The quest to understand the human brain entered a new dimension in the late nineteenth century, shaped by the neuron doctrine pioneered by Camillo Golgi and Santiago Ramón y Cajal. Cajal’s Nobel Prize in 1906 marked a watershed moment—the moment when the brain’s electrical and chemical communication networks were laid bare for all to see. It was a bold stride into the dark corridors of the mind; yet no one at the time could have foreseen that these very networks would one day become instruments for transcending humanity’s cognitive limits.

When Hans Berger recorded the first electroencephalogram (EEG) in 1924, he proved that brain activity could be observed directly. This was no mere technical achievement. It demonstrated that the mysterious boundary between thought and matter could be treated as something measurable—a phenomenon open to investigation rather than mere speculation. Berger’s instruments, perhaps for the first time in human history, cracked open a window through which the voice of the mind might be heard. Half a century later, in 1973, Jacques Vidal’s introduction of “brain-computer communication” to the academic world opened a door behind that window: the brain was no longer merely observed—it was becoming a channel of communication itself.

The experiments conducted in the early 2000s at Miguel Nicolelis’s laboratory at Duke University represented one of the most striking turning points along this historical trajectory. When monkeys learned to control robotic arms through brain implants, it sent a shockwave through the scientific community. These experiments revealed that the brain’s plasticity—its capacity to learn and adapt—was not confined to organic systems alone; it could build bridges to machines as well. The 2012 research published in Nature proved just how sturdy those bridges could become: through the BrainGate system, paralyzed patients could command robotic arms that moved with the force of thought. Limbs that had lain motionless for years were breathing new life, animated by a single intention of the mind.

The 2024 news that Neuralink had received FDA approval for human trials emerged as the most contentious link in this historical chain. While the development sparked widespread public fascination, it also carried with it a profound uncertainty—for the scope and outcomes of these trials remain, to this day, only sparingly disclosed. The fact that companies like Synchron, Paradromics, and others are racing to develop less invasive methods suggests that the competition in this field is not merely a technical race; it is, at its core, a struggle over how to redefine the boundaries of the human body.

Journeying into the Depths of BCI Systems: Signals, Limits, and Misconceptions

Brain-computer interfaces employ methods of varying depth to record brain activity. Invasive techniques offer high signal quality through intracortical electrodes, but they require surgical intervention and carry inherent risks. Semi-invasive electrocorticography (ECoG) stretches this balance a little further by working with electrodes placed on the brain’s surface. Non-invasive systems, using technologies like EEG and functional near-infrared spectroscopy (fNIRS), detect signals from outside the skull—safer, yes, but inevitably at the cost of resolution.

Yet…