1. Physiological Psychology
It’s all about the brain

3. Neurons Nerve cells specialized in communicating information
Present from birth; number about 100 billion
Basic building blocks of the nervous system

4. Types of Neurons
Sensory (afferent) neurons: detect information from the physical world and pass that information along to the brain
Somatosensory nerves provide information from the skin and muscles
Motor neurons: direct muscles to contract or relax
Interneurons: communicate within local or short-distance circuits

6. Parts of a neuron
Dendrite: detects chemical signals from neighboring neurons
Cell body (soma): collects and integrates information
Axon: transmits electrical impulses
Terminal buttons: bulbous end of an axon
Synapse: supports chemical communication between neurons
Synaptic cleft: narrow gap between terminal button (presynaptic membrane) and dendrite (postsynaptic membrane) of neighboring neuron
Myelin sheath: encases and insulates axons
Composed of glial cells
Nodes of Ranvier: Spaces between glial cells

7. Diagram of a Neuron

8. Another view of the neuron

9. Myelinization
Myelin sheath: fatty tissue made of protein that insulates axons and helps speed impulses.
Myelinization occurs during the first 3 years of life and is dependent on dietary fat. Improves conductivity of neural messages.

10. Neural impulses
Action potential—a brief electrical charge or impulse that travels down the axon.
Signals can be excitatory or inhibitory. If excitatory signals outweigh inhibitory ones, a threshold is reached, and an action potential is triggered.
Signals are all or none. The neuron either fires or it doesn’t.

11. How Neurons Communicate
The junction between one neuron’s axon terminal and another’s dendrites or cell body is the synapse.
Action potential triggers release of neurotransmitters (chemical messengers), which crosses the synaptic gap & binds to receptors on the receiving neuron.
Like a key fitting into a lock.
Excess neurotransmitters are reasorbed by the sending neuron in a process called reuptake.

12. Diagram of a Synapse

14. How antidepressants work

16. How drugs work (in general)
Drugs alter the process of synaptic transmission.
They can either mimic the effects of the neurotransmitter (agonists) or
They can inhibit the effects normally produced by the neurotransmitter (antagonist)
Drugs must be able to cross the blood-brain barrier to work.

17. Central Nervous System
Consists of brain and spinal cord
Spinal cord has 2 main functions: 1) carries sensory information to receptors from brain and vice-versa; 2) plays a key role in reflexes
CNS is where information processing occurs.

18. Peripheral Nervous System
Consists of neural pathways that breing information to and from brain. Two branches:
1) Somatic nervous system (voluntary movement; sensation)
2) Autonomic nervous system (involuntary control; processes related to survival)

19. The Nervous System

20. Branches of Autonomic nervous System
Sympathetic division—mobilizes the body to react in the face of threat
Parasympathetic—demobilizes the body to conserve energy; calms the body down after a stress reaction

21. Sympathetic & Parasympathetic Divisions

22. Endocrine System
Neurohormones—hormones that directly interact and affect the nervous system.
They are released into the bloodstream; neurotransmitters are released into synapses.
Neurohormones exert their influences much more slowly, at a greater distance, and often for longer periods of time than neurotransmitters.
Pituitary gland—master gland that controls hormones.

23. Endocrine system works through hormones
The endocrine system is a communication network that influences thoughts, behaviors, and actions
The main difference is that whereas the nervous system uses electrochemical signals, the endocrine system uses hormones
Hormones: chemical substances released into the bloodstream by the ductless endocrine glands, such as the pancreas, thyroid, and testes or ovaries

25. Hormones’ effects on sexual behavior
Endocrine glands influencing sexual behavior are the gonads (testes, ovaries)
Gonadal hormones are identical in males and females, but:
Androgens (testosterone) are more prevalent in males.
Estrogens (estradiol, progesterone) are more prevalent in females
Removal of the gonads impacts sexual desire and in females, terminates estrus
When they are ovulating, heterosexual women find men who look and act masculine more attractive (Gangestad, Simpson, Cousins, Garver-Apgar, & Christensen, 2004)

26. Actions of the endocrine system and nervous system are related
The endocrine system is under the central nervous system’s control
Neural activation causes the hypothalamus to secrete a particular releasing factor, which causes the pituitary gland to release a hormone specific to that factor
Pituitary gland (“master gland”): governs the release of hormones from the rest of the endocrine glands responsible for major bodily processes
Example: Growth hormone (GH) prompts bone, cartilage, and muscle tissue to grow or helps them regenerate after injury

27. The Brain Three major parts that deal with the following functions:
1) Basic bodily functions and survival
2) Motivation and emotion
3) Higher mental processes (language, planning, problem solving, and reasoning)

28. The brain stem houses the basic mechanisms of survival
The spinal cord: coordination of reflexes; carries sensory information to the brain and motor signals away from the brain
Composed of two types of tissue: gray matter and white matter
Brain stem:medulla oblongata, pons, midbrain, reticular formation

29. Brain stem
The portion of the brain that begins just above the spinal cord and continues into the center of the brain
Consists of medulla and pons, and these two contain a dense network of interconnected neurons called the reticular formation or reticular activating system. Retic. Formation is involved in sleep & arousal.
Medulla: vital functions; breathing, heart rate, coughing, BP, sneezing

30. Diagram of the Brain Stem

31. Cerebellum Located behind the medulla and pons
Primarily concerned with regulation of motor activities, serving to orchestrate muscular activities so they occur in synchronized fashion.

32. More about the Cerebellum
Cerebellum (little brain): extremely important for proper motor function, learning, and motor memory
Damage to its different parts produces different effects:
Damage to lobes on either side causes a loss of limb coordination
Damage to the nodes at the very bottom causes balance problems
Cerebellum is activated when a person experiences a painful stimulus or observes a loved one receiving that stimulus, which means the cerebellum may be involved in the experience of empathy

33. The Cerebellum in Relation to the Whole Brain

34. Midbrain
Located above medulla and pons, near the end of the brain stem.
Contains an extension of the reticular formation as well as primitive centers concerned with vision and hearing.
Plays a role in pain-relieving effects of opiates and control of motor movements by sensory input.

35. Diagram of the brain: Cortical and Subcortical Structures

36. Hypothalamus (a subcortical structure)
Less than a cubic centimeter in size but profoundly influential on behavior
Regulates the autonomic nervous system
Plays a key role in homeostasis
Plays a key role in eating and drinking
Plays a role in mating and aggression
Regulates the release of hormones from pituitary gland

37. Thalamus The thalamus is the gateway to the cortex
Excepting smell, it receives all incoming sensory information, organizes it, and relays it to the cortex
During sleep, the thalamus partially shuts the gate on incoming sensations while the brain rests
Called the “great relay station of the brain”

38. Midbrain, hypothalamus, thalamus diagram

39. Limbic system
Plays a role in emotion and motivated behavior such as feeding, fleeing from danger, fighting, and sex.
Largest structure in the limbic system is the hippocampus—plays a key role in the formation of memories
Amygdala—plays a role in emotional control

40. Hippocampus & Amygdala
The hippocampus (Greek, “sea horse”) plays an important role in the storage of new memories
Recently shown to grow larger with increased use; may be involved in how we remember the arrangements of both places and objects in space
Maguire and colleagues (2003) found that one region of the hippocampus in London taxi drivers’ brains was much larger than in most other London drivers’ brains
The amygdala(Latin, “almond”) serves a vital role in our learning to associate things in the world with negative and positive emotional responses

41. Cerebral cortex (Latin: “bark”)
Seat of complex thought, detailed perceptions, & complex behaviors.
Two hemispheres (each hemisphere has 4 lobes), connected by a band of tissue called corpus callosum that allows information to flow between the hemispheres

42. Split-Brain Experiments

43. The lobes of the cortex

44. Four lobes of cortex
Frontal: thinking, language, personality, impulse control; contains motor cortex
Parietal—somatosensory cortex
Occipital—primary function is visual (right occipital lobe-left visual field and vice-versa)
Temporal—key role in hearing; also involved in hallucinations

45. Another diagram of the brain’s lobes

46. The prefrontal cortex in close-up
Phineas Gage: His accident led to major personality changes
Prefrontal cortex: brain region particularly concerned with social phenomena (e.g., following norms). Patients with injury to this region often have profound disturbances in their ability to get along with others
Lobotomy: deliberate damaging of the prefrontal cortex; used in the late 1940s early 1950s
Left patients lethargic and emotionally flat, and much easier to manage in mental hospitals, but it also left them disconnected from their social surroundings

47. Left vs. right hemisphere
Left hemisphere: in general, the verbal hemisphere that specializes in speech and other verbal tasks
Right hemisphere: specializes in controlling certain motor movements; comprehension and communication of emotion

48. The Brain and Speech
Broca’s aphasia: results from damage to Broca’s area in the primary motor cortex. People with this can’t find the words they want to express themselves.
Wernicke’s aphasia: Wernicke’s area is in the temporal lobe. Damage produces inability to recognize speech, understand speech, and convert thought into words.

49. Broca’s and Wernicke’s
Here is a You Tube video showing two patients suffering from Wernicke’s and Broca’s aphasia.

50. Brain plasticity
Ability of the brain to change with experience—both positive and negative experiences (learning new languages, doing drugs, traumatic brain injury, etc.)
Brain can often regenerate lost functions as other areas of the brain take over.