Pain, apathy and depression in dementia -  When feeling and thinking separate

(First-Person Consciousness • Decolonial Neuroscience • Brain Bee • The Feeling and Knowing Taá)

Republican Capitalism of Spirits Without Bodies
Decolonial Spirituality Capitalism Neuroscience

The Feeling and Knowing Taá — opening a crack for decolonization

I walk into a hospital room and see a person with dementia.
The body is there. The eyes, sometimes vacant. Sometimes squeezed shut in pain.
The chart says “dementia,” the scale says “apathy,” the medical record leaves the pain in doubt.

Inside me, something locks up:
I feel that this person is suffering, but the system insists on treating them as if they felt nothing, as if dementia had erased feeling itself.

I also notice that even my words have been colonized.
That the language I use to think the world was shaped to reduce me:
to reduce my body to a defective machine,
my mind to a deficit,
my spirituality to superstition,
my politics to consumption and productivity.

That is why so many neuroscientists avoid asking questions that could reveal what colonial science does not know how to name.
But when I feel my body before I think — when Taá manifests — I realize there is no separation between Neuroscience, Politics and Spirituality (Utupe, Xapiri, living memory).
What colonizes is not only history: it is the word that prevents us from existing whole.

Every scientific discovery, when read with courage, is a crack of freedom that breaks open Zone 3 and gives the body back what it has always been: a living territory of possible worlds.

It is with this whole body that I read the study by Allison J. Huff and colleagues, published in 2025 in NeuroImage Reports:
“Functional near-infrared spectroscopy (fNIRS) detects brain changes for apathy and pain in patients with Alzheimer’s disease and related dementias: An exploratory study.”

And I ask myself, in first person:
How does the brain of someone with dementia express pain, apathy and depression when words are no longer enough?

What the study investigated

The study starts from a very concrete situation:

• people with Alzheimer’s disease and related dementias (ADRD);
  
  

• with chronic pain (knee osteoarthritis);
  
  

• with neuropsychiatric symptoms such as apathy and depression.
  
  

Baseline data from 40 individuals with mild to moderate dementia were analyzed, assessing:

• reported pain,
  
  

• depressive symptoms,
  
  

• apathetic symptoms,
  
  

• and brain hemodynamic responses measured by fNIRS in prefrontal, motor and somatosensory regions during mildly painful thermal stimuli, below the threshold of intense pain.
  
  

The scientific question is direct and powerful:

Can fNIRS see, in the brain, what apathy and dementia hide in expression and speech?

How the signal was analyzed (fNIRS, GLM, HRF, short-channels, ICA/PCA)

The team used portable fNIRS to record changes in:

• O₂-Hb (oxygenated hemoglobin)
  
  

• HHb (deoxygenated hemoglobin)
  
  

in five regions of interest (ROIs): bilateral prefrontal, motor and somatosensory areas.

The pipeline follows an advanced fNIRS standard:

Preprocessing and noise cleaning

• removal of low-quality channels (QTNIRS, artifact inspection);
  
  

• filtering to remove high-frequency components (heartbeat, technical noise);
  
  

• use of ICA/PCA to separate global physiological components (breathing, vasomotor activity) from more local components.
  
  

Modeling the hemodynamic response (GLM + HRF)

• application of a General Linear Model (GLM) to estimate the response to thermal stimulation in each ROI;
  
  

• consideration of the real Hemodynamic Response Function (HRF) in the sample, instead of assuming a single rigid shape for everyone.
  
  

Short-channels and extracortical control

• even though the article emphasizes channel quality more than a full short-channel pipeline, the spirit of the analysis converges with the use of short optical paths and global corrections to better separate cortex from scalp.
  
  

Correlation with symptoms

• calculation of correlations between hemodynamic betas (response to the pain stimulus) and scores for:
  
  

• apathy,
  
  

• depression,
  
  

• pain intensity;
  
  

• stratification by level of cognitive function (more preserved vs more impaired).
  
  

In the background, we can imagine the avatar Math/Hep (from BrainLatam2026) working silently: the statistical avatar, who looks at variables, betas, correlations and p-values, but never forgets that behind each data point there is a body-life.

Main results: different patterns for pain and apathy

The findings are subtle and important:

• In people with lower cognitive function, there was a negative correlation between O₂-Hb in the right prefrontal cortex and apathy: more apathy, lower hemodynamic response there.
  
  

• In individuals with more preserved cognition, positive correlations emerged between:
  
  

• O₂-Hb and apathy in the right somatosensory region;
  
  

• O₂-Hb and pain in the medial prefrontal cortex.
  
  

In Brain Bee language:
The brain of a person with dementia still reacts to pain and apathy, but in different ways, depending on how much cognition they still preserve.

And this opens a dramatic space:

• apathy can “switch off” the prefrontal response in some cases,
  
  

• but can also manifest as hyper-response in sensory or medial prefrontal areas in others,
  
  

which means there is not just one kind of apathy in dementia.

Reading with our concepts

Damasian Mind and the feeling–narrating divorce

The Damasian Mind is born from the encounter between interoception and proprioception.
In dementia, the narrative bridge is often what breaks first:

• the body feels pain,
  
  

• the brain reacts hemodynamically,
  
  

• but the person can no longer articulate speech and, at times, not even clear expressions.
  
  

The study by Huff and colleagues shows that:

• the feeling still exists, but the telling that one feels fragments.
  
  

Pain and apathy coexist in layers that the colonial gaze tends to confuse with “lack of feeling.”

Tensional Selves in dementia

We can imagine specific Tensional Selves:

• a Self of silent pain,
  
  

• a Self of disconnection (apathy),
  
  

• a Self of cognitive effort still trying to understand what is happening.
  
  

fNIRS reveals that these Selves are not poetic metaphors: they leave different hemodynamic signatures.

Broken Human Quorum Sensing (QSH)

Our QSH depends on reciprocal signals:

• gaze,
  
  

• response,
  
  

• gesture,
  
  

• micro-adjustments of the body.
  
  

In dementia with apathy, the quorum breaks:

• the other no longer responds as before,
  
  

• the caregiver feels they are “talking to a wall,”
  
  

• society starts to see this body as less of a subject.
  
  

Here I remember Eduardo Galeano’s “Los nadies”:
“Los nadies: los hijos de nadie, los dueños de nada...”
People with dementia and chronic pain, made invisible, become “nadies” if we are not able to recognize the pain that still pulses in them.

Zones 1, 2 and 3

• Zone 1: routine mechanical care, protocols, medications, without listening.
  
  

• Zone 2: the rare space where the caregiver feels, observes, respects micro-signals of pain, modulates the environment, touches with care.
  
  

• Zone 3: the ideology of uselessness — “old people with dementia don’t feel,” “they don’t understand anyway,” “there’s no point asking.”
  
  

Zone 3 is the most dangerous: it authorizes neglect.
This study is a crack of Zone 2 in the middle of institutional Zone 3.

DANA and the body that still organizes

Even in brains with degeneration, DANA (the intelligence of DNA) continues to:

• reorganize synapses,
  
  

• maintain some level of response to pain,
  
  

• sustain a minimum sense of integrity.
  
  

The hemodynamics that fNIRS sees are the expression of this silent struggle.

Yãy hã mĩy (Maxakali origin)

Remembering that Yãy hã mĩy is a term from the Maxakali people, originally tied to the act of imitating the animal one is going to hunt.
In our extended sense, it is the process of imitating oneself, repeating oneself, reconstructing oneself.

After so many cognitive losses, the person with dementia lives an inverted Yãy hã mĩy:
they try to imitate their former Self, to recompose themselves with fragments of memory, language and gesture.

Where science adjusts our ideas

Evidence-based science shakes several colonial misconceptions:

“Old people with dementia feel less pain”
fNIRS shows the opposite: the brain reacts, and in a way that varies systematically with cognition and apathy.

“Apathy is just weak depression”
The data suggest that apathy, pain and depression have specific relationships modulated by cognitive function — they are not simply weak versions of each other.

“If they don’t speak, they don’t feel”
Here, the body is subject: hemodynamics speak on behalf of those who can no longer do so.

Once again, the scientific snapshot dismantles a colonial belief and forces us back to the whole: the body as territory, not the “deficit patient.”

Normative implications for health and policy in Latin America

• Pain protocols in dementia must include objective measures (such as fNIRS when possible), not only behavioral scales.
  
  

• Health professional training must cover the differences between apathy, depression and silent pain, avoiding the Zone 3 of neglect.
  
  

• Public policies for elder care in Latin America should recognize that making pain invisible is also a form of colonial violence: elderly, Indigenous, poor and demented bodies are the “nadies” of the 21st century, and neuroscience here can be a tool of justice, not only of diagnosis.
  
  

• Research in LATAM using fNIRS should include diverse populations, real-world contexts, local languages and culturally situated care — not just replicate laboratory protocols from the Global North.
  
  

Scientific search keywords

“Huff 2025 functional near-infrared spectroscopy detects brain changes apathy pain depression ADRD dementia NeuroImage Reports fNIRS GLM hemodynamic response”

When Two Brains Receive the Same World - Cooperation, synchrony, and the shared rhythm of attention

Embodied Singing -Voice, interoception, and Body-Territory in vocal expertise

Pleasant Odors and the Breath that Organizes Us - How smell organizes brain–body coupling

Architecture That Thinks With Me - Turning corners and the attentional cost of built environments

Auditory Approach Bias From Birth - How newborns and adults code the desire to listen

Beta Waves and the Moment I Truly Decide - The prefrontal cortex as the space where "feeling" becomes "choosing"

How My Brain Encodes Voice in Midlife - F0, listening effort, and the vitality of human hearing

Learning Beside Another Brain - Hyperscanning and the pedagogy of co-presence

Reproducibility in fNIRS - When can I trust the hemodynamic curve I see?

HRfunc and the True Shape of the Hemodynamic Response - Why every brain breathes light in its own way

Mixed Reality and Decision-Making - How the brain evaluates prototypes and hybrid worlds

Intense Exercise and the Awakening of Zone 2 - The hemodynamics of effort and the body that generates intelligence

Buttoning a Shirt - Everyday actions as windows into attention, gesture, and consciousness

Depression, tDCS, and the Prefrontal Cortex - Reigniting silent circuits

Designing fNIRS Studies in Real-World Environments - Why science must step outside the laboratory to exist

Transformers and Virtual Short-Channels - AI cleaning brain signals and retelling hemodynamics

Mental Fatigue and Performance - When the head gives up before the body

Cold Water and the Brain - Oxygenation, cold, and the consciousness of the limit

Walking After Stroke - Cognitive–motor interference in everyday life

Balance and the Cerebellum in Parkinson’s Disease - Movement, tensions, and reorganization of the Body-Territory

Freezing of Gait and the Loss of the Body’s Own Quorum - When the body stops trusting the next step

Children With Cochlear Implants - Learning to hear through the brain, not just the device

Emotional Processing in Children With Oppositional Behavior - Regulation, conflict, and the birth of Tensional Selves

Mild Cognitive Impairment - Early hemodynamic signs and presence in the world

Pain, Apathy, and Depression in Dementia - When feeling and thinking stop walking together

Cognitive Load - How much does fNIRS really feel my mental effort?

The Brain in Daily Life -Assisted horsemanship, sport, and embodied enjoyment

Linguistic Jiwasa - When language thinks the world

Dialogical Multiplication and Indigenous Psychology - How to let psychology listen without erasing the Other

The Feeling and Knowing Taá of Christmas 

Republican Capitalism of Spirits without Bodies

NIRS fNIRS EEG ERP Multimodal NIRS-EEG

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