PVD construction displaying sex-based variations. On the appropriate, PVD in an grownup hermaphrodite (cyan). On the left, PVD in an grownup male (cyan), alongside 18 neurons innervating the male tail fan (magenta). Scale bar: 0.05 mm (white) in every picture. Credit score: Podbilewicz’s Lab, Technion
Is there a distinction in mind construction between women and men? If we had been to seek out such a distinction in a single neuron, wouldn’t it matter?
One of the vital helpful fashions for finding out these questions is the nematode Caenorhabditis elegans (C. elegans). This tiny worm has a number of traits that make it a wonderful analysis mannequin, considered one of which is that each cell in its physique has a predetermined identification and lineage.
Like people, C. elegans has two sexes. Nevertheless, as a substitute of female and male, the 2 sexes of this worm are male and hermaphrodite—a self-fertilizing particular person able to producing each female and male gametes (sperm and eggs), permitting it to breed with out a associate.
Researchers from the College of Biology on the Technion-Israel Institute of Expertise have examined these sex-specific variations (sexual dimorphism) in C. elegans, and uncovered shocking findings.
The examine, printed in Proceedings of the Nationwide Academy of Sciences, was led by Dr. Yael Iosilevskii and Dr. Menachem Katz from Prof. Beni Podbilewicz’s Lab, in collaboration with Prof. David H. Corridor of the Albert Einstein Faculty of Medication in New York.
The researchers found {that a} extremely branched neuron known as PVD, beforehand characterised in hermaphrodites, types a unique construction in males. Furthermore, whereas in hermaphrodites, PVD features primarily in ache sensing, in males, it has a further position throughout mating; when its improvement is disrupted, males are slower and fewer coordinated. This discovery supplies a singular instance of sexual dimorphism within the construction of a single neuron, which is linked to behavioral variations.
‘Male’ vs. ‘feminine’ brains
It has lengthy been established that women and men have totally different susceptibilities to varied neurological issues. For instance, girls are extra vulnerable to despair, whereas males have the next danger of Parkinson’s illness. May these variations be linked to the construction of particular person neurons within the mind? That is tough to find out because of the sheer variety of neurons within the human mind—roughly 75 billion.
Even when a distinction had been discovered between the sexes in only one neuron, pinpointing its actual contribution can be difficult, as even the best duties require a large number of intricately interconnected neurons.
To discover the importance of a single neuron’s spatial construction, researchers have turned to the nematode C. elegans, only one millimeter lengthy. A singular characteristic of this organism is that the identification of all 302 neurons within the hermaphrodite is invariant, permitting scientists to map their placement, spatial construction, and connections absolutely.
“Furthermore,” mentioned Prof. Podbilewicz, “within the nematode population, there are also male individuals with distinct anatomy, additional neurons, and different behavior. 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?”
To reply these questions, Dr. Iosilevskii and Dr. Katz studied the event of the sensory neuron PVD. This neuron has a extremely branched construction, with repetitive subunits resembling a candelabra (“menorahs”). Its distinctive form and its improvement in the course of the organism’s maturation have made it a analysis focus for over a decade. Whereas a lot is thought about its improvement in hermaphrodites, PVD had not been characterised in males or examined for sexual dimorphism.
The Technion researchers got down to decide whether or not male PVD neurons develop a unique spatial construction and whether or not this distinction influences a male’s conduct.
When inspecting PVD improvement in males, the researchers discovered that its menorah-like buildings remained constant throughout each sexes. Nevertheless, they had been stunned to find that in grownup males, PVD extends further branches into the tail fan—a specialised male organ used for mating. Together with Prof. Corridor, they discovered that these branches are solely separate from the beforehand recognized neurons on this area.
This distinctive branching of PVD doesn’t happen in the course of the tail fan’s improvement however emerges instantly afterward, in the course of the ultimate molt from juvenile to grownup. Shortly afterwards, the male begins to exhibit his sex-specific mating conduct. The researchers additional found that when PVD doesn’t develop correctly, this mating conduct is impaired, inflicting males to turn into slower and fewer coordinated.
This discovery of sexual dimorphism within the construction of a single sensory neuron, which additionally pertains to male-specific conduct, supplies a singular instance in C. elegans and opens new avenues for finding out sex-based neural variations. The invention is predicted to reinforce our understanding of how such sexual dimorphisms alter responses each on the single-cell stage and the conduct of the entire organism.
Extra data:
Yael Iosilevskii et al, The PVD neuron has male-specific construction and mating operate in Caenorhabditis elegans, Proceedings of the Nationwide Academy of Sciences (2025). DOI: 10.1073/pnas.2421376122
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Technion – Israel Institute of Expertise
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Intercourse-based mind variations: Construction of a single neuron in C. elegans supplies new insights (2025, Could 13)
retrieved 14 Could 2025
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