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Transcranial Magnetic Stimulation Improves Memory in Older Adults

A painless and noninvasive brain stimulation technique may help improve some types of memory in older adults, investigators reported.

One possible explanation for age-related memory loss is degradation of the neural connections between the hippocampus and the cortex. Weakening of these connections may lead to difficulties in creating new memories of specific events and the locations of objects. Scientists hypothesized that strengthening the connections between the hippocampus and cortex through repetitive transcranial magnetic stimulation (TMS) may help the storage of new memories. TMS delivers painless magnetic pulses to a particular region of the brain, changing the activity of the neurons within the targeted area.

To determine whether TMS could improve memory, 15 healthy adults over the age of 64 received TMS to a part of the cortex that communicates with the hippocampus. Treatment lasted for five days. During a separate week, each participant received five days of sham treatment, in which the setup was the same, but the stimulation was too low to influence the neural connections. Before and after each five-day session, participants were asked to remember pictures of everyday objects and pictures of outdoor scenes associated with each one. The adults’ ability to recall the scenes associated with the objects improved after receiving TMS, but not after the sham treatment.

“Our study demonstrates that TMS could potentially be used as a way to improve memory for older adults experiencing age-related memory impairments,” said John A. Walker, PhD, postdoctorate fellow at Northwestern University in Evanston, Illinois. “TMS can be used to probe the relationship between brain networks and memory experimentally, opening new doors to understanding the network basis of cognitive decline in aging.”

Heading the Ball Hurts Women More Than Men

Intentionally hitting a soccer ball with the head, or “heading,” may have more adverse brain consequences for women than men, said researchers.

Heading does not typically result in a concussion, yet growing evidence links the move to CNS damage. Previous studies using diffusion tensor imaging (DTI) have revealed that heading damages the integrity of the axons. Women appear to be more vulnerable than men to problems associated with heading, as they report more symptoms that last longer, but the reason for these gender differences remains unknown.

To assess possible gender differences in the effects of heading, researchers used DTI to examine 49 male and 49 female amateur soccer players who were matched on age and frequency of heading. Higher levels of heading were associated with decreased axonal integrity in three brain regions for men and eight brain regions for women. In seven of the areas identified in women, the association between axonal integrity and heading was significantly stronger than it was in men.

“Given similar amounts of exposure to heading, women show a greater volume of abnormality that is significantly different from what is seen in men,” said lead author Todd G. Rubin, MD, a doctoral student at Albert Einstein College of Medicine in Bronx, New York. “Identifying and understanding the basis for differences in susceptibility to injury represent key steps in determining better treatments and guidelines for safer play.”

DBS Can Individualize Treatment for Parkinson’s Disease

A new approach to deep brain stimulation (DBS) adjusts itself to deliver the appropriate amount of stimulation in patients with Parkinson’s disease, according to new research. The approach could improve symptom management and reduce side effects.

DBS has been a valuable treatment for Parkinson’s disease by helping to quell the abnormal movements that are characteristic of the disease. Traditional DBS delivers a constant level of stimulation and cannot adapt if a patient’s symptoms vary over the course of a day. As a result, a patient may sometimes receive too little stimulation, which fails to control symptoms, or too much, which causes side effects such as dyskinesia.

To match stimulation to variations in patient symptoms throughout the day, researchers and engineers developed a novel implantable device that provides DBS and records activity from the surface of the brain. Similar to a cardiac pacemaker, this adaptive device can autoadjust its level of stimulation based on a physiologic signal—in this case, brain activity related to dyskinesia. A high dyskinesia signal indicated greater likelihood of unwanted side effects and caused the device to reduce the stimulation level. A low signal indicated a higher chance of symptoms returning and triggered an increase in stimulation.

The device was tested in two patients inside and outside of the laboratory. Neither patient reported discomfort, adverse events, or worsening symptoms. In addition, the battery used as much as 45% less energy than traditional DBS, which is an important advantage, since battery replacement requires surgery.

“Our study showed that totally implanted, adaptive DBS is feasible and can be used at home in patients,” said lead author Nicole C. Swann, PhD, Assistant Professor of Human Physiology at the University of Oregon in Eugene. “Adaptive stimulation represents one of the first major advances in DBS technology since this technique was first introduced for the treatment of Parkinson’s disease 25 years ago.”

 

 

Contact Sports May Impair Memory Temporarily

Sports-related head injuries may prevent the generation of new neurons in a brain region important for memory, said investigators.

Concussion can lead to cognitive impairments, and recent evidence indicates that subconcussive hits can cause damage. The hippocampus is particularly vulnerable. One way to test the effects of head impacts on the hippocampus is a memory assessment called the mnemonic similarity test (MST), which evaluates a person’s ability to distinguish between images that are novel, previously presented, or similar to images previously presented. Accumulating evidence suggests that MST scores are related to the hippocampus’s ability to generate new neurons.

To investigate changes in memory following sports-related head injuries, researchers assessed different types of athletes in two studies. In the first study, they compared athletes with concussion, uninjured athletes who played the same sport, same-sport athletes with musculoskeletal injuries, and healthy controls. Compared with the other three groups, concussed athletes performed worse on the MST when tested two to four weeks after their injury. The scores did not remain low, however. By the time the athletes were cleared to play, their scores had improved to normal levels.

In the second study, rugby players were given the MST before the season started, halfway through the season, and one month after their last game. Scores dropped midseason, compared with preseason scores, but recovered by the postseason assessment.

“Using a cognitive test believed to be sensitive to hippocampal neurogenesis, we found that athletes with concussion show impairments that resolve following recovery,” said lead author Melissa Danielle McCradden, PhD, a postdoctoral fellow at McMaster University in Toronto. “These findings represent, to the best of our knowledge, the first reported evidence in humans suggesting a brain change that might explain the cognitive and emotional symptoms associated with mild traumatic brain injury.”

Disrupted Brain Networks May Cause Gulf War Illness

The brains of veterans with Gulf War illness (GWI) show widespread communication abnormalities in networks that support various brain functions, researchers reported. The observed patterns of impairment provide objective neurophysiologic evidence to support the self-reported symptoms of veterans with GWI.

As many as 250,000 veterans who served in Iraq, Kuwait, and Saudi Arabia during the 1991 Gulf War may currently experience GWI. Symptoms include difficulty remembering things, trouble finding words while speaking, motor coordination, mood swings, fatigue, and chronic pain. GWI is thought to result from exposure to a mix of chemical and biological warfare agents and hazardous chemicals.

To better understand brain changes in GWI, researchers compared the brains of 22 veterans with GWI to the brains of 30 healthy veterans of similar age. Using resting state functional MRI, researchers analyzed patterns of communication among regions of the brain known to control different functions and behavior. They identified changes in functional networks related to many commonly reported GWI symptoms. Individuals with GWI showed clear deficits in neural communication in the sectors of the brain responsible for visual processing, mood regulation, motor coordination, sensory processing, and language command, but increased communication in networks related to pain perception during rest.

“The results from this study provide strong evidence of neuropathology in GWI patients from exposures to neurotoxic agents,” said lead author Kaundinya Gopinath, PhD, Assistant Professor of Radiology and Imaging Sciences at Emory University in Atlanta. Next, “the aim is to establish brain mechanisms underlying GWI, which in turn can lead to development of treatments.”

Prolonged Sedation May Cause Brain Abnormalities in Infants

Full-term infants who undergo repeated anesthesia and prolonged sedation are at risk for changes in brain development, according to investigators.

Developmental impacts of prenatal exposure to sedatives have been studied widely, but less is known about the immediate and long-term neurologic and developmental effects of prolonged sedation when administered to critically ill infants after birth. Prolonged administration of opioids and benzodiazepines, which commonly are used for infants undergoing surgery, is associated with a high incidence of drug tolerance and dependence. Although negative long-term outcomes have been associated with such drug exposures in infants, these studies could not exclude other possible causes, such as prematurity or heart problems.

To study neurologic effects of prolonged sedation, researchers conducted MRI scans on full-term infants who underwent life-saving surgery that required prolonged exposure to morphine and midazolam before one year of age. Brain imaging showed several brain MRI anomalies that were not present in healthy infants, including abnormalities in gray and white matter structures and the ventricles. The number of brain MRI abnormalities significantly correlated with the average daily dose of these sedative drugs. The higher the daily dose, the more MRI irregularities were seen. The patients also had more brain fluid and a smaller total brain volume, compared with healthy infants. This pattern has been associated with long-term neurodevelopmental outcomes such as autism spectrum disorder. Taken together, these preliminary findings indicate a potential negative impact of prolonged sedation on brain growth during the first year of life, the researchers said.

“We were surprised to find higher incidence of brain abnormalities in full-term infants who underwent life-saving surgery that required prolonged sedation,” said senior author Dusica Bajic, MD, PhD, Principal Investigator at Boston Children’s Hospital. “The constellation of MRI irregularities suggests prolonged sedation may potentially contribute to delayed brain growth.” Future investigations will explore the neural mechanisms of the observed developmental effects and whether early sedation exposure may lead to long-term neurobehavioral impacts.

 

 

The Brain Preferentially Reactivates Negative Memories During Sleep

The brain selectively reactivates negative memories during sleep, prioritizing the retention of these emotional memories, which may be of greater future relevance than neutral memories and thus more worth remembering, according to investigators.

Over the past two decades, neuroscientists have gained increased understanding of how sleep boosts and stabilizes memories in the human brain. In the current study, researchers presented 57 healthy volunteers with a series of neutral and negative images. While staring straight ahead, the volunteers saw all of the negative images on one side of their field of vision (left) and all of the neutral images on the other side (right). Because the brain processes visual information in the opposite hemisphere from where it is viewed, this method allowed researchers to “tag” one hemisphere with negative content and the other with neutral content, thus enabling them to track localized memories. Participants were then shown the previously seen images for memory tests, with some of the images shown immediately after the learning phase and the rest shown after a period of wakefulness or sleep. During all memory tests, volunteers viewed the images directly in front of them, rather than to either side, and researchers asked participants to state whether an image had originally appeared to the left or right.

Participants who stayed awake in between memory tests forgot some of the original image locations, but forgetting was similar for neutral and negative images. Participants who slept between tests, on the other hand, had a much better rate of recall for the negative images than for the neutral ones. EEG recordings made during the learning phase show that the brain has encoded the distinct types of memories in its two hemispheres, with the negative images strongly encoded in the hemisphere opposite to the side of presentation. Researchers are now analyzing data that they hypothesize will show that the waking EEG pattern corresponding to emotional memories is the same pattern that is reactivated most strongly during sleep.

“This [finding] would provide a long sought-after brain-based explanation of how sleep selectively stabilizes emotional memories,” said lead author Roy Cox, PhD, research fellow in psychiatry at Beth Israel Deaconess Medical Center in Boston. “Our research substantially advances the notion that sleep plays a fundamental and complex role in the offline reorganization of waking experiences.”

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Transcranial Magnetic Stimulation Improves Memory in Older Adults

A painless and noninvasive brain stimulation technique may help improve some types of memory in older adults, investigators reported.

One possible explanation for age-related memory loss is degradation of the neural connections between the hippocampus and the cortex. Weakening of these connections may lead to difficulties in creating new memories of specific events and the locations of objects. Scientists hypothesized that strengthening the connections between the hippocampus and cortex through repetitive transcranial magnetic stimulation (TMS) may help the storage of new memories. TMS delivers painless magnetic pulses to a particular region of the brain, changing the activity of the neurons within the targeted area.

To determine whether TMS could improve memory, 15 healthy adults over the age of 64 received TMS to a part of the cortex that communicates with the hippocampus. Treatment lasted for five days. During a separate week, each participant received five days of sham treatment, in which the setup was the same, but the stimulation was too low to influence the neural connections. Before and after each five-day session, participants were asked to remember pictures of everyday objects and pictures of outdoor scenes associated with each one. The adults’ ability to recall the scenes associated with the objects improved after receiving TMS, but not after the sham treatment.

“Our study demonstrates that TMS could potentially be used as a way to improve memory for older adults experiencing age-related memory impairments,” said John A. Walker, PhD, postdoctorate fellow at Northwestern University in Evanston, Illinois. “TMS can be used to probe the relationship between brain networks and memory experimentally, opening new doors to understanding the network basis of cognitive decline in aging.”

Heading the Ball Hurts Women More Than Men

Intentionally hitting a soccer ball with the head, or “heading,” may have more adverse brain consequences for women than men, said researchers.

Heading does not typically result in a concussion, yet growing evidence links the move to CNS damage. Previous studies using diffusion tensor imaging (DTI) have revealed that heading damages the integrity of the axons. Women appear to be more vulnerable than men to problems associated with heading, as they report more symptoms that last longer, but the reason for these gender differences remains unknown.

To assess possible gender differences in the effects of heading, researchers used DTI to examine 49 male and 49 female amateur soccer players who were matched on age and frequency of heading. Higher levels of heading were associated with decreased axonal integrity in three brain regions for men and eight brain regions for women. In seven of the areas identified in women, the association between axonal integrity and heading was significantly stronger than it was in men.

“Given similar amounts of exposure to heading, women show a greater volume of abnormality that is significantly different from what is seen in men,” said lead author Todd G. Rubin, MD, a doctoral student at Albert Einstein College of Medicine in Bronx, New York. “Identifying and understanding the basis for differences in susceptibility to injury represent key steps in determining better treatments and guidelines for safer play.”

DBS Can Individualize Treatment for Parkinson’s Disease

A new approach to deep brain stimulation (DBS) adjusts itself to deliver the appropriate amount of stimulation in patients with Parkinson’s disease, according to new research. The approach could improve symptom management and reduce side effects.

DBS has been a valuable treatment for Parkinson’s disease by helping to quell the abnormal movements that are characteristic of the disease. Traditional DBS delivers a constant level of stimulation and cannot adapt if a patient’s symptoms vary over the course of a day. As a result, a patient may sometimes receive too little stimulation, which fails to control symptoms, or too much, which causes side effects such as dyskinesia.

To match stimulation to variations in patient symptoms throughout the day, researchers and engineers developed a novel implantable device that provides DBS and records activity from the surface of the brain. Similar to a cardiac pacemaker, this adaptive device can autoadjust its level of stimulation based on a physiologic signal—in this case, brain activity related to dyskinesia. A high dyskinesia signal indicated greater likelihood of unwanted side effects and caused the device to reduce the stimulation level. A low signal indicated a higher chance of symptoms returning and triggered an increase in stimulation.

The device was tested in two patients inside and outside of the laboratory. Neither patient reported discomfort, adverse events, or worsening symptoms. In addition, the battery used as much as 45% less energy than traditional DBS, which is an important advantage, since battery replacement requires surgery.

“Our study showed that totally implanted, adaptive DBS is feasible and can be used at home in patients,” said lead author Nicole C. Swann, PhD, Assistant Professor of Human Physiology at the University of Oregon in Eugene. “Adaptive stimulation represents one of the first major advances in DBS technology since this technique was first introduced for the treatment of Parkinson’s disease 25 years ago.”

 

 

Contact Sports May Impair Memory Temporarily

Sports-related head injuries may prevent the generation of new neurons in a brain region important for memory, said investigators.

Concussion can lead to cognitive impairments, and recent evidence indicates that subconcussive hits can cause damage. The hippocampus is particularly vulnerable. One way to test the effects of head impacts on the hippocampus is a memory assessment called the mnemonic similarity test (MST), which evaluates a person’s ability to distinguish between images that are novel, previously presented, or similar to images previously presented. Accumulating evidence suggests that MST scores are related to the hippocampus’s ability to generate new neurons.

To investigate changes in memory following sports-related head injuries, researchers assessed different types of athletes in two studies. In the first study, they compared athletes with concussion, uninjured athletes who played the same sport, same-sport athletes with musculoskeletal injuries, and healthy controls. Compared with the other three groups, concussed athletes performed worse on the MST when tested two to four weeks after their injury. The scores did not remain low, however. By the time the athletes were cleared to play, their scores had improved to normal levels.

In the second study, rugby players were given the MST before the season started, halfway through the season, and one month after their last game. Scores dropped midseason, compared with preseason scores, but recovered by the postseason assessment.

“Using a cognitive test believed to be sensitive to hippocampal neurogenesis, we found that athletes with concussion show impairments that resolve following recovery,” said lead author Melissa Danielle McCradden, PhD, a postdoctoral fellow at McMaster University in Toronto. “These findings represent, to the best of our knowledge, the first reported evidence in humans suggesting a brain change that might explain the cognitive and emotional symptoms associated with mild traumatic brain injury.”

Disrupted Brain Networks May Cause Gulf War Illness

The brains of veterans with Gulf War illness (GWI) show widespread communication abnormalities in networks that support various brain functions, researchers reported. The observed patterns of impairment provide objective neurophysiologic evidence to support the self-reported symptoms of veterans with GWI.

As many as 250,000 veterans who served in Iraq, Kuwait, and Saudi Arabia during the 1991 Gulf War may currently experience GWI. Symptoms include difficulty remembering things, trouble finding words while speaking, motor coordination, mood swings, fatigue, and chronic pain. GWI is thought to result from exposure to a mix of chemical and biological warfare agents and hazardous chemicals.

To better understand brain changes in GWI, researchers compared the brains of 22 veterans with GWI to the brains of 30 healthy veterans of similar age. Using resting state functional MRI, researchers analyzed patterns of communication among regions of the brain known to control different functions and behavior. They identified changes in functional networks related to many commonly reported GWI symptoms. Individuals with GWI showed clear deficits in neural communication in the sectors of the brain responsible for visual processing, mood regulation, motor coordination, sensory processing, and language command, but increased communication in networks related to pain perception during rest.

“The results from this study provide strong evidence of neuropathology in GWI patients from exposures to neurotoxic agents,” said lead author Kaundinya Gopinath, PhD, Assistant Professor of Radiology and Imaging Sciences at Emory University in Atlanta. Next, “the aim is to establish brain mechanisms underlying GWI, which in turn can lead to development of treatments.”

Prolonged Sedation May Cause Brain Abnormalities in Infants

Full-term infants who undergo repeated anesthesia and prolonged sedation are at risk for changes in brain development, according to investigators.

Developmental impacts of prenatal exposure to sedatives have been studied widely, but less is known about the immediate and long-term neurologic and developmental effects of prolonged sedation when administered to critically ill infants after birth. Prolonged administration of opioids and benzodiazepines, which commonly are used for infants undergoing surgery, is associated with a high incidence of drug tolerance and dependence. Although negative long-term outcomes have been associated with such drug exposures in infants, these studies could not exclude other possible causes, such as prematurity or heart problems.

To study neurologic effects of prolonged sedation, researchers conducted MRI scans on full-term infants who underwent life-saving surgery that required prolonged exposure to morphine and midazolam before one year of age. Brain imaging showed several brain MRI anomalies that were not present in healthy infants, including abnormalities in gray and white matter structures and the ventricles. The number of brain MRI abnormalities significantly correlated with the average daily dose of these sedative drugs. The higher the daily dose, the more MRI irregularities were seen. The patients also had more brain fluid and a smaller total brain volume, compared with healthy infants. This pattern has been associated with long-term neurodevelopmental outcomes such as autism spectrum disorder. Taken together, these preliminary findings indicate a potential negative impact of prolonged sedation on brain growth during the first year of life, the researchers said.

“We were surprised to find higher incidence of brain abnormalities in full-term infants who underwent life-saving surgery that required prolonged sedation,” said senior author Dusica Bajic, MD, PhD, Principal Investigator at Boston Children’s Hospital. “The constellation of MRI irregularities suggests prolonged sedation may potentially contribute to delayed brain growth.” Future investigations will explore the neural mechanisms of the observed developmental effects and whether early sedation exposure may lead to long-term neurobehavioral impacts.

 

 

The Brain Preferentially Reactivates Negative Memories During Sleep

The brain selectively reactivates negative memories during sleep, prioritizing the retention of these emotional memories, which may be of greater future relevance than neutral memories and thus more worth remembering, according to investigators.

Over the past two decades, neuroscientists have gained increased understanding of how sleep boosts and stabilizes memories in the human brain. In the current study, researchers presented 57 healthy volunteers with a series of neutral and negative images. While staring straight ahead, the volunteers saw all of the negative images on one side of their field of vision (left) and all of the neutral images on the other side (right). Because the brain processes visual information in the opposite hemisphere from where it is viewed, this method allowed researchers to “tag” one hemisphere with negative content and the other with neutral content, thus enabling them to track localized memories. Participants were then shown the previously seen images for memory tests, with some of the images shown immediately after the learning phase and the rest shown after a period of wakefulness or sleep. During all memory tests, volunteers viewed the images directly in front of them, rather than to either side, and researchers asked participants to state whether an image had originally appeared to the left or right.

Participants who stayed awake in between memory tests forgot some of the original image locations, but forgetting was similar for neutral and negative images. Participants who slept between tests, on the other hand, had a much better rate of recall for the negative images than for the neutral ones. EEG recordings made during the learning phase show that the brain has encoded the distinct types of memories in its two hemispheres, with the negative images strongly encoded in the hemisphere opposite to the side of presentation. Researchers are now analyzing data that they hypothesize will show that the waking EEG pattern corresponding to emotional memories is the same pattern that is reactivated most strongly during sleep.

“This [finding] would provide a long sought-after brain-based explanation of how sleep selectively stabilizes emotional memories,” said lead author Roy Cox, PhD, research fellow in psychiatry at Beth Israel Deaconess Medical Center in Boston. “Our research substantially advances the notion that sleep plays a fundamental and complex role in the offline reorganization of waking experiences.”

Transcranial Magnetic Stimulation Improves Memory in Older Adults

A painless and noninvasive brain stimulation technique may help improve some types of memory in older adults, investigators reported.

One possible explanation for age-related memory loss is degradation of the neural connections between the hippocampus and the cortex. Weakening of these connections may lead to difficulties in creating new memories of specific events and the locations of objects. Scientists hypothesized that strengthening the connections between the hippocampus and cortex through repetitive transcranial magnetic stimulation (TMS) may help the storage of new memories. TMS delivers painless magnetic pulses to a particular region of the brain, changing the activity of the neurons within the targeted area.

To determine whether TMS could improve memory, 15 healthy adults over the age of 64 received TMS to a part of the cortex that communicates with the hippocampus. Treatment lasted for five days. During a separate week, each participant received five days of sham treatment, in which the setup was the same, but the stimulation was too low to influence the neural connections. Before and after each five-day session, participants were asked to remember pictures of everyday objects and pictures of outdoor scenes associated with each one. The adults’ ability to recall the scenes associated with the objects improved after receiving TMS, but not after the sham treatment.

“Our study demonstrates that TMS could potentially be used as a way to improve memory for older adults experiencing age-related memory impairments,” said John A. Walker, PhD, postdoctorate fellow at Northwestern University in Evanston, Illinois. “TMS can be used to probe the relationship between brain networks and memory experimentally, opening new doors to understanding the network basis of cognitive decline in aging.”

Heading the Ball Hurts Women More Than Men

Intentionally hitting a soccer ball with the head, or “heading,” may have more adverse brain consequences for women than men, said researchers.

Heading does not typically result in a concussion, yet growing evidence links the move to CNS damage. Previous studies using diffusion tensor imaging (DTI) have revealed that heading damages the integrity of the axons. Women appear to be more vulnerable than men to problems associated with heading, as they report more symptoms that last longer, but the reason for these gender differences remains unknown.

To assess possible gender differences in the effects of heading, researchers used DTI to examine 49 male and 49 female amateur soccer players who were matched on age and frequency of heading. Higher levels of heading were associated with decreased axonal integrity in three brain regions for men and eight brain regions for women. In seven of the areas identified in women, the association between axonal integrity and heading was significantly stronger than it was in men.

“Given similar amounts of exposure to heading, women show a greater volume of abnormality that is significantly different from what is seen in men,” said lead author Todd G. Rubin, MD, a doctoral student at Albert Einstein College of Medicine in Bronx, New York. “Identifying and understanding the basis for differences in susceptibility to injury represent key steps in determining better treatments and guidelines for safer play.”

DBS Can Individualize Treatment for Parkinson’s Disease

A new approach to deep brain stimulation (DBS) adjusts itself to deliver the appropriate amount of stimulation in patients with Parkinson’s disease, according to new research. The approach could improve symptom management and reduce side effects.

DBS has been a valuable treatment for Parkinson’s disease by helping to quell the abnormal movements that are characteristic of the disease. Traditional DBS delivers a constant level of stimulation and cannot adapt if a patient’s symptoms vary over the course of a day. As a result, a patient may sometimes receive too little stimulation, which fails to control symptoms, or too much, which causes side effects such as dyskinesia.

To match stimulation to variations in patient symptoms throughout the day, researchers and engineers developed a novel implantable device that provides DBS and records activity from the surface of the brain. Similar to a cardiac pacemaker, this adaptive device can autoadjust its level of stimulation based on a physiologic signal—in this case, brain activity related to dyskinesia. A high dyskinesia signal indicated greater likelihood of unwanted side effects and caused the device to reduce the stimulation level. A low signal indicated a higher chance of symptoms returning and triggered an increase in stimulation.

The device was tested in two patients inside and outside of the laboratory. Neither patient reported discomfort, adverse events, or worsening symptoms. In addition, the battery used as much as 45% less energy than traditional DBS, which is an important advantage, since battery replacement requires surgery.

“Our study showed that totally implanted, adaptive DBS is feasible and can be used at home in patients,” said lead author Nicole C. Swann, PhD, Assistant Professor of Human Physiology at the University of Oregon in Eugene. “Adaptive stimulation represents one of the first major advances in DBS technology since this technique was first introduced for the treatment of Parkinson’s disease 25 years ago.”

 

 

Contact Sports May Impair Memory Temporarily

Sports-related head injuries may prevent the generation of new neurons in a brain region important for memory, said investigators.

Concussion can lead to cognitive impairments, and recent evidence indicates that subconcussive hits can cause damage. The hippocampus is particularly vulnerable. One way to test the effects of head impacts on the hippocampus is a memory assessment called the mnemonic similarity test (MST), which evaluates a person’s ability to distinguish between images that are novel, previously presented, or similar to images previously presented. Accumulating evidence suggests that MST scores are related to the hippocampus’s ability to generate new neurons.

To investigate changes in memory following sports-related head injuries, researchers assessed different types of athletes in two studies. In the first study, they compared athletes with concussion, uninjured athletes who played the same sport, same-sport athletes with musculoskeletal injuries, and healthy controls. Compared with the other three groups, concussed athletes performed worse on the MST when tested two to four weeks after their injury. The scores did not remain low, however. By the time the athletes were cleared to play, their scores had improved to normal levels.

In the second study, rugby players were given the MST before the season started, halfway through the season, and one month after their last game. Scores dropped midseason, compared with preseason scores, but recovered by the postseason assessment.

“Using a cognitive test believed to be sensitive to hippocampal neurogenesis, we found that athletes with concussion show impairments that resolve following recovery,” said lead author Melissa Danielle McCradden, PhD, a postdoctoral fellow at McMaster University in Toronto. “These findings represent, to the best of our knowledge, the first reported evidence in humans suggesting a brain change that might explain the cognitive and emotional symptoms associated with mild traumatic brain injury.”

Disrupted Brain Networks May Cause Gulf War Illness

The brains of veterans with Gulf War illness (GWI) show widespread communication abnormalities in networks that support various brain functions, researchers reported. The observed patterns of impairment provide objective neurophysiologic evidence to support the self-reported symptoms of veterans with GWI.

As many as 250,000 veterans who served in Iraq, Kuwait, and Saudi Arabia during the 1991 Gulf War may currently experience GWI. Symptoms include difficulty remembering things, trouble finding words while speaking, motor coordination, mood swings, fatigue, and chronic pain. GWI is thought to result from exposure to a mix of chemical and biological warfare agents and hazardous chemicals.

To better understand brain changes in GWI, researchers compared the brains of 22 veterans with GWI to the brains of 30 healthy veterans of similar age. Using resting state functional MRI, researchers analyzed patterns of communication among regions of the brain known to control different functions and behavior. They identified changes in functional networks related to many commonly reported GWI symptoms. Individuals with GWI showed clear deficits in neural communication in the sectors of the brain responsible for visual processing, mood regulation, motor coordination, sensory processing, and language command, but increased communication in networks related to pain perception during rest.

“The results from this study provide strong evidence of neuropathology in GWI patients from exposures to neurotoxic agents,” said lead author Kaundinya Gopinath, PhD, Assistant Professor of Radiology and Imaging Sciences at Emory University in Atlanta. Next, “the aim is to establish brain mechanisms underlying GWI, which in turn can lead to development of treatments.”

Prolonged Sedation May Cause Brain Abnormalities in Infants

Full-term infants who undergo repeated anesthesia and prolonged sedation are at risk for changes in brain development, according to investigators.

Developmental impacts of prenatal exposure to sedatives have been studied widely, but less is known about the immediate and long-term neurologic and developmental effects of prolonged sedation when administered to critically ill infants after birth. Prolonged administration of opioids and benzodiazepines, which commonly are used for infants undergoing surgery, is associated with a high incidence of drug tolerance and dependence. Although negative long-term outcomes have been associated with such drug exposures in infants, these studies could not exclude other possible causes, such as prematurity or heart problems.

To study neurologic effects of prolonged sedation, researchers conducted MRI scans on full-term infants who underwent life-saving surgery that required prolonged exposure to morphine and midazolam before one year of age. Brain imaging showed several brain MRI anomalies that were not present in healthy infants, including abnormalities in gray and white matter structures and the ventricles. The number of brain MRI abnormalities significantly correlated with the average daily dose of these sedative drugs. The higher the daily dose, the more MRI irregularities were seen. The patients also had more brain fluid and a smaller total brain volume, compared with healthy infants. This pattern has been associated with long-term neurodevelopmental outcomes such as autism spectrum disorder. Taken together, these preliminary findings indicate a potential negative impact of prolonged sedation on brain growth during the first year of life, the researchers said.

“We were surprised to find higher incidence of brain abnormalities in full-term infants who underwent life-saving surgery that required prolonged sedation,” said senior author Dusica Bajic, MD, PhD, Principal Investigator at Boston Children’s Hospital. “The constellation of MRI irregularities suggests prolonged sedation may potentially contribute to delayed brain growth.” Future investigations will explore the neural mechanisms of the observed developmental effects and whether early sedation exposure may lead to long-term neurobehavioral impacts.

 

 

The Brain Preferentially Reactivates Negative Memories During Sleep

The brain selectively reactivates negative memories during sleep, prioritizing the retention of these emotional memories, which may be of greater future relevance than neutral memories and thus more worth remembering, according to investigators.

Over the past two decades, neuroscientists have gained increased understanding of how sleep boosts and stabilizes memories in the human brain. In the current study, researchers presented 57 healthy volunteers with a series of neutral and negative images. While staring straight ahead, the volunteers saw all of the negative images on one side of their field of vision (left) and all of the neutral images on the other side (right). Because the brain processes visual information in the opposite hemisphere from where it is viewed, this method allowed researchers to “tag” one hemisphere with negative content and the other with neutral content, thus enabling them to track localized memories. Participants were then shown the previously seen images for memory tests, with some of the images shown immediately after the learning phase and the rest shown after a period of wakefulness or sleep. During all memory tests, volunteers viewed the images directly in front of them, rather than to either side, and researchers asked participants to state whether an image had originally appeared to the left or right.

Participants who stayed awake in between memory tests forgot some of the original image locations, but forgetting was similar for neutral and negative images. Participants who slept between tests, on the other hand, had a much better rate of recall for the negative images than for the neutral ones. EEG recordings made during the learning phase show that the brain has encoded the distinct types of memories in its two hemispheres, with the negative images strongly encoded in the hemisphere opposite to the side of presentation. Researchers are now analyzing data that they hypothesize will show that the waking EEG pattern corresponding to emotional memories is the same pattern that is reactivated most strongly during sleep.

“This [finding] would provide a long sought-after brain-based explanation of how sleep selectively stabilizes emotional memories,” said lead author Roy Cox, PhD, research fellow in psychiatry at Beth Israel Deaconess Medical Center in Boston. “Our research substantially advances the notion that sleep plays a fundamental and complex role in the offline reorganization of waking experiences.”

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