Scientists at the University of Rochester have discovered that the hormone estrogen plays a pivotal role in how the brain processes sounds.
The findings, published in today's issue of The Journal of Neuroscience, show for the first time that a sex hormone can directly affect auditory function, and point toward the possibility that estrogen controls other types of sensory processing as well. Understanding how estrogen changes the brain's response to sound, say the authors, might open the door to new ways of treating hearing deficiencies.
"We've discovered estrogen doing something totally unexpected," says Raphael Pinaud, assistant professor of brain and cognitive sciences at the University of Rochester and lead author of the study. "We show that estrogen plays a central role in how the brain extracts and interprets auditory information. It does this on a scale of milliseconds in neurons, as opposed to days, months or even years in which estrogen is more commonly known to affect an organism."
Previous studies have hinted at a connection between estrogen and hearing in women who have low estrogen, such as often occurs after menopause, says Pinaud. No one understood, however, that estrogen was playing such a direct role in determining auditory functions in the brain, he says. "Now it is clear that estrogen is a key molecule carrying brain signals, and that the right balance of hormone levels in men and women is important for reasons beyond its role as a sex hormone," says Pinaud.
Pinaud, along with Liisa Tremere, a research assistant professor of brain and cognitive sciences, and Jin Jeong, a postdoctoral fellow in Pinaud's laboratory, demonstrated that increasing estrogen levels in brain regions that process auditory information caused heightened sensitivity of sound-processing neurons, which encoded more complex and subtle features of the sound stimulus. Perhaps more surprising, says Pinaud, is that by blocking either the actions of estrogen directly, or preventing brain cells from producing estrogen within auditory centers, the signaling that is necessary for the brain to process sounds essentially shuts down. Pinaud's team also shows that estrogen is required to activate genes that instruct the brain to lay down memories of those sounds.
"It turns out that estrogen plays a dual role," says Pinaud. "It modulates the gain of auditory neurons instantaneously, and it initiates cellular processes that activate genes that are involved in learning and memory formation."
Pinaud and his group stumbled upon these findings while investigating how estrogen may help change neuronal circuits to form memories of familiar songs in a type of bird typically used to understand the biology of vocal communication. "Based on our findings we must now see estrogen as a central regulator of hearing," he says. "It both determines how carefully a sound must be processed, and activates intracellular processes that occur deep within the cell to form memories of sound experiences."
Pinaud and his team will continue their work investigating how neurons adapt their functionality when encountering new sensory information and how these changes may ultimately enable the formation of memories. They also will continue exploring the specific mechanisms by which estrogen might impact these processes.
"While we are currently conducting further experiments to confirm it, we believe that our findings extrapolate to other sensory systems and vertebrate species," says Pinaud. "If this is the case, we are on the way to showing that estrogen is a key molecule for processing information from all the senses."About the University of Rochester
Jonathan Sherwood | EurekAlert!
Why might reading make myopic?
18.07.2018 | Universitätsklinikum Tübingen
Unique brain 'fingerprint' can predict drug effectiveness
11.07.2018 | McGill University
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
19.07.2018 | Materials Sciences
19.07.2018 | Earth Sciences
19.07.2018 | Life Sciences