Synaptic specializations of dendrites

(Adapted from Fiala and Harris, 1999.)

An enlargement in a thinner dendrite associated with synaptic contacts Retinal amacrine cells
Filopodium A long, thin protrusion with a dense actin matrix and few internal organelles Normally only seen during development
Simple Spine: Sessile
Synaptic protrusions without a neck constriction

  • Stubby spine
  • Crook thorn

Pyramidal cells of cortex

Cerebellar dentate nucleus
Simple Spine: Pedunculated

Bulbous enlargement at tip

  • Thin spine
  • Mushroom spine
  • Gemmule

Pyramidal cells of cortex

Pyramidal cells of cortex

Olfactory bulb granule cell
Branched Spine
Each branch has a unique presynaptic partner and each branch has the shape characteristics of a simple spine CA1 pyramidal cells
Granule cells of dentate gyrus
Cerebellar Purkinje cells
Claw Ending
Synaptic protrusions at the tip of the dendrite associated with one or more glomeruli Granule cells of cerebellar cortex and dorsal cochlear nucleus
Brush Ending
Spray of complex dendritic protrusions at the end of dendrite that extends into glomerulus and contains presynaptic elements Unipolar brush cells of cerebellar cortex and dorsal cochlear nucleus
Thorny Excrescence
Densely lobed dendritic protrusion into a glomerulus Proximal dendrites of CA3 pyramidal cells and dentate gyrus mossy cells
Racemose Appendage
Twig-like branched dendritic appendages that contain synaptic varicosities and bulbous tips Inferior olive
Relay cells of lateral geniculate nucleus
Coralline Excrescence
Dendritic varicosity extending numerous thin protrusions, velamentous expansions and tendrils Cerebellar dentate nucleus
Lateral vestibular nucleus