Functional MRI (fMRI) is a powerful tool for pre-surgical planning—but it’s only as useful as the paradigms you choose. Different tasks, or paradigms, can be designed to activate specific brain regions or networks. Depending on the location of the lesion or the surgeon’s concerns, the operator must select the appropriate tasks to map language, motor, visual, auditory or even memory functions.
Functional MRI (fMRI) is a powerful tool for pre-surgical planning—but it’s only as useful as the paradigms you choose.
Different tasks, or paradigms, can be designed to activate specific brain regions or networks. Depending on the location of the lesion or the surgeon’s concerns, the operator must select the appropriate tasks to map language, motor, visual, auditory or even memory functions.
This blog post outlines the most commonly used clinical fMRI paradigms and explains when and how to use them. Whether you're new to fMRI or looking to refine your workflow, this is a helpful guide to choosing the right paradigm for each patient.
1. Language Mapping Paradigms
Typically used when:
• Lesions are near Broca’s (language production) or Wernicke’s (language comprehension) areas
• The surgeon is assessing the laterality of language function in a patient to assess the risk of surgery
• The surgeon needs to avoid disrupting speech or comprehension areas on the path to resection of pathological tissue
Common paradigms:
• Sentence completion
• Silent word generation
• Verb generation
• Picture naming (for patients with reading difficulties or language barriers)
• Story listening (for patients with reading difficulties or vision impairments)
nordicAktiva includes a wide range of language paradigms in many languages, for both adult and pediatric populations. Both active (e.g., word generation) and passive (e.g., story listening) tasks can be selected according to the patient’s needs. Furthermore, nordicAktiva allows easy customization of paradigm content and timing to suit different patient capabilities.
2. Motor Mapping Paradigms
Typically used when:
• Lesions are near primary motor cortex
• The patient may be at risk of motor function loss due to the route the surgeon will take to resecting pathological brain tissue
Common paradigms:
• Finger tapping (left, right, bilateral)
• Foot tapping (left, right, bilateral)
• Tongue or lip movement
Paradigms should be simple and repetitive.
3. Visual Cortex Mapping
Typically used when:
• Tumors are near the occipital lobe
• Surgeons need to avoid visual field disruption
Common paradigms:
• Flickering checkerboard
These paradigms require clear, high-contrast visual delivery—best achieved with solutions like the InRoomViewingDevice or the VisualSystem HD (VSHD) for clarity.
4. Auditory Cortex Mapping
Used when:
• Tumors are near the primary auditory cortex
• The patient may be at risk of auditory function loss due to the route the surgeon will take to resecting pathological brain tissue
• Descrimination between the neighbouring areas for language comprehension and auditory processing is required for assessing risks
Common paradigms:
• Auditory Tones
The delivery of clear audio content during image acquisition is a significant challenge due to the noise of the scanner. High quality sound with noise cancellation, such as that provided by nordicAudio, can be an enabler not only for auditory cortex mapping, but also for language fMRI in patients with visual impairments or reading difficulties!
5. Memory function – Mapping of hippocampal activation
Used when:
• Surgical targets for resection are near areas of the brain responsible for memory functions, such as the hippocampus.
• Surgeons require information on the laterality of memory function to inform a risk assessment prior to epilepsy surgery
• Temporal lobe resection may affect patient’s verbal or visual memory
Common paradigms:
• Hometown Walking
• Scene-object association (visual or verbal)
Mapping of hippocampal function as a technique is not as well established as mapping of the other functions discussed above. Patient compliance and consistency of results are somewhat more challenging. As such, this has not yet become a clinical standard with widely accepted paradigms. More research is needed to determine the most robust approach to memory mapping.
6. Special Populations: Pediatrics, Stroke, or Impaired Patients
In these cases, paradigms must be:
• Shorter and more engaging, with more simplistic language
• Rely more on passive rather than active tasks
• Paired with tools that reduce stress and confusion, such as immersive visuals and noise cancelling headphones
Common paradigms:
• Passive story listening
• Passive movements performed by a comforter or carer in the room
• Simplified language paradigms such as Word Generation, Antonym Generation or RhymingMovie watching
nordicAktiva allows flexible customization of paradigm content and timings, to best suit the capabilities of each patient.
General considerations
• Think about whether the paradigm answers the clinical question. Always start by asking:What functions are at risk in this patient due to the proximity to the surgical target (tumour or epileptogenic focus)?
• Which areas may be at risk due to the path the surgeon needs to take towards the surgical target?
• Which tasks can this specific patient perform confidently and reliably?
From there, choose 2–3 paradigms that best target the areas of interest. The use of multiple tasks adds confidence—especially when they activate similar regions or networks.
Want to learn more?
In collaboration with ImagingU, we have developed an online course in the ‘Theory and Application of BOLD fMRI’.
It comprises 9 modules which will provide you with a total of 7.5 CE credits on completion!Click here to read more about the course and enroll now!
Link: https://nordicneurolab.imagingu.com/courses
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