Diversity in neurons
Recent studies have highlighted the enormous diversity among apparently similar classes of neurons. The “simple” retina has provided a useful model for these studies which show, for instance, that there are more than a dozen types of ganglion cells and two dozen types of amacrine cell. As a result, researchers believe that this is bad news for the micromodellers who are in the business of developing theories of brain function based on detailed cellular interactions between different types of cell, particularly since similar research in the hippocampus suggests that there are, for instance, up to 50 types of inhibitory interneuron and possibly many more based on other functional estimates. This new information, recently reviewed (see Current Biology1998;8:708–10), has been gained from experiments which allow simultaneous recording from large numbers of neurons using a microelectrode array system, and have shown that the retina displays the neat phenomenon of “tiling”—that is, where there is overlap at the edge of receptive fields for different neurons allowing some degree of redundancy. Redundancy may also be the explanation for the apparently very large diversity of neurons in the brain itself allowing several neurons to perform the same task and thereby explaining the discrepancy between apparent extensive neuronal loss without corresponding loss of function. While the authors suggest that such redundancy is considerably less in the retina, to a degree there must be some of the same effect as evidenced by the known widespread ganglion cell loss which occurs before field defects are detectable in chronic simple glaucoma and following panretinal photocoagulation for conditions such as diabetic retinopathy.
European Association for Vision and Eye Research (EVER) holds first meeting
The first meeting of the European Association for Vision …
