Our understanding of the human brain has come a long way, particularly since the development of functional magnetic resonance imaging (fMRI) in the early 1990s. Unlike traditional MRI, which provides detailed images of the brain's structure, fMRI allows researchers to see which areas of the brain are more active during different tasks. It does this indirectly, by detecting changes in blood oxygenation associated with brain activity. Here are four important insights fMRI and other neuroimaging techniques have helped bring to light.

  1. A clearer map of how the brain works

Long before fMRI existed, scientists knew that certain areas of the brain played specific roles. In 1861, for example, French physician Paul Broca identified a connection between damage to a particular region of the brain and difficulties producing speech. The region would later become known as Broca's area.

Other discoveries followed, including the identification of brain regions involved in movement, touch and vision. However, much of this knowledge came from studying people with brain injuries or from experiments involving animals. The arrival of fMRI opened up new possibilities. For the first time, researchers could study the activity of different brain regions in healthy people, without surgery or other invasive procedures.

This helped them build more detailed maps of the brain, better understand how visual information is processed and explore how different regions work together when we move, perceive our surroundings or perform mental tasks.

  1. A brain that never stops adapting

For a long time, scientists believed that the brain became relatively fixed once we reached adulthood. Today, we know that this isn't the case. Our brains retain the ability to adapt and reorganize throughout life, a phenomenon known as neuroplasticity.

Every time we learn something new, practice a skill, or adapt to a new experience, our brain can change. Connections between neurons may become stronger or weaker, new connections may form, and others may disappear.

Neuroimaging has helped researchers observe some of the larger-scale changes associated with this process. Studies have shown, for instance, that learning and repeated practice can influence patterns of brain activity and, in some cases, even aspects of its physical structure.

This ability to adapt isn't limited to childhood. Although certain types of learning may become more challenging with age, our brains continue to change throughout adulthood, helping us acquire new skills and, to some extent, recover from injuries.

  1. A better understanding of thinking, learning and memory

How do we understand language, solve problems, remember information or make decisions?

These are some of the questions researchers have been exploring for decades. And while studying the brains of animals has provided valuable insights, certain aspects of human thinking are particularly difficult to investigate through animal research alone.

With fMRI, scientists can observe patterns of brain activity while people read, perform calculations, learn new information or carry out other mental tasks.

These observations have contributed to our understanding of how different brain regions participate in language, reasoning, memory and learning. They have also helped researchers investigate conditions such as dyslexia and dyscalculia, as well as neurological diseases that can lead to dementia.

Another fascinating area of research concerns consciousness. By comparing brain activity during wakefulness, sleep and different states of awareness, researchers are beginning to better understand what happens in our brains as our conscious experience changes.

There is still plenty we don't understand. Neuroimaging cannot read our thoughts, nor can it explain every aspect of how we learn or remember. But it has given researchers a valuable new way to explore these complex processes.

  1. The brain works as a network, not a collection of isolated regions

We often hear that one part of the brain controls language, another handles vision, and another is responsible for movement.

While there is some truth to this idea, the reality is considerably more complex.

Most of what we do, especially when it involves thinking, learning or making decisions, depends on several brain regions working together. Scientists had recognized the importance of communication between brain regions long before fMRI. However, neuroimaging has allowed them to explore these connections in much greater detail. Research shows that the brain relies on interconnected networks whose activity changes depending on what we're doing. Some of these networks are even active when we're resting, daydreaming, or simply letting our minds wander.

A single region can also participate in several networks, playing different roles depending on the situation. This doesn't mean that individual brain regions aren't specialized. Rather, it suggests that specialization and collaboration go hand in hand.

Instead of seeing the brain as a collection of separate departments, it may be more useful to think of it as a constantly communicating system, where different regions work together to make our thoughts, actions and experiences possible.

There's still much to discover

Neuroimaging has changed the way we study the brain, but it hasn't answered all our questions. It's worth remembering that fMRI doesn't measure neuronal activity directly. It detects changes in blood flow and oxygenation associated with that activity. And seeing a particular brain region become active doesn't necessarily tell us what someone is thinking or prove that the region is responsible for a specific function.

That's why researchers continue to combine neuroimaging with other methods to better understand what goes on inside our heads.

One thing is clear: the more we learn about the brain, the more we discover just how complex, adaptable and interconnected it really is.

Sources and further reading