The Brain and Behavior Outline

1. The Brain and BehaviorOutline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses: What does the signal do? • Reflexes: A model • Brain Organizing Principles and Functions

2. Functions • Communication • Coordination • Control • Cognition • Complexity

3. Brain Structure

4. Brain Structure DRUGS

5. Outline: Start With A Mechanistic View • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses: What does the signal do? • Reflexes: A model • Brain Organizing Principles and Functions

6. Evolution

7. Evolution • None • Nerve net • Segmented • Cephalization: an organizing principle • brain-mind correlation not always obvious! • Computer analogy (hardware/software) • Kineses • Taxes • Reflexes

8. Simple Behaviors • Kinesis (potato bug, jumping beans) • Taxes (moth / maggot / fly / tick) • Reflex: (knee jerk) • Descartes 1637 St. Germaine on the Seine • Pineal • Mechanist

9. “Synthetic Psychology”Ex. Phototaxis • Braightenberg: Vehicles

10. Outline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses • Reflexes: A model • Brain Organizing Principles and Functions

11. The Neuron • 100 billion with thousands of connections • Varied in size, shape, function • Function of neuron sending signals in real time (ex.) • What is the signal? - electrical / chemical

13. Outline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal originate? • Action Potential: How does a signal move? • Synapses • Reflexes: A model • Brain Organizing Principles and Functions

14. Origin of nerve signal • Function of neuron sending signals in real time (ex.) • What is the signal? - electrical / chemical

15. Generation • Two forces: • Electrical (ionic) • Chemical (concentration) • Give rise to steady-state voltage “resting potential” • Universal in cells

18. Action Potential

19. Outline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses • Reflexes: A model • Brain Organizing Principles and Functions

21. Movement of a Signal

23. Action Potential • Cell actions • Speed: Muller (light), Helmholtz (43 m/sec)--myelinization • Refractoriness • All or none law-above threshold all equal • Coding of intensity: frequency codes intensity + recruitment (organizing principle)

25. Outline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses • Reflexes: A model • Brain Organizing Principles and Functions

26. Synapses: What happens when signal reaches end of neuron? • Two types of actions - excitatory / inhibitory • Chemical model with multiple & functionally different neurotransmitters • Temporal & spatial summation

28. Synapses

29. Release of Neurotransmitter

31. Synapses

32. Outline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses • Reflexes: A model • Brain Organizing Principles and Functions

33. A Model for building behavior out of simple building blocks • Reflexes: • Building a model • Simple to complex • Voting behavior: • Competing inputs • Building complexity

35. Reflexes: A model

36. Outline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses • Reflexes: A model • Brain Organizing Principles and Functions

41. The Brain and BehaviorOutline • Functions • Evolution: structure and behavior • Basic Unit: The Neuron • Generation: How does a signal get started? • Action Potential: How does a signal move? • Synapses: What does the signal do? • Reflexes: A model • Brain Organizing Principles and Functions

42. Methods for studying the brain • Single-cell and population recordings • Animal studies • Surgical patient studies • Stimulation • Animal studies • Surgical patient studies • Damage • Animal lesions • Human injury • Human surgical lesions • Neuroimaging

43. Electroencephalogram (EEG) recording • Electrodes are placed on the surface of the scalp and record/amplify the electrical signal given off by the brain • Event Related Potentials (ERPs) are used to study how the brain responds to different stimuli or events

44. CT scan MRI scan

45. Measures changes in blood-oxygen-level-dependent (BOLD) activation Areas of the brain that are engaged more in a task, require oxygen rich blood Result show a very small but highly significant percent change in BOLD activation (the entire brain is active all the time) Functional Magnetic Resonance Imagingin (fMRI)

46. Connectivity measures Functional connectivity – uses resting-state fMRI data to chart cortical regions with temporal synchrony (correlation of activation patterns) Structural connectivity – measures the movement of water molecules to chart the white matter tracts (visualizing anatomy) Diffusion Tensor Imaging (DTI) Diffusion Spectrum Imaging (DSI)

47. Localization of Function • Different parts of the brain serve specialized functions • Sensory Information • Motor Control • Perception • Language • Planning and Social Cognition

48. Localization of Function

49. Localization/Topographic Projection

50. What does the homunculus tell us? • Localization of motor and sensory function • Topographical organization • Cortical representation related to function not mass