Biophysiology

1. Biophysiology • Was there a difference between the exercised personalities and the meditated personalities? • What factors determine your scores? • The nervous system underlies everything we do. Understanding biology is fundamental to understanding behaviour. • We need to know the mechanics of sensation before we can understand perception.

2. Why are the following images weird?

7. Is the center spinning?

8. Which intersections have white dots and which are black?

9. Is it rotating?

10. Ignore the word and say the color

12. Are the horizontal lines parallel?

13. Which center dot is bigger?

14. Are the horizontal lines straight?

15. Count the spirals

16. Star or square?

17. COUNT THE F’S • FINISHED FILES ARE THE RE- SULT OF YEARS OF SCIENTIF- IC COMBINED WITH THE EXPERIENCE OF YEARS.

18. Straight or parallel?

19. Which center line is longer?

21. The Biological Level of Analysis • Explanations for thoughts, behaviours, perceptions, and emotions are more complicated than this…

22. Three key principles that define the biological level of analysis: • Emotions and behaviour are the products of the anatomy and physiology of the nervous and endocrine systems • Patterns of behaviour can be inherited • Animal research may inform our understanding of behaviour

23. I. Emotions and behaviour are the products of the anatomy and physiology of the nervous and endocrine systems • All observable behaviour, including mental activity (emotions and cognition) can be traced back to physiological events. • Links have been found between physiological events and physiological activity in three areas: • Neurotransmitters • Hormones • Brain localization

24. Where does behaviour/thought come from? • Reflects the idea that causes of emotions, behaviour, and thought lay within the human body. • Requires study of the nervous system and how the brain interacts with the rest of the body and the endocrine system.

25. II. Patterns of behaviour can be inherited • Focused on two branches of research: • Evolutionary psychology – Humans have changed physically and behaviourally according to the demands of the environment. • Genetics – transmitted from parents to children and over time, physical characteristics and behaviours that are helpful to an individual or group will be passed on

26. Examples of topics: • Homosexuality • Intelligence • Criminal behaviour • Schizophrenia • Are these characteristics a product of inherited physiology? Genetics? • What are the implications of the discovery that one or more of these characteristics have a genetic component? How will that change our understanding of these things?

27. Diathesis-stress Model • Diathesis-stress Model – a genetic predisposition to disorders like depression can be inherited however, an environmental trigger like childhood trauma is required to make the depression manifest itself.

28. III. Animal research may inform our understanding of behaviour • Based on the idea that the human being is a type of animal • Therefore it is valid to make inferences about human behaviour based on animal research because the mechanisms that underlie behaviour are the core similarity we share with animals. • The closer the animal is related to humans, the stronger the inference from research we can make.

29. Evolutionary effects can be studied on organisms with shorter lifespans – fruit flies, foxes, mice, etc. • How does Pavlov’s Dog demonstrate this principle? • What are the advantages and disadvantages of using animals in psychological research?

30. The biological level of analysis tends to use three main types of inquiry: • Laboratory experiments • Case studies • Correlational studies

31. Get out a fresh sheet of paper • Write your name on the top right corner. • Put today’s date on the top left. • Take good, neat, colorful notes. • Write the following on the first four lines along the left margin. • Neatness /4 • Comprehensiveness /2 • Organized /2 • Total /8

32. The Biological Basis of Behaviour • In order to understand the mind, psychologists must first understand how the body works and is constructed. • Before becoming a software engineer, you must first know how a computer is put together and how it works.

33. The basic hardware • The nervous system is composed of billions of cells called neurons. • Neuron – individual cells that receive, integrate, and transmit information. • We lose an average of 10,000 per day, but over a lifetime, that amounts to less than 2% of the total.

34. Neurons

35. Receptors – specialized structures capable of turning stimuli in the environment into electrical impulses in the body. • Afferent nerves – nerves that transmit signals into the brain. • Efferent nerves – nerves that carry signals from the brain to the muscles. • If the cell body were the size of a basketball the axon would be a garden hose the length of Manhattan Island.

36. Brain Impulse Stimulus Efferent nerves Afferent nerve Receptor Impulse Impulse Muscle

38. Sensory neurons carry signals from the outer parts of your body (periphery) into the central nervous system. • Motor neurons (motoneurons) carry signals from the central nervous system to the outer parts (muscles, skin, glands) of your body. • Interneurons connect various neurons within the brain and spinal cord.

39. The simplest type of neural pathway is a monosynaptic (single connection) reflex pathway, like the knee-jerk reflex. • When the doctor taps the right spot on your knee with a rubber hammer, receptors send a signal into the spinal cord through a sensory neuron. The sensory neuron passes the message to a motor neuron that controls your leg muscles. Nerve impulses travel down the motor neuron and stimulate the appropriate leg muscle to contract. • The response is a muscular jerk that happens quickly and does not involve your brain. • As tasks become more complex, the pathway "circuitry" gets more complicated and the brain gets involved.

40. Triggering the threshold • When a sensation reaches the threshold a signal is triggered in the dendrites of the neuron. • Threshold – the minimum intensity required to trigger a chain reaction in a neuron. (55 millivolts in mammals) • Some threshold stimuli… • A candle flame 50kms away on a clear dark night. • A ticking watch at 6 meters in a quiet room • One teaspoon of sugar in 7 liters of water. • The wing of a bee falling on your cheek from 1 cm away.

41. The electrochemical signal • The signal that travels the length of the neuron is actually a change in the polarity of the outside of the axon. • The resting charge on the cell is -70 millivolts. • This charge is created by a membrane around the cell that keeps positively charged sodium ions (Na+) on the outside of the cell and positively charged potassium ions (K+) in the inside.

43. Impulse • Once the threshold is achieved in the cell body, the protein “gates” of the axon open and Na+ ions rush in. • For 1 millisecond, the outside of the axon body becomes – and the interior becomes +.

44. Propagation • The polarity of the axon body is reversed as the threshold is achieved. • Gates in the cell membrane open briefly to let Na+ ions rush in. • These gates quickly close and K+ ions slowly leak out and the cell begins to actively pump Na+ ions back out. • This returns the cell to it’s resting state. • The depolarization of the cell produces electric currents that stimulate the threshold value in neighboring regions as the impulse travels down the axon.

45. All or None Law • Once the impulse is triggered, the intensity of the signal is constant. • All or None Law – the stimulus does not provide the energy of the nervous impulse. • This means that a stronger sensation is caused by a greater number of neurons being stimulated, not a stronger impulse.

46. Pain • The All or None Law is important for the study of sensations like pain. • Intense sensation can be caused by two factors: • A strong stimulus will trigger a higher NUMBER of neurons to fire • A strong stimulus will trigger a greater FREQUENCY in the neuron impulse. • The highest frequency in the human body is 1,000 impulses/second

47. Synaptic Transmission • Scientists had always believed that there was some mechanism connecting two neurons together. • This was finally proven in 1920 by Otto Loewi. • Lowei’s experiment proved that the transmission from one neuron to the next involved a chemical substance.

49. Synapse • Synapse – the gap between the axon terminals of the transmitting neuron and the dendrites of the receiving neuron.

50. Synaptic Transmission • As the impulse reaches the axon terminals, tiny sacs of specialized proteins called synaptic vesicles rupture at the surface of the terminal. • These vesicles pop and release a chemical into the synapse called a neurotransmitter.