lobe Association Areas
Click to reveal bullets. Some abilities managed by association areas in this “by the temples” lobe: recognizing specific faces managing sensory input related to sound, which helps the understanding of spoken words

63 Whole-brain Association Activity
Whole-brain association activity involves complex activities which require communication among association areas across the brain such as: memory language attention meditation and spirituality consciousness Click to reveal list.

64 Specialization and Integration Five steps in reading a word aloud:
No animation. This slide should be considered optional here, or presented as such to the students, because this chapter no longer includes this image or this level of detail. If any of these processes are not working properly (e.g because of damage to one of these brain areas in the left hemisphere), aphasia can result. Aphasia refers to the impairment of language, usually caused by left hemisphere damage either to Broca’s area (speech impairment) or to Wernicke’s area (impairing understanding or causing the inability to produce meaningful words).

65 Plasticity: The Brain is Flexible
This 6-year-old had a hemispherectomy to end life-threatening seizures; her remaining hemisphere compensated for the damage. If the brain is damaged, especially in the general association areas of the cortex: the brain does not repair damaged neurons, BUT it can restore some functions it can form new connections, reassign existing networks, and insert new neurons, some grown from stem cells Click to reveal bullets and example. Despite lists of lateralized functions, there are many areas of overlap and duplication in the hemispheres. This is part of the reason that the girl with only one hemisphere was able to adapt.

66 Our Two Hemispheres Lateralization (“going to one side”)
The two hemispheres serve some different functions. How do we know about these differences? Brain damage studies revealed many functions of the left hemisphere. Brain scans and split brain studies show more about the functions of the two hemispheres, and how they coordinate with each other. Click to reveal bullets. Brain scan studies show normal individuals engage their right brain when completing a perceptual task and their left brain when carrying out a linguistic task. However, many functions of the two hemispheres overlap.

67 The intact but lateralized brain Right-Left Hemisphere Differences
Right Hemisphere Feelings and intuition Big picture such as “forest” Language: tone, inflection, context Inferences and associations Perception Wholes, including the self Thoughts and logic Details such as “trees” Language: words and definitions Linear and literal Calculation Pieces and details No animation. I’ve included this here rather than later because it helps with understanding the split brain studies. Note (from the “Handedness” close-up box in the text): about 3 percent of people, mostly lefties, do not follow this pattern as clearly, e.g. they process language in the right, or both, hemispheres.

68 Split- Brain Studies To end severe whole-brain seizures, some people have had surgery to cut the corpus callosum, a band of axons connecting the hemispheres. Click to reveal two sentences. Researchers have studied the impact of this surgery on patients’ functioning.

69 Separating the Hemispheres: Factors to Keep in Mind
Each hemisphere controls the opposite side of the body AND is aware of the visual field on that opposite side. Without the corpus callosum, the halves of the body and the halves of the visual field do not work together. Only the left half of the brain has enough verbal ability to express its thoughts out loud. Click to reveal bullets. Before going on to the next three slides, see if students can speculate on the implications of these three factors. What happens when a person with separated hemispheres tries to read a sign, or reach for something, or describe what he or she sees?

70 Split visual field Each hemisphere does not perceive what each EYE sees. Instead, it perceives the half of the view in front of you that goes with the half of the body that is controlled by that hemisphere. No animation. Notice that the optic chiasm is not cut when the corpus callosum is cut. Instructor: you may want to switch the text, move the slide’s bullet point to the notes and the note to the slide.

71 Divided Awareness in the Split Brain Try to explain the following result:
No animation. See if the students can piece it together: the left hemisphere is the one that does verbal language, and that hemisphere is processing the right visual field, so what it can verbally report is “Art.”

72 The divided brain in action
Talent: people are able to follow two instructions and draw two different shapes simultaneously Drawback: people can be frustrated that the right and left sides do different things Click to reveal second bullet. People with ‘divided brains’ may be more likely to report frustration with what the LEFT hand is doing; see if students can figure out why that is (the left hemisphere is the one talking to you and doesn’t know what input or purposes the right hemisphere is acting on).

73 The Future of Brain Research Can these questions be answered?
Is every part of the mind’s functioning going to be found someday on some brain scan? If so, have we found the mind, or is that still something separate from the brain? Click to show text and fade picture.

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