When the Parietal Cortex Weakens, Ambiguity Grows: A Decolonial Reading of Decision, Body, and Uncertainty

The new article by Figueroa-Vargas and colleagues presents something extremely valuable for contemporary neuroscience: a robust multimodal dataset, combining structural MRI, diffusion imaging, fMRI, and EEG together with inhibitory TMS, to investigate how the parietal cortex participates in decision-making under ambiguity.

The dataset includes T1 and T2 structural scans from 52 participants, diffusion imaging from 45, fMRI from 38, and EEG-TMS recordings from 24, with 10 participants included in both experimental phases. All data are organized using the BIDS standard and made publicly available for scientific reuse.

What the Article Showed

The key point of this dataset is not simply identifying where ambiguity occurs in the brain, but rather how causal perturbation of the parietal cortex alters the way humans estimate uncertainty.

This dataset accompanies and extends previous work from the same research group showing that the parietal cortex plays a causal role in ambiguity computation. In the earlier study, parietal activity correlated with the objective degree of ambiguity, while TMS inhibition increased the subjective perception of uncertainty and altered oscillatory dynamics in the cingulate cortex and frontal regions.

In simple terms: when the parietal cortex is perturbed, the mind becomes less efficient at transforming uncertainty into viable decisions.

This finding is particularly important because it challenges the simplistic idea that decisions under ambiguity are merely cold calculations or purely frontal processes. Instead, the evidence points to a distributed circuit involving parietal, cingulate, and frontal regions, suggesting that decision-making in incomplete contexts depends on the integration of perception, bodily states, prediction, and evaluation of consequences.

A Decolonial Neuroscience Perspective

From the perspective of Decolonial Neuroscience, this study helps dismantle a long-standing WEIRD assumption: that human decision-making is fundamentally an abstract rational process detached from the body.

The data point in the opposite direction.

Ambiguity is not only a logical problem. It is also a lived state, involving perceptual, proprioceptive, attentional, and value-based components. The brain does not calculate ambiguity as an external machine detached from the world; it does so as a situated body embedded in context.

Here the concept of the Damasian Mind becomes particularly relevant. Making decisions under ambiguity is not simply about choosing between probabilities. It involves reorganizing interoception, proprioception, memory, and expectation in a sufficiently stable way to allow action.

When parietal efficiency decreases, individuals may begin to experience the world as more uncertain than it actually is. This does not represent merely a “cognitive error.” It also reflects a disturbance in the coupling between body and world.

For this reason, the study resonates strongly with the concept of APUS / Body-Territory. The most appropriate interpretative avatar here is APUS, because the parietal cortex plays a central role in adjusting position, attention, spatial context, and action.

Under this lens, the parietal cortex is not merely a computational hub. It helps maintain bodily orientation within a field of possibilities.

Connection with Tensional Selves and Zones 1, 2, and 3

This study can also be interpreted through the concept of Tensional Selves (Eus Tensionais).

In ambiguous environments, individuals must sustain a functional self capable of acting without having all the answers. The parietal cortex appears to contribute to this stabilization.

Zone 1
The individual operates within functional tensions of everyday life: choosing, comparing, calculating, moving forward.

Zone 2
A state of fruition and critical reorganization, where uncertainty does not paralyze action but instead enables creativity and adaptive refinement.

Zone 3
When ambiguity becomes excessive or poorly metabolized, the mind may become captured by rigid narratives, dogmas, or ready-made ideological solutions.

The true value of this dataset lies in enabling researchers to investigate when ambiguity becomes critical plasticity and when it becomes a seizure of consciousness. It helps differentiate a mind capable of tolerating uncertainty from one that escapes uncertainty through ideological rigidity.

DREX Citizen and Metabolic Belonging

This discussion also opens a broader societal reflection.

Entire societies exposed to material insecurity often live under chronic ambiguity. When the metabolic base of life is unstable, human decision-making may become more defensive, narrower, and less creative.

From this perspective, the concept of DREX Citizen can be interpreted as a form of metabolic support for the social body, analogous to how cells require a stable supply of energy to function effectively.

This is not about romanticizing money. Rather, it reframes money as minimal social metabolism, capable of reducing destructive uncertainty and expanding the conditions for Zone 2 states of belonging, creativity, critical thinking, and cooperation.

While the article does not test this hypothesis directly, it provides a neurobiological foundation for understanding how uncertainty contexts shape the very act of decision-making.

New Questions for BrainLatam

1. In contexts of strong collective belonging, is ambiguity metabolized with lower neural cost?

2. Do physiological regulation states, reflected in respiration and HRV, reduce decision-making overload under ambiguity?

3. Does the parietal cortex respond differently in cooperative tasks compared to purely individual decisions?

4. Do young individuals living in social vulnerability contexts show greater neural rigidity when facing ambiguous choices?

5. Could SpO₂, HRV, and EEG markers reveal transitions between Zones 1, 2, and 3 during uncertain decision processes?

Possible Experimental Designs

One promising approach would be to combine EEG, fNIRS, HRV, and respiration measurements during ambiguous decision-making tasks with social context manipulation: alone, in pairs, and in groups.

Another compelling design would involve cooperative hyperscanning, allowing researchers to investigate whether collective belonging reduces the need for rigid individual responses to uncertainty.

In a more original BrainLatam direction, ambiguity could also be studied in mother-infant dyads or musical coordination tasks, where body and decision emerge simultaneously through interaction.

BrainLatam Conclusion

This article is important because it offers more than technical data. It opens a deeper question:

What happens to consciousness when the body loses its capacity to metabolize ambiguity?

The emerging answer is clear: human decision-making depends on circuits that connect body, value, attention, and world.

Within a decolonial scientific framework, this insight becomes crucial. It is not enough to measure isolated brains. We must understand how belonging, territory, and metabolic stability shape the very possibility of making good decisions.

Reference

Figueroa-Vargas, A., Valdebenito-Oyarzo, G., Martínez-Molina, M. P., Zamorano, F., & Billeke, P. (2026). A comprehensive multimodal MRI and EEG-TMS dataset on the impact of parietal cortex inhibition on decision-making under ambiguity. Data in Brief, 65, 112535.
https://doi.org/10.1016/j.dib.2026.112535