Posts tagged brain activation
Articles and news from the latest research reports.
Brain Activation in Motor Sequence Learning Is Related to the Level of Native Cortical Excitability
Cortical excitability may be subject to changes through training and learning. Motor training can increase cortical excitability in motor cortex, and facilitation of motor cortical excitability has been shown to be positively correlated with improvements in performance in simple motor tasks. Thus cortical excitability may tentatively be considered as a marker of learning and use-dependent plasticity. Previous studies focused on changes in cortical excitability brought about by learning processes, however, the relation between native levels of cortical excitability on the one hand and brain activation and behavioral parameters on the other is as yet unknown. In the present study we investigated the role of differential native motor cortical excitability for learning a motor sequencing task with regard to post-training changes in excitability, behavioral performance and involvement of brain regions. Our motor task required our participants to reproduce and improvise over a pre-learned motor sequence. Over both task conditions, participants with low cortical excitability (CElo) showed significantly higher BOLD activation in task-relevant brain regions than participants with high cortical excitability (CEhi). In contrast, CElo and CEhi groups did not exhibit differences in percentage of correct responses and improvisation level. Moreover, cortical excitability did not change significantly after learning and training in either group, with the exception of a significant decrease in facilitatory excitability in the CEhi group. The present data suggest that the native, unmanipulated level of cortical excitability is related to brain activation intensity, but not to performance quality. The higher BOLD mean signal intensity during the motor task might reflect a compensatory mechanism in CElo participants.
Hypnosis study unlocks secrets of unexplained paralysis
Hypnosis has begun to attract renewed interest from neuroscientists interested in using hypnotic suggestion to test predictions about normal cognitive functioning.
To demonstrate the future potential of this growing field, guest editors Professor Peter Halligan from the School of Psychology at Cardiff University and David A. Oakley of University College London, brought together leading researchers from cognitive neuroscience and hypnosis to contribute to this month’s special issue of the international journal, Cortex.
The issue illustrates how methodological and theoretical advances, using hypnotic suggestion, can return novel and experimentally verifiable insights for the neuroscience of consciousness and motor control. The research also includes novel brain imaging studies, which address sceptics’ concerns regarding the subjective reality and comparability of hypnotically suggested phenomena that previously depended on subjects’ largely unverifiable report and behaviour.
Halligan and Oakley also contribute to a new and revealing brain imaging study in the special issue that explores the brain systems involved in hypnotic paralysis. This research follows their earlier pioneering work on hypnotic leg paralysis reported in the Lancet in 2000.
Patients with “functional” or “psychogenic” conversion disorders present symptoms, such as paralyses, are clinically challenging. They comprise between 30 and 40% of patients attending neurology outpatient clinics and place a huge strain on public health services.
Professor Halligan of Cardiff University’s School of Psychology said: “This new study, working with colleagues at the Institute of Psychiatry in London, suggests that hypnosis can provide insights into of the brain systems involved in patients who display symptoms of neurological illness, but without evidence of brain damage. New insights show that symptoms experienced by patients with functional or dissociative conversion disorders (e.g. medically unexplained paralysis) can be simulated using targeted hypnotic suggestion.
"In this study we monitored brain activations of healthy volunteers with hypnosis induction who experienced paralysis-like experiences which could be turned ‘on’ and ‘off’. The suggestion resulted in subjects being unable to move a joystick together with a realistic and compelling experience of being unable to move and control their left hand despite trying.
"When compared to the completed movements, the suggested paralysis condition revealed increased activity in brain regions know to be active during motor planning and intention to move – and also brain areas involved in response selection and inhibition."
Comparing symptoms conveyed by conversion disorder patients and those produced by ‘paralysis’ suggestions in hypnosis, has revealed similar patterns of brain activation associated with attempted movement of the affected limb.
These findings could inform future studies of the brain mechanisms underpinning limb paralysis in patients with conversion disorders. More importantly they could lead to effective treatments.
(Source: cardiff.ac.uk)
The Science of Storytelling: Why Telling a Story is the Most Powerful Way to Activate Our Brains
We all enjoy a good story, whether it’s a novel, a movie, or simply something one of our friends is explaining to us. But why do we feel so much more engaged when we hear a narrative about events?
It’s in fact quite simple. If we listen to a powerpoint presentation with boring bullet points, a certain part in the brain gets activated. Scientists call this Broca’s area and Wernicke’s area. Overall, it hits our language processing parts in the brain, where we decode words into meaning. And that’s it, nothing else happens.
When we are being told a story, things change dramatically. Not only are the language processing parts in our brain activated, but any other area in our brain that we would use when experiencing the events of the story are too.
![Study supports link between stress, epileptic seizures
Scientists have long thought that stress plays a role in epileptic seizures, and new evidence suggests that epilepsy patients who believe this is the case experience a different brain response when faced with a nerve-wracking situation.
Researchers from the University of Cincinnati performed functional MRI brain scans during a stressful math exercise on 16 epilepsy patients who pegged stress as a factor in their seizure control and seven patients who did not. While both groups performed similarly on the test, those who perceived stress to have an impact on their epilepsy showed greater brain activation than the others during intimidating parts of the test.
"One of the things we often hear is that a lot of epilepsy patients feel their seizures are affected by stress … but no one had really looked at their [brain response] or other elements of their physiological response," said study author Jane Allendorfer, an instructor of neurology at the University of Alabama at Birmingham. Allendorfer worked at University of Cincinnati while the study was conducted.
"We were a bit surprised to see this difference," she added, "but really excited to see it as well because this is something that hadn’t been done before."
The research was scheduled to be presented Monday at the annual meeting of the American Epilepsy Society, in San Diego. Data presented at scientific conferences often has not been peer-reviewed or published and is considered preliminary.
A brain disorder producing repeated seizures, epilepsy affects more than 2 million people in the United States, according to the U.S. Centers for Disease Control and Prevention. An estimated 50 million to 65 million people are affected by the condition worldwide.](http://40.media.tumblr.com/tumblr_mekh5tZpLz1rog5d1o1_500.jpg)
Study supports link between stress, epileptic seizures
Scientists have long thought that stress plays a role in epileptic seizures, and new evidence suggests that epilepsy patients who believe this is the case experience a different brain response when faced with a nerve-wracking situation.
Researchers from the University of Cincinnati performed functional MRI brain scans during a stressful math exercise on 16 epilepsy patients who pegged stress as a factor in their seizure control and seven patients who did not. While both groups performed similarly on the test, those who perceived stress to have an impact on their epilepsy showed greater brain activation than the others during intimidating parts of the test.
"One of the things we often hear is that a lot of epilepsy patients feel their seizures are affected by stress … but no one had really looked at their [brain response] or other elements of their physiological response," said study author Jane Allendorfer, an instructor of neurology at the University of Alabama at Birmingham. Allendorfer worked at University of Cincinnati while the study was conducted.
"We were a bit surprised to see this difference," she added, "but really excited to see it as well because this is something that hadn’t been done before."
The research was scheduled to be presented Monday at the annual meeting of the American Epilepsy Society, in San Diego. Data presented at scientific conferences often has not been peer-reviewed or published and is considered preliminary.
A brain disorder producing repeated seizures, epilepsy affects more than 2 million people in the United States, according to the U.S. Centers for Disease Control and Prevention. An estimated 50 million to 65 million people are affected by the condition worldwide.
Biking Restores Brain Connectivity in Parkinson’s
PROBLEM: It’s commonly known that Parkinson’s Disease is a chronic, progressive, disease of central nervous system that affects motor ability — its recognizable early stages are characterized by shakiness and difficulty walking. No cure exists, which is why back in 2003, the best Dr. Jay Alberts of the Cleveland Clinic Lerner Research Institute rode a tandem bicycle across Iowa with a Parkinson’s patient (to raise awareness). Unexpectedly, the patient showed improvements in her condition after the trip. In what now much be common lore at the Institute, Alberts attempted to explain the inexplicable by noticing that his own pace was faster than that of his partner, who was forced, by the cruel mechanics of tandem cycling, to pedal faster in order to keep up.
METHODOLOGY: Alberts and his colleagues used functional connectivity MRI to study the brains of 26 patients with Parkinson’s Disease before and after they engaged in an 8-week exercise program and then, as a follow-up, one month later. Three times a week, the patients worked out on stationary bicycles. The experimental group used a modified bike that, using an algorithm in the place of a super in-shape doctor, would measure their rate of exertion and use it as a basis to push them harder than they would otherwise choose.
RESULTS: What the researchers referred to as “forced rate activity,” others might feel is more accurately labeled “torture.” But when they calculated the brain activation of the patients forced to pedal past their comfort level, they found lasting increases in connectivity between two areas of the brain responsible for motor ability: the primary motor cortex and the posterior region of the thalamus.
CONCLUSION: Forced-rate bicycle exercise appears to be an effective therapy for Parkinson’s disease.
IMPLICATION: The treatment delivered dramatic results, and has the distinction of being inexpensive and accessible. Alberts contends that even those without access to their own algorithm for forced-rate activity may be able to see improvement by using an at-home stationary bike. The next step is to evaluate the possible effects of other forms of exercise, like swimming.
The full study was presented at the annual meeting of the Radiological Society of North America.
Why does vivid memory ‘feel so real?’
Scientists find evidence that real perceptual experience and mental replay share similar brain activation patterns
Toronto, Canada – Neuroscientists have found strong evidence that vivid memory and directly experiencing the real moment can trigger similar brain activation patterns.
The study, led by Baycrest’s Rotman Research Institute (RRI), in collaboration with the University of Texas at Dallas, is one of the most ambitious and complex yet for elucidating the brain’s ability to evoke a memory by reactivating the parts of the brain that were engaged during the original perceptual experience. Researchers found that vivid memory and real perceptual experience share “striking” similarities at the neural level, although they are not “pixel-perfect” brain pattern replications.
The study appears online this month in the Journal of Cognitive Neuroscience, ahead of print publication.
"When we mentally replay an episode we’ve experienced, it can feel like we are transported back in time and re-living that moment again," said Dr. Brad Buchsbaum, lead investigator and scientist with Baycrest’s RRI. "Our study has confirmed that complex, multi-featured memory involves a partial reinstatement of the whole pattern of brain activity that is evoked during initial perception of the experience. This helps to explain why vivid memory can feel so real."
But vivid memory rarely fools us into believing we are in the real, external world – and that in itself offers a very powerful clue that the two cognitive operations don’t work exactly the same way in the brain, he explained.
In the study, Dr. Buchsbaum’s team used functional magnetic resonance imaging (fMRI), a powerful brain scanning technology that constructs computerized images of brain areas that are active when a person is performing a specific cognitive task. A group of 20 healthy adults (aged 18 to 36) were scanned while they watched 12 video clips, each nine seconds long, sourced from YouTube.com and Vimeo.com. The clips contained a diversity of content – such as music, faces, human emotion, animals, and outdoor scenery. Participants were instructed to pay close attention to each of the videos (which were repeated 27 times) and informed they would be tested on the content of the videos after the scan.
A subset of nine participants from the original group were then selected to complete intensive and structured memory training over several weeks that required practicing over and over again the mental replaying of videos they had watched from the first session. After the training, this group was scanned again as they mentally replayed each video clip. To trigger their memory for a particular clip, they were trained to associate a particular symbolic cue with each one. Following each mental replay, participants would push a button indicating on a scale of 1 to 4 (1 = poor memory, 4 = excellent memory) how well they thought they had recalled a particular clip.
Dr. Buchsbaum’s team found “clear evidence” that patterns of distributed brain activation during vivid memory mimicked the patterns evoked during sensory perception when the videos were viewed – by a correspondence of 91% after a principal components analysis of all the fMRI imaging data.
The so-called “hot spots”, or largest pattern similarity, occurred in sensory and motor association areas of the cerebral cortex – a region that plays a key role in memory, attention, perceptual awareness, thought, language and consciousness.
Dr. Buchsbaum suggested the imaging analysis used in his study could potentially add to the current battery of memory assessment tools available to clinicians. Brain activation patterns from fMRI data could offer an objective way of quantifying whether a patient’s self-report of their memory as “being good or vivid” is accurate or not.
Source: EurekAlert!