Brain-computer interfaces: Input/Output vs Read/Write

From Neuromancer, to The Matrix and most recently Surrogates, Dollhouse and Avatar, brain-computer interfaces (BCI) have always been popular in science fiction. Frequently the depiction of this technology have a tendency to put a greater emphasis on “fiction” than on “science” by perpetuating the fundamentally flawed metaphor of the human brain as a hardware and software composite.

Unfortunately, the human brain is the farthest thing from a von-neumann computer (a.k.a. a stored-program computer) we could possibly imagine. Natural processes lead to the emergence of neuronal topology that then give rise to complex human behavior. Your mind is not your brain’s software – because in reality there is no software at all – information flows through the brain and computation happens naturally due to the physical properties of the neuronal pathways.

The key concept I want you to embrace is that your mind is fully described by the physical configuration of your brain. To “edit” your mind – for example, to implant a memory or instantly learn a skill – it would be necessary to either physically rewire your neurons or have your brain significantly augmented to support on-demand topology modification.

Input/Output interfaces are the most feasible in the short term

Right now we are only able to communicate with the brain by stimulating neurons (input) and measuring specific properties of neurons (output). There a lot of incredible things we can do using this approach, the key concept is to think in terms of what could be done using real-time input and output streams:

• Give people senses they don’t have (vision to the blind, GPS to the willing);
• Give people actuators they don’t have (arms to amputees, drive a car with your mind);
• Read active thoughts and intentions, including memories a person is actively conjuring;
• Give people artificial experiences using multi-sensorial stimulation;
• External knowledge databases (Google in your head);
• Ultimately, we could have an isolated brain with full-digital I/O, enabling for example, full-prosthetic bodies and disembodied living;

Science-fiction examples of I/O interfaces:

• The Matrix: the Matrix simulated world;
• Ghost in the Shell: full-prosthetic bodies, “the net”, external memories;
• Avatar and Surrogates: remote control of a prosthetic body;

Read/Write interfaces are possible but they will probably require advanced brain augmentation

There are things however, we might never be able to do using I/O interfaces because they require being able to read and modify the brain’s neuronal topology directly (read/write):

• Read a memory, without the subject actively conjuring it;
• Write a memory without generating an experience (“imprinting”);
• Significantly faster-than-real-time learning or instant knowledge transfer;
• “Editing” personality traits;

We currently lack significant understanding of how to address the challenge of building such R/W interface to the brain. First we would need significant advancements in neuroscience in order to learn how to design useful neuronal pathways. Secondly, we will need a few fundamental breakthroughs in nanofabrication and nanorobotics to gain the ability to manipulate matter with the degree of accuracy needed to make useful (and desirable) changes to a living human brain.

Science-fiction examples of R/W interfaces:

• The Matrix: instant learning through downloads;
• Ghost in the Shell: hacked memories, “puppet” agents;
• Dollhouse: personality imprints, “tabula rasa” programming;

Talking to the brain and altering the brain are two fundamentally different tasks

Although limited, I/O interfaces are the easiest to build. Even though every bit of information that enters the brain indirectly leads to neuronal topology change, the minutia and scope of these changes are not under our direct control. This means that there are fundamental limits of what we can do with I/O interfaces alone.

However, I/O brain-computer interfaces will significantly expand our mental landscape in the near term by adding new information streams to our conscious experience of the world. Yet, the dream of instant learning and mental imprints might never be achieved before we move on to considerably enhanced or artificial brains that provide easy R/W access to neuronal topology.

In other words, for the foreseeable future, you will not be downloading a kung-fu app into your brain. And when you are finally able to do so, you might not have what you currently call a brain anymore.