PSY100H1 Lecture Notes - Lecture 6: Axon Hillock, Inferior Colliculus, Superior Colliculus
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PSY100H1 Full Course Notes
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Neurons: particular cells in the brain (around 84-100 billion) Cognitive/psychological functions don"t derive from single neutron, but from networks of neurons. Myelin: insulates/coats axon; prevents signals in adjacent cells from interfering with each other; reduces resistance (speeding up conduction of neural impulses) White = myelinated axons (white because myelin"s fat is white) Action potential: wave of electrical activity originating at base of axon (axon hillock); rapidly travels down it"s length (pg. Concentration gradient: there are different amounts of ions (charged particle) inside/outside cell. Electrostatic gradient: inside and outside of cell differ in charge. Neuron"s firing threshold = -55mv (neuron explodes and sends message) Ion channels: allow ions to flow in and out of cell, changing its polarity/charge/potential. Depolarization: getting more positive/less negative (up to +35mv) Repolarization: ion channels close, get"s negative once again (overshoots -> refractory period) Refractory period: after repolarization (no action potential possible during this period)
