Neurobiologists at Indiana University showed that if the actions of mesotocin are blocked in the brains of zebra finches, a highly social songbird, the birds shift their social preferences.
They spend significantly less time with familiar individuals and more time with unfamiliar individuals. The birds also become less social, preferring to spend less time with a large group of same-sex birds and more time with a smaller group. Conversely, if birds are administered mesotocin instead of the blocker, the finches become more social and prefer familiar partners.
Perhaps most striking is the fact that none of the treatments affect males -- only females.
According to James Goodson, lead author on the study, the sex differences in birds provide important clues to the evolutionary history of oxytocin functions in humans and other mammals. "Oxytocin is an evolutionarily descendant of mesotocin and has long been associated with female reproductive functions -- things such as pair bonding with males, giving birth, providing maternal care and ejecting milk for infants," said Goodson.
Goodson and colleagues have found hints of similar processes in fish, and he speculates that oxytocin-like neuropeptides have played special roles in female affiliation ever since the peptides first evolved. That was sometime around 450 million years ago, about the same time that jaws evolved.
"The ancient properties of this system appear to be retained in all major vertebrate groups, and date back to our common ancestor with sharks," says co-author Marcy Kingsbury, associate scientist at IU Bloomington.
But if all vertebrates possess similar neuropeptide circuits, why don't they all live in big groups -- flocks, schools or herds? A possible answer to that question is provided in the second part of the Science study. The authors speculated that the behavioral actions of mesotocin may differ across species depending upon the distribution of "receptors" for the chemical in the brain -- that is, places where mesotocin can attach to brain cells and alter their activity.
Using a radioactive compound that attaches to oxytocin-like receptors, the authors mapped the distribution of receptors in three finch species that form flocks and two species that are territorial and highly aggressive. What they found was that the flocking species had many more receptors in a part of the brain known as the lateral septum. And when they blocked those receptors in female zebra finches, the birds became less social.
According to Goodson, these findings suggest that it is actually the concentration and location of receptors that determines whether an individual prefers spending time in large groups. Natural selection could act to increase the number of receptors expressed by certain lateral septum neurons, or by altering the regions where receptor genes are expressed, depending on whether female sociality is favored or not among the individuals of a species.
If Goodson's discovery holds true for other birds and even mammals, the concentration of receptors for mesotocin (and oxytocin) in the lateral septum could accurately predict whether an individual is naturally gregarious.
"The lateral septum is structurally very similar in reptiles, birds and mammals," Goodson said. "To our knowledge, it plays an important role in the social and reproductive behaviors of all land vertebrates."
What might be next for Goodson's research group?
"We still don't understand why mesotocin and oxytocin are so potent in females, but not always in males," Goodson said. "And we also don't fully understand how the lateral septum functions to influence sociality." But he is convinced that his group's ongoing studies of songbirds will soon provide the answers.
IU Bloomington Associate Scientist Marcy Kingsbury, postdoctoral fellow David Kabelik, research associate Sara Schrock and Ph.D. student James Klatt also contributed to this research. It was funded with a grant from the National Institutes of Health (NIMH).
To speak with James Goodson, please contact him at 812-856-4756 or at firstname.lastname@example.org.
James Goodson | Newswise Science News
Two Group A Streptococcus genes linked to 'flesh-eating' bacterial infections
25.09.2017 | University of Maryland
Rainbow colors reveal cell history: Uncovering β-cell heterogeneity
22.09.2017 | DFG-Forschungszentrum für Regenerative Therapien TU Dresden
At the productronica trade fair in Munich this November, the Fraunhofer Institute for Laser Technology ILT will be presenting Laser-Based Tape-Automated Bonding, LaserTAB for short. The experts from Aachen will be demonstrating how new battery cells and power electronics can be micro-welded more efficiently and precisely than ever before thanks to new optics and robot support.
Fraunhofer ILT from Aachen relies on a clever combination of robotics and a laser scanner with new optics as well as process monitoring, which it has developed...
Plants and algae use the enzyme Rubisco to fix carbon dioxide, removing it from the atmosphere and converting it into biomass. Algae have figured out a way to increase the efficiency of carbon fixation. They gather most of their Rubisco into a ball-shaped microcompartment called the pyrenoid, which they flood with a high local concentration of carbon dioxide. A team of scientists at Princeton University, the Carnegie Institution for Science, Stanford University and the Max Plank Institute of Biochemistry have unravelled the mysteries of how the pyrenoid is assembled. These insights can help to engineer crops that remove more carbon dioxide from the atmosphere while producing more food.
A warming planet
Our brains house extremely complex neuronal circuits, whose detailed structures are still largely unknown. This is especially true for the so-called cerebral cortex of mammals, where among other things vision, thoughts or spatial orientation are being computed. Here the rules by which nerve cells are connected to each other are only partly understood. A team of scientists around Moritz Helmstaedter at the Frankfiurt Max Planck Institute for Brain Research and Helene Schmidt (Humboldt University in Berlin) have now discovered a surprisingly precise nerve cell connectivity pattern in the part of the cerebral cortex that is responsible for orienting the individual animal or human in space.
The researchers report online in Nature (Schmidt et al., 2017. Axonal synapse sorting in medial entorhinal cortex, DOI: 10.1038/nature24005) that synapses in...
Whispering gallery mode (WGM) resonators are used to make tiny micro-lasers, sensors, switches, routers and other devices. These tiny structures rely on a...
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
25.09.2017 | Power and Electrical Engineering
25.09.2017 | Health and Medicine
25.09.2017 | Physics and Astronomy