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Stretchable Electronics Could Aid Stroke Recovery Treatment
A device designed to be worn on the throat could aid stroke rehabilitation, researchers said.
John A. Rogers, PhD, Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering, Biomedical Engineering, and Neurological Surgery at Northwestern University in Evanston, Illinois, developed the device in partnership with Shirley Ryan AbilityLab, a research hospital in Chicago. The sensor is the latest in Dr. Rogers’s portfolio of stretchable electronics that are appropriate for use in advanced medical care and portable enough to be worn outside the hospital and during exercise.
Dr. Rogers’s sensors stick directly to the skin, moving with the body and providing measurements, including heart function, muscle activity, and quality of sleep.
“Stretchable electronics allow us to see what is going on inside patients’ bodies at a level traditional wearables simply cannot achieve,” said Dr. Rogers. “The key is to make them as integrated as possible with the human body.”
The new bandage-like throat sensor measures patients’ swallowing ability and patterns of speech. The sensors aid in the diagnosis and treatment of aphasia.
The tools that speech-language pathologists have traditionally used to monitor patients’ speech function, such as microphones, cannot distinguish between patients’ voices and ambient noise.
“Our sensors solve that problem by measuring vibrations of the vocal cords,” Dr. Rogers said. “But they only work when worn directly on the throat, which is a sensitive area of the skin. We developed novel materials for this sensor that bend and stretch with the body, minimizing discomfort to patients.”
Shirley Ryan AbilityLab uses the throat sensor in conjunction with electronic biosensors, also developed in Dr. Rogers’s laboratory, on the legs, arms, and chest to monitor stroke patients’ recovery progress. The intermodal system of sensors streams data wirelessly to clinicians’ phones and computers, providing a quantitative picture of patients’ advanced physical and physiologic responses in real time.“One of the biggest problems we face with stroke patients is that their gains tend to drop off when they leave the hospital,” said Arun Jayaraman, PhD, research scientist at the Shirley Ryan AbilityLab. “With the home monitoring enabled by these sensors, we can intervene at the right time, which could lead to better, faster recoveries for patients.”
Because the sensors are wireless, they eliminate barriers posed by traditional health monitoring devices in clinical settings. Patients can wear them after they leave the hospital, allowing doctors to understand how their patients are functioning in the real world.
“Talking with friends and family at home is a completely different dimension from what we do in therapy,” said Leora Cherney, PhD, research scientist at the Shirley Ryan AbilityLab. “Having a detailed understanding of patients’ communication habits outside of the clinic helps us develop better strategies with our patients to improve their speaking skills and speed up their recovery process.”
Data from the sensors will be presented in a dashboard that is easy for clinicians and patients to understand. It will send alerts when patients are underperforming on a certain metric and allow them to set and track progress toward their goals.
Inhibiting an Enzyme May Aid Memory Creation
Aging or impaired brains can once again form lasting memories if an enzyme that impedes the function of a key gene too strongly is inhibited, according to neurobiologists at the University of California, Irvine.
“What we have discovered is that if we free up that DNA again, now the aging brain can form long-term memories normally,” said senior author Marcelo Wood, PhD, Francisco J. Ayala Chair in Neurobiology and Behavior at the university. “To form a long-term memory, you have to turn specific genes on. In most young brains, that happens easily, but as we get older and our brains get older, we have trouble with that.”
That is because the six feet of DNA spooled into every cell in our bodies has a harder time releasing itself as needed, he explained. Like many body parts, “it is no longer as flexible as it used to be,” said Dr. Wood. The stiffness in this case is due to a molecular brake pad called histone deacetylase 3 (HDAC3), that has become “overeager” in the aged brain and is compacting the material too hard, blocking the release of a gene called Period1, said Dr. Wood. Removing HDAC3 restores flexibility and allows internal cell machinery to access Period1 to begin forming new memories.
Researchers had previously theorized that the loss of transcription and encoding functions in older brains resulted from deteriorating core circadian clocks. But Dr. Wood and his team found that the ability to create lasting memories was linked to a different process—the enzyme blocking the release of Period1—in the hippocampus.
“New drugs targeting HDAC3 could provide an exciting avenue to allow older people to improve memory formation,” said Dr. Wood.
Unaffected Hemisphere Assumes Language Function After Perinatal Stroke
Babies sometimes have stroke around the time of birth. Birth is hard on the brain, as is the change in blood circulation from the mother to the neonate. At least one in 4,000 babies have stroke shortly before, during, or after birth.
But a stroke in a baby, even a big one, does not have the same lasting impact as a stroke in an adult. A study led by investigators at Georgetown University Medical Center in Washington, DC, found that a decade or two after a perinatal stroke damaged the left language side of the brain, affected teenagers and young adults used the right sides of their brains for language.The findings demonstrate how plastic brain function is in infants, said Elissa L. Newport, PhD, Professor of Neurology at Georgetown University School of Medicine, and Director of the Center for Brain Plasticity and Recovery at Georgetown University and MedStar National Rehabilitation Network.Her study found that the 12 individuals studied, aged 12 to 25, who had a left-brain perinatal stroke all used the right side of their brains for language. “Their language is good—normal,” she said.
The only signs of prior damage to their brains are that some participants limp, and many have learned to make their left hands dominant because their right hands had impaired function after stroke. They also have executive function impairments—slightly slower neural processing, for example—that are common in individuals with brain injuries. But basic cognitive functions, like language comprehension and production, are excellent, said Dr. Newport.
Furthermore, imaging studies revealed that language in these participants is based entirely in the right hemisphere, in the region opposite to the normal language areas in the left hemisphere. This result had been recorded in previous research, but earlier findings were inconsistent, perhaps because of the heterogeneity of the types of brain injuries included in those studies, said Dr. Newport. Her research, which was carefully controlled in terms of the types and areas of injury included, suggests that while “these young brains were plastic, meaning they could relocate language to a healthy area, it does not mean that new areas can be located willy-nilly on the right side.
“We believe there are important constraints on where functions can be relocated,” she continued. “There are specific regions that take over when part of the brain is injured, depending on the particular function. Each function, like language or spatial skills, has a particular region that can take over if its primary brain area is injured. This is an important discovery that may have implications in the rehabilitation of adult stroke survivors.”
This finding is consistent with the behavior of young brains, said Dr. Newport. “Imaging shows that children up to about age 4 can process language in both sides of their brains, and then the functions split up: the left side processes sentences, and the right processes emotion in language.”
Dr. Newport and her colleagues are extending their study of brain function after a perinatal stroke to a larger group of participants. They are examining stroke in the left and right hemispheres and also whether brain functions other than language are relocated and where. Her group is also collaborating on studies that may reveal the molecular basis of plasticity in young brains. This information might help promote plasticity in adults with stroke or brain injury.
Why Do We Sleep?
Evidence supports the synaptic homeostasis hypothesis about the function of sleep, said researchers. The debate about sleep’s function has continued for a generation and arose following observations that people and animals sicken and die if they are deprived of sleep.
Chiara Cirelli, MD, PhD, and Giulio Tononi, MD, PhD, psychiatrists at the Center for Sleep and Consciousness in Madison, Wisconsin, proposed the synaptic homeostasis hypothesis in 2003. This hypothesis holds that sleep is the price we pay for brains that are plastic and able to keep learning new things. They subsequently undertook a four-year research effort that could show direct evidence for their theory. The result was published in February 2017 in Science and offered direct visual proof of the hypothesis.
Striking electron-microscope pictures from inside the brains of mice suggest what happens in our own brains every day. Our synapses grow strong and large during the stimulation of daytime, then shrink by nearly 20% while we sleep, thus creating room for more growth and learning the next day.
A large team of researchers sectioned the brains of mice and used a scanning electron microscope to photograph, reconstruct, and analyze two areas of cerebral cortex. They were able to reconstruct 6,920 synapses and measure their size.
The team remained blinded about whether they were analyzing the brain cells of a well-rested mouse or one that had been awake. When they finally correlated the measurements with the amount of sleep the mice had had during the six to eight hours before the image was taken, they found that a few hours of sleep led on average to an 18% decrease in the size of the synapses. These changes occurred in both areas of the cerebral cortex and were proportional to the size of the synapses.
Dr. Cirelli’s laboratory is now looking at new brain areas, and at the brains of young mice, to understand the role that sleep plays in brain development.
Statistics and Neuroscience Can Improve Anesthesiology
Anesthesia is believed to act on the brain, but the standard protocol among anesthesiologists for monitoring and dosing patients during surgery is to rely on indirect signs of arousal, like movement and changes in heart rate and blood pressure. Research in brain science and statistical modeling has allowed Emery N. Brown, MD, PhD, an anesthetist at Massachusetts General Hospital in Boston, to safely give patients less anesthesia, which can be beneficial.
Dr. Brown has developed a theoretical (ie, neuroscientific) and analytical (ie, statistical) understanding of EEG brain wave measurements of patients under general anesthesia. Anesthesia’s effects in the brain produce specific patterns of brain waves, and monitoring them via EEG data can improve care.
“We should use neuroscience and neuroscience paradigms to try to understand what is happening in the brain under general anesthesia,” said Dr. Brown. “It is a neurophysiologic process that affects the brain and CNS, so how can it be that what is being developed in the neuroscience field is not being brought to bear on the question of the brain under anesthesia?”
In numerous papers over more than a decade, Dr. Brown has examined how various anesthesia drugs such as propofol, dexmedetomidine, and sevoflurane interact with various neuronal receptors, affecting circuits in different regions of the brain. Those neurophysiologic effects ultimately give rise to a state of unconsciousness—essentially a reversible coma—characterized by powerful, low-frequency brain waves that overwhelm the normal rhythms that synchronize brain functions such as sensory perception, higher cognition, or motor control.
Understanding anesthesia to this degree allows for practical insights. In a study published in October 2016 in Proceedings of the National Academy of Sciences, for example, Dr. Brown and colleagues showed how stimulating dopamine-producing neurons in the ventral tegmental area of the brain could wake mice up from general anesthesia. The study suggests a way that human patients could be awakened as well, which could lessen side effects, recover normal brain function more rapidly, and help patients move more quickly out of the operating room and into recovery.
In parallel with illuminating the neuroscience of general anesthesia, Dr. Brown has developed statistical methods to analyze EEG measurements in a way that anesthesiologists can apply to patients. Dr. Brown has shown that EEG readings of level of unconsciousness vary in characteristic ways based on the drug, its dose, and the patient’s age.
“The deciphering of how these drugs are acting in the brain turns out to be an important signal-processing question,” said Dr. Brown. “The drugs work by producing oscillations, these oscillations are readily visible in the EEG and change systematically with drug dose, class, and age.”
During every surgery, Dr. Brown uses real-time EEG readings to keep a patient adequately dosed without giving too much anesthetic. While treating an 81-year-old patient with cancer, Dr. Brown was able to administer about one-third of the dose considered necessary. This dose reduction can be especially important for older patients. “We already know you do not have to give older people as much, but it turns out it can be even less,” said Dr. Brown.
Older patients are especially susceptible to problematic side effects when they wake up, including delirium or postoperative cognitive dysfunction. Neuroscientifically informed ways to prevent giving too much anesthesia can help prevent such problems, said Dr. Brown.
As more anesthesiologists acquire knowledge and EEG equipment, the field can move to a model where doctors have a direct view of the patient’s brain when monitoring and maintaining their consciousness during surgery, said Dr. Brown.
Stretchable Electronics Could Aid Stroke Recovery Treatment
A device designed to be worn on the throat could aid stroke rehabilitation, researchers said.
John A. Rogers, PhD, Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering, Biomedical Engineering, and Neurological Surgery at Northwestern University in Evanston, Illinois, developed the device in partnership with Shirley Ryan AbilityLab, a research hospital in Chicago. The sensor is the latest in Dr. Rogers’s portfolio of stretchable electronics that are appropriate for use in advanced medical care and portable enough to be worn outside the hospital and during exercise.
Dr. Rogers’s sensors stick directly to the skin, moving with the body and providing measurements, including heart function, muscle activity, and quality of sleep.
“Stretchable electronics allow us to see what is going on inside patients’ bodies at a level traditional wearables simply cannot achieve,” said Dr. Rogers. “The key is to make them as integrated as possible with the human body.”
The new bandage-like throat sensor measures patients’ swallowing ability and patterns of speech. The sensors aid in the diagnosis and treatment of aphasia.
The tools that speech-language pathologists have traditionally used to monitor patients’ speech function, such as microphones, cannot distinguish between patients’ voices and ambient noise.
“Our sensors solve that problem by measuring vibrations of the vocal cords,” Dr. Rogers said. “But they only work when worn directly on the throat, which is a sensitive area of the skin. We developed novel materials for this sensor that bend and stretch with the body, minimizing discomfort to patients.”
Shirley Ryan AbilityLab uses the throat sensor in conjunction with electronic biosensors, also developed in Dr. Rogers’s laboratory, on the legs, arms, and chest to monitor stroke patients’ recovery progress. The intermodal system of sensors streams data wirelessly to clinicians’ phones and computers, providing a quantitative picture of patients’ advanced physical and physiologic responses in real time.“One of the biggest problems we face with stroke patients is that their gains tend to drop off when they leave the hospital,” said Arun Jayaraman, PhD, research scientist at the Shirley Ryan AbilityLab. “With the home monitoring enabled by these sensors, we can intervene at the right time, which could lead to better, faster recoveries for patients.”
Because the sensors are wireless, they eliminate barriers posed by traditional health monitoring devices in clinical settings. Patients can wear them after they leave the hospital, allowing doctors to understand how their patients are functioning in the real world.
“Talking with friends and family at home is a completely different dimension from what we do in therapy,” said Leora Cherney, PhD, research scientist at the Shirley Ryan AbilityLab. “Having a detailed understanding of patients’ communication habits outside of the clinic helps us develop better strategies with our patients to improve their speaking skills and speed up their recovery process.”
Data from the sensors will be presented in a dashboard that is easy for clinicians and patients to understand. It will send alerts when patients are underperforming on a certain metric and allow them to set and track progress toward their goals.
Inhibiting an Enzyme May Aid Memory Creation
Aging or impaired brains can once again form lasting memories if an enzyme that impedes the function of a key gene too strongly is inhibited, according to neurobiologists at the University of California, Irvine.
“What we have discovered is that if we free up that DNA again, now the aging brain can form long-term memories normally,” said senior author Marcelo Wood, PhD, Francisco J. Ayala Chair in Neurobiology and Behavior at the university. “To form a long-term memory, you have to turn specific genes on. In most young brains, that happens easily, but as we get older and our brains get older, we have trouble with that.”
That is because the six feet of DNA spooled into every cell in our bodies has a harder time releasing itself as needed, he explained. Like many body parts, “it is no longer as flexible as it used to be,” said Dr. Wood. The stiffness in this case is due to a molecular brake pad called histone deacetylase 3 (HDAC3), that has become “overeager” in the aged brain and is compacting the material too hard, blocking the release of a gene called Period1, said Dr. Wood. Removing HDAC3 restores flexibility and allows internal cell machinery to access Period1 to begin forming new memories.
Researchers had previously theorized that the loss of transcription and encoding functions in older brains resulted from deteriorating core circadian clocks. But Dr. Wood and his team found that the ability to create lasting memories was linked to a different process—the enzyme blocking the release of Period1—in the hippocampus.
“New drugs targeting HDAC3 could provide an exciting avenue to allow older people to improve memory formation,” said Dr. Wood.
Unaffected Hemisphere Assumes Language Function After Perinatal Stroke
Babies sometimes have stroke around the time of birth. Birth is hard on the brain, as is the change in blood circulation from the mother to the neonate. At least one in 4,000 babies have stroke shortly before, during, or after birth.
But a stroke in a baby, even a big one, does not have the same lasting impact as a stroke in an adult. A study led by investigators at Georgetown University Medical Center in Washington, DC, found that a decade or two after a perinatal stroke damaged the left language side of the brain, affected teenagers and young adults used the right sides of their brains for language.The findings demonstrate how plastic brain function is in infants, said Elissa L. Newport, PhD, Professor of Neurology at Georgetown University School of Medicine, and Director of the Center for Brain Plasticity and Recovery at Georgetown University and MedStar National Rehabilitation Network.Her study found that the 12 individuals studied, aged 12 to 25, who had a left-brain perinatal stroke all used the right side of their brains for language. “Their language is good—normal,” she said.
The only signs of prior damage to their brains are that some participants limp, and many have learned to make their left hands dominant because their right hands had impaired function after stroke. They also have executive function impairments—slightly slower neural processing, for example—that are common in individuals with brain injuries. But basic cognitive functions, like language comprehension and production, are excellent, said Dr. Newport.
Furthermore, imaging studies revealed that language in these participants is based entirely in the right hemisphere, in the region opposite to the normal language areas in the left hemisphere. This result had been recorded in previous research, but earlier findings were inconsistent, perhaps because of the heterogeneity of the types of brain injuries included in those studies, said Dr. Newport. Her research, which was carefully controlled in terms of the types and areas of injury included, suggests that while “these young brains were plastic, meaning they could relocate language to a healthy area, it does not mean that new areas can be located willy-nilly on the right side.
“We believe there are important constraints on where functions can be relocated,” she continued. “There are specific regions that take over when part of the brain is injured, depending on the particular function. Each function, like language or spatial skills, has a particular region that can take over if its primary brain area is injured. This is an important discovery that may have implications in the rehabilitation of adult stroke survivors.”
This finding is consistent with the behavior of young brains, said Dr. Newport. “Imaging shows that children up to about age 4 can process language in both sides of their brains, and then the functions split up: the left side processes sentences, and the right processes emotion in language.”
Dr. Newport and her colleagues are extending their study of brain function after a perinatal stroke to a larger group of participants. They are examining stroke in the left and right hemispheres and also whether brain functions other than language are relocated and where. Her group is also collaborating on studies that may reveal the molecular basis of plasticity in young brains. This information might help promote plasticity in adults with stroke or brain injury.
Why Do We Sleep?
Evidence supports the synaptic homeostasis hypothesis about the function of sleep, said researchers. The debate about sleep’s function has continued for a generation and arose following observations that people and animals sicken and die if they are deprived of sleep.
Chiara Cirelli, MD, PhD, and Giulio Tononi, MD, PhD, psychiatrists at the Center for Sleep and Consciousness in Madison, Wisconsin, proposed the synaptic homeostasis hypothesis in 2003. This hypothesis holds that sleep is the price we pay for brains that are plastic and able to keep learning new things. They subsequently undertook a four-year research effort that could show direct evidence for their theory. The result was published in February 2017 in Science and offered direct visual proof of the hypothesis.
Striking electron-microscope pictures from inside the brains of mice suggest what happens in our own brains every day. Our synapses grow strong and large during the stimulation of daytime, then shrink by nearly 20% while we sleep, thus creating room for more growth and learning the next day.
A large team of researchers sectioned the brains of mice and used a scanning electron microscope to photograph, reconstruct, and analyze two areas of cerebral cortex. They were able to reconstruct 6,920 synapses and measure their size.
The team remained blinded about whether they were analyzing the brain cells of a well-rested mouse or one that had been awake. When they finally correlated the measurements with the amount of sleep the mice had had during the six to eight hours before the image was taken, they found that a few hours of sleep led on average to an 18% decrease in the size of the synapses. These changes occurred in both areas of the cerebral cortex and were proportional to the size of the synapses.
Dr. Cirelli’s laboratory is now looking at new brain areas, and at the brains of young mice, to understand the role that sleep plays in brain development.
Statistics and Neuroscience Can Improve Anesthesiology
Anesthesia is believed to act on the brain, but the standard protocol among anesthesiologists for monitoring and dosing patients during surgery is to rely on indirect signs of arousal, like movement and changes in heart rate and blood pressure. Research in brain science and statistical modeling has allowed Emery N. Brown, MD, PhD, an anesthetist at Massachusetts General Hospital in Boston, to safely give patients less anesthesia, which can be beneficial.
Dr. Brown has developed a theoretical (ie, neuroscientific) and analytical (ie, statistical) understanding of EEG brain wave measurements of patients under general anesthesia. Anesthesia’s effects in the brain produce specific patterns of brain waves, and monitoring them via EEG data can improve care.
“We should use neuroscience and neuroscience paradigms to try to understand what is happening in the brain under general anesthesia,” said Dr. Brown. “It is a neurophysiologic process that affects the brain and CNS, so how can it be that what is being developed in the neuroscience field is not being brought to bear on the question of the brain under anesthesia?”
In numerous papers over more than a decade, Dr. Brown has examined how various anesthesia drugs such as propofol, dexmedetomidine, and sevoflurane interact with various neuronal receptors, affecting circuits in different regions of the brain. Those neurophysiologic effects ultimately give rise to a state of unconsciousness—essentially a reversible coma—characterized by powerful, low-frequency brain waves that overwhelm the normal rhythms that synchronize brain functions such as sensory perception, higher cognition, or motor control.
Understanding anesthesia to this degree allows for practical insights. In a study published in October 2016 in Proceedings of the National Academy of Sciences, for example, Dr. Brown and colleagues showed how stimulating dopamine-producing neurons in the ventral tegmental area of the brain could wake mice up from general anesthesia. The study suggests a way that human patients could be awakened as well, which could lessen side effects, recover normal brain function more rapidly, and help patients move more quickly out of the operating room and into recovery.
In parallel with illuminating the neuroscience of general anesthesia, Dr. Brown has developed statistical methods to analyze EEG measurements in a way that anesthesiologists can apply to patients. Dr. Brown has shown that EEG readings of level of unconsciousness vary in characteristic ways based on the drug, its dose, and the patient’s age.
“The deciphering of how these drugs are acting in the brain turns out to be an important signal-processing question,” said Dr. Brown. “The drugs work by producing oscillations, these oscillations are readily visible in the EEG and change systematically with drug dose, class, and age.”
During every surgery, Dr. Brown uses real-time EEG readings to keep a patient adequately dosed without giving too much anesthetic. While treating an 81-year-old patient with cancer, Dr. Brown was able to administer about one-third of the dose considered necessary. This dose reduction can be especially important for older patients. “We already know you do not have to give older people as much, but it turns out it can be even less,” said Dr. Brown.
Older patients are especially susceptible to problematic side effects when they wake up, including delirium or postoperative cognitive dysfunction. Neuroscientifically informed ways to prevent giving too much anesthesia can help prevent such problems, said Dr. Brown.
As more anesthesiologists acquire knowledge and EEG equipment, the field can move to a model where doctors have a direct view of the patient’s brain when monitoring and maintaining their consciousness during surgery, said Dr. Brown.
Stretchable Electronics Could Aid Stroke Recovery Treatment
A device designed to be worn on the throat could aid stroke rehabilitation, researchers said.
John A. Rogers, PhD, Louis Simpson and Kimberly Querrey Professor of Materials Science and Engineering, Biomedical Engineering, and Neurological Surgery at Northwestern University in Evanston, Illinois, developed the device in partnership with Shirley Ryan AbilityLab, a research hospital in Chicago. The sensor is the latest in Dr. Rogers’s portfolio of stretchable electronics that are appropriate for use in advanced medical care and portable enough to be worn outside the hospital and during exercise.
Dr. Rogers’s sensors stick directly to the skin, moving with the body and providing measurements, including heart function, muscle activity, and quality of sleep.
“Stretchable electronics allow us to see what is going on inside patients’ bodies at a level traditional wearables simply cannot achieve,” said Dr. Rogers. “The key is to make them as integrated as possible with the human body.”
The new bandage-like throat sensor measures patients’ swallowing ability and patterns of speech. The sensors aid in the diagnosis and treatment of aphasia.
The tools that speech-language pathologists have traditionally used to monitor patients’ speech function, such as microphones, cannot distinguish between patients’ voices and ambient noise.
“Our sensors solve that problem by measuring vibrations of the vocal cords,” Dr. Rogers said. “But they only work when worn directly on the throat, which is a sensitive area of the skin. We developed novel materials for this sensor that bend and stretch with the body, minimizing discomfort to patients.”
Shirley Ryan AbilityLab uses the throat sensor in conjunction with electronic biosensors, also developed in Dr. Rogers’s laboratory, on the legs, arms, and chest to monitor stroke patients’ recovery progress. The intermodal system of sensors streams data wirelessly to clinicians’ phones and computers, providing a quantitative picture of patients’ advanced physical and physiologic responses in real time.“One of the biggest problems we face with stroke patients is that their gains tend to drop off when they leave the hospital,” said Arun Jayaraman, PhD, research scientist at the Shirley Ryan AbilityLab. “With the home monitoring enabled by these sensors, we can intervene at the right time, which could lead to better, faster recoveries for patients.”
Because the sensors are wireless, they eliminate barriers posed by traditional health monitoring devices in clinical settings. Patients can wear them after they leave the hospital, allowing doctors to understand how their patients are functioning in the real world.
“Talking with friends and family at home is a completely different dimension from what we do in therapy,” said Leora Cherney, PhD, research scientist at the Shirley Ryan AbilityLab. “Having a detailed understanding of patients’ communication habits outside of the clinic helps us develop better strategies with our patients to improve their speaking skills and speed up their recovery process.”
Data from the sensors will be presented in a dashboard that is easy for clinicians and patients to understand. It will send alerts when patients are underperforming on a certain metric and allow them to set and track progress toward their goals.
Inhibiting an Enzyme May Aid Memory Creation
Aging or impaired brains can once again form lasting memories if an enzyme that impedes the function of a key gene too strongly is inhibited, according to neurobiologists at the University of California, Irvine.
“What we have discovered is that if we free up that DNA again, now the aging brain can form long-term memories normally,” said senior author Marcelo Wood, PhD, Francisco J. Ayala Chair in Neurobiology and Behavior at the university. “To form a long-term memory, you have to turn specific genes on. In most young brains, that happens easily, but as we get older and our brains get older, we have trouble with that.”
That is because the six feet of DNA spooled into every cell in our bodies has a harder time releasing itself as needed, he explained. Like many body parts, “it is no longer as flexible as it used to be,” said Dr. Wood. The stiffness in this case is due to a molecular brake pad called histone deacetylase 3 (HDAC3), that has become “overeager” in the aged brain and is compacting the material too hard, blocking the release of a gene called Period1, said Dr. Wood. Removing HDAC3 restores flexibility and allows internal cell machinery to access Period1 to begin forming new memories.
Researchers had previously theorized that the loss of transcription and encoding functions in older brains resulted from deteriorating core circadian clocks. But Dr. Wood and his team found that the ability to create lasting memories was linked to a different process—the enzyme blocking the release of Period1—in the hippocampus.
“New drugs targeting HDAC3 could provide an exciting avenue to allow older people to improve memory formation,” said Dr. Wood.
Unaffected Hemisphere Assumes Language Function After Perinatal Stroke
Babies sometimes have stroke around the time of birth. Birth is hard on the brain, as is the change in blood circulation from the mother to the neonate. At least one in 4,000 babies have stroke shortly before, during, or after birth.
But a stroke in a baby, even a big one, does not have the same lasting impact as a stroke in an adult. A study led by investigators at Georgetown University Medical Center in Washington, DC, found that a decade or two after a perinatal stroke damaged the left language side of the brain, affected teenagers and young adults used the right sides of their brains for language.The findings demonstrate how plastic brain function is in infants, said Elissa L. Newport, PhD, Professor of Neurology at Georgetown University School of Medicine, and Director of the Center for Brain Plasticity and Recovery at Georgetown University and MedStar National Rehabilitation Network.Her study found that the 12 individuals studied, aged 12 to 25, who had a left-brain perinatal stroke all used the right side of their brains for language. “Their language is good—normal,” she said.
The only signs of prior damage to their brains are that some participants limp, and many have learned to make their left hands dominant because their right hands had impaired function after stroke. They also have executive function impairments—slightly slower neural processing, for example—that are common in individuals with brain injuries. But basic cognitive functions, like language comprehension and production, are excellent, said Dr. Newport.
Furthermore, imaging studies revealed that language in these participants is based entirely in the right hemisphere, in the region opposite to the normal language areas in the left hemisphere. This result had been recorded in previous research, but earlier findings were inconsistent, perhaps because of the heterogeneity of the types of brain injuries included in those studies, said Dr. Newport. Her research, which was carefully controlled in terms of the types and areas of injury included, suggests that while “these young brains were plastic, meaning they could relocate language to a healthy area, it does not mean that new areas can be located willy-nilly on the right side.
“We believe there are important constraints on where functions can be relocated,” she continued. “There are specific regions that take over when part of the brain is injured, depending on the particular function. Each function, like language or spatial skills, has a particular region that can take over if its primary brain area is injured. This is an important discovery that may have implications in the rehabilitation of adult stroke survivors.”
This finding is consistent with the behavior of young brains, said Dr. Newport. “Imaging shows that children up to about age 4 can process language in both sides of their brains, and then the functions split up: the left side processes sentences, and the right processes emotion in language.”
Dr. Newport and her colleagues are extending their study of brain function after a perinatal stroke to a larger group of participants. They are examining stroke in the left and right hemispheres and also whether brain functions other than language are relocated and where. Her group is also collaborating on studies that may reveal the molecular basis of plasticity in young brains. This information might help promote plasticity in adults with stroke or brain injury.
Why Do We Sleep?
Evidence supports the synaptic homeostasis hypothesis about the function of sleep, said researchers. The debate about sleep’s function has continued for a generation and arose following observations that people and animals sicken and die if they are deprived of sleep.
Chiara Cirelli, MD, PhD, and Giulio Tononi, MD, PhD, psychiatrists at the Center for Sleep and Consciousness in Madison, Wisconsin, proposed the synaptic homeostasis hypothesis in 2003. This hypothesis holds that sleep is the price we pay for brains that are plastic and able to keep learning new things. They subsequently undertook a four-year research effort that could show direct evidence for their theory. The result was published in February 2017 in Science and offered direct visual proof of the hypothesis.
Striking electron-microscope pictures from inside the brains of mice suggest what happens in our own brains every day. Our synapses grow strong and large during the stimulation of daytime, then shrink by nearly 20% while we sleep, thus creating room for more growth and learning the next day.
A large team of researchers sectioned the brains of mice and used a scanning electron microscope to photograph, reconstruct, and analyze two areas of cerebral cortex. They were able to reconstruct 6,920 synapses and measure their size.
The team remained blinded about whether they were analyzing the brain cells of a well-rested mouse or one that had been awake. When they finally correlated the measurements with the amount of sleep the mice had had during the six to eight hours before the image was taken, they found that a few hours of sleep led on average to an 18% decrease in the size of the synapses. These changes occurred in both areas of the cerebral cortex and were proportional to the size of the synapses.
Dr. Cirelli’s laboratory is now looking at new brain areas, and at the brains of young mice, to understand the role that sleep plays in brain development.
Statistics and Neuroscience Can Improve Anesthesiology
Anesthesia is believed to act on the brain, but the standard protocol among anesthesiologists for monitoring and dosing patients during surgery is to rely on indirect signs of arousal, like movement and changes in heart rate and blood pressure. Research in brain science and statistical modeling has allowed Emery N. Brown, MD, PhD, an anesthetist at Massachusetts General Hospital in Boston, to safely give patients less anesthesia, which can be beneficial.
Dr. Brown has developed a theoretical (ie, neuroscientific) and analytical (ie, statistical) understanding of EEG brain wave measurements of patients under general anesthesia. Anesthesia’s effects in the brain produce specific patterns of brain waves, and monitoring them via EEG data can improve care.
“We should use neuroscience and neuroscience paradigms to try to understand what is happening in the brain under general anesthesia,” said Dr. Brown. “It is a neurophysiologic process that affects the brain and CNS, so how can it be that what is being developed in the neuroscience field is not being brought to bear on the question of the brain under anesthesia?”
In numerous papers over more than a decade, Dr. Brown has examined how various anesthesia drugs such as propofol, dexmedetomidine, and sevoflurane interact with various neuronal receptors, affecting circuits in different regions of the brain. Those neurophysiologic effects ultimately give rise to a state of unconsciousness—essentially a reversible coma—characterized by powerful, low-frequency brain waves that overwhelm the normal rhythms that synchronize brain functions such as sensory perception, higher cognition, or motor control.
Understanding anesthesia to this degree allows for practical insights. In a study published in October 2016 in Proceedings of the National Academy of Sciences, for example, Dr. Brown and colleagues showed how stimulating dopamine-producing neurons in the ventral tegmental area of the brain could wake mice up from general anesthesia. The study suggests a way that human patients could be awakened as well, which could lessen side effects, recover normal brain function more rapidly, and help patients move more quickly out of the operating room and into recovery.
In parallel with illuminating the neuroscience of general anesthesia, Dr. Brown has developed statistical methods to analyze EEG measurements in a way that anesthesiologists can apply to patients. Dr. Brown has shown that EEG readings of level of unconsciousness vary in characteristic ways based on the drug, its dose, and the patient’s age.
“The deciphering of how these drugs are acting in the brain turns out to be an important signal-processing question,” said Dr. Brown. “The drugs work by producing oscillations, these oscillations are readily visible in the EEG and change systematically with drug dose, class, and age.”
During every surgery, Dr. Brown uses real-time EEG readings to keep a patient adequately dosed without giving too much anesthetic. While treating an 81-year-old patient with cancer, Dr. Brown was able to administer about one-third of the dose considered necessary. This dose reduction can be especially important for older patients. “We already know you do not have to give older people as much, but it turns out it can be even less,” said Dr. Brown.
Older patients are especially susceptible to problematic side effects when they wake up, including delirium or postoperative cognitive dysfunction. Neuroscientifically informed ways to prevent giving too much anesthesia can help prevent such problems, said Dr. Brown.
As more anesthesiologists acquire knowledge and EEG equipment, the field can move to a model where doctors have a direct view of the patient’s brain when monitoring and maintaining their consciousness during surgery, said Dr. Brown.
