Neurons, Hormones, and the Brain

1. Neurons, Hormones, and the Brain

2. Study of the brain Neuropsychologists Study the brain and the rest of the nervous system in hopes of gaining a better understanding of behavior. Includes the study of the biological foundations of consciousness, perception, memory, emotion, stress, and mental disorders.

3. Nervous System Basic Anatomy

4. The central nervous system Brain and Spinal cord

5. Spinal reflexes Automatic behaviors that occur on their own, without any help from the brain Ex. pulling your hand away from a burning hot surface.

6. The peripheral nervous system Handles the central nervous system’s input and output Somatic nervous system Autonomic nervous system • Sympathetic nervous system • Parasympathetic nervous system

7. Organization of the nervous system

8. NEURONS

9. Neurons • The brain’s communication specialists, transmitting information to, from, and within the central nervous system Glial cells • Provide the neurons with nutrients, insulate them, protect the brain from toxic agents, and remove cellular debris when neurons die. • communicate chemically with each other and with neurons.

10. Structure of a neuron Dendrites Receive information from other neurons and transmit messages toward the cell body. Cell body Keeps the neuron alive and determines whether it should fire. Axon Transmits messages away from the cell body to other neurons, or to muscles or glands.

11. Myelin sheath • A fatty material that may surround the axon of a neuron • Speeds up the conduction of neural impulses

12. Types of neurons

13. Neurons in the news Neurogenesis The production of new neurons from immature stem cells Stem cells Immature cells that renew themselves and have the potential to develop into mature cells

14. Stem-cell research • Embryonic stem cells can differentiate into any kind of human cell. • In recent years, scientists have successfully reprogrammed cells from adult organs (skin cells), to become stem cells. These are called “induced pluripotent stem (IPS)” cells. • Patient-advocacy groups hope that transplanted stem cells will eventually help people recover from diseases of the brain (such as Parkinson’s) and from damage to the spinal cord and other parts of the body.

15. Action potential • A brief change in electrical voltage that occurs between the inside and outside of an axon when a neuron is stimulated • Produces an electric impulse that travels down the axon into the axon terminal and stimulates the release of neurotransmitters

17. Communication

18. How neurons communicate • Axon terminals release neurotransmitters from synaptic vesicles. • Neurotransmitters enter synapse. • Neurotransmitters bind to receptors that they fit.

19. Neurotransmitter • Chemical released by a transmitting neuron at the synapse that alters the activity of a receiving neuron

20. Major neurotransmitters • Serotonin - sleep, appetite, sensory perception, temperature regulation, pain suppression, and mood • Dopamine - voluntary movement, learning, memory, emotion, pleasure or reward, and, possibly, response to novelty • Acetylcholine – muscular action, cognitive functioning, memory and emotion – Alzheimer’s patients have a loss of brain cells that produce acetylcholine • Norepinephrine – increased heart rate, slowing of intestinal activity during stress, learning, memory, dreaming, waking, sleep and emotion • GABA (gamma aminobutyric acid) - major inhibitory neurotransmitter in the brain; abnormal levels linked to sleep and eating disorders • Glutamate - major excitatory neurotransmitter in the brain, and is released by about 90 percent of the brain’s neurons • Endorphins – reduce pain, promote pleasure

21. The endocrine system Endocrine glands release hormones into the bloodstream… …Hormones are chemical substances that affect the functioning of other organs.

22. Hormones Melatonin • Regulates daily biological rhythms and promotes sleep. Oxytocin • Facilitates lactation and, with vasopressin, facilitates bonding at birth. Adrenal hormones • Involved in emotions and stress Ex. Cortisol, epinephrine, and norepinephrine Sex hormones • Regulate development and functioning of reproductive organs, as well as secondary sexual characteristics in males and females. Ex. Androgens, estrogens, and progesterone

23. Which is correct? Which type of nervous-system chemical enables neurons to excite or inhibit each other? • Neurotransmitters • Endorphins • Hormones

24. Which is correct? Which type of nervous-system chemical affects functioning of target organs and tissues? • Neurotransmitters • Endorphins • Hormones

25. Mapping The Brain

26. Electroencephalogram (EEG) • A recording of neural activity detected by electrodes

27. Transcranial magnetic stimulation (TMS) Involves delivering an electrical current through a wire coil on a person’s head Can be used to • Produce motor responses • Temporarily inactivate an area of the brain • Treat depression (however the effectiveness of TMS for this use is unclear)

28. Active areas have increased blood flow. Different tasks show distinct activity patterns. Positron emission tomography A method for analyzing biochemical activity in the brain, using injections of a glucose-like substance containing a radioactive element

29. Magnetic fields produce vibrations in atoms. These signals are detected by special receivers. A computer turns them into pictures of the brain. Functional MRI (fMRI) accomplishes this at a much higher rate than MRI. Magnetic resonance imaging (MRI) Method for studying body and brain tissue

30. Anatomy of the Brain

31. The brain stem Pons Involved in sleeping, waking, and dreaming Medulla Responsible for certain automatic functions such as breathing and heart rate Reticular activating system Arouses cortex and screens incoming information

32. The cerebellum • Regulates movement and balance • Involved in remembering simple skills and acquired reflexes • Plays a part in: • Analyzing sensory information • Solving problems • Understanding words

33. The thalamus Relays sensory messages to the cerebral cortex Includes all sensory messages except those of smell, which are “processed” by the olfactory bulb

34. Hypothalamus and pituitary gland Involved in drives vital to survival Hunger, thirst, emotion, sex, and reproduction Controls the autonomic nervous system Pituitary gland Small endocrine gland which releases hormones and regulates other endocrine glands

35. The amygdala Responsible for Arousal Regulation of emotion Initial emotional response to sensory information Plays important role in Forming and retrieving emotional memories

36. The hippocampus Responsible for Storage of new information in memory Comparing sensory information with what the brain expects about the world Enabling us to form spatial memories for navigating the environment

37. The cerebrum • Largest brain structure • Two cerebral hemispheres connected by a bundle of nerve fibers called the corpus callosum • In charge of our higher forms of thinking • Surrounded by cerebral cortex, a collection of several thin layers of cells (gray matter)

38. Lobes of the cerebral cortex • Occipital lobes (visual cortex) • Parietal lobes (somatosensory cortex) • Temporal lobes Memory, perception, emotion, and auditory cortex Left lobe: Wernicke’s area 4. Frontal lobes Emotion, planning, creative thinking, initiating, and motor cortex Left lobe: Broca’s area

39. The Two Hemispheres Nearly all right-handed and the majority of left-handed individuals process language mainly in the left hemisphere. Many researchers believe in left-hemisphere dominance. Others insist right-hemisphere is important for spatial visual problem solving, comprehending non-verbal sounds, and some language abilities.

40. Where is the Self? • Modern brain scientists explain the mind or soul in physical terms as a product of the cerebral cortex. • Frontal lobes may play a critical role. • Many still question the relationship between subjective experience and physical processes of the brain.

41. “His” and “her” brains? Women have relatively larger areas of the frontal lobe and limbic system, whereas men have larger parts of the amygdala and parietal cortex. There do appear to be sex differences in lateralization of language. Males show left hemisphere activation only. Females show left and right hemisphere activation.

42. What do differences mean for behavior? Supposed differences are stereotypes. Brain difference does not necessarily explain behavior or performance. Sex differences in the brain could be the result rather than the cause of behavioral differences.