Lecture 5Outline of Last Lecture I. Why study the Brain?II. Cognitive Sciencea. 1970’sb. David Marri. Computationalii. Algorithmiciii. Implementation III. YouTube Clipsa. Loosing Who You Are The Frontal Lobes: Cognition and Awareness b. Traumatic Brain Injuries: Effects of Damage to Different Lobes of the BrainIV. From Stimulus to ResponseOutline of Current Lecture I. Review of Brain Structures and Functions a. Neuronal Information Transmissioni. Parts of a Neuronii. Examples of Neuronsiii. Action Potentialsb. Learning in the Brainc. Facts about the Human BrainCurrent LectureI. Review of Brain Structures and Functionsa. Neuronal Information Transmissioni. Parts of a Neuron (see diagram at bottom of notes)1. Cell Body2. Soma: central part of the body3. Axon: contacts other neurons4. Terminal Button: endings of the axon5. Dendrites: branch extension of a nerve cell6. Dendritic Spines: storage site for synaptic ii. Examples of Neurons1. Neurons all have the same basic structure, but may vary in overall appearance a. Chandelier Cellsb. Purkinje Cell or Cerebellar Cortexc. Pyramidal Neuron of Neo-cortexiii. Action Potentials (see diagram at bottom of notes)1. A neuron normally has a resting potential of -70 mV PSY 2601 1st Edition2. If sufficient depolarization occurs, an action potential is generated3. Information Transmissiona. Action Potential travels down axon of presynaptic neuronb. Neurotransmitter is released into synaptic clefc. Neurotransmitter binds with receptors on postsynaptic neurond. Ions flow into the postsynaptic cells, generating a postsynaptic potentiale. An excitatory postsynaptic potential may cause an action potential (a spike) to be generated in the axonf. An inhibitory postsynaptic potential may prevent the cell from firing a spikeb. Learning in the Braini. A synapse is repeatedly stimulatedii. Dendritic receptors are releasediii. Neurotransmitters are releasediv. A link between neurons formsv. The consequence1. The next time a stimulus leads to action potential in first (presynaptic) neuron, it will more reliably lead to an action potential in the second (postsynaptic) neuron2. A long-term change in responding has occurred3. Learning has occurred4. “Long-term potentiation”c. Facts about the Human Braini. 100 billion neuronsii. ~60 trillion synapse (or more)iii. Lose about 85,000 neurons/day (~1/sec)iv. Uses about 20% of total resting oxygenv. 10,000 taste budsvi. 12,000,000 olfactory receptors (dog: 1 billion)vii. 5-6 million cones; 130 million rodsviii. 30,000 fibers in auditory nerve ix. 17,000 tactile receptors/hand x. 1,300-1,400grams (3lbs.); (2,500 cm, 2.5f)1. Newborn: 350-400grams2. Cow: 440grams3. Goldfish: 0.1grams4. Elephant: 6,000grams (13lbs)Parts of a Neuron DiagramAction