Summary: For decades, neuroscience has operated under the theory that sensory processing circuits are “locked in” during early childhood and remain fixed throughout adulthood. However, a groundbreaking study has overturned this paradigm.
They discovered that the brain’s “sensory checkpoint”—the thalamic reticular nucleus (TRN)—undergoes an elaborate reorganization during the transition from adolescence to adulthood. This proactive remodeling is essential for high-resolution sensory perception, allowing the adult brain to filter out background noise and focus on subtle, important stimuli with greater precision than a child’s brain.
Key Facts
- Overturning Dogma: Contrary to the “critical period” theory, the TRN circuit continues to mature and refine itself well into adulthood.
- The “Sensory Filter”: The TRN acts as a gatekeeper between the thalamus and the cerebral cortex; the study shows this filter “upgrades” to higher resolution during adulthood.
- The LRRTM3 Molecule: Researchers identified the synaptic adhesion protein LRRTM3 as the key driver of this upgrade. Without it, the brain fails to switch to “high-definition” sensory mode.
- Proactive Maturation: This change isn’t just a result of learning from experience; it is a physical, molecular redesign of the brain’s hardware.
- Neuropsychiatric Implications: Imbalances in this sensory filtering process are hallmarks of ADHD, autism, and schizophrenia. Understanding adult TRN maturation could lead to new therapeutic targets for these disorders.
Source: DGIST
The dominant theory in neuroscience has been that the sensory processing circuits in our brain are finalized in early childhood and fixed afterwards.
A recently published study, however, overturned this widely believed theory, and suggested that the brain remodels its own circuits even during adulthood and increases the precision of sensory perception.
In a collaborative study, Professor Jaewon Ko of the Center for Synapse Diversity and Specificity, Department of Neuroscience, Daegu Gyeongbuk Institute of Science & Technology (DGIST; President Kunwoo Lee) and Professor Eunji Cheong of the Division of Life Sciences, Yonsei University showed for the first time that the brain’s “sensory checkpoint” is elaborately reorganized even during adulthood and this process is essential for high-resolution sensory perception.
This study, which suggests a new paradigm that the maturation of brain circuits continue beyond adolescence into adulthood, was published online on February 18 in Neuron, which is one of the most prestigious neuroscience journals in the world.
The reason humans are able to adapt and survive in complex environments is our ability to selectively receive only important information from other stimuli. The thalamic reticular nucleus (TRN) located in the thalamus of the brain serves as a “sensory checkpoint” that modulates external stimuli before they are transmitted to the cerebral cortex.
Academia has long believed that the design of this checkpoint is fixed after the “critical period” in childhood. By precisely analyzing the developmental stages of the mouse model, however, the research team found that the TRN circuits are reorganized during the transition from adolescence to adulthood.
According to the findings, certain excitatory inputs to the TRN decrease during adulthood, which subsequently reinforces the ability to distinguish subtle tactile differences.
The research team suggested that this change is not simply an accumulation of experiences but a proactive maturation process, during which the adult brain readjusts its circuits to optimize the way it processes sensory information.
In other words, the brain “upgrades” at the circuit level even during adulthood to filter out unnecessary sensory signals more precisely and receive only important information more clearly.
The research team pinpointed synaptic adhesion protein LRRTM3 as a key molecule in this process. LRRTM3, which is specifically distributed in the TRN, fine-tunes connections between neurons and helps the brain switch to adult high-resolution sensory perception mode.
In fact, mice, which had the LRRTM3 gene removed from the TRN, did not have sufficient readjustment of the circuits, which should have occurred in adulthood. As a result, the mice’s ability to distinguish subtle tactile sensations was greatly reduced.
The findings demonstrate that the enhanced sensory ability during adulthood is not just a learning effect but is directly linked to circuit redesign based on modulation at the molecular level.
The findings of this study hold social and industrial significance. Imbalances in sensory information processing are reported as an important feature across a variety of neuropsychiatric disorders, including autism spectrum disorder, attention deficit hyperactivity disorder (ADHD), and schizophrenia.
This study provided a scientific reference for understanding sensory and cognitive disorders not as a personality or behavioral problem but in terms of adult maturation and modulation mechanisms of the sensory checkpoint (TRN) circuits.
Moreover, by specifically presenting the existence of brain plasticity during adulthood, this study is expected to provide important clues for identifying therapeutic targets aimed at restoring sensory and cognitive functions, establishing circuit-based neuromodulation strategies, and developing digital therapeutic and rehabilitation technologies in the future.
At a time when the population is aging across society, sensory and cognitive decline is directly linked to quality of life. Hence, this study has a huge impact as it broadens the potential for functional recovery even in adulthood.
□ This interdisciplinary collaboration research was conducted by Professor Jaewon Ko at DGIST and Professor Eunji Cheong at Yonsei University, who combined their respective expertise. Dr. Dongsu Lee (Yonsei University) and Professor Kyungah Han at Chungnam National University (formerly a research professor at the Department of Neuroscience, DGIST), participated in this study as co-first authors.
Funding: This study was funded by the Leader Research Program by the Ministry of Science and ICT and National Research Foundation of Korea, the Samsung Future Technology Development Program, the Mid-Career Research Program, and the Sejong Fellowship.
Key Questions Answered:
A: Yes! While the general structure is there, this study shows your brain’s “sensory checkpoint” actually goes through a hardware upgrade in adulthood. It gets better at filtering out the junk so you can perceive subtle details more clearly—like distinguishing the texture of a fabric or the nuance of a sound.
A: Early development is about building the foundation. The adult upgrade is about optimization. By thinning out unnecessary excitatory inputs, the brain switches from “learning everything” mode to “high-resolution” mode, allowing for more sophisticated interaction with complex environments.
A: That’s the hope. Many conditions involve a “leaky” sensory filter where the brain is overwhelmed by unimportant information. Since we now know this filter is still being remodeled in adults, we can look for ways to boost proteins like LRRTM3 to help “sharpen” the filter in people who struggle with sensory overload.
Editorial Notes:
- This article was edited by a Neuroscience News editor.
- Journal paper reviewed in full.
- Additional context added by our staff.
About this neuroplasticity research news
Author: Wankyu Lim
Source: DGIST
Contact: Wankyu Lim – DGIST
Image: The image is credited to Neuroscience News
Original Research: Open access.
“Juvenile-to-adult refinement of thalamic reticular circuits via LRRTM3 enables high-resolution sensory encoding” by Dongsu Lee, Kyung Ah Han, Hyeonyeong Jeong, Go Eun Ha, Hyeongjin Lee, Beom Soo Kim, Chanmi Park, Yao Piao, Haeun Lee, Joon Kim, Taek Han Yoon, Seungjoon Kim, Byeongchan Kim, Jungsu Shin, Yujin Cho, Sunghyun Kang, Han-Eol Park, Ji Won Um, Chang Ho Sohn, John R. Huguenard, Jaewon Ko, and Eunji Cheong. Neuron
DOI:10.1016/j.neuron.2025.12.020
Abstract
Juvenile-to-adult refinement of thalamic reticular circuits via LRRTM3 enables high-resolution sensory encoding
Sensory processing enables adaptive behavior by accurately encoding dynamic environmental stimuli. Within thalamocortical (TC) circuits, the thalamic reticular nucleus (TRN) functions as a key inhibitory gate that regulates cortical access to sensory input.
While classical models posit that sensory circuits stabilize after early critical periods, we uncover a previously unrecognized phase of synaptic refinement in TRN circuitry extending from the juvenile period into adulthood.
This late-stage remodeling is driven by a progressive reduction in corticothalamic (CT) excitatory input and is essential for enhancing sensory gain, response linearity, and stimulus discriminability.
We identify LRRTM3, a TRN-enriched synaptic adhesion molecule, as a molecular gatekeeper of this process. TRN-specific deletion of LRRTM3 disrupts CT–TRN refinement, elevates TRN-mediated inhibition, and impairs fine tactile discrimination.
These findings revise canonical views of sensory circuit maturation, revealing that LRRTM3-mediated juvenile-to-adult TRN plasticity is essential for the emergence of high-resolution sensory encoding in the adult brain.
