What Changes When We Stimulate a Brain Network - Electricity, Cells, or Experience?

From Ca²⁺ signaling and glial cells to network responses: what can TMS–EEG reveal about neuroplasticity, memory, and consciousness?

TMS–EEG · Neuroplasticity · Astrocytes · Ca²⁺ · Engrams · Connectomic Reserve · EEG Microstates · Damasian Mind · Body-Territory

Imagine pressing a piano key. Your finger moves, the string vibrates, and the sound changes your perception. Repeat that movement thousands of times, and you may develop a skill you did not previously possess.

Now imagine applying a magnetic pulse over a brain region. The magnetic field induces electrical currents, temporarily changes the activity of excitable neural elements, and may produce responses across connected networks.

But what has actually changed?

An electrical response is not necessarily plasticity. Plasticity is not necessarily learning. And learning does not automatically correspond to the conscious experience of transformation.

In Blog 09 of BrainLatam's W47/2026 series, we investigate these distinctions and how they might be connected experimentally.

1. Perturbation does not necessarily mean permanent transformation

Transcranial magnetic stimulation, or TMS, uses changing magnetic fields to induce electric fields in brain tissue.

Depending on stimulation parameters, the targeted region, and physiological conditions, these fields can evoke neuronal responses.

When TMS is combined with electroencephalography, researchers can investigate the electrical activity recorded after a perturbation.

This approach allows us to study cortical reactivity and aspects of responses across connected brain networks.

However, observing a response to a magnetic pulse does not demonstrate that a synaptic connection has been strengthened or that a new memory has emerged.

To investigate lasting plasticity, we need appropriate baseline comparisons, follow-up measurements, and experimental controls.

2. Bertazzoli: when a brain network responds to perturbation

In September 2026, Giacomo Bertazzoli and colleagues published Network-targeted neurophysiological biomarkers of dysconnectivity and cognitive decline in Alzheimer's disease.

The researchers investigated 86 participants: 28 healthy controls, 27 individuals with mild cognitive impairment, and 31 individuals with Alzheimer's dementia.

They used functional magnetic resonance imaging to identify individualized targets within the default mode and executive control networks.

They then applied TMS while recording EEG activity.

Their analyses identified differences in early components of TMS-evoked responses, including measures related to the stimulated networks and hemispheres.

Among 55 participants followed for approximately 18 months, certain responses were also associated with subsequent cognitive decline.

The study demonstrates the potential of TMS–EEG for investigating functional network alterations.

It does not demonstrate cognitive recovery caused by TMS.

3. Are new experiments already hidden within the recordings?

Bertazzoli's contribution allows us to formulate additional questions without immediately changing the original experimental design.

Instead of analyzing only averaged responses, we could investigate differences between individual stimulation pulses.

Does the same participant respond identically when receiving a pulse during different brain states?

Do responses vary according to preceding oscillatory power, the phase of particular oscillations, or EEG Microstates?

Such analyses would depend on the availability and quality of the original recordings.

One possibility would be to investigate whether pre-stimulation brain-state measurements explain additional differences between participants.

Another would be to examine whether response variability contains prognostic information not captured by averaged signals.

We would not simply repeat the original research. We would formulate new questions based on its experimental design.

4. EEG Microstates: does the timing of stimulation matter?

In Influence of Large-Scale Brain State Dynamics on the Evoked Response to Brain Stimulation, researchers combined prefrontal TMS with EEG to investigate brain states preceding magnetic stimulation.

They observed larger evoked responses when stimulation occurred during configurations resembling microstate C.

The finding was reproduced in another session and in an independent dataset.

This provides evidence that the response to an identical intervention may depend on the brain configuration present at the moment of stimulation.

However, microstates are not thoughts, feelings, or individual anatomical connections.

Researchers must also control for equipment sounds, sensory stimulation, muscle activity, and electrical artifacts.

TMS–EEG requires distinguishing cortical responses from those indirectly produced by the peripheral effects of stimulation.

5. Ca²⁺: ionic movement and cellular transformation

Calcium participates in several cellular processes, including synaptic transmission, intracellular signaling, and mechanisms associated with plasticity.

However, no single Ca²⁺ dynamic explains all forms of learning.

Neurons and glial cells exhibit different signaling mechanisms and temporal scales.

Scalp EEG records voltage differences primarily associated with the coordinated electrical activity of neuronal populations, but it does not directly measure intracellular Ca²⁺.

Therefore, an electrical change recorded at the scalp cannot automatically be interpreted as evidence of a particular molecular process.

Integration requires complementary methods, appropriate experimental models, and questions that explicitly connect the scales being investigated.

6. Bukalo: astrocytes also participate in memory

In February 2026, Olena Bukalo and colleagues published Astrocytes enable amygdala neural representations supporting memory in Nature.

The researchers used mice, in vivo Ca²⁺ imaging, electrophysiological recordings, and astrocyte-specific manipulations in the basolateral amygdala.

They investigated the retrieval and extinction of fear-associated memories.

Manipulating astrocytic signaling modified behavioral responses and neuronal representations associated with memory.

The findings also involved communication between the amygdala and prefrontal regions.

Astrocytes did not appear merely as supporting cells: their activity contributed causally to the processes being investigated.

This does not demonstrate that astrocytes independently generate the conscious experience of fear, nor that their mechanisms can be inferred directly from human EEG.

7. Astroengrams: where does a memory begin?

In Astroengrams: rethinking the cellular substrate for memory, Javier Sánchez Romero and Marta Navarrete discuss evidence that astrocytic ensembles participate in mechanisms associated with memory formation and retrieval.

Another 2026 investigation, Hippocampal astrocytic sequences emerge during learning and memory recall, by Ryan Senne and colleagues, used calcium imaging in mice.

The researchers identified temporal sequences of astrocytic activity related to contextual learning and re-encounters with a conditioned environment.

These investigations expand the study of engrams beyond exclusively neuronal ensembles.

A new question emerges: how do cellular processes operating at different temporal scales contribute to the functional organization supporting memory retrieval?

8. Connectomic Reserve: do available connections also matter?

In 2026, Brazilian researchers Roberto Lent and Fernanda Tovar-Moll, together with Diego Szczupak, proposed The secret connections of the brain: a connectomic reserve for neuroplasticity?.

The Connectomic Reserve hypothesis considers whether relatively underused anatomical connections may contribute to the brain's capacity for reorganization.

This opens another question about stimulation responses.

Could individuals with different structural characteristics exhibit different capacities for responding and adapting?

A future investigation could combine tractography, TMS–EEG, and longitudinal measures of learning.

However, functional connectivity measured through EEG is not equivalent to identifying anatomical reserve connections.

We need to distinguish structural availability, functional recruitment, and behavioral change.

9. The Damasian Mind: who experiences the transformation?

In Homeostatic Feelings and the Emergence of Consciousness, António Damasio and Hanna Damasio relate interoceptive feelings, images organized from the organism's perspective, and subjectivity.

This approach introduces a dimension that is not automatically visible in TMS-evoked responses.

A perturbation can produce electrical changes without generating an identifiable conscious experience.

Similarly, physiological alterations may influence feelings and possibilities for action without being immediately perceived.

BrainLatam proposes investigating these relationships through the hypothesis:

“Consciousness is a movement that perceives itself as BEING within the metabolism produced.”

We do not claim that every ionic movement is conscious.

We ask how material processes, bodily regulation, and experience may participate in the same Body-Territory.

10. Triple-Aspect Monism and Decolonial Neuroscience

Brazilian researcher Alfredo Pereira Jr., in Triple-aspect monism: Physiological, mental unconscious and conscious aspects of brain activity, distinguishes physiological, unconscious mental, and conscious aspects.

This perspective helps us avoid two forms of reductionism: treating experience as merely an electrical recording or separating consciousness entirely from biological processes.

In BrainLatam's proposal, we extend the investigation toward the Body-Territory situated within a Biome.

APUS and Tekoha provide conceptual perspectives for relating positioning, possibilities for action, metabolism, and embodied experience.

These categories must be translated into observable variables without losing their interpretative character or their original cultural contexts.

We isolate processes to understand mechanisms; we return to the Body-Territory to investigate the lived event.

11. An experiment connecting the scales

We could propose a human investigation combining TMS–EEG, a learning task, ECG, respiration, and subjective assessments.

First, we would record brain activity preceding stimulation pulses, including microstates and oscillations.

Next, we would investigate how these conditions relate to evoked responses.

Finally, we would compare subsequent performance and retention without assuming that larger electrical responses represent better learning.

A complementary cellular study could investigate glial mechanisms and Ca²⁺ signaling in appropriate experimental models.

Connections between these experiments would need to be established through explicit hypotheses and converging results, rather than assuming they directly measure the same phenomenon.

Within Metanoia of the Metastable Brain, we would ask which modifications persist after successive encounters.

To perturb is to produce a change. To learn is to modify possibilities for action and retrieval. To perceive oneself as BEING involves the experience of an organism participating in these transformations.

In Blog 10, we will investigate how practice transforms repertoires and performance: expertise, high performance, Rock–Scissors–Paper, and the limits of our local optima.

Meta description: Explore 2026 research on TMS–EEG, astrocytes, Ca²⁺ signaling, memory, and Connectomic Reserve. What does it mean to transform a brain network?

Scientific framing: The studies by Bertazzoli, Bukalo, Senne, and Lent and colleagues provide evidence at distinct biological and functional scales. Their connections to 5D Consciousness, Metanoia, and the Body-Territory framework are integrative hypotheses proposed by BrainLatam, not findings directly demonstrated by those experiments.

BRAINLATAM | W47/2026 | BLOG 09/12 — ENGLISH VERSION