Posts tagged mood
Articles and news from the latest research reports.
Researchers uncover brain molecule regulating human emotion, mood
A RIKEN research team has discovered an enzyme called Rines that regulates MAO-A, a major brain protein controlling emotion and mood. The enzyme is a potentially promising drug target for treating diseases associated with emotions such as depression.
Monoamine oxidase A (MAO-A) is an enzyme that breaks down serotonin, norephinephrine and dopamine, neurotransmitters well-known for their influence on emotion and mood. Nicknamed the “warrior gene”, a variant of the MAOA gene has been associated with increased risk of violent and anti-social behavior.
While evidence points to a link between MAO-A levels and various emotional patterns, however, the mechanism controlling MAO-A levels in the brain has remained unknown.
Now, a research team headed by Jun Aruga at the RIKEN Brain Science Institute has shown for the first time that a ligase named Rines (RING finger-type E3 ubiquitin ligase) regulates these levels. Their research shows that mice without the Rines gene exhibit impaired stress responses and enhanced anxiety, controlled in part through the regulation of MAO-A levels. The study is published today in Journal of Neuroscience.
As the first study to demonstrate regulation of MAO-A protein via the ubiquitin proteasomal system, this research presents a promising new avenue for analyzing the role of MAO-A in brain function. Further research promises insights into the treatment of anxiety, stress-related disorders and impaired social functions.
Reference:
Miyuki Kabayama, Kazuto Sakoori, Kazuyuki Yamada, Veravej G. Ornthanalai, Maya Ota, Naoko Morimura, Kei-ichi Katayama, Niall P. Murphy, and Jun Aruga. “Rines E3 Ubiquitin Ligase Regulates MAO-A Levels and Emotional Responses.” The Journal of Neuroscience, 2013.
‘Good Vibrations’! Brain Ultrasound Improves Mood
Non-invasive brain stimulation techniques aimed at mental and neurological conditions include transcranial magnetic stimulation (TMS) for depression, and transcranial direct current (electrical) stimulation (tDCS), shown to improve memory. Transcranial ultrasound stimulation (TUS) has also shown promise.
Ultrasound consists of mechanical vibrations, like sound, but with frequencies far greater than the upper limit of human hearing, around 20 thousand to 20 million cycles per second (20 kilohertz to 20 megahertz). Ultrasound vibrations penetrate bodily tissue including bone, and are widely used to image anatomical structures via echo effects, e.g. visualizing unborn babies in mothers’ wombs, and organs, blood vessels, nerves and other structures in medical procedures. Virtually every part of the body, including the brain, has been safely imaged with low to moderate intensity ultrasound.
High intensity, focused ultrasound can damage tissue by heating and cavitation, and has been used to ablate tumors and other lesions. ‘Sub-thermal’ ultrasound can safely stimulate neural tissue. In 2002 a UCLA group led by Alexander Bystritsky noticed beneficial side effects in psychiatric patients whose brains were imaged by TUS. A team led by Virginia Tech’s W. Jamie Tyler has shown TUS-induced behavioral and electrophysiological changes in animals. A Harvard group led by S-S Yoo has used focused ultrasound aimed at mouse motor cortex to wag the mouse’s tail. But clinical trials of TUS aimed at human mental states have been lacking.
Now, in an article in the journal Brain Stimulation, a group from the Departments of Anesthesiology and Radiology at the University of Arizona Medical Center in Tucson, Arizona has investigated TUS for modulating mental states in a pilot study in human volunteers suffering from chronic pain. A clinical ultrasound imaging device (General Electric LOGIQe) was used, with the ultrasound probe applied at the scalp overlying the brain’s temporal and frontal cortex (visible on the imaging screen). In random order, each subject received two 15 second exposures: sham/placebo, and 8 megahertz ultrasound (undetectable to subjects). Following exposure, subjects reported (by visual analog scales) significant improvement in mood both 10 minutes and 40 minutes after TUS, but not after sham/placebo. In a followup study (led by University of Arizona psychologists Jay Sanguineti and John JB Allen) preliminary results suggest 2 megahertz TUS (which traverses skull more readily) may be more effective in mood enhancement than 8 megahertz TUS.
The mechanism by which TUS can affect mental states is unknown (as is the mechanism by which the brain produces mental states). Tyler proposed TUS acts by vibrational stretching of neuronal membranes and/or extracellular matrix, but two recent papers from the group of Anirban Bandyopadhyay at National Institute of Material Sciences (NIMS) in Tsukuba, Japan (Sahu et al. [2013] Appl. Phys. Letts.; Sahu et al [2013] Biosensors and Bioelectronics) have suggested another possibility. The NIMS group used nanotechnology to study conductive properties of individual microtubules, protein polymers of tubulin (the brain’s most prevalent protein). Major components of the neuronal cytoskeleton, microtubules grow and extend neurons, form and regulate synapses, are disrupted in Alzheimer’s disease, and theoretically linked to information processing, memory encoding and mental states. Bandyopadhyay’s NIMS group found that microtubules have remarkable electronic conductive properties when excited at certain specific resonant frequencies, e.g. in the low megahertz, precisely the range of TUS.
Dr. Stuart Hameroff, lead author on the new TUS study, said: “This suggests TUS may stimulate natural megahertz resonances in brain microtubules, enhancing not only mood and conscious mental states, but perhaps also microtubule functions in synaptic plasticity, nerve growth and repair. We plan further studies of TUS on traumatic brain injury, Alzheimer’s disease and post-traumatic stress disorders. ‘Tuning the tubules’ may help a variety of mental states and cognitive disorders.”
(Source: newswise.com)
Trying to be Happier Works When Listening to Upbeat Music
The song, “Get Happy,” famously performed by Judy Garland, has encouraged people to improve their mood for decades. Recent research at the University of Missouri discovered that an individual can indeed successfully try to be happier, especially when cheery music aids the process. This research points to ways that people can actively improve their moods and corroborates earlier MU research.
“Our work provides support for what many people already do – listen to music to improve their moods,” said lead author Yuna Ferguson, who performed the study while she was an MU doctoral student in psychological science. “Although pursuing personal happiness may be thought of as a self-centered venture, research suggests that happiness relates to a higher probability of socially beneficial behavior, better physical health, higher income and greater relationship satisfaction.”
In two studies by Ferguson, participants successfully improved their moods in the short term and boosted their overall happiness over a two week period. During the first study, participants improved their mood after being instructed to attempt to do so, but only if they listened to the upbeat music of Copland, as opposed to the more somber Stravinsky. Other participants, who simply listened to the music without attempting to change their mood, also didn’t report a change in happiness. In the second study, participants reported higher levels of happiness after two weeks of lab sessions in which they listened to positive music while trying to feel happier, compared to control participants who only listened to music.
However, Ferguson noted that for people to put her research into practice, they must be wary of too much introspection into their mood or constantly asking, “Am I happy yet?”
“Rather than focusing on how much happiness they’ve gained and engaging in that kind of mental calculation, people could focus more on enjoying their experience of the journey towards happiness and not get hung up on the destination,” said Ferguson.
Ferguson’s work corroborated earlier findings by Ferguson’s doctoral advisor and co-author of the current study, Kennon Sheldon, professor of psychological science in MU’s College of Arts and Science.
“The Hedonic Adaptation Prevention model, developed in my earlier research, says that we can stay in the upper half of our ‘set range’ of potential happiness as long as we keep having positive experiences, and avoid wanting too much more than we have,” said Sheldon. “Yuna’s research suggests that we can intentionally seek to make mental changes leading to new positive experiences of life. The fact that we’re aware we’re doing this, has no detrimental effect.”
Ferguson is now assistant professor of psychology at Pennsylvania State University Shenango. The study, “Trying to Be Happier Really Can Work: Two Experimental Studies,” was published in The Journal of Positive Psychology.
The BCMI-MIdAS (Brain-Computer Music Interface for Monitoring and Inducing Affective States) project
The central purpose of the project is to develop technology for building innovative intelligent systems that can monitor our affective state, and induce specific affective states through music, automatically and adaptively. This is a highly interdisciplinary project, which will address several technical challenges at the interface between science, technology and performing arts/music (incorporating computer-generated music and machine learning).
Research questions
- How can music change affective states and what are the specific musical traits (i.e., the parameters of a piece of music) that elicit such states?
- How can we control such traits in a piece of music in order to induce specific affective states in a participant?
- How can we effectively detect information about affective states induced by music in the EEG signal, going beyond EEG asymmetry and characterising information contained in synchronisation patterns?
- How can we use the EEG to monitor the affective state induced by music on-line (i.e., in “real-time”)?
- How can we produce a generative music system capable of generating music embodying musical traits aimed at inducing specific affective states, observable in the EEG of the participant?
- How can we build an intelligent adaptive system for monitoring and inducing affective states through music on-line?
(Source: cmr.soc.plymouth.ac.uk)
Brain’s Stem Cells “Eavesdrop” to Find out When to Act
Release Date: 08/06/2012
Working with mice, Johns Hopkins researchers say they have figured out how stem cells found in a part of the brain responsible for learning, memory and mood regulation decide to remain dormant or create new brain cells. Apparently, the stem cells “listen in” on the chemical communication among nearby neurons to get an idea about what is stressing the system and when they need to act.
A single parvalbumin-expressing interneuron (red) surrounded by many adult neural stem cells (green) in the brain’s hippocampus. Credit: Gerry Sun
The researchers say understanding this process of chemical signaling may shed light on how the brain reacts to its environment and how current antidepressants work, because in animals these drugs have been shown to increase the number of brain cells. The findings are reported July 29 in the advance online publication of Nature.
“What we learned is that brain stem cells don’t communicate in the official way that neurons do, through synapses or by directly signaling each other,” says Hongjun Song, Ph.D., professor of neurology and director of Johns Hopkins Medicine’s Institute for Cell Engineering’s Stem Cell Program. “Synapses, like cell phones, allow nerve cells to talk with each other. Stem cells don’t have synapses, but our experiments show they indirectly hear the neurons talking to each other; it’s like listening to someone near you talking on a phone.”
The “indirect talk” that the stem cells detect is comprised of chemical messaging fueled by the output of neurotransmitters that leak from neuronal synapses, the structures at the ends of brain cells that facilitate communication. These neurotransmitters, released from one neuron and detected by a another one, trigger receiving neurons to change their electrical charges, which either causes the neuron to fire off an electrical pulse propagating communication or to settle down, squelching further messages.
To find out which neurotransmitter brain stem cells can detect, the researchers took mouse brain tissue, attached electrodes to the stem cells and measured any change in electrical charge after the addition of certain neurotransmitters. When they treated the stem cells with the neurotransmitter GABA – a known signal-inhibiting product the stem cells’ electrical charges changed, suggesting that the stem cells can detect GABA messages.
To find out what message GABA imparts to brain stem cells, the scientists used a genetic trick to remove the gene for the GABA receptor — the protein on the surface of the cell that detects GABA — only from the brain stem cells. Microscopic observation of brain stem cells lacking the GABA receptor over five days showed these cells replicated themselves, or produced glial cells — support cells for the neurons in the brain. Brain stem cells with their GABA receptors intact appeared to stay the same, not making more cells.
Next, the team treated normal mice with valium, often used as an anti-anxiety drug and known to act like GABA by activating GABA receptors when it comes in contact with them. The scientists checked the mice on the second and seventh day of valium use and counted the number of brain stem cells in untreated mice and mice treated with the GABA activator. They found the treated mice had many more dormant stem cells than the untreated mice.
“Traditionally GABA tells neurons to shut down and not continue to propagate a message to other neurons,” says Song. “In this case the neurotransmitter also shuts off the stem cells and keeps them dormant.”
The brain stem cell population in mice (and other mammals, including humans) is surrounded by as many as 10 different kinds of intermingled neurons, says Song, and any number of these may be keeping stem cells dormant. To find out which neurons control the stem cells, the researchers inserted special light-activating proteins into the neurons that trigger the cells to send an electrical pulse, as well as to release neurotransmitter, when light shines on them. By shining light to activate a specific type of neuron and monitoring the stem cells with an electrode, Song’s team showed that one of the three types of neurons tested transmitted a signal to the stem cells causing a change in electrical charge in the stem cells. The neurons messaging the stem cells are parvalbumin-expressing interneurons.
Finally, to see if this stem cell control mechanism aligns with what an animal may be experiencing, the scientists created stress for normal mice by socially isolating them, and did the same in mice lacking GABA receptors in their brain stem cells. After a week, socially isolated normal mice had an increase in the number of stem cells and glial cells. But the socially isolated mice without GABA receptors did not show increases.
“GABA communication clearly conveys information about what brain cells experience of the outside world, and, in this case, keeps the brain stem cells in reserve, so if we don’t need them, we don’t use them up,” says Song.
Source: Johns Hopkins Medicine
Neuroscientist keeps astronauts awake with ISS lighting tweaks
A neuroscientist is working with Nasa to develop special lamps that could help restore the circadian rhythm of exhausted astronauts working aboard the International Space Station (ISS).
Thomas Jefferson University neuroscientist George C Brainard, who has headed up the university’s Light Research Program since 1984, received approval for the lights in early 2012 and 100 of the LED models are due to be sent to Nasa by mid-2015. The lights have three different colour temperatures to help ease the astronauts into morning, nighttime and normal working mode.
"An astronaut here on Earth experiences a 24-hour day/night cycle just like you and I," explained Brainard. "Now when they’re on the space station, they’re circling the planet every 90 minutes. So they’ve gone from a 24-hour day to a 90-minute day."