Sex-Based Neural Differences: New Insights from Single Neuron Structure in C. elegans

Recent research has shed light on how sex-specific differences in neural structures can influence behavior, using the tiny nematode Caenorhabditis elegans as a model. C. elegans, a widely used organism in neuroscience, has two sexes — hermaphrodites, capable of self-fertilization, and males. Despite its simplicity, this organism offers remarkable insights because all of its 302 neurons are consistent in location and identity, allowing detailed mapping of neural architecture.

A study conducted by scientists at the Technion-Israel Institute of Technology focused on the PVD neuron, a highly branched sensory nerve cell involved in pain sensation in hermaphrodites. Researchers discovered that in males, the PVD neuron develops additional branches into the tail fan, a structure crucial for mating behaviors. These male-specific branches form after the final stage of development and are linked to mating activities, which are slower and less coordinated when the PVD structure is disrupted.

This finding reveals a distinct sexual dimorphism at the cellular level, directly associated with sex-specific behaviors. Interestingly, the overall core structure of PVD remains similar in both sexes, signifying that subtle morphological differences can have significant behavioral implications.

The implications extend beyond nematodes. In humans, differences in brain structure between men and women are linked to susceptibility to various neurological conditions, such as depression and Parkinson’s disease. However, identifying how individual neurons contribute to these differences remains challenging given the complexity of the human brain, which contains approximately 75 billion neurons.

The simplicity of C. elegans makes it an ideal model to investigate how sex-specific neural differences develop and influence behavior. By understanding these mechanisms at the cellular level, scientists hope to gain insights into how sex differences in the brain may affect individual responses and neurological health in humans.

This research opens exciting avenues for exploring how structural variability in neurons can drive behavioral diversity and disease susceptibility based on sex.

Source: https://medicalxpress.com/news/2025-05-sex-based-brain-differences-neuron.html