Dendritic Spines

Definition

Many types of neurons receive synaptic inputs on dendritic spines which are short protrusions of membrane composed of a bulbous “head” connected to the dendrite by a thin “stem” or “neck” (Yuste 2010). Although spines are typically small in size, they occur in high densities along dendrites and may compose 40–60 % of the total dendritic surface area. There are two straightforward methods for including spines in computational models of neurons without representing every spine explicitly.

Detailed Description

Spines are widely regarded to serve a biochemical function by providing an isolated compartment where highly localized calcium signals and subsequent reactions can occur. An electrical function was initially proposed by Rall who showed that the steady-state attenuation of a signal from the spine head to the dendrite could be expressed as V_SH/V_BI = 1 + R_SS/R_BI, where V_SH and V_BI are the voltages at the spine head and dendrite, respectively; R_SSis the spine stem...