A groundbreaking new study has uncovered remarkable sex-based differences in the structure of a single neuron in the tiny nematode—Caenorhabditis elegans (C. elegans)—offering fresh insight into the underpinnings of sex-specific neural and behavioral differences, with far-reaching implications for understanding the human brain. Published in the Proceedings of the National Academy of Sciences and conducted by a collaborative team at Technion-Israel Institute of Technology and Albert Einstein College of Medicine, the research reveals that a single neuron, previously believed to function identically in both sexes, displays structural and functional differences linked to sex-specific behaviors in this simple organism (MedicalXpress).
The relevance of this discovery goes well beyond worms. For years, scientists have known that men and women are prone to different neurological diseases: women report higher rates of depression, while men are more susceptible to Parkinson’s disease. The biological roots of such differences have been elusive, largely because pinpointing the impact of specific neurons in the vast human brain—with its estimated 75 billion neurons and complex connections—is a formidable challenge. Yet, even among Thais, questions about how sex-based differences influence brain health and disease outcomes resonate deeply, especially with an aging population and growing prevalence of neurological disorders. By showing how sexual dimorphism can manifest in the simple but thoroughly mapped nervous system of C. elegans, this new study offers clues to the subtle but critical variations that may influence human health.
C. elegans is a favored model in neuroscience due to its simplicity—hermaphrodites contain exactly 302 neurons, each with a predetermined identity and lineage. In the natural world, these nematodes exist as either males or hermaphrodites (which can self-fertilize), simplifying the study of sex-based differences. The Technion research team examined the PVD neuron in C. elegans, a highly branched cell previously studied mostly in hermaphrodites and known to play a key role in sensing pain. The study revealed, for the first time, that male worms develop an additional set of branches from this neuron into a male-specific organ known as the tail fan, a structure used exclusively during mating.
This sex-specific development does not occur during the larval formation of the tail fan, but emerges only during the final molt to adulthood—the very stage at which males begin to display mating behaviors. The researchers further demonstrated that when the PVD neuron’s development is disrupted in males, their mating becomes notably slower and less coordinated (PNAS, 2025). In contrast, the neuron in hermaphrodites maintains its familiar structure and function, primarily focused on pain sensation. These findings provide convincing evidence of sexual dimorphism at the cellular level and its direct link to behavioral differences—an achievement hardly possible to replicate in higher animals, let alone humans.
Professor Podbilewicz, the leader of the research group, explained, “This makes for a remarkably simple system where we can directly ask: What determines the structure of each neuron in the nervous system? Are there sex-specific differences, and do they affect behavior?” For Thai neuroscientists, these types of model systems are essential—allowing clear, traceable experimentation on questions that remain nearly impossible to answer in more complex organisms (MedicalXpress).
The study’s strengths are rooted both in the simplicity of the C. elegans model and in the thorough mapping of its nervous system, where every neuron’s identity, connections, and purpose can be traced. Previous research had established the branching, candelabra-like (“menorah”) structure of the PVD neuron in hermaphrodites, but the discovery of its additional male-specific branches in adults marks an important advance in understanding how such subtle, late-emerging changes can drive sex-specific behaviors. Notably, this divergent branching does not arise during the early development of the tail fan organ, but precisely after the final juvenile-to-adult molt, synchronizing with the beginning of sex-specific behavioral expression.
“This discovery is expected to enhance our understanding of how such sexual dimorphisms alter responses both at the single-cell level and the behavior of the whole organism,” a spokesperson for the research team said (MedicalXpress). In the context of Thai science, this insight is especially valuable for ongoing efforts to find the cellular bases of neuropsychiatric and neurodevelopmental conditions that show clear sex differences—such as autism spectrum disorder, which has higher prevalence in males, and depression, which predominates among females (World Health Organization).
For Thais, understanding the role of sexual dimorphism is becoming increasingly urgent, not only for its scientific interest but also for public health. The growing rate of neurological disorders underscores the need for tailored prevention and intervention strategies. Recognizing that even the structure of a single neuron may tilt the prevalence or presentation of disease can shape research priorities and health policy.
Historically, Thai culture has paid close attention to the balance of masculine and feminine energies—a theme reflected in traditional medicine and Buddhist thought, where the mind is believed to be shaped by a confluence of inherited and environmental factors. This scientific discovery fits into a broader context of inquiry about how biological factors, beyond social conditioning and lifestyle, may determine males’ and females’ susceptibility to stress, pain, or neurodegeneration.
Looking ahead, this research opens new avenues for neuroscientists worldwide and in Thailand. Cutting-edge research institutions from Mahidol University to Chulalongkorn University have invested in C. elegans and other model organisms to dissect the roots of brain development, function, and disease (Mahidol University). The ability to manipulate, visualize, and genetically modify single neurons offers the hope of understanding how sex-based differences in the nervous system contribute to whole-organism behaviors—and, ultimately, to unequal patterns of disease risk that affect real lives.
The immediate impact may seem distant, but it sets a foundation for future research that could, in time, allow Thai scientists to develop sex-appropriate diagnostic markers or treatments for brain diseases. There may even be applications in the growing field of personalized medicine, where biological sex is recognized as a key determinant in predicting disease risk and response to therapy.
As for practical recommendations, Thai readers can take inspiration from this research: When seeking information or care for neurological and mental health conditions, be aware that sex-based differences can play an important role in disease patterns, progression, and treatment response. Supporting local neuroscience and mental health research, especially studies that stratify results by sex, is a step forward for everyone’s well-being. Those interested in deeper understanding can explore educational resources or public programs at Thailand’s leading universities and hospitals, which increasingly offer online and in-person seminars on genetics, neuroscience, and sex-based medicine.
Further, for educators and policymakers, the study is a reminder of the value of science education and research infrastructure. The story of a single neuron’s difference in a one-millimeter worm—painstakingly mapped by international collaboration—may well change how we understand the most complex structure in the human body: the brain.
For continued advances, readers are encouraged to follow developments in neuroscience, advocate for inclusive research funding, and participate in public health forums that recognize both cultural wisdom and modern medical science in understanding the Thai brain.
Sources: MedicalXpress, PNAS, World Health Organization, Mahidol University