Diversity of ganglion cells in the mouse retina: unsupervised morphological classification and its limits.
The dendritic structures of retinal ganglion cells in the mouse retina were visualized by particle-mediated transfer of DiI, microinjection of Lucifer yellow, or visualization of green fluorescent protein expressed in a transgenic strain. The cells were imaged in three dimensions and the morphologies of a series of 219 cells were analyzed quantitatively. A total of 26 parameters were studied and automated cluster analysis was carried out using the k-means methods. An effective clustering, judged by silhouette analysis, was achieved using three parameters: level of stratification, extent of the dendritic field, and density of branching. An 11-cluster solution is illustrated. The cells within each cluster are visibly similar along morphological dimensions other than those used statistically to form the clusters. They could often be matched to ganglion cell types defined by previous studies. For reasons that are discussed, however, this classification must remain provisional. Some steps toward more definitive methods of unsupervised classification are pointed out.
Kong
Jee-Hyun
JH
Howard Hughes Medical Institute, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02114, USA.
Fish
Daniel R
DR
Rockhill
Rebecca L
RL
Masland
Richard H
RH
D000596:Amino Acids / Q000378:metabolism; D000818:Animals; D002452:Cell Count / Q000379:methods; D048429:Cell Size; D003712:Dendrites; D049452:Green Fluorescent Proteins / Q000096:biosynthesis; D007546:Isoquinolines / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D012160:Retina / Q000166:cytology*; D012165:Retinal Ganglion Cells / Q000145:classification* / Q000166:cytology* / Q000378:metabolism
D000596:Amino Acids; D007546:Isoquinolines; C098463:dolaisoleucine; D049452:Green Fluorescent Proteins; C017475:lucifer yellow