Course Introduction: The Brain, chemistry, neural signalingOverviewInstructor AccessThe Neural Theory of Language and ThoughtSlide 5Slide 6Slide 7Single Cell (Protozoan) BehaviorsSlide 10Earliest Nervous SystemsSlide 13Neural ProcessingSlide 15Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Brains ~ ComputersSlide 23Slide 24Slide 25Slide 26Slide 27Neural Communication: 1 Communication within the cellTransmission of informationThe MembraneThe Resting PotentialSlide 33Ions and the Resting PotentialSlide 35Maintaining the Resting PotentialNeuronal firing: the action potentialBefore DepolarizationAction potentials: Rapid depolarizationDepolarizationSlide 41Action potentials: RepolarizationRepolarizationSlide 44The Action PotentialSlide 47Action PotentialConduction of the action potential.MyelinationSaltatory ConductionSynaptic transmissionStructure of the synapseSlide 55Slide 56Slide 57Ionotropic receptors (ligand gated)Ionotropic ReceptorsMetabotropic Receptors (G-Protein)Excitatory postsynaptic potentials (EPSPs)Inhibitory postsynaptic potentials (IPSPs)Postsynaptic Ion motionRequirements at the synapseIntegration of informationThree Nobel Prize Winners on Synaptic TransmissionSlide 69How does it all work?Course Introduction: The Brain, chemistry, neural signalingSrini NarayananCS182/Ling109/CogSci110Spring [email protected]Course introduction Neural Processing: Basic IssuesNeural Communication: BasicsInstructor AccessInstructor : Srini NarayananOffice Hours : Tuesday 2 - 3Email : [email protected]TA: Joseph MakinOffice Hours :Email : [email protected]TA: Johno BryantOffice Hours:Email : [email protected] Neural Theory of Language and ThoughtThis is a course on the current status of interdisciplinary studies that seek to answer the following questions: How is it possible for the human brain, which is a highly structured network of neurons, to think and to learn, use, and understand language? How are language and thought related to perception, motor control, and our other neural systems, including social cognition? How do the computational properties of neural systems and the specific neural structures of the human brain shape the nature of thought and language? What are the applications of neural computing?ScheduleLearningI hear and I forgetI see and I rememberI do and I understand attributed to Confucius 551-479 B.C.Tinbergen’s Four QuestionsHow does it work?How does it improve fitness?How does it develop and adapt?How did it evolve?Single Cell (Protozoan) BehaviorsNo Nervous SystemForaging Behavior (swim toward food)Positive chemotaxisDefensive/Avodiance BehaviorNegative chemotaxisReproductionAsexual and Sexual reproduction using chemical messenger proteins (pheromones)Earliest Nervous SystemsHydra, jellyfish, corals, sea anemonesBasic neural cell (Neuron)Early differentiation into 3 types of neuronsSTIMULUSSensoryNeuronInter-NeuronMotorNeuronEffectorOverviewCourse introduction Neural Processing: BasicsNeural Communication: BasicsNeural ProcessingNeurons•cell body•dendrites (input structure)receive inputs from other neuronsperform spatio-temporal integration of inputsrelay them to the cell body•axon (output structure)a fiber that carries messages (spikes) from the cell to dendrites of other neuronspostsynapticneuronscience-education.nih.govSynapse•site of communication between two cells•formed when an axon of a presynaptic cell “connects” with the dendrites of a postsynaptic cellSynapseaxon of presynapticneurondendrite ofpostsynapticneuronbipolar.about.com/librarySynapse•a synapse can be excitatory or inhibitory•arrival of activity at an excitatory synapse depolarizes the local membrane potential of the postsynaptic cell and makes the cell more prone to firing• arrival of activity at an inhibitory synapse hyperpolarizes the local membrane potential of the postsynaptic cell and makes it less prone to firing•the greater the synaptic strength, the greater the depolarization or hyperpolarizationUNIPOLAR BIPOLARMULTIPOLAR CELLSBrains ~ Computers1000 operations/sec100,000,000,000 units10,000 connections/graded, stochasticembodiedfault tolerantevolves, learns1,000,000,000 ops/sec1-100 processors~ 4 connectionsbinary, deterministicabstractcrashesdesigned, programmedBroca’sareaParsopercularisMotor cortex Somatosensory cortexSensory associativecortexPrimaryAuditory cortexWernicke’sareaVisual associativecortexVisualcortexPET scan of blood flow for 4 word tasksSomatotopy of Action ObservationSomatotopy of Action ObservationFoot ActionFoot ActionHand ActionHand ActionMouth ActionMouth ActionBuccino et al. Eur J Neurosci 2001Neural Communication: 1 Communication within the cellTransmission of informationInformation must be transmittedwithin each neuronand between neuronsThe MembraneThe membrane surrounds the neuron.It is composed of lipid and protein.The Resting PotentialThere is an electrical charge across the membrane.This is the membrane potential.The resting potential (when the cell is not firing) is a 70mV difference between the inside and the outside. insideoutsideResting potential of neuron = -70mV+-+-+-+-+-Artist’s rendition of a typical cell membraneIons and the Resting PotentialIons are electrically-charged molecules e.g. sodium (Na+), potassium (K+), chloride (Cl-).The resting potential exists because ions are concentrated on different sides of the membrane.Na+ and Cl- outside the cell.K+ and organic anions inside the cell. insideoutsideNa+Cl-Na+K+Cl-K+Organic anions (-)Na+Na+Organic anions (-)Organic anions (-)Ions and the Resting PotentialIons are electrically-charged molecules e.g. sodium (Na+), potassium (K+), chloride (Cl-).The resting potential exists because ions are concentrated on different sides of the membrane.Na+ and Cl- outside the cell.K+ and organic anions inside the cell. insideoutsideNa+Cl-Na+K+Cl-K+Organic anions (-)Na+Na+Organic anions (-)Organic anions (-)Maintaining the Resting PotentialNa+ ions are actively transported (this uses energy) to maintain the resting potential.The sodium-potassium pump (a membrane protein) exchanges three Na+ ions for two K+ ions.insideoutsideNa+Na+K+K+Na+Neuronal firing: the action potentialThe action potential is a rapid depolarization of the membrane.It
View Full Document