Posted tagged ‘brain imaging’

New imaging study investigates role of dopamine in migraine attacks

April 7, 2017

Many people suffer from migraines —throbbing, painful headaches that last up to 72 hours and are often accompanied by nausea, vomiting and sensitivity to light and sound.

Although not fully understood, an imbalance in a brain neurotransmitter is thought to contribute to migraines. The neurotransmitter, dopamine, is a chemical in your brain that affects your movements, emotions, motivations and sensory perceptions, including the ability to modulate pain.

Now, researchers at the University of Michigan have shown that dopamine levels in the brain fall during a migraine attack relative to their baseline level between attacks, as reported in a recent news release.

The research team performed two PET scans on different days to study eight migraine sufferers during a spontaneous migraine and in between attacks, comparing their brain activity and dopamine levels with and without a headache. On average, these patients were 27 years old and experienced migraines about six times per month. The scientists also imaged eight healthy adults, comparing migraine sufferers to controls.

They found that dopamine levels in the brain fluctuated, temporarily reducing during migraine attacks. They also found that the study participants were more sensitive to non-painful stimuli, such as warmth applied to the forehead, during a migraine.

“With this study, we better understand how dopamine is related to the suffering during a migraine attack,” said Alex DaSilva, DDS, DMedSc, assistant professor of dentistry and of the Center for Human Growth and Development at the University of Michigan, in the video above. “Lower dopamine levels mean you are more sensitive to pain and stimulation. Second, lower dopamine levels also inhibit your behavior. You want a dark room. You want to avoid social interactions.”

In their paper, the researchers call for additional studies to confirm the results and evaluate how they can be used to develop more effective migraine therapies.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Stanford researchers map brain circuitry affected by Parkinson’s disease

February 2, 2017

In the brain, neurons never work alone. Instead, critical functions of the nervous system are orchestrated by interconnected networks of neurons distributed across the brain — such as the circuit responsible for motor control.

Researchers are trying to map out these neural circuits to understand how disease or injury disrupts healthy brain cell communication. For instance, neuroscientists are investigating how Parkinson’s disease causes malfunctions in the neural pathways that control motion.

Now, Stanford researchers have developed a new brain mapping technique that reveals the circuitry associated with Parkinson’s tremors, a hallmark of the disease. The multi-disciplinary team turned on specific types of neurons and observed how this affected the entire brain, which allowed them to map out the associated neural circuit.

Specifically, they performed rat studies using optogenetics to modify and turn on specific types of neurons in response to light and functional MRI to measure the resulting brain activity based on changes in blood flow. These data were then computationally modeled to map out the neural circuit and determine its function.

The research was led by Jin Hyang Lee, PhD, a Stanford electrical engineer who is an assistant professor of neurology and neurological sciences, of neurosurgery and of bioengineering. A recent Stanford News release explains the results:

“Testing her approach on rats, Lee probed two different types of neurons known to be involved in Parkinson’s disease — although it wasn’t known exactly how. Her team found that one type of neuron activated a pathway that called for greater motion while the other activated a signal for less motion. Lee’s team then designed a computational approach to draw circuit diagrams that underlie these neuron-specific brain circuit functions.”

“This is the first time anyone has shown how different neuron types form distinct whole brain circuits with opposite outcomes,” Lee said in the release.

Lee hopes their research will help improve treatments for Parkinson’s disease by providing a more precise understanding of how neurons work to control motion. In the long run, she also thinks their new brain mapping technique can be used to help design better therapies for other brain diseases.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Motor control problems may be core issue for people with autism

December 28, 2016
Photograph by Michael Phillips

Photograph by Michael Phillips

If you’ve ever had an MRI scan, you know that it can be hard to lie still in the noisy, claustrophobic scanner. People often move involuntarily, requiring scientists to correct or eliminate the imaging data during movement.

Recently, a collaboration of Rutgers University and Columbia University researchers used this seemingly unhelpful data to further their understanding of a neurodevelopmental disease.

“We asked ourselves, ‘What could these involuntary movements, which researchers usually consider a nuisance, tell us about autism?’” Elizabeth Torres, PhD, an associate professor of cognitive psychology at Rutgers University, said in a news release.

The neuroscientists analyzed functional magnetic resonance imaging (fMRI) data for 1048 participants, aged 6 to 50 years old, including individuals with autism spectrum disorders and healthy controls. The data was publicly available primarily through the Autism Brain Imaging Data Exchange databases.

The researchers determined that people with autism had more problems controlling their head movements than healthy controls. They also found that motor control problems were exacerbated with the presence of secondary neuropsychiatric diagnoses, lower verbal and performance intelligence and autism severity, as reported in a recent paper in Scientific Reports.

“For the first time, we can demonstrate unambiguously that motor issues are core issues that need to be included in the diagnosis criteria for autism,” Torres said in the release.

In addition, they found that psychotropic medications, commonly used to treat people on the autism spectrum, were associated with lower levels of motor control. These medications include anti-convulsants and anti-depressants. Autistic people who were taking more than one psychotropic medication moved the most during the fMRIs, and their movement worsened over the scanning session.

The researchers conclude in their paper, “Nevertheless, it remains to be demonstrated if changes in head micro-movements directly capture targeted changes in symptomology brought about by a specific medication.” Their findings are also complicated by the simultaneous presence of autism and other diseases, such as attention deficit hyperactivity disorder. So more research is needed.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.


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