Researchers at Johns Hopkins University recently released findings related to the ability to manipulate brain cells in test tube studies. The purpose was to determine if new drugs might be used to stop the brain-destroying impact of a genetic mutation at work in some forms to two incurable diseases: Dementia and ALS (amyotrophic lateral sclerosis or Lou Gehrig's disease ALS, sometimes known as Lou Gehrig's disease, named for the Yankee baseball great who died from it, which destroys nerve cells in the brain and spinal cord that control voluntary muscle movement.) Traditionally, “Efforts to treat neurodegenerative diseases have the highest failure rate for all clinical trials,” says J. D. Rothstein MD, PhD, professor of neurology and neuroscience at the Johns Hopkins University School of Medicine and leader of the research described online in the journal Neuron. The research was funded by grants from several organizations including the National Institutes of Health’s National Institute of Neurological Disorders and Stroke. This is very good news. In the future, this may mean that scientists analyze cerebral spinal fluid from patients with dementia and ALS in a new way. These may pave the way to develop markers that can be studied by clinicians to see if the treatment is working once the drug therapy is moved to clinical trials.
Saturday, November 30, 2013
Friday, November 29, 2013
Is there anything you can do to influence how people perceive you in terms of perception and group interactions? It appears that the answer is “yes.” Gavin J. Kilduff of New York University and Adam D. Galinsky of Columbia University, how you feel at the moment you join a new group has a significant impact on your initial status among the members of the group as well as your perceived status later on. Their findings suggest that whatever your typical baseline mindset, you can achieve a perceived higher status by increasing your happiness, eagerness, or sense of power just before you join a group. Harvard Business review summarized it this way: people who were induced to feel happy (via writing about a happy experience) were subsequently rated by their teammates in a hypothetical snowstorm-survival task as having higher status (2.13 on a 1-to-7 scale) than those who hadn’t been primed to feel happy (1.79); similar effects were seen when people were primed to feel eager and powerful, and the status perceptions lingered for days, probably because of the reinforcing nature of group hierarchies. Studies have shown the positive benefits to brain and body of maintaining a happy, positive mindset. Now it appears that this impacts the way others perceive the person, as well.
Thursday, November 28, 2013
- It's quite well established now that pugilistic trauma to your brain can actually break off the axon, the one large projection from each neurons. So what happens in conditions such as Alzheimer's? It seems that one of the ways in which Alzheimer's negatively impacts thinking ability involves the size of the synapse. Nerve endings begin to shrink and increase the distance between the end of an axon and the dendrite or another neuron. This increased space not only means that thinking takes longer but sometimes the message just cannot make it across the space. The process in the brain that should be sprouting nerve endings die and eventually, the person can no longer handle short-term memory or the retrieval of long-term memory. Are you afraid you are developing Alzheimer's? Get your brain evaluated and be sure you are doing a minimum of 30 minutes of challenging mental exercise every day. Avoid worrying, however, as worry is lethal for brain function. One bottom line says that you know you don't have dementia just because you misplace your car keys. On the other hand, you know you may have Alzheimer's when you see your car keys and forget what you would use them for.
Wednesday, November 27, 2013
Most people now know the term neuron (nerve cells in the brain, spinal cord, and peripheral nervous system) that have a special ability to talk with each other. They hold these conversations throughout a vast and intricate network. Estimates are that your brain alone contains about 100 billion neurons (and that there are thousands of neurons in your heart and at least a million in your intestines, and so on). These 100 billion neurons connect with each other via a quadrillion connections known as synapses (the tiny space between each neurons). The book Super Brain describes it this way: neurons project wormlike threads known as axons and dendrites, which deliver both chemical and electrical signals across the space between synapses. A neuron contains many dendrites to receive information from other nerve cells. But it has only one axon, which can extend out to over a meter (about 39 inches) in length. An adult human brain contains well over 100,000 miles of axons and countless dendrites--enough to wrap around the earth over four times. Wow!
Tuesday, November 26, 2013
The McGurk effect (perceiving what you see rather than what you hear) arises during phonetic processing because the integration of audio and visual information happens early in speech perception. And it’s not limited to syllables. The effect can occur in whole words. The McGurk effect has also been examined in relation to witness testimony. Wareham and Wright's 2005 study showed that inconsistent visual information can change the perception of spoken utterances. It likely impacts daily interactions in a way that many are unaware of. According to Wikipedia, people who are used to watching dubbed movies may be among those who are not susceptible to the McGurk effect because they have, to some extent, learned to ignore the information they are getting from the mouth of the person speaking. The take-away? Learn to pay attention and be aware of this phenomenon. If your eyes and ears register different meanings, ask for clarification. Of course, that’s assuming it involves in-person conversations and not something occurring on a movie screen!
Monday, November 25, 2013
Some people, including those that have been researching the phenomenon for more than twenty years, have reported experiencing the McGurk effect even when they are aware that it is taking place. Although some people can identify most of what is being said from lip reading along, the majority of individuals are rather limited in their ability to identify speech from visual-only signals. An ability to use visual speech to increase the intelligibility of heard speech in a noisy environment can be a definite asset. Most think of speech perception as an auditory process. Studies have shown, however, that one’s use of information is immediate, automatic, and, to a large degree, unconscious. This means that speech is not only something that is heard, it is perceived by all of the senses working together (seeing, touching, and listening to a face move). The brain is often unaware of the separate sensory contributions of what it perceives, so when it comes to recognizing speech the brain cannot differentiate whether it is seeing or hearing the incoming information.
Sunday, November 24, 2013
New studies by researchers at the University of Utah have added to the body of knowledge related to the McGurk effect, suggesting a mechanistic underpinning for the McGurk effect (a perceptual phenomenon related to hearing and seeing in decoding speech). In the brain, information from the visual cortex may be instructing the auditory cortex which sound to “hear” even before an auditory stimulus is received. According to the researchers, the McGurk effect is strong enough to be perceived even if the viewer knows the illusion is occurring, suggesting that visual stimuli can influence early representations of auditory stimuli. Meaning that knowledge about the phenomenon seems to have little effect on one's perception of it. This is different from some specific optical illusions which break down once one 'sees through' them. This understanding of multisensory neocortical language processing provides insight into the multisensory neural mechanisms underlying language perception and has implications for rehabilitation therapy and neural prostheses.
Saturday, November 23, 2013
Have you experienced the McGurk effect? This effect may be experienced when a video of one sound production is dubbed with a sound-recording of a different sound being spoken. Often, the perceived sound is a third, intermediate sound. For example, the syllable “ba-ba” is spoken over the lip movements of “ga-ga”, and the perception is of “da-da”. Reserachers McGurk and MacDonald believed that this resulted from the common sound and visual properties of “b” and “g” and involved the brain's effort to provide the consciousness with its best guess about the incoming information. The information coming from the eyes and ears is contradictory, and in this instance, the eyes (visual information) had a greater effect on the brain and thus the fusion and combination responses have been created. Vision is a primary sense for humans while speech perception is multimodal, meaning it involves information from more than one sensory modality, in particular, auditory and visual.
Friday, November 22, 2013
Do you know about the McGurk effect? It describes a perceptual phenomenon, an illusion really, related to hearing and seeing in decoding speech. The illusion occurs when the auditory component of one sound is paired with the visual component of another sound, leading to the perception of a third sound. Reportedly it was first described in 1976 in a paper by Harry McGurk and MacDonald entitled "Hearing Lips and Seeing Voices." The phenomenon was discovered accidently when McGurk and his research assistant, MacDonald, asked a technician to dub a video with a different sound from the one spoken while conducting a study on how infants perceive language at different developmental stages. When the video was played back, both researchers heard a third sound rather than the one spoken or mouthed in the video. If a person is getting poor quality auditory information but good quality visual information, they may be more likely to experience the McGurk effect and go with what they “saw” rather than what they “heard.”
Thursday, November 21, 2013
The last myth we'll discuss in this cluster is the belief that you lose millions of brain cells every day and that they cannot be replaced. Yes, studies estimate that the average human brain loses about 85,000 neurons every day from the cortex. This is about one every second. However, when you really look at what this means, it's a tiny percentage of the neurons in your brain. Some estimates are that at the rate of one neuron per second, it would take you nearly 600 years to lose even half of your brain's neurons. Indeed because of neurogenesis (the growth of new neurons) Researcher Paul Coleman at the University of Rochester showed that the total number of nerve cells in your brain at age twenty does not significantly change when you reach age seventy. That's great news. How do you stimulate the neurons you do have? By engaging in 30 minutes of challenging mental exercise every day--and by 30 minutes of moderate physical exercise every day. Studies with rats by Sam Sisodia, U of Chicago Alzheimer's researcher, showed that physical exercise and mental stimulation protected mice from exhibiting symptoms of Alzheimer's even when they had been engineer to carry a human Alzheimer's mutation in their genome. So get busy . . . one hour a day is great prevention and can help you have a healthier older life. It may not only extend your years but help you keep life in those years.
Wednesday, November 20, 2013
Have you been told that your brain is hardwired and that it cannot be changed? Studies by Karl Lashley with rats have shown that this myth needs to be viewed with a great deal of skepticism. Yes the brain has circuitry but its connections are composed of living tissue. There are no wires that cannot be altered, so to speak. Your brain's circuitry is definitely able to be reshaped by what you think and by the experiences you give your brain. There's an old saying: neurons that fire together, wire together. This means that as you expose your brain to new experience and practice new skills, you can, in effect, rewire some of this circuitry and enhance your brain's function. The bottom line is that you are no hardwired in the sense that you are unable to alter your brain's circuitry. You brain is resilient. The process of neuroplasticity allows you to actually reshape your brain through your thoughts, feelings, and actions. Go for it!
Tuesday, November 19, 2013
A very prevalent myth is that aging of the brain is not only inevitable and irreversible but also that there's little you can do about the process. Dump this myth now! Studies suggest that in most cases you can slow down the onset of symptoms of aging through the lifestyle that you create and embrace. Even the definition of old age is shifting. New slogans are emerging: 70 is the new 50; old age begins after age 85. The bottom line is that many people get lazy and apathetic about learning as they age. This is lethal for optimum brain function, which loves variety and responds well to learning new information. Many people relatively secure about what they know and avoid going out of their way to continually challenge their brain by learning something new. That's one reason travel is so good for the brain: you give it new things to look at, smell, taste, hear, and different people and cultures with which to relate. You can increase your awareness of what is around you and converse with others about what you are perceiving and learning. You can choose to follow an upward learning curve no matter how old you are. This is one way you can create new dendrites on your new neurons, new synapses, and pathways that can help to stave off Alzheimer's disease. My brain's opinion? It's more than worth the effort!
Monday, November 18, 2013
A second myth that limits many individuals is a belief that when the brain becomes injured it likely will be unable to heal again. The brain may be injured in many different ways: trauma due to strokes or a vehicle accident or being hit or damaged as in playing some sports. And, yes, due to this type of damage some of the connections between neurons are destroyed. Recent studies have shown that although this damage to neuronal connections (synapses) do interfere with brain functions, this often can be compensated for by other neurons stepping up their game and growing new connections. The nerves in brain and spinal column do not seem to regenerate as quickly as do nerves in the peripheral nervous system, but growth can and does happen. Neuroplasticity is better than mind over matter. One saying goes this way: if you want to know what your thoughts were like in the past, look at your body today. If you want to know what your body will be like in the future, look at your thoughts today." What are your thoughts doing today?
Sunday, November 17, 2013
Myths about brain function abound. One is that the brain is rather one-dimensional in that you are pretty much as the whim of genetics and how your brain was developed by genes and chromosomes; that you are preprogrammed to be successful or unsuccessful. Dump this myth. The brain is multidimensional beyond imagination. Yes, you are the product of genes and chromosomes and you are impacted by epigenetics (cellular memory). However, accepting the position that biology is destiny runs in the face of what we know of the human brain. For example, more than half the facts that impact your rate of aging are within your partial if not complete control. This is very important to understand, especially in relation to the plasticity of the brain. "Your brain made you do it" is an unfortunate default explanation for every behavior that is undesirable. That could be considered an example of allowing your brain use you, when in actuality you need to take responsibility for programming your brain and for using it in a way that will help you achieve the positive outcomes that you are able to picture.
Saturday, November 16, 2013
I'm making a list of key "secrets" about the brain, or perhaps "laws of the brain" might be a better phrase. Expectations are extremely powerful, personal expectations, the expectations of others that you may buy into, and so on. Low expectations translate to low results. Studies have shown that the same school room of students performed entirely differently depending on the expectations of the teachers. One teacher thought the students were not very bright and actually made comments that the students would be lucky to pass. The next year a different teacher to the same group of students thought the students were capable of doing very well in school, making comments that she expected them all to be able to earn good grades. The outcome? The students performed to the expectations of their teacher. One of the laws of the brain states: all things being equal you brain performs to your expectations. Low expectations mean low results. As Deepak Chopra put it in his book Super Brain, "Your brain is always evesdropping on your thoughts. As it listens, it learns. If you teach it about limitation, your brain will become limited." Take a few minutes today and identify some of the expectations you have for your brain.
Friday, November 15, 2013
The term dendrite likely comes from a Greek word meaning “tree.” Dendrites are the branches projections from a neuron that are able to conduct the electrochemical stimulation from other neurons to the cell body of the neuron from which the dendrites project. Meaning that the dendrites pull information into the cell so learning can take place. If a brain is enriched, estimates are that each neuron may have thousands of dendrites. Recently, researchers at the University of North Carolina at Chapel Hill have discovered that dendrites do more than passively relay information—they actively process information, according to Spencer Smith, PhD, an assistant professor in the UNC School of Medicine. The dendritic spikes apparently “increase the selectivity of neuronal responses to the orientation of a visual stimulus (orientation tuning). Dendritic spines may have something to do with your ability to process visual information.
Thursday, November 14, 2013
There’s new studies about the role of dendrites. Think of your hand as a neuron—those special cells that have an ability to transmit information. Your palm can represent the cell body; your thumb as the axon, the largest project from a neuron; and your fingers can represent dendrites, projections from the cell. Some estimates say you can alter the shape of a dendrite in thirty seconds and can grow a new one in 30 minutes. Some types of dendrites such as the Purkinje cells in the cerebral cortex, contain additional small hair-like projections often known as dendritic spines. There are approximately 200,000 dendritic spines per cell. Increased neural activity at spines increases their size and conduction which is thought to play a role in learning and memory formation. Now, new research is expanding knowledge of the role of dendrites and their dendritic spines.
Wednesday, November 13, 2013
Researchers at the University of Kent in Canterbury, England, and other institutions reported on an experiment related to exercise fatigue and mindset (the article was published in Medicine & Science in Sports & Exercise). On one level, these findings indicate that “motivational self-talk improves endurance performance compared to not using it,” said Samuele Marcora, the director of exercise research at the University of Kent and senior author of the study. But a deeper reading of the data, he continued, buttresses the idea that physical exhaustion develops, to a considerable degree, in your head. “If the point in time at which people stop exercising was determined solely biologically,” he said, self-talk would have no effect. But it did. However, to be effective, self-talk likely must be consistent and systematic.
Tuesday, November 12, 2013
In a recent advertisement for products related to Emotional Intelligence, the Harvard Business Review included these two sentences : "Emotional intelligence is a combination of self-management and social skills that can transform and optimize individual and team performance. Now you can learn to develop and leverage your own emotional intelligence to improve your own and your team's productivity." I like that because it makes it clear that Emotional Intelligence is more than emotions and feelings. Yes, you need to be be aware of emotions and use the information they provide to help you make sound and safe decisions but "knowing" isn't enough in and of itself. You need to build social skills and exhibit them successfully; you need to self-manage your behaviors. I often describe personal EQ as an ability to know when you feel good, when you feel bad, and how to get from bad to good in a way that gives you positive outcomes. Following that dictum has certainly helped me to avoid pitfalls such as taking things personally, jumping to conclusions, and overreacting . . . Since the sky may be the limit for raising one's EQ, it involves an ongoing journey of skill building and implementation.
Monday, November 11, 2013
I've never used this word, at least not in public, although there have been times when I've been sorely tempted to do so. This adjective pertains to an individual who criticizes, judges, or gives advice outside the area of the person's expertise. I love the derivation of the word. According to several dictionaries it probably resulted from a combination of the word ultra with the Latin word crepidam, meaning the sole of a shoe or sandal. My brain finds that so humorous: unenlightened criticism coming out of the brain and the word describing it relates to the bottom of a shoe. That's about as far away from the brain and you can get! One source suggested that ultracrepidarian might be an allusion to the words of Pliny the Elder "ne supra crepidam sutor judicare," translated as "Let the cobbler not judge above the sandal," and perhaps referred to in the English proverb “Let the cobbler stick to his last." The next time someone criticizes or judges or gives you advice outside of his or her area of expertise, just smile and say, "Thank you for that ultracrepidarian comment." And move on.
Sunday, November 10, 2013
And what are nematodes? They’re slender round worms; likely the most numerous multicellular animals on earth. Estimates are that a handful of soil will contain thousands of the microscopic worms, many of them parasites of insects, plants or animals. Nematodes have even been found at great depth (0.9–3.6 kilometers) below the surface of the earth in gold mines in South Africa. Free-living species are abundant, including nematodes that feed on bacteria, fungi, and other nematodes, yet the vast majority of species encountered are poorly understood biologically. There are nearly 20,000 described species classified in the phylum Nemata, although the total number of nematode species has been estimated to be about 1 million. Nematodes have been described as a tube within a tube; referring to the alimentary canal which extends from the mouth on the anterior end to the anus located near the tail. Nematodes possess digestive, nervous, excretory, and reproductive systems, but lack a discrete circulatory or respiratory system. In size they range from 0.3 mm to over 8 meters in length. Some can cause diseases affecting human beings, including ascariasis, trichuriasis, and hookworm disease. And now we know they have a brain. I wonder what they "think?" Scary thought!
Saturday, November 9, 2013
It has a brain! The nematode, Caenorhabditis elegans! Who knew? Actually, I’d never even thought about it before but it turns out that this worm has a brain with 302 neurons connected by approximately 8000 synapses. Austrian scientists were able to identify and record the activity of this worm’s brain with high remporal and spatial resolution. Hmmm. Who knew? Supposedly it is the only creature for which a complete nervous system has been anatomically mapped. According to neurobiologist Tina Schrodel of, the neurons in the worm’s head were so densely packed that they could not distinguish them on the first images. Visualizing the neurons required tagging them with a fluorescent protein that lights up when it binds to calcium, signaling the nerve cells’ activity. With this new kind of microscopy, they were able to record the activity of 70% of the nerve cells in a worm’s head with high spatial and temporal resolution. This new technique, based on “sculpting” the three-dimensional distribution of light in the brain, may open up the way for experiments that were not possible before. One of the questions that will be addressed is how the brain processes sensory information to “plan” specific movements and then executes them.
Thursday, November 7, 2013
Consciousness. It has intrigued me for a long time. As an article in New Scientist put it, how does a kilogram or so of nerve cells conjure up the seamless kaleidoscope of sensations, thoughts, memories and emotions that occupy every waking moment. In Ramachandran's book The Tell-Tale Brain: A Neuroscientist's Quest for What Makes Us Human he put it this way: How can a three-pound mass of jelly that you can hold in your palm imagine angels, contemplate the meaning of infinity, and even question its own place in the cosmos? And Dennett in Consciousness Explained wrote: Human consciousness is just about the last surviving mystery. A mystery is a phenomenon that people don't know how to think about—yet. Well, my brain's opinion is that whether or not we understand it or know how to think about it, conscious awareness is critical to living human life successfully by design. When you can label and describe something, you just might be able to do something about it, to manage it in a way that provides you with positive outcomes. It’s sort of like watching your mind in action and then collaborating with it . . .
Wednesday, November 6, 2013
The art of gongoozling has all but disappeared from our modern work-a-day world and I, for one, think it's time we brought it back--to our vocabulary and to our lifestyle. The word gongoozle, according to Wiktionary, may have come from the Lincolnshire dialect (e.g., gawn and goose both mean stare or gape) and suggests some leisurely watching of something or other, originally probably boats going by from the bank of a canal or bridge. The other day I realized that gongoozling is something I love doing whenever I visit my cousin in Victoria, BC. His house is located on the banks of the inside passage and sitting on the deck, steaming cup of hot tea at the ready, it is a delicious treat to watch sea creatures, passing cruise ships, the ebb and flow of the waves, eagles and seagulls circling overhead, the movement of leaves in the breeze . . .nothing and everything. I often recall that pleasure and look forward to the next opportunity. Recently I realized there's no reason to gongoozle only when I visit Canada. I can do a bit of gongoozling here at home. There's plenty of opportunity. I just had to look for it. You just might want to add it to your vocabulary and to your lifestyle, too.
Tuesday, November 5, 2013
Researchers at the University of Montreal and Boston’s Brigham and Women’s Hospital have linked light with cognitive brain function and theorized that light is key to maintaining sustained attention (e.g., the brain’s performance is improved when light is present during tasks). Specialized photoreceptors in the retina (intrinsically photosensitive retinal ganglion cells or ipRGCs appear to function even in the brains of individuals who were totally blind. According to senior co-author Steven Lockley, fMRI studies showed that during an auditory working memory task, less than a minute of blue light activated brain regions important to perform the task. These regions are involved in alertness and cognition regulation as well being as key areas of the default mode network. This default network apparently helps to keep a minimal amount of resources available for monitoring the environment when the individual is not actively doing something, which could indicated that light is key to maintaining sustained attention.
Monday, November 4, 2013
Did you know that “light” stimulates cognitive brain activity, even in individuals who are sight-challenged? That’s the result of research from the University of Montreal and Boston’s Brigham and Women’s Hospital. Senior co-author Julie Carrier reported that light stimulates day-like brain activity, improving alertness and mood, and enhancing performance on many cognitive tasks. More surprisingly, the brain appears to still respond to light in the brains of individuals who have no conscious vision. Their study results showed that their brains could still “see,” or detect, light via a novel photoreceptor in the ganglion cell layer of the retina, different from the rods and cones signted individuals use to see. Known as intrinsically photosensitive retinal ganglion cells (ipRGCs). These specialized photoreceptors in the retina contribute to visual function in the brain even when cells in the retina responsible for normal image formation have lost their ability to receive or process light.
Sunday, November 3, 2013
Do you have difficulty recalling names? Do you assume that this is because you are getting older? What are you telling your brain? Recently I was speaking for a group of senior citizens (whatever that term really means). During the Q&A the majority of questions related to a perceived failure to readily recall names and labels. I explained that new research showed that some individuals recall labels very quickly which others are much slower. This difference appeared to relate to the use of differing pathways across the corpus callosum, the largest band of horizontal connecting fibers in the brain (and one of several bridges between the right and left hemispheres). In addition, since the brain wants "congruence," telling yourself that you cannot recall "such and such" stimulates the brain to search its memory banks for other instances when you could not recall "such and such." This can not only help the individual to believe he or she is really losing it but also may program the brain to stop trying to recall. What you tell yourself is critically important. When I asked several of these individuals whether they had ever had very fast recall of names and labels, the answer was no. As they aged, however, they began to ascribe the slower recall to aging. Stop it! Tell yourself, "I am recalling the information I need to remember," and then be patient while the brain searches for it. When it does give it to you, thank you brain: "Good job! Thank you!"
Saturday, November 2, 2013
A recent article by Alison Wood Brooks, Harvard Business School, discussed existing apology research, which has conceptualized apologies as a tool to rebuild relationships following a transgression. She also included information from four studies that discussed something called superfluous apologies, defined as expression of regret for an undesirable circumstance for which the apologizer is clearly not responsible (e.g., heavy traffic, bad weather). This strategy was found to demonstrate empathetic concern for the victim and increase that person’s trust in the apologizer. My understanding of the difference between the words “I’m sorry” (you personally contributed to the event or mishap) versus “I regret” (you are demonstrating empathetic concern for what happened although you are not culpable), plays into this in my opinion. Women sometimes overuse the term “I’m sorry.” Therefore I reserve “I’m sorry” for an apology related to my own actions. I am becoming increasingly comfortable, however, using the words “I regret” to express empathy for an adverse or unfortunate event to which I did not contribute. Empathy is good as reinforced by these studies.
Friday, November 1, 2013
A study at the University of Rochester in New York has found that individuals whose brains are better at automatically suppressing background motion perform better on IQ tests. As a person’s IQ increases, so too does his or her ability to filter out distracting background motion, with a correlation of 71 percent. By comparison, research on the relationship between intelligence and color discrimination, sensitivity to pitch, and reaction times have found only a 20 to 40 percent correlation. This is the first purely sensory assessment to be strongly correlated with IQ and may provide a non-verbal and culturally unbiased tool for scientists seeking to understand neural processes associated with general intelligence. However, in life you often give up something to get something. When presented with larger images, the higher a person’s IQ, the slower they were at detecting movement. According to the researchers, the counter-intuitive inability to perceive large moving images is a perceptual marker for the brain’s ability to suppress background motion.