The "Jennifer Aniston" Neuron

Recent research has shown that we may remember certain concepts, ideas, or people (such as "Bill Clinton" or "Jennifer Aniston" or my "grandmother") using a single neuron in the brain.  In other words, our memories are not holistically (or holigraphically) spread across the brain, but may be stored in very specific locations.

When we learn a new concept, it is temporarily stored as "short-term memory" by neurons in the center of the brain (in the hippocampus and related regions).  For example, the first time you saw "Jennifer Aniston" on TV, your hippocampus stored the "Jennifer Aniston" concept in your short-term memory.  Later, that memory was transferred to your higher brain (the cortex), which resembles an enormous switchboard of neurons.  It seems that the memory gets further refined into a pure concept over time, represented by fewer and fewer neurons, until it is represented by a single neuron.

This research has implications for how our genes can affect our personality.  If our mental concepts are stored all over the brain, it wouldn't be possible for our genes to exploit them.  But if our memories are consolidated and categorized (e.g. keep all memories of pretty girls stored in the same place), a genetic signal (or a boost of testosterone?) could affect how we use those memories.