Does Each Neuron in the Human Brain Serve a Particular Purpose?

As they strive to explain how the brain's memory functions work, neuroscientists are zeroing in on the hippocampus, the part of the brain that is crucial to the formation of long-term memories. Since 2005, much neuroscience research has focused on image recognition of well-known people, such as Jennifer Aniston or Bill Clinton, and whether visual memories associated with those images cause hyper-specific neurons in the brain to fire.

More recent studies have tried to explain the relationship between these "Jennifer Aniston neurons" and episodic memory, which is how our brains catalog autobiographical events. The hope is that one day neuroscientists will know how to prevent, or reverse, memory loss in patients with Alzheimer's disease or traumatic brain injury.

More on neurons and long-term memory:

• For a number of patients, various pictures of Jennifer Aniston elicited responses from a single neuron inside the medial temporal lobe. But images of her with Brad Pitt did not register.
• At the most recent estimate, the brain contains about 86 billion neurons, so there's plenty of room for a person's memories and associations.
• In the 1960s, neuroscientist Jerry Lettvin suggested that a single neuron may be keyed to a single concept, such as a grandmother -- the so-called “grandmother cells” -- but the idea was rejected for being too simplistic.