Neuroscientists have been trying to understand how the human brain supports numerous advanced capabilities for centuries. The cerebral cortex, the outer layer of the brain, is now known to be responsible for many of these capabilities, including reasoning, decision-making, the processing of sensory facts and voluntary movement.Neurons in the cerebral cortex often become active consecutively or together for brief periods of time, following recurrent patterns of activity.These recurring neuron firing patterns have been linked to sensorimotor coordination, the brain’s ability to link sensory inputs (i.e., the information collected via the senses) to movements.

For decades, repeating neuronal activity has been described in the context of attractor dynamics theory, a physics-based framework that frames recurring neuron firing patterns as so-called attractors. Attractors are stable states or activity patterns toward which a system naturally returns to.

The return to the same firing patterns was so far assumed to arise from strong connections between the same neurons, wiht groups of neurons acting as “pattern-completion” units. Neurons in these groups were theorized to elicit the same recurring activity patterns when only part of the neurons were activated.## An choice explanation for recurrent patterns of activity in the cerebral cortex

Researchers at the University of Geneva and the École Polytechnique Fédérale de Lausanne (EPFL) have proposed a new explanation for repeating patterns of activity in the cerebral cortex, challenging the conventional understanding that these patterns arise from strongly connected neurons firing together. Their findings, published in *Nature Neuroscience*, suggest that these patterns are instead driven by “core” neurons acting as hubs within a hierarchically modular network.

The team, working at the CortexLab, analyzed data from mouse brains using a combination of two-photon imaging, electrophysiology, and electron microscopy. By analyzing this data, the team first identified repeating activity patterns in the cortex.They then mapped connections between neurons and looked at how strongly neurons that repeatedly fired together were connected.

“Using multimodal datasets-including two-photon imaging, electrophysiology and electron microscopy-we show that these reproducible patterns do not involve strongly interconnected neurons,” Domenico Guarino, Anton Flipchuk, and Alain Destexhe wrote in their paper.

Increasing input correlations rescues population event reproducibility but introduces network-wide oscillations. Credit: Nature Neuroscience (2025). DOI: 10.1038/s41593-025-02128-5

“Instead,we show that cortical networks exhibit hierarchical modularitywith core neurons serving as high-information-flow nodes at module interfaces. These cores funnel activity but lack the structural signatures of pattern-completion units that are typically found in attractor networks.”

## Rethinking repeating brain activity

Guarino, Flipchuk and Destexhe also used computational models and computational tools to simulate neural networks and better understand the underpinnings of widely observed recurrent patterns of activity in the cerebral cortex. They found that these patterns are more likely to emerge from the activity of “core” neurons that act as “hubs,” funneling informa

Gut Bacteria Significantly Impact chemotherapy Effectiveness, Study Finds

Publication Date: 2025/12/20 16:00:38

Chemotherapy, a cornerstone of cancer treatment, doesn’t work the same way for everyone. Now, groundbreaking research published in Science reveals a critical factor influencing its success: the composition of bacteria in your gut. A new study demonstrates a direct link between specific gut microbes and how effectively patients respond to chemotherapy, opening doors for personalized cancer treatment strategies.

How Gut Bacteria Influence Chemotherapy

Researchers at the University of Texas MD Anderson Cancer Center discovered that certain gut bacteria can either enhance or diminish the effectiveness of chemotherapy drugs. Specifically, the study focused on patients undergoing chemotherapy for melanoma. They found that individuals with a higher abundance of the bacterium Akkermansia muciniphila experienced significantly better responses to treatment and had longer progression-free survival rates.

Akkermansia muciniphila isn’t working alone. It appears to boost the immune system, making it more capable of recognizing and attacking cancer cells. chemotherapy works by damaging cancer cells, and a robust immune system can then clear away the debris and prevent the cancer from returning. Without this immune boost,chemotherapy’s impact is lessened.

The Role of Microbial Metabolites

The study didn’t stop at identifying the bacteria. Researchers also investigated how these microbes exert their influence. They found that Akkermansia muciniphila produces specific metabolites – small molecules created during bacterial metabolism – that directly interact with immune cells. These metabolites essentially “train” the immune system to be more effective at fighting cancer.

Conversely, other bacteria were associated with poorer outcomes. The presence of certain microbes correlated with reduced immune response and decreased chemotherapy effectiveness. This suggests that a less diverse gut microbiome, or one dominated by unfavorable bacteria, can hinder treatment.

Implications for Personalized Cancer Treatment

This research has profound implications for the future of cancer treatment. Instead of a one-size-fits-all approach, doctors may soon be able to analyze a patient’s gut microbiome before starting chemotherapy. This analysis could predict how well a patient will respond to treatment and guide decisions about the best course of action.

“Imagine being able to tailor chemotherapy regimens based on a patient’s gut bacteria,” says Dr. Jennifer Wargo, lead author of the study.”We could potentially enhance treatment effectiveness by manipulating the microbiome – perhaps through dietary changes, probiotics, or even fecal microbiota transplantation.”

What Can You Do?

While more research is needed, there are steps you can take to support a healthy gut microbiome. Focus on a diet rich in fiber, found in fruits, vegetables, and whole grains. Fermented foods like yogurt, kefir, and sauerkraut contain beneficial bacteria. Avoid needless antibiotic use, as antibiotics can disrupt the gut microbiome.

This study underscores the vital connection between our gut health and overall well-being, particularly when facing a serious illness like cancer. It’s a powerful reminder that the microbes within us play a far more significant role in our health than we previously understood.

Journal information: Medical Xpress, Science