Questions to check your understanding:

1. Questions to check your understanding: • What happened to Phineas Gage? • What philosophical tradition views the mind and body as separate? • Define reductionism • Explain what ‘Morgan's law of parsimony’ is. • Why is the biological LOA reductionist? • Why can taking a reductionist approach sometimes be problematic? • What's the difference between dualism & materialism? • Why is it important to take a holistic approach? • What is biological determinism? • What is genetic determinism?

2. The IB Syllabus says: • Using one or more examples, explain the effects of neurotransmission on behavior

3. Learning goals……… • Gain an understanding of the anatomy of the neuron & how neuronal transmission works • Explain the effect of neurotransmitters on human behavior (serotonin & depression) • Examine structure and function on the brain, as well as ‘neural plasticity’

4. Divisions of the Nervous System

5. “The decade of the brain” • The 1990s was called the ‘decade of the brain’ • We learnt more than ever before • New technologies such brain scanning machines allowed researchers to identify areas of the brain active during different activities - fMRI, PET

6. It all Starts with the Neuron – the ‘building block’ of the nervous system

7. Neural and Hormonal Systems Will Explain Why We FEEL…… Nervous Strong Sick Pain

8. The Neuron • The nerve cells of the brain are called neurons. The average brain has 100 billion neurons • Neurons are different from other cells because fibers that extend out from the cell body, allowing it to receive and transmit messages – this are called dendrites • An axon is a single long fiber extending out from the cells body –its job is to to pick up incoming messages from other neurons • There is a white fatty covering that covers the axon called a myelin sheath. Its function is to provide insulation, and ensure that signals from adjacent neurons don’t interfere with each other. Myelin also increases the speed of transmission

9. Neuron Structure Neurons do NOT touch each other- the space in between is call the synapse.

10. The Synapse • The gap between neurons is called the synapse • At the end of each axon there a synaptic button - neuronal impulses must cross the synaptic gap to travel to the next neuron • This transfer is made by chemicals called neurotransmitters, released when synaptic vesicles release when the neural impulse reaches the terminals • Each neurotransmitter has its own specific receptor cite – just like a key that fits a lock

11. Activity – label the diagram with the following and describe the mechanism of neural transmission – Crane 39 &40; slides 11-16. • Dendrites • Cell nucleus • Cell Body • Axon • Myelin sheath • Terminal buttons

12. The Neuron

13. The Neuron

14. How Neurons Communicate

15. How do neurons communicate with each other? • Neurons ‘talk to each other’ or communicate through electrochemical impulses • These are simple ‘yes’ ‘no’ or ‘on/off’ impulses • A neuron is either at rest or activated

16. The Synapse

17. The neuron The synapse Relay activity: label both as quickly as possible

18. Types of Neurons Sensory Neurons Motor Neurons Inter Neurons

19. Sensory Neurons(Afferent Neurons) • Take information from the senses to the brain.

20. Inter Neurons • Take messages from Sensory Neurons to other parts of the brain or to Motor Neurons.

21. Motor Neurons(Efferent Neurons) • Take information from brain to the rest of the body.

22. Quick Quiz: The Neuron • What are the nerve cells of the brain called? How many of these does the average human have? • What makes the neuron different from other cells? • What is an axon? • What is the white fatty covering that covers the axon? What's its function? • What are neurons that collect messages from the sense organs and carry them to the brain called? • What are neurons that carry messages from the spinal cord or the brain are called? • What do glial cells do? • How do neurons ‘talk to each other’? • What happens to the membrane of the neuron when it is resting? • When the neuron is at rest – where are there more negative ions, on the inside or the outside? • What does an inflow of sodium from the pores in the cell membrane do?

23. The synapse: Questions to check your understanding The Synapse 1)) What is the name of the gap between neurons? 2) What is at the end of each axon? 3) What must the neuronal impulses do to travel to the next neuron? 4) What is the transfer between neurons made by? 5) What do the synaptic vesicles release when the neural impulse reaches the terminals? 6) Why is this described as a ‘lock & key’ process’?

24. Neurotransmitters • Chemical messengers released by terminal buttons through the synapse. • Neurotransmitters have been studied quite a bit in relation to psychology and human behavior. • What we have found is that several neurotransmitters play a role in the way we behave, learn, the way we feel, and sleep. • And, some play a role in mental illnesses. The following are those neurotransmitters which play a significant role in our mental health.

25. Some examples of NTs

26. Acetylcholine • Its function is motor movement and maybe memory. Too much and you will….?? Not enough and you will….?? Lack of ACH has been linked to Alzheimer’s disease.

27. Dopamine Its function is motor movement and alertness. Lack of dopamine is associated with Parkinson’s disease. Overabundance is associated with schizophrenia.

28. Serotonin • Function deals with mood control. Lack of serotonin has been linked to depression.

29. Endorphins • Function - deals with pain control. We become addicted to endorphin causing feelings.

30. Neurotransmitters and their Effects • Please note that these associations are merely correlations, and do not necessarily demonstrate any cause and effect relationship. • We don’t know what other variables may be affecting both the neurotransmitter and the mental illness, and we don’t know if the change in the neurotransmitter causes the illness, or the illness causes the change in the neurotransmitter

31. Using one or more examples, explain the effects of neurotransmission on behavior The effect of serotonin on human behavior -focus on depression • Serotonin is a neurotransmitter and it has several functions in humans: • the regulation of intestinal movements, • the regulation of mood, appetite, sleep, muscle contraction, • cognitive functions including memory and learning.

32. The effect of serotonin on human behavior • Research with non human animals suggests serotonin appear to have a role in social behavior: • Kravitz (1988) injected lobsters with serotonin and found that they behaved like a dominant animal • With humans, a great deal of research has been done on the connection between serotonin and depression

33. The Monoamine hypothesis • Barlow (1995) found that low levels of the neurotransmitters serotonin,norepinephrine and dopamine in the synaptic gap between neurons in the brain, are associated with depression • Because of this, psychoactive drugs have been developed to increase the effect peoples behavior by increasing amount of these monoamines at the synapse, these are called SSRI’s,MAOI’s & TCA’s they have been very successful

34. Depression - One of most common reason for going to the doctor 20% lifetime risk. Clinical Characteristics of Unipolar Depression

35. Quick quiz: • What is at the end of each axon? • Neurotransmitters need to cross the synaptic _________ and bind onto receptor cites. • Give four clinical characteristics of depression • What did Kravitz (1988) find out about serotonin? • What is serotonin? What role does it play in humans and animals? • What is the monoamine hypothesis? • What does SSRI stand for? • How do these work?

36. In pairs, read and explain one section: • TCA’s • MAOIs • SSRI’s • Effectiveness in reducing symptoms • Comparing effectiveness and side effects of TCAs and MAOIs • Prozac, the wonder drug? • Use of anti depressants with older and younger people

37. The different types of antidepressants • Monoamine-oxidize inhibitors (MAOIs) • This antidepressant was discovered by accident when a new drug for TB was found to induce euphoria. • MAOIs work by blocking the action of the enzyme that breaks down nor-adrenaline and serotonin, so this increases the availability of these neurotransmitters in the nervous system • Tricyclics (TCAs) • These work in a similar way to MAOIs but are milder antidepressant, although they are slower in acting, the have fewer severe side effects • Selective serotonin re-uptake inhibitors (SSRIs) • SSRIs such as Prozac inhibit the re-uptake of serotonin at the synapse and thus make more of the neurotransmitter available. • Recently the natural herb hypericum, commonly known as St. Johns Wort has been found in clinical trials to have anti-depressant qualities with very few side effects. It is thought that the herb alters serotonin function in some way.

38. Evaluation: The use of antidepressants • Effective in reducing symptoms – Antidepressents have been found to be effective in reducing symptoms of severe depression in around 65% to 75% of cases, compared to 33% for placebos (Prien et al, 1988) • Comparing effectiveness and side effects of TCAs and MAOIs – Spiegel (1989) found that around 65% of depressed patients improved with tricyclics (TCAs), although there are potential side effects, the most serious being cardiac problems • MAOIs are equally effective, but require dietary restriction and can react dangerously with other drugs such as cold remedies. Tricyclics are prescribed more often because they are milder and have less severe side effects

39. Evaluation: The use of antidepressants • Prozac, the wonder drug? – Prozac (an SSRI) was hailed the ‘wonder drug’ when it was first introduced in the late 1980s and it is currently the most frequently prescribed of all anti depressants. However, it has recently become a media target because of many anecdotal reports of serious side effects, including a preoccupation with violence and suicide in users (Steiner, 1991) • Use with older and younger people – antidepressants are less effective with children, but very effective with older people, although with more side effects

40. Questions to check your understanding: • What does MAOI stand for? How to they work? • What is the most commonly prescribed of all antidepressants? • How effective are antidepressants in reducing the symptoms of depression? • With which age group are antidepressants more effective, older or younger people?

41. Quick quiz • What is serotonin? • What is the monoamine hypothesis? • What does SSRI stand for? How do they work? • What does MAOI stand for? How to they work? • What is the most commonly prescribed of all antidepressants? • How effective are antidepressants in reducing the symptoms of depression? • What are the strengths and weaknesses of drug treatments? • With which age group are antidepressants more effective, older or younger people?

42. SAQ Planning activity • Using one or more examples, describe the effects of neurotransmission on behavior • Using one or more examples, explain the effects of neurotransmission on behavior • Using one or more examples, analyze the effects of neurotransmission on behavior

43. SAQ Planning activity: ExampleUsing one or more examples, describe the effects of neurotransmission on behavior • Say at the start how you will answer the question • Describe how neurons communicate with each other: axon & the synapse • Highlight the importance of neurotransmitter Serotonin & the monoamine hypothesis • Give further detail on how antidepressant drugs work • Conclude by going back to the question

44. SAQs – what the syllabus says:

45. Neural Plasticity • Neural plasticity is the ability of the brain to change structurally and chemically by experience. • Rosenzwig’s (1984) experiment with rats showed that enriched environments – larger neurons in the rats – so the brain is organized as a result of experience. • Neurogensis is growth of new brain cells.

46. Rosenzweig’s (1984) study of neural plasticity • Aim: To examine the effect of environment on neuronal development • Procedure: Laboratory experiment • IV – environment of the rats (enriched/ impoverished) • DV – Neuronal development in post mortem • Findings: Enriched environment – larger neurons with more synaptic connections • Conclusion: The environment can influence neurons – neural plasticity • Criticisms: Ethics? Does it apply to humans?

47. Activity: complete a key study sheet on this study

48. Reading Homework • Read page 47 to 57 in the textbook and make notes on the class and text notes worksheet. • Also answer the questions on the reading

49. P.47-57 Questions to check your understanding • What era was called the ‘decade of the brain?’ why? The Neuron • What are the nerve cells of the brain? How many of these does the average human have? • What makes the neuron different from other cells? • What is an axon? What’s its job? • What is the white fatty covering that covers the axon? What's its function • What are neurons that collect messages from the sense organs and carry them to the brain called? • What are neurons that carry messages from the spinal cord or the brain are called? • What do glial cells do? • How do neurons ‘talk to each other’? • What happens to the membrane of the neuron when it is resting? • When the neuron is at rest – where are there more negative ions, on the inside or the outside • How is a resting or polarized neuron compared to a guitar string? • What does an inflow of sodium from the pores in the cell membrane do? • How long does it take for a neuron to ‘fire’? • What is a graded potential? • What must be exceeded for the neuron to fire? • Does the neurons connections to other neurons determine whether the neuron is likely to fire or not?

50. P.47-57 Questions to check your understanding The Synapse 1)) What is the name of the gap between neurons? 2) What is at the end of each axon? 3) What must the neuronal impulses do to travel to the next neuron? 4) What is the transfer between neurons made by ? 5) What do the synaptic vesicles release when the neural impulse reaches the terminals? 6) What does each neurotransmitter have? 7) What does the neurotransmitter ACh do? 8) What does the neurotransmitter dopamine do? 9) What does the neurotransmitter serotonin do? 10) What does do the neurotransmitter endorphins do? How is this linked to heroin addiction Psychopharmacology 1) What do psychoactive drugs do? Give one example. Neural Plasticity 1)What is neural plasticity? 2) What did Rosenzweig’s (1984) experiment with rats show 3) What is neurogensis?