The Birth of Brain Cells
This might look like a distant web of galaxies captured by a powerful telescope, but it’s actually a microscopic image of a newborn nerve cell. The human brain contains more cells than there are stars in our galaxy, and the most important cells are neurons, which are nerve cells responsible for transmitting and processing electro-chemical signals at up to 320 km/h. This chemical signalling occurs through synapses—specialised connections with other cells, like wires in a computer. Each cell can receive input from thousands of others, so a typical neuron can have up to ten thousand synapses—i.e., can communicate with up to ten thousand other neurons, muscle cells, and glands. Estimates suggest that adult humans have approximately 100 billion neurons in their brain, but unlike most cells, neurons don’t undergo cell division, so if they’re damaged they don’t grow back—except, apparently, in the hippocampus (associated with memory) and the olfactory bulb (associated with sense of smell). The process by which this occurs is unclear, and this image was taken during a project to determine how neurons are born—it actually depicts newborn nerve cells in an adult mouse’s brain.
(Image Credit: Dana Bradford)