Dendritic spines form 'collars' in hippocampal granule cells.
A quantitative study of the distribution of dendritic spines was carried out in three orders of dendritic branches of granule cells from the dentate gyrus of the rat hippocampus. Golgi-stained preparations (7-19 neurones in each of seven rats) were analysed using computerized microscopy. Identification of spines and quantification of stem-spine geometry was performed using a segmentation algorithm and a line skeleton transformation of dendritic images. Analysis of data using the statistics of point processes revealed that, in all three branch orders, the distribution of visible spines along dendrites was not evenly random, but included dense clusters of spines surrounding the dendritic stem (spine 'collars'). Three-dimensional reconstructions from serial ultrathin sections have confirmed the presence of such spine groups. We speculate the spine collars represent a functional element in which associative synaptic plasticity is fostered by the proximity of individual synapses.
Rusakov
D A
DA
Department of Biology, The Open University, Milton Keynes, London, UK.
Stewart
M G
MG
Sojka
M
M
Richter-Levin
G
G
Bliss
T V
TV
D000818:Animals; D003712:Dendrites / Q000648:ultrastructure*; D006624:Hippocampus / Q000166:cytology* / Q000648:ultrastructure; D007091:Image Processing, Computer-Assisted; D008297:Male; D008854:Microscopy, Electron; D009474:Neurons / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D013269:Stochastic Processes