Uncovering the secrets of 3D vision: How glossy objects can fool the human brain

It’s a familiar sight at the fairground: rows of people gaping at curvy mirrors as they watch their faces and bodies distort. But while mirrored surfaces may be fun to look at, new findings by researchers from the Universities of Birmingham, Cambridge and Giessen, suggest they pose a particular challenge for the human brain in processing images for 3D vision.

The researchers have taken advantage of the unusual visual behaviour of curved mirrors to study stereopsis: the process by which the brain combines images from the two eyes to see in 3D.

The work, published online in the Proceedings of the National Academy of Sciences (PNAS), used mathematical analysis and perceptual measurements to show that people often see the ‘wrong’ shape for glossy objects (like chrome bumpers or brass door knobs) because of the way the brain employs ‘quality control’ mechanisms when it views the world with two eyes. This reveals how the brain checks the ‘usefulness’ of the signals it receives from the senses, explaining why we sometimes misperceive shapes and distances. It also has some connections with the design of robotic systems.

‘We often think that the 3D information we get from having two eyes provides the gold standard for seeing in depth; but glossy objects pose a difficult challenge to the brain because the stereoscopic information often indicates depths that don’t match the physical shape of the object’ explains Dr Andrew Welchman, a Wellcome Trust Senior Research Fellow at the University of Birmingham. ‘We found that the brain is sometimes ‘fooled’ into seeing the wrong 3D shape, but this depends on statistical properties of the stereo images that indicate how ‘useful’ the information is,’ he adds.

To carry out the project, the team developed mathematical models that calculate the pattern of reflections seen when viewing glossy objects, and measured the perceived 3D appearance of these shapes.

‘When a curved mirrored object reflects its surroundings, the reflections appear at a different depth than the glossy surface itself. This makes it difficult for the brain to work out the true 3D distance to the surface’ explains Dr Alex Muryy, a research fellow at Birmingham who conducted the analyses. ‘We found that even simple objects can produce very complex depth profiles, and reflections can behave very differently from normal stereoscopic information.’ Understanding these differences provided the key to reveal the generalised way in which the brain analyses incoming information to judge the circumstances in which information should be trusted.

‘Stereoscopic information is often highly informative, but in certain circumstances it can tell us the wrong thing or be unreliable. The challenge is therefore to understand how the brain knows when it should or should not trust this 3D information,’ says Professor Roland Fleming, Giessen University in Germany. ‘We have uncovered signals that are likely to be important in guiding the brain’s use of the information by studying glossy objects. In particular, we can understand people’s misperceptions because in these circumstances 3D reflections fall within the normal range of values, meaning that the brain takes the depth signals at face value.’

FDA Approves Clinical Trial of Auditory Brainstem Implant Procedure for Children in the U.S.

L.A.-based House Research Institute and Children’s Hospital Los Angeles announced today that the United States Food and Drug Administration (FDA) has given final approval to begin a clinical trial of an Auditory Brainstem Implant (ABI) procedure for children. The trial is a surgical collaboration sponsored by the House Research Institute in partnership with Children’s Hospital Los Angeles and Vittorio Colletti, MD of the University of Verona Hospital, Verona, Italy.

The ABI was developed at the House Research Institute and is the world’s first successful prosthetic hearing device to stimulate neurons directly at the human brainstem, bypassing the inner ear and hearing nerve entirely. Since the procedure began, more than 1,000 adults worldwide have received the ABI, with surgeons at the House Clinic leading the way.

“This will be the first FDA-approved trial of its kind, and represents a major step forward to bring a sense of hearing to deaf children in the U.S. who are born without a hearing nerve or cochlea (hearing organ) and therefore are unable to benefit from hearing aids or cochlear implants,” said Neil Segil, Ph.D, executive vice president for research, House Research Institute. “Since its development at the House Research Institute in 1979 by Drs. William House and William Hitselberger, the ABI has been successful in providing a sense of sound to many adults in the U.S., however it has never been approved by the FDA for treating deafness in children. This study has the potential to expand the use of this remarkable device, which represents the only effective sensory prosthetic for direct brain stimulation in use today.”

The Pediatric ABI team includes physicians and researchers from the House Research Institute, including Eric Wilkinson, MD, Laurie Eisenberg, Ph.D., Robert Shannon, Ph.D.; Marc Schwartz, MD; Laurel Fisher, Ph.D.; Steve Otto, M.A., and Margaret Winter, M.S., as well as Children’s Hospital Los Angeles’ Mark Krieger, MD and Gordon McComb, MD; and Verona Hospital’s Vittorio Colletti, MD; Marco Carner, MD; and Liliana Colletti, Ph.D.

“We’re excited to have reached this milestone and look forward to being able to offer this amazing technology to children in the United States who currently have no other option for hearing rehabilitation,” said Eric Wilkinson, MD, co-principal investigator and lead physician for the clinical trial.

Reviewing alcohol’s effects on normal sleep

Sleep is supported by natural cycles of activity in the brain and consists of two basic states: rapid eye movement (REM) sleep and non-rapid eye movement (NREM) sleep. Typically, people begin the sleep cycle with NREM sleep followed by a very short period of REM sleep, then continue with more NREM sleep and more REM sleep, this 90 minute cycle continuing through the night. A review of all known scientific studies on the impact of drinking on nocturnal sleep has clarified that alcohol shortens the time it takes to fall asleep, increases deep sleep, and reduces REM sleep.

Results will be published in the April 2013 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"This review has for the first time consolidated all the available literature on the immediate effects of alcohol on the sleep of healthy individuals," said Irshaad Ebrahim, medical director at The London Sleep Centre as well as corresponding author for the study.

"Certainly a mythology seems to have developed around the impact of alcohol on sleep," added Chris Idzikowski, director of the Edinburgh Sleep Centre. "It is a good time to review the research as the mythology seems to be flourishing more rapidly than the research itself. Also, our understanding of sleep has accelerated in the past 30 years, which has meant that some of the initial interpretations need to be revisited."

Some of the review’s key themes are:

• At all dosages, alcohol causes a reduction in sleep onset latency, a more consolidated first half sleep, and an increase in sleep disruption in the second half of sleep.

  "This review confirms that the immediate and short-term impact of alcohol is to reduce the time it takes to fall asleep," said Ebrahim. "In addition, the higher the dose, the greater the impact on increasing deep sleep. This effect on the first half of sleep may be partly the reason some people with insomnia use alcohol as a sleep aid. However, the effect of consolidating sleep in the first half of the night is offset by having more disrupted sleep in the second half of the night."

• The majority of studies, across alcohol dose, age, and gender, confirm an increase in slow-wave sleep (SWS) in the first half of the night. SWS, often referred to as deep sleep, consists of stages 3 and 4 of NREM. During SWS, the body repairs and regenerates tissues, builds bone and muscle, and appears to strengthen the immune system. Alcohol’s impact on SWS in the first half of the night appears to be more robust than its effect on REM sleep.

  "SWS or deep sleep generally promotes rest and restoration," said Ebrahim. "However, when alcohol increases SWS, this may also increase vulnerability to certain sleep problems such as sleepwalking or sleep apnoea in those who are predisposed."

• Alcohol’s effects on REM sleep in the first half of sleep appear to be dose related. Low and moderate doses show no clear effects on REM sleep in the first half of the night, whereas at high doses, REM sleep reduction in the first part of sleep is significant. Total night REM sleep percent is decreased in the majority of studies at moderate and high doses.

  "Dreams generally occur in the REM stage of sleep," said Ebrahim. "During REM sleep the brain is more active, and may be regarded as ‘defragmenting the drive.’ REM sleep is also important because it can influence memory and serve restorative functions. Conversely, lack of REM sleep can have a detrimental effect on concentration, motor skills, and memory. REM sleep typically accounts for 20 to 25 percent of the sleep period."

• The onset of the first REM sleep period is significantly delayed at all doses and appears to be the most recognizable effect of alcohol on REM sleep, followed by a reduction in total night REM sleep.

"One consequence of a delayed onset of the first REM sleep would be less restful sleep," said Idzikowski. "The first REM episode is often delayed in stressful environments. There is also a linkage with depression."

Brain structure of infants predicts language skills at 1 year

Using a brain-imaging technique that examines the entire infant brain, researchers have found that the anatomy of certain brain areas – the hippocampus and cerebellum – can predict children’s language abilities at 1 year of age.

The University of Washington study is the first to associate these brain structures with future language skills. The results are published in the January issue of the journal Brain and Language.

“The brain of the baby holds an infinite number of secrets just waiting to be uncovered, and these discoveries will show us why infants learn languages like sponges, far surpassing our skills as adults,” said co-author Patricia Kuhl, co-director of the UW’s Institute for Learning & Brain Sciences.

Children’s language skills soar after they reach their first birthdays, but little is known about how infants’ early brain development seeds that path. Identifying which brain areas are related to early language learning could provide a first glimpse of development going awry, allowing for treatments to begin earlier.

“Infancy may be the most important phase of postnatal brain development in humans,” said Dilara Deniz Can, lead author and a UW postdoctoral researcher. “Our results showing brain structures linked to later language ability in typically developing infants is a first step toward examining links to brain and behavior in young children with linguistic, psychological and social delays.”

Discovering ‘Needle in a Haystack’ For Muscular Dystrophy Patients

Muscular dystrophy is caused by the largest human gene, a complex chemical leviathan that has confounded scientists for decades. Research conducted at the University of Missouri and described this month in the Proceedings of the National Academy of Sciences has identified significant sections of the gene that could provide hope to young patients and families.

MU scientists Dongsheng Duan, PhD, and Yi Lai, PhD, identified a sequence in the dystrophin gene that is essential for helping muscle tissues function, a breakthrough discovery that could lead to treatments for the deadly hereditary disease. The MU researchers “found the proverbial needle in a haystack,” according to Scott Harper, PhD, a muscular dystrophy expert at The Ohio State University who is not involved in the study.

Duchenne muscular dystrophy (DMD), predominantly affecting males, is the most common type of muscular dystrophy. Children with DMD face a future of rapidly weakening muscles, which usually leads to death by respiratory or cardiac failure before their 30th birthday.

Patients with DMD have a gene mutation that disrupts the production of dystrophin, a protein essential for muscle cell survival and function. Absence of dystrophin starts a chain reaction that eventually leads to muscle cell degeneration and death. While dystrophin is vital for muscle development, the protein also needs several “helpers” to maintain the muscle tissue. One of these “helper” molecular compounds is nNOS, which produces nitric oxide that can keep muscle cells healthy during exercise.

"Dystrophin not only helps build muscle cells, it’s also a key factor to attracting nNOS to the muscle cell membrane, which is important during exercise," Lai said. "Prior to this discovery, we didn’t know how dystrophin made nNOS bind to the cell membrane. What we found was that dystrophin has a special ‘claw’ that is used to grab nNOS and bring it to the muscle cell membrane. Now that we have that key, we hope to begin the process of developing a therapy for patients."

Circadian rhythms can be modified for potential treatment of disorders

UC Irvine-led studies have revealed the cellular mechanism by which circadian rhythms – also known as the body clock – modify energy metabolism and also have identified novel compounds that control this action. The findings point to potential treatments for disorders triggered by circadian rhythm dysfunction, ranging from insomnia and obesity to diabetes and cancer.

UC Irvine’s Paolo Sassone-Corsi, one of the world’s leading researchers on the genetics of circadian rhythms, led the studies and worked with international groups of scientists. Their results are detailed in two companion pieces appearing this week in the early online edition of the Proceedings of the National Academy of Science (1 , 2).

“Circadian rhythms of 24 hours govern fundamental physiological functions in almost all organisms,” said Sassone-Corsi, the Donald Bren Professor of Biological Chemistry. “The circadian clocks are intrinsic time-tracking systems in our bodies that anticipate environmental changes and adapt themselves to the appropriate time of day. Disruption of these rhythms can profoundly influence human health.”

He added that up to 15 percent of people’s genes are regulated by the day-night pattern of circadian rhythms.

Researchers map emotional intelligence in the brain

A new study of 152 Vietnam veterans with combat-related brain injuries offers the first detailed map of the brain regions that contribute to emotional intelligence – the ability to process emotional information and navigate the social world.

The study found significant overlap between general intelligence and emotional intelligence, both in terms of behavior and in the brain. Higher scores on general intelligence tests corresponded significantly with higher performance on measures of emotional intelligence, and many of the same brain regions were found to be important to both. (Watch a video about the research.)

The study appears in the journal Social Cognitive & Affective Neuroscience.

“This was a remarkable group of patients to study, mainly because it allowed us to determine the degree to which damage to specific brain areas was related to impairment in specific aspects of general and emotional intelligence,” said study leader Aron K. Barbey, a professor of neuroscience, of psychology and of speech and hearing science at the Beckman Institute for Advanced Science and Technology at the University of Illinois.

A previous study led by Barbey mapped the neural basis of general intelligence by analyzing how specific brain injuries (in a larger sample of Vietnam veterans) impaired performance on tests of fundamental cognitive processes.

In both studies, researchers pooled data from CT scans of participants’ brains to produce a collective, three-dimensional map of the cerebral cortex. They divided this composite brain into 3-D units called voxels. They compared the cognitive abilities of patients with damage to a particular voxel or cluster of voxels with those of patients without injuries in those brain regions. This allowed the researchers to identify brain areas essential to specific cognitive abilities, and those that contribute significantly to general intelligence, emotional intelligence, or both.

They found that specific regions in the frontal cortex (behind the forehead) and parietal cortex (top of the brain near the back of the skull) were important to both general and emotional intelligence. The frontal cortex is known to be involved in regulating behavior. It also processes feelings of reward and plays a role in attention, planning and memory. The parietal cortex helps integrate sensory information, and contributes to bodily coordination and language processing.

“Historically, general intelligence has been thought to be distinct from social and emotional intelligence,” Barbey said. The most widely used measures of human intelligence focus on tasks such as verbal reasoning or the ability to remember and efficiently manipulate information, he said.

“Intelligence, to a large extent, does depend on basic cognitive abilities, like attention and perception and memory and language,” Barbey said. “But it also depends on interacting with other people. We’re fundamentally social beings and our understanding not only involves basic cognitive abilities but also involves productively applying those abilities to social situations so that we can navigate the social world and understand others.”

The new findings will help scientists and clinicians understand and respond to brain injuries in their patients, Barbey said, but the results also are of broader interest because they illustrate the interdependence of general and emotional intelligence in the healthy mind.

Less tau reduces seizures and sudden death in severe epilepsy

Deleting or reducing expression of a gene that carries the code for tau, a protein associated with Alzheimer’s disease, can prevent seizures in a severe type of epilepsy linked to sudden death, said researchers at Baylor College of Medicine and the Mayo Clinic in Jacksonville, Fla., in a report in the current issue of the Journal of Neuroscience.

A growing understanding of the link between epilepsy and some forms of inherited Alzheimer’s disease led to the finding that could point the way toward new drugs for seizure disorders said Dr. Jeffrey Noebels, professor of neurology at BCM, and director of the Blue Bird Circle Developmental Neurogenetics Laboratory.

In her research, Jerrah Holth, a graduate student in molecular and human genetics at BCM who was working with mice with the severe form of epilepsy in Noebel’s laboratory, deleted the gene for tau. She found that reducing or eliminating tau also prevented the seizures in a severe form of epilepsy that has been associated with sudden death and reduced deaths in the animals.

In an earlier experiment, Noebels, in collaboration with Dr. Lennart Mucke at the Gladstone Research Laboratory at the University of California San Francisco, found that mice who carried a human gene that leads to accumulation of the beta amyloid protein and the amyloid plaques that accumulate in the brains of people with Alzheimer’s disease, also had epileptic seizures arising in the hippocampus, the region of the brain associated with memory storage and retrieval.

"This led to the paradigm-shifting hypothesis that excessive neuronal network activity, rather than too little, may contribute to lower cognitive performance and dementia in some forms of Alzheimer’s disease. When this happens, the progression of memory loss may accelerate," said Noebels.

The finding also demonstrated the two disorders may share defects in signaling within brain memory circuits.

The two labs went on to show that deleting the second gene for tau ameliorated both cognitive losses and seizures in the mice whose inherited disorder mimicked Alzheimer’s disease found in humans.

Holth’s finding demonstrates that tau is involved in a far broader range of epilepsy than previously suspected, said Noebels. The type of epilepsy she studied resulted from an inherited potassium ion channel defect that affects the flow of the potassium in and out of nerve cells. She found that removing the gene encoding Tau not only dramatically reduced seizures, but prevented the mice from dying early, which typically happens in these animals.

"Even a partial reduction of the amount of tau protein by 50 percent was highly effective," said Holth. Her finding suggests developing new drugs that lower the normal interactions of the tau protein may reduce seizures and sudden unexpected death for persons with intractable epilepsies, a problem in nearly one-third of the 5 million Americans with this disorder.

Currently, Noebels and his colleagues in the Blue Bird Laboratory are studying whether the loss of tau can correct a seizure disorder once it is already established. If these studies prove fruitful, “the pharmacological discovery programs under development for treatment of Alzheimer’s disease may one day find their way to the epilepsy clinic,” said Noebels.

(Image: ALAMY)

UCLA study first to image concussion-related abnormal brain proteins in retired NFL players

Now, for the first time, UCLA researchers have used a brain-imaging tool to identify the abnormal tau proteins associated with this type of repetitive injury in five retired National Football League players who are still living. Previously, confirmation of the presence of this protein, which is also associated with Alzheimer’s disease, could only be established by an autopsy.

The preliminary findings of the small study are reported Jan. 22 in the online issue of the American Journal of Geriatric Psychiatry, the official journal of the American Association for Geriatric Psychiatry.

Previous reports and studies have shown that professional athletes in contact sports who are exposed to repetitive mild traumatic brain injuries may develop ongoing impairment such as chronic traumatic encephalopathy (CTE), a degenerative condition caused by a build up of tau protein. CTE has been associated with memory loss, confusion, progressive dementia, depression, suicidal behavior, personality changes, abnormal gait and tremors.

"Early detection of tau proteins may help us to understand what is happening sooner in the brains of these injured athletes," said lead study author Dr. Gary Small, UCLA’s Parlow–Solomon Professor on Aging and a professor of psychiatry and biobehavioral sciences at the Semel Institute for Neuroscience and Human Behavior at UCLA. "Our findings may also guide us in developing strategies and interventions to protect those with early symptoms, rather than try to repair damage once it becomes extensive."

Small notes that larger follow-up studies are needed to determine the impact and usefulness of detecting these tau proteins early, but given the large number of people at risk for mild traumatic brain injury — not only athletes but military personnel, auto accident victims and others — a means of testing what is happening in the brain during the early stages could potentially have a considerable impact on public health.