What were neurons invented for? - cs.wellesley.educs125/slides/LAB1_Brain-Neurons-Spikes.pdf ·...

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What were neurons invented for?

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“To move things is all that mankind can do...for such the sole executant is muscle, whether in whispering a syllable or in felling a forest.”

Charles Sherrington 1924

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“Sensorimotorsystem”

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Sensors

Brain

Muscles

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Lab 1: Neurons and the Brain(and Matlab)

Neuroscience primer:Brain & neuronMembrane potentialAction potentialSynaptic transmission

• Lab part 1: Neurons in Matlab• Lab part 2: Brain in 3D Online

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SENSINGACTING!

The Brain

• Approximately 1011 neurons in a human brain• Approximately 1015 synapses connecting them

visualcortex

motor cortex(voluntary movement)

prefrontal cortex(planning;working memory)

brainstem(involuntary, reflexive behaviors)

cerebellum(movement coordination

movement learning)

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Neurons and synapses (~10-3 mm)

10 μm

Lab 1: Neurons and the Brain(and Matlab)

Neuroscience primer:Brain & neuronMembrane potentialAction potentialSynaptic transmission

• Lab part 1: Neurons in Matlab• Lab part 2: Brain in 3D Online

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Neurons send fast long-distance signals

Membranepotential:chargeimbalance

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+

-65mV

-

Theelectricalpropertiesofneuronsarewhatenablesthemtoregulateeveryaspectofbehavior.

Membranepotentialakamembranevoltageisthedifferencebetweentheelectricpotentialoutsidevs insidethecell:Vm=Vin– Vout

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Addingpluscharge(positivecurrent)insidethecellmakestheinsidelessnegativecomparedtotheoutside

16http://howmed.net/physiology/action-potential/

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Spikes!Firing rate = (number of spikes)/(time)

Excitation: higher firing rate Inhibition: lower firing rateand membrane is hyperpolarized

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http://www.rci.rutgers.edu/~uzwiak/AnatPhys/APFallLect18.html

Propagation

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Lab 1: Neurons and the Brain(and Matlab)

Neuroscience primer:Brain & neuronMembrane potentialAction potentialSynaptic transmission

• Lab part 1: Neurons in Matlab• Lab part 2: Brain in 3D Online

Neuron-to-neuron Synapse

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