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Anatomy of Memory
As you read this, chemical signals are zipping through your brain via structures like this snippet of a dendrite, spindly fingers that branch off from neurons and receive signals from other neurons at contact points called synapses (red and blue). The dendrites' thorny protrusions come in all shapes and sizes, and neuroscientists are busy trying to figure out what role these play in memory and learning. Researchers at Boston University created these dendrite reconstructions (about 9 micrometers long) by slicing rat hippocampus into thin sections, imaging them with an electron microscope, then reassembling the sections on computers. Their Synapse Web* site offers software for researchers also wishing to make reconstructions, along with a brain anatomy tutorial that zooms from micrographs of tissue slices and cells to virtual reality models of dendrites.