Ectopic granule cells of the rat dentate gyrus.
Granule cells of the mammalian dentate gyrus normally form a discrete layer, and virtually all granule cells migrate to this location. Exceptional granule cells that are positioned incorrectly, in 'ectopic' locations, are rare. Although the characteristics of such ectopic granule cells appear similar in many respects to granule cells located in the granule cell layer, their rare occurrence has limited a full evaluation of their structure and function. More information about ectopic granule cells has been obtained by studying those that develop after experimental manipulations that increase their number. For example, after severe seizures, the number of ectopic granule cells located in the hilus increases dramatically. These experimentally-induced ectopic granule cells may not be equivalent to normal ectopic granule cells necessarily, but the vastly increased numbers have allowed much more information to be obtained. Remarkably, the granule cells that are positioned ectopically develop intrinsic properties and an axonal projection that are similar to granule cells that are located normally, i.e., in the granule cell layer. However, dendritic structure and synaptic structure/function appear to differ. These studies have provided new insight into a rare type of granule cell in the dentate gyrus, and the plastic characteristics of dentate granule cells that appear to depend on the location of the cell body.
Scharfman
Helen
H
Department of Pharmacology, Columbia University, New York, NY, USA. scharfmanh@helenhayeshosp.org
Goodman
Jeffrey
J
McCloskey
Daniel
D
D000818:Animals; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure; D064026:Calbindins; D002828:Choristoma / Q000503:physiopathology*; D003712:Dendrites / Q000502:physiology* / Q000648:ultrastructure; D018891:Dentate Gyrus / Q000166:cytology / Q000502:physiology*; D004827:Epilepsy / Q000503:physiopathology; D018398:Homeodomain Proteins / Q000378:metabolism; D009434:Neural Pathways / Q000166:cytology / Q000502:physiology*; D009473:Neuronal Plasticity / Q000502:physiology; D051381:Rats; D064030:S100 Calcium Binding Protein G / Q000378:metabolism; D009435:Synaptic Transmission / Q000502:physiology; D025521:Tumor Suppressor Proteins; D000098551:Prospero-Related Homeobox 1 Protein
D064026:Calbindins; D018398:Homeodomain Proteins; D064030:S100 Calcium Binding Protein G; D025521:Tumor Suppressor Proteins; D000098551:Prospero-Related Homeobox 1 Protein