Shrinking in Hippocampus precedes Alzheimer's Disease

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In an article printed in the American Academy of Neurology, researchers found that people who have lost a substantial amount of cells in the hippocampus area of the brain are more likely to develop dementia.

They performed a study with 64 Alzheimer's patients, 44 people with mild cognitive impairment, and 34 people with no thinking or memory problems. MRI scans were performed at the beginning of the study and then performed half a year later. During that time 23 people with mild cognitive problems had developed Alzheimer's, along with three of the healthy patients. Researchers measured the whole volume of the brain and the hippocampus area. At the beginning and end of the study they calculated the rank of shrinking in the brain over that time. For the people who did not have dementia at the beginning of the study, those with smaller hippocampal volumes, and higher rates of shrinkage were two to four times as likely to develop dementia as those with larger volumes and a slower rate of atrophy. These findings demonstrate that people with mild cognitive impairment have already experienced atrophy within the hippocampus. In people who already have Alzheimer's disease, the loss of nerve cells is spread throughout the brain.

Alzheimer's disease affects millions of people worldwide with no cure at hand. By 2050 it is projected that this disease will affect 1 in 85 people worldwide.

Here is a short video which discusses the effects of the disease:
http://video.about.com/alzheimers/Alzheimer-s-Disease.htm

1234 Red Blue Green Yellow?

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How different would our perception of the world be if we could hear colors and taste words? That is the case for people who experience the neural condition, synesthesia. Understanding synesthesia will make it easier to understand how the brain is organized. Synesthesia is condition in which one sense is simultaneously perceived as if by one or more additional senses. Another form of synesthesia joins different objects such as letters and shapes with a sensory perception such as smell, color, or flavor.

Synesthesia was first documented in 1812 but the perceptions of this condition was widely misunderstood. Scientists believe that it is caused from "cross-wiring" in the brain. One theory is that neurons and synapses that are supposed to be confined within one sensory system cross to another sensory system. Some scientists believe that at birth, infants have cross wiring, but it is than refined later in development. Researchers are still discovering which part of the brain is connected with this condition. Some believe that the limbic system is primarily responsible for synesthesia experiences. Others believe that the cerebral cortex is responsible. Also, this condition is seen to be inheritable which indicates a genetic component. Some believe that synesthesia survived evolutionary effects because it benefited some with the addition of a creative thinking process.

A tool to help scientists take a closer look at brain connections is DTI (diffusion tensor imaging). Not only are they able to visualize connections between brain sensory regions, but it can help explain why syesthesia exists and why it is undirectional. For example, why is it that numbers evoke colors but typically colors don't evoke numbers. Different studies could help test the idea that all humans possess synesthesia but in most cases it's suppressed.

Is it beneficial to have synesthesia? Recent research has shown that this condition is seven times more prevalent in artists, poets, and novelists than the rest of the population. Some scientists have hypothesized that people who have the condition are better at linking unrelated problems. One person who had synesthesia was able to memorize 22,514 digits of pi. Others are able to distinguish colors which seem similar, and others have a heightened sense of touch. Even though many advances have been made in understanding this condition, there is still a vast amount which is still misunderstood. The mechanism for which it occurs is still being studied. Scientists are also trying to understand if animals experience synesthesia as well. The exact role of genetics is still being researched, but one of the most interesting questions that remains is, why don't we all possess this trait?

Mind over Chocolate

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Fighting that craving to overindulge in sweets this holiday season? Next time you pick up that piece of chocolate, don't let it melt in your mouth, but in your mind. Sound weird and unsatisfying? Read on...

In a article published by National Geographic, according to new research, imagining eating a specific food reduces your interest in that food, so you end up eating less of it. They make it sound so easy! Well the reaction to repeated food exposure is called habituation and its known to occur while eating. But the aim of a recent study was to show that habituation can occur solely via that power of the mind. People who diet try to avoid thinking about stimuli they crave. This research suggests that may not be the best strategy. If you think about the food itself, it increases your appetite. This research suggests that by forcing yourself to repeatedly think about tasting, swallowing, and chewing the food you crave, it will help reduce your cravings.

Carey Morewedge and colleagues from Carnegie Mellon University in Pittsburgh, conducted five experiments which revealed that people who repeatedly imagined eating chocolate or cheese would eat less of that food than people who pictured eating the food fewer times, eating a different food, or not eating at all. In one experiment 51 subjects were split into 3 groups. One group was asked to imagine inserting 30 quarters into a laundry machine--which requires the same motor skills as eating M&M's, the study says--and then eating three M&M's. Another group imagined inserting three quarters into a laundry machine and then eating 30 M&M's. The control group imagined inserting 33 quarters into a laundry machine without eating any M&M's. Afterwards, participants were allowed to eat freely from bowls which contained 1.5oz of M&M's each. After the subjects were done eating the M&M's the bowls were taken away and weighed.

Results showed that the group who imagined eating 30 M&M's each ate fewer chocolates than the control group and the group who imagined eating 3 M&M's.
This study is important because it looks at the triggers which explain why we overeat. Digestive cues are only a small part of what tells us when we're finished with a meal Research also suggests that psychological factors, such as habituation or the size of a plate, also influence how much a person eats.These studies are important due to the increasing obesity rate in the U.S. In 2009 nearly 30% of adults were obese. Children's obesity is at an all time high and increasing rapidly. Obesity increases chances of Type II Diabetes, heart disease, stroke, and other fatal conditions. This study may lead to new behavioral techniques for people looking to control their addictions such as overeating and smoking.

Mystery behind the yawn

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No one knows why we yawn. There are many theories to why we do, such as signaling tiredness, getting oxygen to the brain, reducing CO2 levels, or clearing out stale air from the lungs. These are all false. However, we all know how infectious yawns can be. No matter how much we resist, if we see someone yawn, we do the same. According to sciencebase.com, if we see someone yawning, nine out of ten times we yawn within a few seconds. Why we yawn remains a mystery.

However, researchers have found that people with autism spectrum disorder don't have the tendency to yawn when seeing others do it. Crazy, right? The Center for Brain and Cognitive Development at Birkbeck, University of London have shown that children with some degree of autism are not susceptible to contagious yawning. Atsushi Senju and colleagues set up a study where 24 children with autism spectrum and 25 non-ASD children were shown videos of people yawning or making some kind of mouth movement. The results showed that both groups yawned the same number of times when they watched the video of general mouth movements, but the non-ASD children yawned more when watching the video of people yawning.

This study is important because it displays that a neuropsychological or psychiatric condition can selectively impair contagious yawning. Autism is a developmental disability that severely affects social interaction and communication including empathy. Yawning is thought to share similar cognitive and neural mechanisms as empathy.This study confirms the 'empathy theory' in that individuals with autism, who show abnormal developments in empathy, also show selective impairment in contagious yawning.
Even though this doesn't help us to understand why we yawn, the empathy scenario provides us with and understanding regarding group behavior. So, why do we yawn and is it beneficial? Research continues to strive for an answer.

Extrasensory Perception

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We have all watched those corny movies with aliens or humans possessing the power of ESP. Does it exist? That's for you to decide. I came across an interesting article on Discovery Health and decided to read on. Is it possible for twins to feel each others pain? People who believe in this paranormal activity would call this scenario extrasensory perception (ESP), or perception beyond the five senses. Is there evidence of ESP locked away in our brain? "ESP" was first coined by parapsychologist, Joseph Banks Rhine. It is composed of three major manifestations: the ability to read minds, ability to predict the future, and knowledge or a remote person or object. Rhine conducted studies at Duke University where students were able to predict symbols on cards they couldn't see with accuracy. He was convinced that this proved ESP's existence. However, many scientists and skeptics have had a hard time replicating the same results in their experiments which leads to the idea of experimental design flaws in Rhine's work. Trying to convince the scientific community is difficult but 3 out of 4 Americans believe in at least one paranormal belief. Princeton University's Engineering Anomalies Research (PEAR) conducted experiments in which subjects tried to use their minds to influence machines. Over 27 years of conducting these experiments, the observed effects were very small. They claim that mind power can influence technology, but only very slightly.
If there is a part of the brain associated with ESP, what part would it be? Parapsychologists believe that the right hemisphere is the area most associated with psychic abilities. This may be due to the fact that most tests are visual, and the right hemisphere stores nonverbal information. In 2008 a group of Harvard graduates students tested for the existence of ESP while monitoring brain activity. In the test each participant was placed in a MRI scanner and shown two photographs, while at the same time the participant's friend or family member were shown one of the photos in another room and asked to "send" that image to the participant. The participant had to choose which of the 2 photos were "sent" to them. Results published in the Journal of Cognitive Neuroscience explained that the participant's brain would have responded differently to ESP and non-EPS stimuli. Participants didn't act differently, which resulted in no evidence of ESP existing among the participants. Still believe in ESP? If so, what am I thinking of right now? ;)

Zeta Inhibitory Peptide

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I was watching a clip on the discovery channel and was interested in learning about the drug, zeta inhibitory peptide and its relation to memory. A medical center in New York performed a study where they put lab rats in a chamber. Whenever the rats ran into a certain are in the electric chamber, they received a shock. Due to negative feedback they learned to stay away from this area. Then the researchers injected zeta inhibitory peptide (ZIP) directly into the rats brains. The effect of this drug made the rats forget what they learned which resulted in them running into the shock zone all over again. These results are important in demonstrating how memory works. This research helped to demonstrate what the molecular mechanism for storing information. The protein responsible is protein kinase m zeta. This protein can interact chemically to activate other proteins similar to it and form clusters. ZIP breaks these clusters of kinase m zeta which causes them to go away from the synapses which are clustered to store information. This is specifically targeting long-term memory but there is no specificity to which memories. This research is applicable to humans because people suffering from post-traumatic stress disorder suffer from painful memories. By understanding how memories are formed, researchers will be able to produce different types of therapies to influence those mechanisms.

Video: http://curiosity.discovery.com/question/how-ongoing-stress-affect-memory

Epilepsy

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Recently I read a paper which mentioned the disorder epilepsy; I was not too familiar with this condition so I decided to do a little research. It is estimated that 1.4-2.7 million people in the U.S. are currently suffering from this disorder. It especially affects the very young and the elderly. So what exactly is epilepsy? Epilepsy is a neurological condition that causes the brain to produce sudden bursts of electrical energy. For the brain to function, there needs to be a balance between increased activity (excitation) and restraint (inhibition). When this balance is changed, a seizure may result (epilepsyadvocate.com).
Epilepsy occurs when there is significant and permanent changes in brain tissue which causes the brain to be too easily excitable. This then causes the brain to send out abnormal signals, which result in repeated, unpredictable seizures. Common causes of epilepsy includes: stroke, dementia, brain tumor, brain injury near birth, and several other causes. However, it can also be inherited. Symptoms vary from person to person but can include violent shaking and loss of alertness. Treatment for epilepsy can include medication or surgery. When medication does not help with the side effects of epilepsy after two or three anti-seizure drugs it is called "medically refractory epilepsy" (PubMed). Some surgical procedures include, removing abnormal brain cells or replacing a vagus nerve stimulator (similar to a heart pacemaker),and has helped to reduce the number seizures a person may experience. Today, there is a large quantity of research being executed. Studies are looking at: early age development of epilepsy, possible trigger points of epilepsy, drug development, and much more.

Robotic Therapy & Cerebral Palsy

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In class PZ mentioned the condition cerebral palsy which I am not too familiar with, so I decided to learn more about it. Cerebral palsy is condition, sometimes thought of as a group of disorders that can involve brain and nervous system functions such as movement, learning, hearing, seeing, and thinking (www.ncbi.nlm.nih.gov). There are different types: spastic, dyskinetic, ataxic, hypotonic, and mixed. This condition is caused by an abnormality in the brain which can occur during growth in the womb, but can also happen within the first 2 years of life. Researchers are investigating the roles of mishaps early in brain development, including genetic defects, which are sometimes responsible for the brain malformations and abnormalities that result in cerebral palsy. I was interested in what recent research has recently been performed and found an article on science daily in which robotic therapy was implemented.

Krebs and colleagues at MIT have been using robotic therapy since the 1980's which has become increasingly popular. They have found that robotic therapy can reduce impairment and facilitate neuro-development in children suffering from cerebral palsy. These gentle robots for shoulder-and-elbow, wrist, hand and ankle have been used in trials for over 15 years and used on 400 stroke patients. Krebs and colleagues have the goal in mind that these robots will help to rebuild brain connections using robotic devices that gently guide the limb as a patient tries to make a specific movement. Children's minds are more plastic than adults so its hopeful that they will be able to establish new connections. They are trying to help patients improve on their ability to grasp objects, which is often a difficult task. Even though patients who experience a stroke will experience loss of large amounts of neurons, the remaining neurons can establish new synapses or reinforce dormant ones.
Results from three studies involving 36 children indicated that the robots helped the children reduce impairment and improve smoothness and speed of their reaching motions. Most research has focused on upper body therapy, but a project for a pediatric robot pertaining to the ankle has been initiated.

Study suggests, moving your eyes improves memory

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I recently looked at a article on the livescience website which said that moving your eyes improves your memory. I was a little skeptical of this article but decided to read on. Researchers say that if your looking for a quick memory fix, move your eyes from side-to-side for 30 seconds. Research has shown that horizontal eye movements are thought to cause the two hemispheres of the brain to interact with one another, and communication between the brain is important for retrieving certain types of memory. In the article it was stated that previous studies has shown that horizontal eye movement improve how well people recall words they have just seen. The research that Andrew Parker and colleagues at Manchester Metropolitan University in England were looking at focusing on whether such eye movements also help people recognize words they have just seen. Recognition memory differs from recall memory in that people trying to recognize words tend to make false memory errors called source monitoring errors. This happens because they recognize words but attribute it to the wrong source.

Parker and colleagues performed a lure study; they presented 102 college students with recordings of a male voice reading aloud 20 lists of 15 words. The concept of a "lure" study was that in some of the lists converged around a "lure" word that wasn't presented. For example they could have heard words that were associated with a needle such as thread, sharp, eye, and sewing but the word needle was never said. After the subjects went through the lists, a third of them followed a computer prompt that initiated 30 second side-to-side eye movements. Another third did the same with up-to-down eye movements and the third did neither. The subjects were then handed a list of words and asked to pick out the ones that they had just heard. The ones who picked the "lure" words were making source monitoring errors.

Researchers found that those who performed the horizontal eye movements correctly remembered more than 10% more words, and falsely recognized about 15% fewer "lure" words than the people who performed the vertical eye test and those who performed no test at all.

So, leftward eye movement activates the right brain hemisphere and rightward movement activates the left hemisphere. Therefore, horizontal eye movements might improve memory recall by helping the hemispheres interact. However, the mechanism for linking eye movement to memory is still very speculative and more research needs to be performed.

So, should we all start wiggling our eyes from left to right to help us remember where we left those darn keys? Might look a little crazy but its worth a shot.

Since the first homo sapien roamed our vast Earth, we have had unique interactions with the animals around us. Whether we were running from or running after animals, they have left their mark in the human brain. According to the latest issue of Nature Neuroscience, no matter now urbanized or tech savvy our nation becomes, animals affect our brain unlike any other person, place, or thing. There are numerous reasons for why we detect animals including the necessity to avoid predators and catch prey. This is important to our suvival and is a natural instinct instilled in all of us.

In the study that I read about, researchers looked at 41 neurosurgical patients that underwent epilepsy monitoring. They responded to various images of people, landmarks, objects, or animals. There were 111 experimental sessions in which researchers monitored the subject's brain activity as they viewed about 100 images per session. The equipment that was used was efficient enough to show how each individual neuron reacted. It was found that neurons in the right amygdala responded preferentially to the pictures of animals and this was regardless of whether the animals were cute or threatening. In this article I learned that the right amygdala has been connected to the processing of stimuli that are aversive and of stimuli that are rewarding. Well this makes sense since in our evolutionary past, animals were either seen as predators (aversive) or prey (rewarding). Also, besides being in an experimental setting, we can hear and smell animals which affect our other senses as well. The research focused on visual aids but researchers think that the amygdala would have also reacted to animal calls. We cannot conclusively say that animals directly trigger our emotions but it's possible that they affect our fear and arousal response in unique ways. Animal images "mobilize" the brain's resource to process information about them. Our amygdala helps us to detect where an animal is, to pay attention to it, encode it in our memory, and mount a behavior response. For our early ancestors the most likely response was to either kill for food, hide, admire, or run for their lives.

Recent Comments

  • lewisjefferson546@yahoo.com: Alzheimer's disease affects millions of people worldwide with no cure. read more
  • pharyngula@azkidsnet.com: I think you are misconceiving ESP. It is my contention read more
  • jt512@jt512.dyndns.org: I'm thinking that your post would be a lot easier read more
  • viscous@fizzygoo.com: So this was the first blog from PZ's site that read more
  • ppiantad@psych.ubc.ca: I'll be reading your blog with interest! My current masters read more

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