The discovery of a mechanism in the brain that controls the physical and verbal tics in adolescents with Tourette syndrome may lead to new non-drug therapies.
“This new study is very important as it indicates that motor and vocal tics in children may be controlled by brain changes that alter the excitability of brain cells ahead of voluntary movements,” says Stephen Jackson, professor in the University of Nottingham’s School of Psychology.Related Articles On Futurity
“You can think of this as a bit like turning the volume down on an over-loud motor system. This is important as it suggests a mechanism that might lead to an effective non-pharmacological therapy for Tourette syndrome,” adds Jackson.
The research appears in the British Psychological Society’s Journal of Neuropsychology.Brain re-structuring
The neurological condition Tourette syndrome (TS) affects around one child in every 100 and usually starts during early childhood. Scientists believe that the tics that affect children with TS are caused by faulty wiring in the brain that leads to hyper excitability in the brain regions controlling motor function.
In adolescence, there is a period of ‘pruning back’ in which redundant brain connections are removed and other structural and functional brain changes occur.
During this time, around one-third of children with TS will find that their tics disappear and another third are able to more effectively control their tics. Unfortunately, the remaining third of individuals will see little or no change in their tics and are likely to remain troubled by their symptoms into adulthood.
This clinical observation suggests that there are mechanisms in the brain that are involved in controlling tics and undergo development or re-organization during the teenage years.
“The research is based on the general hypothesis that an area in the brain called the striatum is overactive as a result of alterations in the early development of the brain,” explains PhD student Amelia Draper, who carried out the study. “As a result, the signals that are relayed to the brain’s cortex region lead to hyper-excitability and cause tics to occur.”
“We have looked at how that hyperactivity and the resultant tics might be controlled by finding a way to ‘turn down the volume’ on that “cortical excitability.” This is potentially extremely important as the parents of children with tics are desperate to find a safe and effective therapy that is an alternative to drug treatments.”Unwanted movements
In the current study the team used a method called transcranial magnetic stimulation (TMS) in which a magnetic field is passed over the brain to produce a weak electrical current that stimulates motor function to induce a twitch response.
By delivering TMS at different points in time as participants were about to undertake a hand movement, the researchers were able to measure alterations in brain excitability ahead of the movement and chart the differences between each person.
The study showed that subjects with TS, unlike those of a similar age without the condition, were least able to modulate the hyperactivity in the brain.
“If there is a relationship between this cortical excitability or hyperactivity and tics then this is really important as it means that there may be something that we might be able to do to help children with TS to better control these unwanted movements,” explains Jackson.
Further research by the team has involved the use of a similar type of brain stimulation called transcranial direct current stimulation (TDCS) to study the brains of children with TS. Early results suggest that TDCS can be applied to decrease neuronal excitability and this may be effective in suppressing tics for extended periods.
In addition, if another form of TDCS is applied, one that increases neuronal excitability, it may act to improve learning and memory function, particularly in the context of behavioral therapies. Following use of these treatments lasting effects can be applied to the brain.Effective and lasting
If proven to be effective, the technology could be adapted into a TENS machine-style device that would offer a cheap, portable, and individualized therapy for children with TS.
“For the one-third of people who aren’t going to get better this could offer them a much needed assistance with controlling their tics, while relying less on other conventional pharmaceutical therapies which can have associated side effects such as weight gain or tiredness,” says Jackson.
“It can be applied at home while the child is watching TV or eating their cornflakes so it would reduce the amount of school they would miss and potentially we can use the TDCS to both control the tics and make that control more effective and longer lasting.”
As part of her work Amelia Draper is also using MRI scanning technology to examine the potential relationship between cortical excitability and a brain chemical that appears to be strongly linked to neuronal excitability in TS.
The James Tudor Foundation supported the research.
Source: University of Nottingham
Two results from astrophysical instruments at the South Pole named Physics World's "Discoveries of the Year"
Discoveries made by researchers using two large-scale, National Science Foundation (NSF)-funded instruments at Antarctica's Amundsen-Scott South Pole Station have been named among 2013's top 10 breakthroughs in physics by the British magazine Physics World.
The IceCube Neutrino Observatory's first-ever observations of cosmic neutrinos leads the list, which also includes a separate discovery made by the 10-meter telescope at the South Pole.
The IceCube Collaboration, an ...
More at http://www.nsf.gov/news/news_summ.jsp?cntn_id=129871&WT.mc_id=USNSF_51&WT.mc_ev=click
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If a smell is associated with a threatening situation, that smell can trigger a fear reaction at the sensory level, even before the brain interprets the odor.
“What is surprising is that we tend to think of learning as something that only happens deep in the brain after conscious awareness,” says John McGann, associate professor of behavioral and systems neuroscience in the Department of Psychology at Rutgers University. “But now we see how the nervous system can become especially sensitive to threatening stimuli and that fear-learning can affect the signals passing from sensory organs to the brain.”Related Articles On Futurity
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McGann and students Marley Kass and Michelle Rosenthal made this discovery by using light to observe activity in the brains of genetically engineered mice through a window in the mouse’s skull. They found that those mice that received an electric shock simultaneously with a specific odor showed an enhanced response to the smell in the cells in the nose, before the message was delivered to the neurons in the brain. The study appears in the journal Science.PTSD
This new research—which indicates that fearful memories can influence the senses—could help to better understand conditions like post traumatic stress disorder (PTSD), in which feelings of anxiety and fear exist even though an individual is no longer in danger.
“We know that anxiety disorders like PTSD can sometimes be triggered by smell, like the smell of diesel exhaust for a soldier,” says McGann. “What this study does is gives us a new way of thinking about how this might happen.”
In their study, the scientists also discovered a heightened sensitivity to odors in the mice traumatized by shock. When these mice smelled the odor associated with the electrical shocks, the amount of neurotransmitter—chemicals that carry communications between nerve cells—released from the olfactory nerve into the brain was as big as if the odor were four times stronger than it actually was.
This created mice whose brains were hypersensitive to the fear-associated odors. Before now, scientists did not think that reward or punishment could influence how the sensory organs process information.
The next step in the continuing research, McGann says, is to determine whether the hypersensitivity to threatening odors can be reversed by using exposure therapy to teach the mice that the electrical shock is no longer associated with a specific odor. This could help develop a better understanding of fear learning that might someday lead to new therapeutic treatments for anxiety disorders in humans, he says.
The National Institute of Mental Health and the National Institute on Deafness and Other Communication Disorders provided funding for the research.
Congress readies plan to end mandatory cuts until 2016.
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