Pixelating the Brain
- Department of Neurology and the Ernest Gallo Clinic and Research Center, University of California at San Francisco, Emeryville, California 94608, USA
This extract was created in the absence of an abstract.
This layer presents a great variety of forms and of sizes of cells. In general, the cells of which it is composed are more or less globular and much inferior in size to the large pyramid. But it is also possible to see, as did Golgi, who has recognized them before in man and higher mammals, a great number of fusiform cells and also true pyramids oriented in the same manner as the cells of the second and third layers.
—Santiago Ramon y Cajal (describing neuronal cell types in cortical layers 2 and 3)
Gene expression profiling provides a powerful tool for examining alterations in the state of a cell. First in yeast, and increasingly in more complex systems, expression profiling is providing a unique means of rapidly identifying specific genes whose expression is altered (Brown and Botstein 1999; Sorlie et al. 2001). Perhaps more importantly, it provides the means of gaining a broad perspective on changes that involve networks made up of many genes (Kim et al. 2001).
The central nervous system provides a unique set of challenges for the application of expression profiling technologies. First and foremost is the overwhelming number of cell types that are present in the brain. Each cell type makes up only a small fraction of the total, making it impossible to identify minority opinions with a simple polling strategy. …
