Giulio Ruffini

www.mdpi.com/1099-4300/26...

What does Kolmogorov Complexity have to do with brain stimulation? I say ... a lot!

www.dropbox.com/scl/fi/7dekr...

My slides from The Science of Consciousness (Barcelona 2025) Plenary talk this week! "From Kolmogorov Theory to Computational Modeling and Brain Stimulation". #consciousness #neuromodulation

If you like the music, consider sending a paper to our special Issue, "The Mathematics of Structured Experience: Exploring Dynamics, Topology, and Complexity in the Brain". See www.mdpi.com/journal/entr...

Here's our poster – "Algorithmic Structure and Lie Groups" – at ICMNS 2025 (Barcelona): www.dropbox.com/scl/fi/qbn55...

It is a summary of our recent paper, Structured Dynamics in the Algorithmic Agent (www.mdpi.com/1099-4300/27...).

Efficacy of optimized multichannel vs conventional tDCS for major depression treatment: A randomized controlled trial. Starstim. Neuroelectrics

🔬🧠 Can optimized stimulation protocols offer better outcomes for major #depression? This randomized trial, featuring our @ruffini.bsky.social and Ricardo Salvador, & our friend Mohammad Ali Salehinejad, used our Starstim (www.neuroelectrics.com/products/res...) to deliver multichannel tDCS.

Preliminary Evidence for Perturbation-Based tACS-EEG Biomarkers of Gamma Activity in Alzheimer's Disease. Starstim. Neuroelectrics

How can brain stimulation uncover patterns of cognitive decline in #AlzheimersDisease? 🔍 This study, featuring our CTO @ruffini.bsky.social used our Starstim (www.neuroelectrics.com/products/res...) to explore how 40 Hz tACS-EEG gamma activity relates to cognitive severity & inflammation.

Great work, Rodrigo!

Compression Represents Intelligence Linearly There is a belief that learning to compress well will lead to intelligence. Recently, language modeling has been shown to be equivalent to compression, which offers a compelling rationale for the succ...

Case in point! Check this nice work out -> arxiv.org/abs/2404.09937

13. Conclusion
LaNMM is not just another NMM — it’s a physically grounded, biophysically realistic platform that integrates structure, dynamics, and function. Expect to see more work where biology meets theory, with LaNMM at the core!

@neurotwin @galvani_lab @neuroelectrics.bsky.social

12. Why This Matters
Together, these papers show how LaNMM provides a unified, mechanistic scaffold for studying:

• Neurodegeneration (AD)
• Psychedelic states
• Predictive inference
• Oscillatory biomarkers
• Interneuron dynamics

11. Comparator Hypothesis
CFC in LaNMM instantiates the analog version of the hierarchical XOR-like error computation central to predictive coding and KT/AIF. This formalization bridges algorithmic models with real electrophysiology.

10. Comparator Disruption Across Conditions
→ In AD: Interneuron loss disrupts CFC, leading to inflated early prediction errors and their later suppression.

→ In psychedelics: Increased gain weakens prediction precision → “relaxed beliefs” and increased error signaling.

9. Key Mechanisms
• Signal-Envelope Coupling (SEC): Low-freq rhythms modulate the amplitude of fast oscillations (PAC-like).
• Envelope-Envelope Coupling (EEC): Slow envelopes modulate fast envelopes — allowing gating and precision weighting (think Kalman gain).

Cross-Frequency Coupling as a Neural Substrate for Prediction Error Evaluation: A Laminar Neural Mass Modeling Approach Predictive coding frameworks suggest that neural computations rely on hierarchical error minimization, where sensory signals are evaluated against internal model predictions. However, the neural imple...

8. Prediction Error & CFC (2025)
www.biorxiv.org/content/10.1...
Our latest paper goes deeper into theory. It proposes that LaNMM supports biologically plausible Comparator functions via cross-frequency coupling (CFC), enabling local prediction error evaluation in predictive coding.

7. Activation of 5-HT2A receptors (mimicking psychedelics) increases excitability in L5 pyramidal cells — counteracting some AD-related oscillatory deficits.

Restoring Oscillatory Dynamics in Alzheimer’s Disease: A Laminar Whole-Brain Model of Serotonergic Psychedelic Effects Classical serotonergic psychedelics show promise in addressing neurodegenerative disorders such as Alzheimer’s disease by modulating pathological brain dynamics. However, the precise neurobiological m...

6. Psychedelics + AD (2024)
www.biorxiv.org/content/10.1...
In this follow-up study, the LaNMM is embedded in whole-brain models personalized to AD patients.

5. Aβ oligomers impair PV+ interneurons → disinhibition → hyperactivity. Later, tau pathology hits pyramidal neurons → hypoactivity. The LaNMM shows that PV+ dysfunction alone explains the early-phase EEG biomarkers, but tau-induced hypoactivity is required in advanced stages.

Fast Interneuron Dysfunction in Laminar Neural Mass Model Reproduces Alzheimer’s Oscillatory Biomarkers Alzheimer’s disease (AD) is characterized by a progressive cognitive decline underpinned by disruptions in neural circuit dynamics. Early-stage AD is associated with cortical hyperexcitability, wherea...

4. AD Study (2025)
www.biorxiv.org/content/10.1...
In this AD-focused work, the model simulates fast interneuron (PV+) dysfunction and later-stage pyramidal cell loss. This reproduces AD’s biphasic M/EEG trajectory: early hyperexcitability (↑gamma, ↑alpha), followed by slowing and hypoactivity.

3. Alpha/beta (slow/fast) rhythms are generated in deep layers, gamma in superficial ones. The model’s structure allows us to simulate realistic depth-resolved LFP, bipolar LFP, and CSD.

Now comes the trilogy of applied studies using LaNMM:

P118 A Biophysically realistic Laminar Neural Mass Modeling framework for transcranial Current Stimulation

2. Our original LaNMM papers introduced a physics-grounded neural mass model capable of generating both alpha/beta and gamma oscillations across cortical layers. It embeds synaptic sources into a spatially layered medium.

www.sciencedirect.com/science/arti...
www.biorxiv.org/content/10.1...

🧵 Thread: 1. The Laminar Neural Mass Model (LaNMM) — A Unified Framework for Oscillatory Dynamics in Health and Disease (news!)

The Laminar Neural Mass Model (LaNMM) links circuit-level mechanisms to M/EEG biomarkers across brain states — from healthy function to disease and altered consciousness.

Haha, thanks, Nick!

Cross-Frequency Coupling as a Neural Substrate for Prediction Error Evaluation: A Laminar Neural Mass Modeling Approach Predictive coding frameworks suggest that neural computations rely on hierarchical error minimization, where sensory signals are evaluated against internal model predictions. However, the neural imple...

Interesting piece! We just explored related questions here, using our laminar neural mass model and an oscillatory information encoding scheme: www.biorxiv.org/content/10.1...

Bridging Dynamics, Symmetry, and Consciousness in Brain Modeling Discover how brain dynamics and symmetry shape cognition, neural networks, and structured experience through mathematical modeling and information compression.

Blog! Post on our recent paper on symmetry, dynamics and neural networks (wet or dry) for the Entropy Special issue on “The Mathematics of Structured Experience: Exploring Dynamics, Topology, and Complexity in the Brain," still welcoming contributions! =>
www.neuroelectrics.com/blog/bridgin...

Structured dynamics in the algorithmic agent In the Kolmogorov Theory of Consciousness, algorithmic agents utilize inferred compressive models to track coarse-grained data produced by simplified world models, capturing regularities that structur...

I am happy to announce that an updated/improved version of "Structured dynamics in the algorithmic agent" has been released! www.biorxiv.org/content/10.1...

We bridge perspectives from AIT (Kolmogorov C., compression), symmetry (group theory), and dynamics (conservation laws, reduced manifolds).

Information, complexity, brains and reality (Kolmogorov Manifesto) I discuss several aspects of information theory and its relationship to physics and neuroscience. The unifying thread of this somewhat chaotic essay is the concept of Kolmogorov or algorithmic complex...

... into a small number of parameters. They effectively build a model of the world behind the scenes. 🤖✨ #AI #MachineLearning #LLM #Tech Cognition as compression (1999-2007). arxiv.org/abs/0704.1147, a key feature required by AGI. See more in recent pubs: www.mdpi.com/1099-4300/26...

Information, complexity, brains and reality (Kolmogorov Manifesto) I discuss several aspects of information theory and its relationship to physics and neuroscience. The unifying thread of this somewhat chaotic essay is the concept of Kolmogorov or algorithmic complex...

LLMs aren’t just statistical 🦜s. Learning the probability of the next letter based on the prior 100 brute-force would involve ~28¹⁰⁰ possibilities. This is cosmically impossible: ~28¹⁰⁰ is more than the atoms in the universe! 🌌 Instead, LLMs learn patterns—compressing vast amounts of information...

Want to dive deeper into this fascinating intersection of psychedelics, AD, and computational modeling? Check out the full study and others here:
biorxiv.org/content/10.1...
journals.plos.org/ploscompbiol...
mdpi.com/1099-4300/26...
biorxiv.org/content/10.1...
@Neuroelectrics Neurotwin H2020

The findings suggest that psychedelics may help in prodromal/mild AD phases by restoring oscillatory dynamics. The post-acute phase of psychedelics enhances neural plasticity, w. potential for long-term benefits. Timing and dosage are key to avoiding hyperexcitability.