A recent research study, funded by the NIH of Neurological Disorders and Stroke (NINDS), reveals the differences in male and female brains in the nematode worms due to the gender specific circuits and neurological patterns in the brain. It was released on 16th May by NIH, but was originally published in Nature on 4th May, 2016.

The NINDS is one of the leading funder of research on the brain and nervous system, with a mission to investigate knowledge about the brain and nervous system for reducing the extent of neurological disease.

The findings of the research work done on the species of nematodes — ‘Caenorhabditis Elegans’ — showed that there are some neurons which are specifically present in either males or females, while others can be found in both, irrespective of the gender.

The US based researchers found that these worms demonstrate a very interesting phenomenon in their early years of life by possessing the brain connections in a mixed state i.e., they contain the neurons that are same in both males and females. However, after reaching maturity, a process called pruning is experienced which dictates the gender specific brain connections and arrangements. This finding is being considered as a revolutionary outcome in the field of neurological sciences, with this study stating that the gender specific wiring of neurons determines the dimorphic behavior.

The team of researchers also found out that PHB neurons, containing the chemosensory brain cells, have the ability to detect ‘chemical cues’ in the environment relating to food, predators or potential mates, and this is the reason why these neurons work differently in males and females.

The functioning of these neurons for males centered on the recognition of the mating partner, whereas PHB neurons in females helped them avoid specific tastes. However, it should be noted that the PHB neurons in males, in their early developmental stages, were associated with the regulation of taste. This finding strengthened the point that the pruning process helps differentiate between the sex-specific characters which occur due to the wiring in the brain.

The results of the research work done by Dr. Hobert PhD, Professor at the Columbia University Department of Biochemistry and Molecular Biophysics, and an Investigator of the Howard Hughes Medical Institute, along with his team validated the findings of their study by developing genetically engineered nematodes for observing the individual connections between brain cells more closely. These specialized nematodes were created for understanding the changed wiring patterns and behavioral differences after swapping the sex of the nematodes.

“We found that differences in male and female brains develop from a ground state, which contains features of both sexes. From this developmental state, distinctly male or female features eventually emerge,” said Dr Hobert.

The scientists highlighted one of the possible reasons for the pruning process, identified by the help of experiments, to be the ‘genes’ and certain ‘transcriptions factors’ which regulate the functions of the genes responsible for establishing the dimorphic, gender specific connections for pruning process in the nematodes.

The current research work is expected to pave ways for reveling the new insights into sex-specific circuit development of brain. Moreover, Dr Hobert, along with his colleagues, plans to examine how these molecules target specific connections for pruning in his future project plans.

Coryse St Hillaire-Clarke, PhD, and Program Officer on this NINDS project, gave her viewpoint by saying, “For decades, there has been little focus on the impact of sex on many areas of biomedical research.” She further added that, “This study helps us understand how sex can influence brain connectivity.”

National Institutes of Health (NIH) is a US based medical research agency which conducts and supports high quality advanced medical research for the investigation of causes, development of diagnostic tools and treatment facilities aimed for targeting common or fatal diseases. It holds 27 institutes and centers under its control. Furthermore, it is a component of the US Department of Health and Human Services.

Dr Hobert received a Senator Jacob Javits Award in the Neurosciences, with regard to this research. The award has been associated with providing funding to exceptional scientists who are nominated by the NINDS for up to 7 years. The award is given in the name of the late Senator Jacob Javits, who was a strong advocate of neuroscience research.

Another study on similar lines of studying the dimorphic behavior of brain functioning due to gender based differences in the animal kingdom, was published in the Hormone and Metabolic Research in August 1992. In that study, the researchers discussed developmental mechanisms and implications of the nervous system. Moreover, findings about the neuroendocrine mechanisms and dimorphic neural circuits along with neuronal physiology were the main objective of the study.

In the near future, this study has the potential to act as a revolutionizing step in understanding the field of neurological development featuring gender based neurological differences, which are caused by the genetic factors in human subjects.