For eighteen years, Jan Scheuermann has been paralyzed from the neck down. She is six feet tall, and she spends all day and all night in a sophisticated, battery-powered wheelchair that cradles her--half sitting, half reclining--from head to toe. In effect, the chair has become an extension of her body. To navigate the world in it, Scheuermann manipulates a cork-tipped joystick with her chin. She can move in this way with remarkable agility, but her height, combined with the bulk of the chair and the unrelenting nature of gravity and matter, can limit her.

It's been more than a century since Spanish neuroanatomist Santiago Ramón y Cajal won the Nobel Prize for illustrating the way neurons allow you to walk, talk, think, and be. In the intervening hundred years, modern neuroscience hasn't progressed that much in how it distinguishes one kind of neuron from another. Sure, the microscopes are better, but brain cells are still primarily defined by two labor-intensive characteristics: how they look and how they fire. Which is why neuroscientists around the world are rushing to adopt new, more nuanced ways to characterize neurons. Sequencing technologies, for one, can reveal how cells with the same exact DNA turn their genes on or off in unique ways--and these methods are beginning to reveal that the brain is a more diverse forest of bristling nodes and branching energies than even Ramón y Cajal could have imagined.

In November of 2012, Jan Scheuermann did something she never thought she would do again: She fed herself a piece of chocolate. For the last decade Scheuermann, 54, has been a prisoner in her own body. She suffers from a mysterious degenerative disorder that attacks the nervous system, severing the connections between the brain and muscles. Now a quadriplegic, Scheuermann has no movement below her neck. She can't move her limbs, let alone grasp, move, or hold anything.

What the real monkey thinks, the virtual monkey does.