Functional MRI (fMRI): Mapping the Brain’s Activity and Connectivity
Have you ever paused to imagine what your brain looks like while you’re solving a tricky puzzle, recalling your very first day at school, or listening to your favourite song? For a long time, medical imaging methods such as CT scans or conventional MRI could only reveal the structure of the brain, including its size, shape, and the presence of any visible abnormalities. What they couldn’t do was reveal the brain in motion, the way it functions moment by moment.
This is where the functional MRI (fMRI) scan has been revolutionary. At Picture This by Jankharia, we often meet patients who arrive intrigued by what an fMRI brain scan can uncover. Some even ask if the scan can actually “read their thoughts.” While that is not the case, fMRI does something equally fascinating: it allows us to map both activity and connectivity within the living brain, giving us insights into how different regions interact while you think, speak, or move.
In this blog, we’ll see how functional MRI radiology works, why it is such an important tool in medicine and research, and what you should expect if you or a loved one is ever advised to undergo an fMRI.
What Exactly Is Functional MRI (fMRI)?
At its simplest, a functional MRI of the brain measures activity by detecting subtle changes in blood oxygen levels.
- When a particular area of the brain is active, it requires more oxygen to keep working efficiently, and blood flow to that region increases to meet the demand.
- The scanner can detect these small but significant shifts in oxygen levels, using what is known as the BOLD (Blood Oxygen Level-Dependent) signal, to highlight areas of activity.
- The result is a dynamic picture that shows which regions are “working harder” during different tasks or thought processes.
Think of it as switching on a spotlight in the brain, illuminating areas that come alive in response to specific actions or stimuli.
| Feature | MRI | fMRI |
| Purpose | Displays brain structure in precise detail | Shows brain function and connectivity in real time |
| What It Detects | Tumours, injuries, bleeding, and structural changes | Blood flow patterns, neural activity, and communication between regions |
| Common Use | Diagnosing strokes, trauma, tumours, and neurological changes | Pre-surgical mapping, neurological research, and understanding brain disorders |
| Duration | Typically 20–40 minutes | Generally 30–60 minutes |
| Patient Experience | Requires lying still inside the scanner, with no active tasks | Requires lying still, sometimes while performing tasks such as moving a finger or reading words |
At Picture This by Jankharia, we frequently combine both scans. This provides not only an anatomical view of the brain but also a functional map of its operation, which is invaluable for patient care.
How Does an fMRI Scan Work?
From a patient’s perspective, undergoing an fMRI scan feels very similar to a standard MRI, though the scientific process behind it is more intricate.
1. Preparation
- You will lie flat inside the MRI machine, much like in a conventional scan.
- In many cases, you will be asked to perform simple tasks, such as tapping your fingers, reading words, or imagining moving a part of your body, to activate different brain regions.
2. Data Collection
- As you complete these tasks, blood flow shifts in specific areas of the brain in response to increased demand for oxygen.
- The scanner detects these fluctuations in blood oxygenation, capturing them as detailed sets of signals.
3. Image Processing
- The computer software then processes these signals and translates them into colourful maps.
- These maps clearly show which areas of the brain were active during specific tasks, effectively allowing us to see the brain in action.
The result is a visualisation of the brain that doesn’t just show its physical form, but how its different regions light up and work together as you think, feel, and move.
Why is fMRI Important?
The importance of functional MRI radiology lies in the breadth of its applications in both clinical medicine and research.
1. Pre-Surgical Mapping
One of the most vital uses of fMRI is in preparing for brain surgery.
- If a tumour is located near a part of the brain that controls speech, language, or movement, fMRI allows surgeons to identify these critical regions with precision. This ensures they can plan surgery in a way that removes the tumour while preserving essential functions.
- For patients undergoing surgery for epilepsy, fMRI helps in pinpointing the areas where seizures begin, improving the likelihood of a successful outcome.
2. Studying Brain Disorders
fMRI is a valuable tool for understanding and tracking various neurological and psychiatric conditions.
- In Alzheimer’s disease, fMRI can reveal functional changes in the brain long before structural changes are visible.
- In conditions like depression and anxiety, researchers study connectivity differences that may explain why certain symptoms occur.
- In autism, fMRI has been used to explore how communication and social networks function differently compared to neurotypical brains.
3. Understanding Brain Connectivity
The brain works not as isolated units but as a highly connected network. fMRI enables us to study these connections (often called the connectome) by showing how activity in one area influences or relates to activity in another.
4. Research Into Human Behaviour
Beyond clinical applications, fMRI is also a powerful tool for exploring human thought and behaviour. It has been used in studies on decision-making, memory recall, and emotional processing, offering new perspectives on how we think, feel, and act.
What to Expect During an fMRI Brain Scan
Patients often ask me whether undergoing an fMRI feels very different from a regular MRI. While the overall experience is similar, there are a few important distinctions.
Similarities:
- You will be asked to lie flat and remain very still inside the scanner, just as with a conventional MRI.
- The procedure is entirely painless, with no injections required in most cases.
- fMRI, like standard MRI, uses strong magnetic fields rather than radiation, making it safe for most people.
Differences:
- Instead of simply lying passively, you may be asked to perform simple cognitive or motor tasks, such as moving your fingers, repeating words, or visualising an action. These tasks are designed to stimulate specific areas of the brain.
- The scanning session may last slightly longer than a routine MRI, usually between 30 and 60 minutes, depending on the complexity of the tasks.
- The results are also different, producing activity maps that highlight the functioning of the brain, not just its physical appearance.
Preparation Tips:
- It is advisable to wear loose, comfortable clothing without metal fastenings or accessories.
- Try to practise remaining still, as even small movements can blur the results and reduce accuracy.
- If you are claustrophobic or anxious about being in the scanner, let your radiologist know beforehand, as they can offer reassurance or adjustments to make the experience more comfortable.
The Future of fMRI
The story of fMRI is far from complete. Technological advances are making scans faster, sharper, and more insightful.
- Resting-state fMRI is now being used to study brain activity when a person is not performing any task, offering new insights into baseline brain function.
- Real-time fMRI (rt-fMRI) allows patients to see their brain activity live on a screen, which could be used to help them regulate their own emotional or pain responses.
- Artificial Intelligence (AI) is increasingly being integrated into analysis, enabling more accurate predictions of outcomes and more personalised treatment planning.
The future could see fMRI guiding not just brain surgery but also mental health treatments and early interventions for neurodegenerative disease.
Key Takeaways
- A functional MRI scan goes beyond anatomy, giving us maps of brain activity and connectivity.
- It plays a crucial role in surgical planning, understanding neurological and psychiatric disorders, and advancing brain research.
- For patients, the experience of fMRI is safe and similar to a standard MRI, though tasks may be required and scans may last a little longer.
- We use fMRI not just as a diagnostic tool, but as a window into how the brain works at its most fundamental level.
Conclusion
The human brain has long been called the most complex structure in the universe. For centuries, we could only study it after injury or by examining anatomy in isolation. Today, thanks to the functional MRI of the brain, we can see living thought in motion: the sparks of memory, the flow of language, the networks of emotion.
This is one of the most exciting frontiers in radiology. It allows doctors to perform safer surgeries, helps researchers uncover the mysteries of human behaviour, and empowers patients with a clearer understanding of their own health.
So, the next time you hear about an fMRI brain scan, think of it not as just another medical test but as a window into the very essence of what makes us human: our thoughts, our connections, and our ability to imagine, feel, and create.
Frequently Asked Questions
While both techniques use the same basic MRI technology, their purpose is quite different.
- Standard MRI produces highly detailed images of the brain’s structure, helping us detect physical abnormalities such as tumours, bleeding, or injury.
- fMRI, in contrast, measures changes in blood oxygenation to create a dynamic picture of brain activity, revealing which areas are active during different tasks or at rest.
When combined, they provide a complete view of the brain’s health, covering both structure and function.
Yes, in most cases, an fMRI is more expensive. This is because it requires longer scanning times, additional task-based sequences, advanced computer software, and specialised interpretation by experienced radiologists.
Costs vary based on:
- The city or healthcare setting (a hospital versus a diagnostic centre).
- The type of scan performed (a simple resting-state fMRI versus a task-based scan for surgery planning).
- Whether the scan is being carried out for research, diagnosis, or surgical guidance.
At Picture This by Jankharia, we often advise patients to view the cost in terms of value: fMRI provides information that can make surgery safer and treatment more precise, which in the long run can prevent complications and improve outcomes.
Some of the most frequent uses include:
- Brain tumours, to identify critical areas near the tumour before surgery.
- Epilepsy, to pinpoint the brain regions where seizures begin.
- Neurodegenerative diseases, such as Alzheimer’s, to detect functional decline early.
- Psychiatric research, in conditions such as depression or autism, is more research-based than clinical at present.
For most people, fMRI is entirely safe. Unlike X-rays or CT scans, it does not use radiation. However, there are a few considerations:
- People with certain metal implants, such as pacemakers, aneurysm clips, or cochlear implants, may not be able to undergo the scan.
- Some patients may experience claustrophobia inside the scanner, although strategies such as music, communication with the technician, or mild sedation can help.
- The scanner is naturally quite loud, but earplugs or headphones are provided to protect your hearing and make the experience more comfortable.
With appropriate screening beforehand, these issues are usually manageable.
Both fMRI and PET (Positron Emission Tomography) scans are used to study brain activity, but their methods are different.
- fMRI measures blood oxygen changes non-invasively, without the need for injections, and can be repeated many times without risk.
- PET scans involve injecting a radioactive tracer to study metabolism or detect abnormalities such as cancer or dementia.
fMRI is often preferred for neurological studies because it is safer and does not involve radiation, but PET remains important in certain conditions where metabolic information is required.
Not directly. While fMRI research has shown that conditions such as depression, schizophrenia, or PTSD often involve changes in brain connectivity, the technology is not yet used as a diagnostic tool in clinical psychiatry.
Instead, it helps researchers understand how these conditions affect the brain, and in the future, it may lead to personalised therapies that are guided by brain activity patterns.
