The minds of man and machine suffer from a glaring disconnect: The inability to interface directly with one another. We have to use our hands, keyboards, and mice to issue commands to our robotic minions and they can only respond via physical sensory mediums. But we can do better. We can use our minds. In fact, we already are.
Every minute of the day, whether awake or asleep, your brain fires off millions of minuscule electrical charges between neurons as it processes your thoughts and feelings. Each one of these thoughts activates the differing regions within the brain in specific and unique patterns, patterns that can be detected through your skull and scalp via the network of neural sensors that make up an electroencephalogram (EEG). This technology has the potential to radically alter our interactions with machines, giving us a sort of digital telepathy over everything from children's toys to military hardware to Maj. Kusanagi-level prosthetics. Consider this the first step towards the singularity.
What Is EEG and How Does It Work?
We first discovered that brains were electrified back in 1875, when British physician Richard Caton first opened the skulls of animal subjects and pressed two galvanometer leads onto their cerebral cortices and detected electrical impulses. This discovery set off a firestorm of interest leading, in 1924, to German neurologist Hans Berger's invention of the world's first electroencephalograph (EEG).
To understand how an EEG works, you need to understand brain waves. Here's the short version. The brain's electrical charge is the result of the movement of billions of charged particles through selective cellular membranes—that is as ions of sodium, potassium, calcium, and chloride are actively pumped across the membranes of individual neurons, they generate noticeable oscillations within the overall electrical state of the brain. This pumping action causes a cascade effect, wherein one neuron pumps ions into its neighbor, causing that neuron to activate and begin pumping ions into its neighbor, which activates the third neuron and it begins pumping ions into its neighbor, and so on. The jostling of ion particles resemble the wavelike movement of sound through a gas, and the pattern of firing neurons often resembles the motion of ocean waves—hence the term "brainwaves." And since these waves of activity carry electrical charges, they can be measured by a voltometer which, over time, generates an EEG reading.
The type, or shape, of brainwave generated depends on the state of the brain itself. When you're deep asleep, your brain forms delta waves. These occur about four times a second. Light sleep generates slightly faster theta waves that pop about six times a second. Alpha waves only occur when you're awake but relaxed, doing so about 10 times a second. But when you're focused and attentive, your brain creates beta waves, up to 40 per second. These are not mutually exclusive events, mind you, the brain routinely produces a harmony of waves, though one waveform always dominates.
To collect this electrical data, doctors employ a conventional EEG. This involves affixing a large number of electrodes—usually about 19 of them—to the patient's scalp using a conductive gel or paste. The leads may be placed individually or they may be affixed as a net or cap, which takes significantly less time to set up. These electrodes then sample the scalp's electrical activity thousands of times a second (up to 50 Hz in some clinical applications) and record any impulses that they detect. The impulses that these electrodes pick up are generally far too weak to be readable, so the signal has to first be diverted through a differential amp for a 100 dB boost (magnifying the signal a factor of 100,000) before being displayed and interpreted.
Mind Reading For Fun and Profit
The human brain is a massively complex organ, most of whose functions remain a mystery to medical science. But while scalp EEG can only show us the overall oscillations of brain activity between the various wave forms and brain functions (walking, for example, produces a different mix of waveforms than speaking or watching porn does), it's still both a valuable medical tool and an increasingly popular consumer product.
EEG has become a vital resource in diagnosing a variety of neurological disorders such as epilepsy since those afflicted by the disease exhibit abnormal baseline EEG readings. Additionally, EEG is routinely used to determine a patient's coma level (much like there are differing depths of sleep, there are differing depths of coma) or whether a patient qualifies as clinically brain dead.
And thanks to recent technical advances that have reduced the number of leads from nearly two dozen to as few as one, EEG technology has rapidly grown out of its medical community base and increasingly entered the consumer electronics market. Devices such as the Neurosky Mindwave, the Emotiv EPOC, the Interaxon Muse and even the Necomimi Brainwave Cat Ears all perform the same basic tasks as their clinical counterparts do, albeit in a much less refined manner, by interpreting the mix of wave forms as commands. The Necomimi for example, perk up when beta waves spike but flop over when alpha waves dominate.