Designing fNIRS Studies in Real-World Environments
Designing fNIRS Studies in Real-World Environments
Science that Needs to Leave the Lab to Exist
(First-Person Consciousness • Decolonial Neuroscience • Brain Bee • Feeling and Knowing Taá)
Feeling and Knowing Taá — when the city becomes the lab
I imagine the optodes on my head, but this time I’m not in a silent, dim, air-conditioned room.
I’m crossing a noisy avenue, dodging people, feeling the sun on my face, the heart beating a bit faster as I hurry to the other side.
If I were only looking at the fNIRS trace, I would see:
slow waves of O₂-Hb and HHb,
motion artifacts when my foot hits the ground,
big systemic changes from heart and breathing,
tiny, fragile cognitive effects trying to emerge in the middle of this biological chaos.
Inside, Taá — my feeling-before-knowing — says:
“This is how life really is.
If our science cannot measure my brain here, in the middle of all this, maybe what is wrong is not my body — it’s the way we designed the experiment.”
I also notice how my language was colonized by the lab.
On the street, everything that makes my life alive – noise, movement, heat, birds, motorbikes – the traditional fNIRS pipeline calls “noise”.
The “clean signal” is what happens when I’m immobilized, almost abstracted from the world.
That’s the seed of this blog:
How do we design fNIRS studies that respect real life instead of trying to erase it?
The study and why it matters
Recent methodological work on mobile / naturalistic fNIRS asks exactly this:
how to design experiments outside the classic lab that still allow rigorous GLM analysis, reliable HRF estimation and meaningful statistical modelling.
I’m thinking of the family of papers you’ll find by searching expressions like:
“fNIRS naturalistic environment experimental design”
“mobile fNIRS ecological validity NeuroImage”
“real-world fNIRS motion-robust GLM short-channels”
These articles converge on one big point:
If we want fNIRS to say something real about education, rehabilitation, sports, urban life and inequality in Latin America, it has to learn to walk on the street with us.
The scientific question
In plain Brain Bee language, the core questions are:
How do we design tasks for fNIRS in real-world environments
(classroom, street, therapy, sports, daily activities)
so that we can still say this part of the hemodynamic signal is cognitive,
and that part is physiology, posture, or environment?What must change in the classic lab pipeline
(GLM, HRF, preprocessing)
when people are moving, talking, sweating, looking around, interacting?What is the minimum set of controls
(short-channels, motion sensors, baselines, triggers)
that makes a “messy” ecological experiment scientifically trustworthy?
Methods and analysis — beyond the silent chair
Across these methodological fNIRS papers, I see some common pillars:
1. GLM adapted to the real world
Still using General Linear Models (GLM),
but with more flexible regressors:
variable trial duration,
event-related and block-design mixed,
nuisance regressors for motion, heart rate, breathing.
Sometimes adding data-driven HRF shapes instead of a rigid canonical HRF.
2. Short-channels as “skin and skull sensors”
Short-distance channels (8–10 mm) near each optode cluster
to capture scalp blood flow and systemic effects.These signals enter the GLM as regressors to subtract extracortical noise
from the long-channel cortical signal.
3. ICA / PCA in a kind of “fNIRS x-ray”
Principal Component Analysis (PCA)
to identify global trends (like blood pressure swings and posture shifts).Independent Component Analysis (ICA)
to isolate clear motion artifacts and systemic components.Components are then regressed out before final GLM.
4. Motion and environment tracking
Use of accelerometers and gyroscopes on the head cap to model movement.
Sometimes video or event markers to sync behavioral events with fNIRS data.
5. HRF in context
Estimating the Hemodynamic Response Function (HRF) separately
for each task type and even for each environment,
acknowledging that a prefrontal HRF during quiet reading
is different from a prefrontal HRF during walking or therapy.
All of this is still Brain Bee-friendly: we’re asking
how to keep the math honest while accepting that life is messy.
The Feeling-and-Knowing Taá — opening a decolonial crack
When I look at these “real-world fNIRS” designs, I feel something important:
I also notice how my scientific training tried to make me believe that only the lab is “real science”.
That field recordings in schools, riverside communities or rehabilitation centers are “less pure” because they are full of noise, culture, affect and politics.
But when Taá wakes up in my body, I notice another truth:
The lab is also a kind of fiction:
a very specific, WEIRD way of organizing time, silence and control.
Here, a decolonial intuition appears in me:
Many neuroscientists simply avoid designing experiments that could show what the colonial lens does not know how to name – spirituality, community, territory, inequality.
As long as we keep the lab as the only “proper” place for cognition,
we keep ignoring most of the cognitive life of non-WEIRD peoples.
In this sense, real-world fNIRS design is not only a technical move.
It is a political-spiritual move:
bringing Neuroscience, Politics and Spirituality back into the same body,
where spirituality is not dogma, but Utupe / Xapiri –
semantic, living memory encarnated in gestures, gazes and shared rhythms.
Reading this through our concepts
When I read these design proposals, my own framework wakes up:
Mente Damasiana
The Damasian mind needs interoception + proprioception + environment.
If we study only the motionless subject in the chair,
we amputate half of this mind.Quorum Sensing Humano (QSH)
Real-world fNIRS is perfect for capturing QSH:
children in a circle, therapist and patient walking, group learning.
Synchrony is no longer just “noise” — it is a social vital sign.Zona 1 / Zona 2 / Zona 3
Zona 1: automatic routines of the city (commuting, work).
Zona 2: moments of fruição, creative attention emerging in real interactions.
Zona 3: ideological, algorithmic and architectural capture of our bodies.
A good ecological fNIRS design can map these transitions in the wild.DANA
DANA, the intelligence of DNA, organizes how our bodies adapt to heat, noise, altitude, rhythm.
To understand DANA, we must measure in the environments where DANA actually works.Yãy hã mĩy (always naming its Maxakali origin)
In each real-world experiment, there is an implicit “imitation-to-become”:
the participant imitates walking, working, playing, believing —
Yãy hã mĩy as extended imitation guiding how the brain recruits circuits.Avatares Referências
In this topic, I feel especially guided by the Math/Hep avatar
(the avatar of tense connections, statistics and energetic balance),
because everything depends on how we model variance and control.
But the Olmeca avatar is equally present, reminding me that
culture is not noise — it is part of the signal.
Where science corrects our ideas
Before reading these methodological proposals,
I could be tempted to say:
“The more controlled the task, the better the science.”
Now I see a correction:
Too much control kills ecological validity.
Too little control kills interpretability.
Real-world fNIRS design forces us to inhabit this tension creatively,
like an indigenous bricoleur in the sense of Lévi-Strauss:
using what we have, in the context we have, to reveal patterns the lab would never show.
Normative implications for Latin America
For Latin America, this is not just a technical detail; it is a path:
Educational policy:
evaluating attention and learning inside real classrooms,
not only in imported, air-conditioned labs.Health and rehabilitation:
measuring recovery after stroke, Parkinson’s or cochlear implantation
during authentic daily activities – walking, cooking, talking to family.Urban policy and inequality:
using mobile fNIRS and physiology to understand
how transport, noise, heat and violence tax the brain of the poor
much more than the brain of the 0.1% (os 01).Decolonial science:
taking fNIRS to indigenous territories, riverside communities,
quilombos and periferias – designing studies with the people,
not only about the people.
Keywords for scientific search
“fNIRS real-world design mobile fNIRS ecological validity GLM short-channels ICA PCA naturalistic environment NeuroImage Neurophotonics experimental fieldwork non-WEIRD”
