Posts tagged neuroscience
Articles and news from the latest research reports.
Disorders of consciousness: How should clinicians respond to new therapeutic interventions?
August 2, 2012
New tools have confirmed high rates of misdiagnosis of patients with chronic disorders of consciousness, such as the vegetative state. An increasing number of patients’ families wish to use these novel techniques for diagnosis, prognosis, and treatment. An international team of researchers, including Dr. Éric Racine, researcher at the IRCM, analyzed the clinical, social and ethical issues that clinicians are now facing. Their article is published in the August edition of The Lancet Neurology, a renowned journal in the field of clinical neurology.
"Patients with disorders of consciousness have traditionally been regarded as unaware by definition, but findings from recent clinical studies have revealed astounding cases of awareness despite clinical unresponsiveness," explains Dr. Racine, a Montréal neuroethics specialist.
Severe brain injury can leave patients with chronic disorders of consciousness, which are medical conditions that inhibit consciousness. Patients thus have severe motor and cognitive impairments, remain fully dependent on others for all activities of daily living, and have no or very limited means to functionally communicate their thoughts or wishes, depending on their state.
Even with a careful neurological assessment of these types of disorders, some signs of awareness can elude the clinician because the clinical diagnosis relies on the observation of motor signs of awareness, which can be very subtle and fluctuate over time.
New technological developments can now measure brain function both in resting states and in response to simple commands, independent of muscle function, which could help establish a more accurate diagnosis. As a result, diagnostic classifications have been revised and prognostic knowledge is improving. For the first time, therapeutic studies have recently shown the effects of treatment on the improvement of patient responsiveness.
"The medical decision to stop or continue rehabilitation, or to transfer a patient to a long-term care facility can be hard to accept for the family, but one of the most difficult treatment decisions by family members remains whether to continue life-sustaining therapy or to discontinue it and only provide palliative care," says Dr. Racine.
Media coverage of disorders of consciousness has increased and information on the subject is increasingly available to the public. Clinicians such as neurologists, rehabilitation specialists, family doctors, and nurses must answer more requests from patients’ family members for novel diagnostic and therapeutic procedures.
"Clinicians therefore need to be prepared to discuss disorders of consciousness with ethical sensitivity, especially considering that the new procedures remain investigational," adds Dr. Racine. "They must be aware of the level of evidence supporting them and of the unavoidable ethical and social issues involved in responding to requests from patients’ family members."
Provided by Institut de recherches cliniques de Montreal
Source: medicalxpress.com
Fixing the way we fix the brain
Of all the health challenges humans face, few are as insidious as those that involve the death or dysfunction of cells in our brains. These illnesses, a category known as neurodegenerative disease, take from us the very things that make us who we are — our thoughts and our memories, our ability to recognize loved ones, control of our bodies, even our cognitive identity.
For most, diseases such as Alzheimer’s or Parkinson’s attack slowly, leading us down a slope of gradually deteriorating mental or physical function that current scientific methods are able to diagnose only after debilitating symptoms have set in. Even if discovered early, there is no way to prevent their onset, no way to reverse the damage, and no cures.
Driven by the desperate need for better understanding and treatments, a coalition of academic researchers, pharmaceutical companies, and state government is now coming together to confront this challenge in a novel way.
Is the singularity near, or is it already history?
The Singularity is Near is a hybrid of documentary and drama, co-directed by Kurzweil, that tries to explain the why and how of its title. Kurzweil’s alter ego, an animated character called Ramona, illustrates the evolutionary arc of thinking machines. She starts out as a primitive, choppy animation but gradually acquires consciousness.
As Ramona goes about her life, at one point seeing a clinical psychologist, her story is interwoven with documentary footage of Kurzweil explaining why the singularity is near. He tells us how machines are becoming atom-sized and how we are already implanting devices into the brains of people with Parkinson’s disease.
Using Data to Predict Your Future Health
Have you ever gone on a trip and unexpectedly found yourself in need of medical care? What if your condition could have been predicted? Better yet, what if you already had the medicine needed to treat that condition in your luggage?
The Hierarchical Association Rule Model (HARM), which I co-developed with Tyler McCormick of the University of Washington and David Madigan of Columbia University, can help patients be better prepared by warning them (and their doctors) about the conditions they may likely experience next. The predictive modeling tool checks data about an individual patient against other patients in the database with similar situations to help determine future conditions. It also alerts patients about any higher risks they may have for certain types of conditions.
Implantable Telescope Technology
Implantable Miniature Telescope along with the cornea, enlarges images in front of the eye approximately 2.2 or 2.7 times their normal size (depending on the model used). The magnification allows central images to be projected onto healthy perimacular areas of the retina instead of the macula alone, where breakdown of photoreceptors and loss of vision has occurred. This helps reduce the ‘blind spot’ and allows the patient to distinguish and discern images that may have been unrecognizable or difficult to see.
The telescope is about the size of a pea (3.6 mm diameter; 4.4 mm length) and is surgically placed inside the eye.
The patient, known only as TN, was left blind after damage to the visual (striate) cortex in both hemispheres of the brain following consecutive strokes. His eyes are normal but his brain cannot process the information they send in, rendering him totally blind.
Researchers say TN’s successful performance was an example of the phenomenon “blindsight,” and say it suggests that some small amount of information is being transmitted from his undamaged eyes to a more primitive part of his brain, which operates beneath the level of consciousness.
See video
(Credit: audiodude)
Brain at rest by Martijn Steenwijk (Winner Art of Neuroscience 2012)
Molecular Link Between Circadian Clock Disturbances and Inflammatory Diseases Discovered
ScienceDaily (Aug. 1, 2012) — Scientists have known for some time that throwing off the body’s circadian rhythm can negatively affect body chemistry. In fact, workers whose sleep-wake cycles are disrupted by night shifts are more susceptible to chronic inflammatory diseases such as diabetes, obesity and cancer.
Researchers at the Salk Institute for Biological Studies have now found a possible molecular link between circadian rhythm disturbances and an increased inflammatory response. In a study published July 9 in Proceedings of the National Academy of Sciences, the Salk team found that the absence of a key circadian clock component called cryptochrome (CRY) leads to the activation of a signaling system that elevates levels of inflammatory molecules in the body.
"There is compelling evidence that low-grade, constant inflammation could be the underlying cause of chronic diseases such as diabetes, obesity and cancer," says senior author Inder Verma, a professor in Salk’s Laboratory of Genetics and the Irwin and Joan Jacobs Chair in Exemplary Life Science. "Our results strongly indicate that an arrhythmic clock system, induced by the absence of CRY proteins, alone is sufficient to increase the stress level of cells, leading to the constant expression of inflammatory proteins and causing low-grade, chronic inflammation."
Cryptochrome serves as a break to slow the circadian clock’s activity, signaling our biological systems to wind down each evening. In the morning, CRY stops inhibiting the clock’s activity, helping our physiology ramp up for the coming day.
To gain insight into the role of circadian clock components on immune function, the Salk scientists measured the expression of inflammatory mediators in the hypothalamus (the area of the brain responsible for sleep-wake cycle regulation) of mice with deleted CRY genes. Through a variety of tests, these knockout mice showed a significant increase in the expression of certain inflammatory proteins known as cytokines, including interleukin-6 and tumor necrosis factor-α, compared to mice with CRY genes.
"Our findings demonstrate that a lack of cryptochrome activates these proinflammatory molecules, indicating a potential role for cryptochrome in the regulation of inflammatory cytokine expression," says Satchidananda Panda, an associate professor in Salk’s Regulatory Biology Laboratory and one of the senior authors of the study.
In addition, the researchers found that a lack of CRY activated the NF-kB pathway, a molecular signaling conduit that controls many genes involved in inflammation. NF-kB is a protein complex in a cell’s cytoplasm, “just happily doing nothing,” says Verma. In response to stimuli, it is transferred to the cell’s nucleus, where it binds to inflammation genes and turns them on. The regulation of these genes is tightly controlled, but NF-kB does not completely shut off their expression. This lingering expression causes inflammation.
"Every time this pathway is turned on, there is a residual amount of inflammation left in the body," says Rajesh Narasimamurthy, a research associate in Verma’s laboratory and the paper’s first author. "That adds up over time, contributing to inflammation-related diseases like obesity and diabetes."
Previous research has shown that suppressing the activity of the NF-kB pathway might be a suitable therapy for some diseases. For example, NF-kB is activated automatically in cancer cells of multiple myeloma, which affects infection-fighting plasma cells in the bone marrow and allows the cells to proliferate. Drugs that inhibit this activity might be able to degrade NF-kB to the point that it may kill off the disease.
The researchers say the goal now is to find out how to suppress NF-kB activation in the short term to treat diseases like diabetes. They caution that any long-term suppression of the pathway could lead to chronic infection. “We would like to find molecules that modify this activity and focus on those small-molecule inhibitors to treat disease,” Verma adds.
Source: Science Daily
Unique Cell Type Implicated in Multiple Sclerosis
The new study, published in Science Translational Medicine, shows that one effect of daclizumab is to thin the ranks of lymphoid tissue inducer (LTi) cells. These cells are known to promote the development of lymph nodes and related tissues during fetal life, but their role during adulthood has been unclear. The new study marks the first time that LTi cells have been implicated in any human autoimmune disorder.
"While further study is required to confirm the role of LTi cells in autoimmunity, our results point to the cells as a promising target for the development of new drugs to treat autoimmune disorders," said Bibiana Bielekova, M.D., an investigator at NIH’s National Institute of Neurological Disorders and Stroke (NINDS).
Scientists Turn Fly Neurons Into Gorgeous Art
Using technology affectionately dubbed “Brainbow,” scientists can color-code individual neurons inside the tiny brain of a fruit fly.