UI study finds twitches during sleep activate the brain in a unique way
A University of Iowa study has found twitches made during sleep activate the brains of mammals differently than movements made while awake.
UI graduate students Alexandre Tiriac, left, and Carlos Del Rio-Bermudez say the findings of their new study provide further evidence that newborns learn about their bodies by twitching in their sleep.
Researchers say the findings show twitches during rapid eye movement (REM) sleep comprise a different class of movement and provide further evidence that sleep twitches activate circuits throughout the developing brain. In this way, twitches teach newborns about their limbs and what they can do with them.
Mark Blumberg, a psychology professor at the UI and senior author of the study, says this latest discovery is further evidence that sleep twitches— whether in dogs, cats or humans—are connected to brain development, not dreams.
“Because twitches are so different from wake movements,” he says, “these data put another nail in the coffin of the ‘chasing rabbits’ interpretation of twitches.”
For this study, Blumberg, Tiriac and fellow graduate student Carlos Del Rio-Bermudez studied the brain activity of unanesthetized rats between 8 and 10 days of age. They measured the brain activity while the animals were awake and moving and again while the rats were in REM sleep and twitching.
What they discovered was puzzling, at first.
“We noticed there was a lot of brain activity during sleep movements but not when these animals were awake and moving,” Tiriac says.
The researchers theorized that sensations coming back from twitching limbs during REM sleep were being processed differently in the brain than awake movements because they lacked what is known as “corollary discharge.”
First introduced by researchers in 1950, corollary discharge is a split-second message sent to the brain that allows animals—including rats, crickets, humans and more—to recognize and filter out sensations generated from their own actions. This filtering of sensations is what allows animals to distinguish between sensations arising from their own movements and those from stimuli in the outside world.
So, when the UI researchers noticed an increase in brain activity while the newborn rats were twitching during REM sleep but not when the animals were awake and moving, they conducted several follow-up experiments to determine whether sleep twitching is a unique self-generated movement that is processed as if it lacks corollary discharge.
The experiments were consistent in supporting the idea that sensations arising from twitches are not filtered: And without the filtering provided by corollary discharge, the sensations generated by twitching limbs are free to activate the brain and teach the newborn brain about the structure and function of the limbs.
“If twitches were like wake movements, the signals arising from twitching limbs would be filtered out,” Blumberg says. “That they are not filtered out suggests again that twitches are special—perhaps special because they are needed to activate developing brain circuits.”
The UI researchers were initially surprised to find the filtering system functioning so early in development.
“But what surprised us even more,” Blumberg says, “was that corollary discharge appears to be suspended during sleep in association with twitching, a possibility that – to our knowledge – has never before been entertained.”
Sara Agnew | Eurek Alert!
Gene therapy shows promise for treating Niemann-Pick disease type C1
27.10.2016 | NIH/National Human Genome Research Institute
'Neighbor maps' reveal the genome's 3-D shape
27.10.2016 | International School of Advanced Studies (SISSA)
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences