NROC61H3 Lecture 3: Lecture 3
Document Summary
An action potential in a central neuron is only triggered if a certain threshold is reached. Synaptic integration is a summation of all the synaptic inputs near the soma: dendrites are the principle sites for synaptic input and are responsible for delivering these inputs to the site of integration near soma. The dendritic spines have different morphological features; filopodia, thin, mushroom, stubby. Functional differences between these morphologies of the spines are not yet known. Passive properties of dendrites: cable theory- models how passive current flows along cylindrical neuronal process (axon and dendrites) using the garden water hose analogy. Internal resistance (ri)- ability for charges to spread through cell"s cytoplasm. Larger dendrites have less ri: membrane capacitance (cm)- ability for membrane to store charges, directionally proportional to area, inversely related to thickness. Larger dendrites have higher capacitance: membrane resistance. Ability of charges to move across membrane: higher membrane resistance leads to less ability to move across.
