Summary:
A comprehensive meta-analysis of rodent brain studies reveals consistent molecular mechanisms that enable environmental stimulation to enhance neuroplasticity. Published in Molecular Neurobiology, the study was co-led by Federico Miozzo at the Institute for Neurosciences (IN CSIC-UMH) and Bartek Wilczyński at the University of Warsaw.
By harmonizing bulk and single-cell RNA-sequencing datasets across multiple research facilities, the investigators uncovered a conserved transcriptomic signature focused on synaptic communication and immediate-early activation. The findings confirm that the AP-1 transcription factor complex acts as a central genomic driver connecting enriched life experiences to long-term cognitive adaptation, supported by an interactive open-access platform called mEEtaBrain.
Key Facts:
- Conserved Molecular Signature: Analyzing RNA-sequencing datasets screened from over 300 studies revealed recurrent gene expression changes across rodent brains exposed to complex physical, cognitive, and social housing.
- AP-1 Transcription Factor Centrality: The meta-analysis identified Fos and Jun family immediate-early genes, which assemble into the AP-1 transcription factor complex, as primary regulators orchestrating downstream synaptic remodeling.
- Open-Science Platform Launched: The team created mEEtaBrain, an open-access interactive web application allowing researchers to query transcriptomic enrichment signatures across distinct brain regions, genes, and statistical criteria.
Source: CSIC / Miguel Hernández University of Elche / University of Warsaw
Environmental enrichment, providing laboratory animals with enhanced physical exercise, social interaction, and novel cognitive exploration opportunities, has long been recognized as a powerful non-pharmacological stimulus for brain resilience. Enriched environments enhance adult neurogenesis, strengthen synaptic density, and protect against neurodegenerative models of Alzheimer’s and Huntington’s disease.
Despite decades of experimental validation, pinning down the exact molecular transcriptomic cascade driving these cerebral benefits has proved elusive. Individual laboratories employ varied enrichment enclosures, diverse rodent strains, distinct exposure durations, and disparate gene-expression profiling protocols, leading to fragmented and sometimes conflicting single-study findings.
To overcome this experimental heterogeneity, a collaborative research team led by Federico Miozzo, PhD, at the Institute for Neurosciences (IN), a joint center of the Spanish National Research Council (CSIC) and Miguel Hernández University of Elche (UMH), and Bartek Wilczyński, PhD, at the University of Warsaw, executed a large-scale meta-analysis.
Publishing in the journal Molecular Neurobiology, the team harmonized independent transcriptomic datasets to isolate the core molecular signature through which enriched living conditions remodel the mammalian brain.
Harmonizing 300 Studies to Find Common Signals
The researchers initiated a comprehensive systematic review, screening over 300 publications investigating rodent brain responses to environmental enrichment.
To ensure analytical rigor, the team narrowed the cohort to 20 benchmark studies that utilized standardized high-throughput RNA-sequencing (RNA-seq). By reprocessing raw data through uniform computational pipelines and combining outcomes using three independent statistical meta-analytic models, the investigators eliminated single-lab idiosyncrasies to extract biological patterns that hold true across experimental boundaries.
“One of the strengths of meta-analysis is that, although the studies differ from one another, analysing them together increases the number of samples available,” explains Dr. Federico Miozzo, a researcher in the Transcriptional and Epigenetic Mechanisms of Neuronal Plasticity laboratory at the IN CSIC-UMH. “This makes it possible to detect common patterns that might otherwise go unnoticed in individual studies.”
Synaptic Plasticity and the AP-1 Master Switch
The unified transcriptomic screen highlighted significant enrichment in genes directly responsible for the architecture and function of chemical synapses:
- Synaptic Communication & Structural Remodeling: Genes governing neurotransmitter receptor trafficking, postsynaptic density scaffolding, and dendritic spine reorganization were consistently upregulated across multiple brain regions.
- Immediate-Early Genomic Waves: The meta-analysis singled out rapid-response gene families, specifically immediate-early genes belonging to the Fos (such as c-Fos, Fosb) and Jun (c-Jun, Junb) families.
These proteins dimerize to assemble the Activator Protein 1 (AP-1) transcription factor complex. AP-1 operates as an activity-dependent molecular gateway: when an animal engages with complex sensory or social environments, neural activation triggers rapid AP-1 assembly, which subsequently initiates downstream transcription of structural synaptic proteins.
This independent emergence of AP-1 reinforces previous work led by Dr. Ángel Barco at the Institute for Neurosciences, whose laboratory demonstrated in Nature Communications that AP-1 serves as an epigenetic bridge translating early-life sensory experiences into lifelong cognitive gains.
“The fact that the AP-1 transcription factor emerges again in this broader analysis is important because it reinforces and generalises our findings, pointing to these proteins as key regulators of the brain’s molecular response to environmental enrichment,” said Dr. Barco.
Interactive Data Exploration via mEEtaBrain
To ensure the meta-analytic data serves as an active discovery tool for the international neuroscience community, the researchers designed and deployed mEEtaBrain, a freely accessible online application.
The platform allows scientists to:
- Query individual genes of interest across enriched housing experiments.
- Filter expression profiles by anatomical brain regions (such as the hippocampus, cortex, or striatum).
- Adjust statistical significance thresholds and comparative parameters to design future targeted mechanistic experiments.
While the investigators caution that rodent genomic profiles cannot be seamlessly generalized to human clinical contexts without validation, defining this conserved transcriptomic backbone provides a concrete molecular roadmap. Understanding how lifestyle factors engage the AP-1 pathway could lead to novel therapeutic strategies aimed at promoting healthy cognitive aging and mitigating neurodegeneration.
Questions and Answers
What is the core molecular finding of the new environmental enrichment meta-analysis?
The study found that across varied laboratory conditions, environmental enrichment consistently upregulates genes essential for synaptic communication and synaptic plasticity, orchestrated by immediate-early genes forming the AP-1 transcription factor complex.
Why was the AP-1 transcription factor a significant discovery in this dataset?
AP-1, composed of proteins from the Fos and Jun families, acts as a primary molecular bridge that translates electrical neural activity into long-term gene expression. Its recurrence across 20 independent RNA-seq datasets establishes it as a universal driver of experience-dependent brain remodeling.
What is mEEtaBrain?
mEEtaBrain is an open-access web application created by the researchers that allows the global scientific community to explore, query, and re-analyze the meta-analysis data across specific genes, brain regions, and statistical parameters.
Funding: This study is part of the international EPI-3E project (JPND2022-115), funded by the Instituto de Salud Carlos III (AC22-00030) under the European Joint Programme for Neurodegenerative Disease Research (JPND). The research was also supported by the Spanish State Research Agency, the European Regional Development Fund (ERDF), the ”la Caixa” Foundation and the Generalitat Valenciana. The Institute for Neurosciences CSIC-UMH is a Severo Ochoa Centre of Excellence.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this genetics and synaptic plasticity Research:
- Media Contact: Angeles Gallar
- Source: UMH
- Image Credit: Image credited to Neuroscience News
- Original Research is Open Access: Molecular Neurobiology (Nov 5, 2026). “Systematic Review and Transcriptomic Meta-analysis of Environmental Enrichment Reveal Core Molecular Programs of Brain Plasticity.” Authors: Marcelina Kurowska, Federico Miozzo, Robert Schroeder, Magdalena A. Machnicka, Rocío Pérez-González, Karine Merienne, André Fischer, Angel Barco, Anne-Laurence Boutillier & Bartek Wilczyński.
- DOI: 10.1007/s12035-026-06133-y
Abstract
Systematic Review and Transcriptomic Meta-analysis of Environmental Enrichment Reveal Core Molecular Programs of Brain Plasticity
Environmental enrichment (EE) paradigms in rodents have long demonstrated that enhanced sensory, cognitive, social, and motor stimulation positively impacts brain function, improving learning, memory, and neuroplasticity. These effects have significant implications for understanding cognitive development and mitigating cognitive decline and brain aging. While numerous transcriptomic studies have explored EE-induced molecular changes, a unified view of the genes and pathways consistently modulated remains lacking. To address this gap, we performed a systematic review and meta-analysis.
We conducted a comprehensive PubMed search for all studies published up to February 2025 that matched all the following inclusion criteria: (1) employed EE paradigms; (2) were conducted on rodents; (3) utilized genome-wide transcriptomic methods; (4) examined brain regions or neuronal populations. The 323 retrieved articles were manually screened for relevance to the study aims and data availability. Datasets from 20 eligible RNA-seq reports were reprocessed using a unified analysis pipeline and subjected to a meta-analysis with three complementary statistical methods.
Despite considerable heterogeneity across studies, our integrative analysis identified consistent gene expression signatures linked to synaptic function, plasticity and their transcriptional regulation. In particular, our findings highlight the upregulation of the activity-dependent transcriptional program, including Fos and Jun family members.
These molecular insights advance our understanding of how EE impacts on neuronal and behavioral outcomes, and may inform therapeutic strategies aimed at replicating or enhancing EE benefits. To promote open science and foster further research, we developed an accessible web application, mEEtaBrain, that enables the neuroscience community to navigate and interrogate our meta-analysis results.
Substantial methodological heterogeneity across source studies increased variability in the meta-analysis outcomes. The use of stressors or disease models, particularly in rat studies, introduced a major confounding factor and limited reliable interspecies comparison. Overall, the studies exhibited a low to moderate risk of bias.
