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The Brain and Behavior Outline

The Brain and Behavior 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: What does the signal do? Reflexes: A model Brain Organizing Principles and Functions. Functions.

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The Brain and Behavior Outline

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  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. 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

  4. Evolution • None • Nerve net • Segmented • Cephalization: an organizing principle (brain-mind correlation not always obvious!) • Kineses • Taxes • Reflexes

  5. Evolution

  6. Brain Structure

  7. Brain Structure

  8. Brain Structure DRUGS

  9. Evolution • None • Nerve net • Segmented • Cephalization: organizing principle + brain-function rel. • Kineses • Taxes • Reflexes

  10. Reflexes • Kinesis (potato bug) • Taxis (moth / maggot / fly / tick) • Reflex: (knee jerk) • Descartes 161 St. Germaine on the Seine • Pineal • Mechanist

  11. Reflexes • Braightenberg: Vehicles

  12. 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

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

  14. 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

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

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

  17. 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

  18. Action Potential

  19. Movement of a Signal

  20. Action Potential • Cell actions • Speed: Muller (light), Helmholtz (43 m/sec) • Refractoriness • All or none law • Coding of intensity: analog-digital + recruitment (organizing principle)

  21. Neuron Communication • Propagation is much faster if the axon is myelinated: • Depolarization proceeds down the axon by a number of skips or jumps. • The action potential obeys the all-or-none law: • Once it’s launched, further increases in stimulus intensity have no effect on its magnitude.

  22. Neuron Communication • Propagation is much faster if the axon is myelinated: • Depolarization proceeds down the axon by a number of skips or jumps. • The action potential obeys the all-or-none law: • Once it’s launched, further increases in stimulus intensity have no effect on its magnitude. • Frequency signals intensity

  23. 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

  24. 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

  25. Synapses

  26. Release of Neurotransmitter

  27. Synapses

  28. 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

  29. A Model for building behavior out of simple building blocks • Reflexes • Voting behavior • Mirror neurons • Other examples to follow

  30. Reflexes: A model

  31. 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

  32. Brain Structure (midline)

  33. Structure: Central Core

  34. Structure: X-Ray View

  35. 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

  36. 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

  37. CT scan MRI scan

  38. 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)

  39. 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)

  40. Homunculus Map of Human Cortex

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