Why can we recognize a familiar face so quickly, even in a crowd? At Harvard University in Cambridge, Massachusetts, Nancy Kanwisher, Josh McDermott, and Marvin Chun used functional MRI to investigate whether particular brain regions responded especially strongly to faces.

Their study, published on June 1, 1997, identified a region in the fusiform gyrus that responded more strongly to faces than to assorted everyday objects. They called it the fusiform face area.

The researchers tested alternative explanations, including whether the response reflected visual attention or a broader interest in living things. Their findings supported a specialization for face perception.

The breakthrough showed how neurotechnology could reveal functional organization within the living human brain. MRI was becoming more than a tool for locating injury or disease: it could help researchers investigate how the brain makes sense of the world.

Could an MRI scanner reveal more than the brain’s anatomy? At Massachusetts General Hospital in Massachusetts, Kenneth Kwong and colleagues used rapid MRI scanning to detect changes associated with brain activation.

Their study, published on June 15, 1992, showed that visual stimulation produced measurable changes in the visual cortex. The technique exploited changes in blood oxygenation and flow accompanying neural activity, without requiring an injected contrast agent.

Alongside independent work by other research groups, these experiments helped establish functional magnetic resonance imaging, or fMRI. Researchers could now investigate which brain regions responded during particular tasks, using repeated scans of the living brain.

The images did not directly photograph thoughts or individual neurons firing. They measured a physiological response associated with neural activity, creating a powerful new tool for studying human brain function.

What if surgeons could suppress tremor without permanently destroying brain tissue? In Grenoble, France, neurosurgeon Alim-Louis Benabid and neurologist Pierre Pollak investigated electrical stimulation of the thalamus in people with severe tremor.

In 1987, their team reported combining a surgical lesion on one side of the brain with continuous stimulation on the other. High-frequency stimulation could suppress tremor through an implanted electrode connected to a pulse generator.

Crucially, the stimulation could be adjusted or switched off. The work helped establish modern deep brain stimulation as an alternative to destructive surgery.

Later developments extended the approach to other brain targets and additional symptoms of Parkinson’s disease. The breakthrough introduced a way to influence malfunctioning brain circuits through controlled, adjustable electrical stimulation.

Could a magnetic field make a hand move without touching the brain? At the University of Sheffield in England, Anthony Barker, Reza Jalinous, and Ian Freeston developed a device that delivered a brief magnetic pulse through a coil held above the head.

The pulse induced an electrical current in the motor cortex, producing a muscle response without surgery. Their report, published in The Lancet on May 11, 1985, demonstrated non-invasive magnetic stimulation of the human motor cortex.

Transcranial magnetic stimulation gave researchers a new way to investigate the pathways connecting brain and muscle. Instead of simply recording activity, they could briefly stimulate a brain region and measure its effects.

The demonstration helped establish a new branch of neurotechnology. Later developments brought applications in brain research and treatments such as repetitive TMS for depression.

Instead of amplifying sound, what if a device could speak directly to the nervous system? Modern cochlear implants convert sound into electrical signals that stimulate the auditory nerve, allowing many profoundly deaf people to perceive speech. They demonstrated that technology could successfully replace part of a damaged sensory system. Cochlear implants remain one of neurotechnology’s greatest clinical successes.

What if doctors could see the brain without using ionizing radiation? Magnetic resonance imaging (MRI) answered that question by using powerful magnets and radio waves to produce exceptionally detailed images of soft tissue. MRI rapidly became one of medicine’s most important diagnostic tools. Today’s structural and functional brain imaging depends on the technologies pioneered through MRI.