September 2011 Archives

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.

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.

I recently found an article on ada.org which stated that amalgam fillings do not affect children's brain development. This article was interesting to me because I plan on attending dental school upon leaving Morris. This past summer I had the opportunity to work as a dental assistant so I am familiar with some of the materials used for fillings. The dentists that I worked for used a composite material which is a synthetic resin. The composite material was used 80% of the time because the material allows for good adhesion and is aesthetically pleasing to the eye. However, amalgam is a cheaper option.

Authors of this study looked at the neurological effects. As many people don't know amalgam contains mercury combined with other metals such as silver, copper, tin, and zinc. Researchers performed studies on Portuguese children who received either amalgam or composite fillings and performed routine neurological examinations. I learned that they look for two types of neurological signs, hard and soft. Hard indicates damage to specific neural structures and soft indicates central nervous system dysfunctions. Children were also checked for the presence of tremor. The children were checked after 7 years to see if there were any damaging effects. Researchers found that even though the amalgam contains mercury, the mercury did not affect their neurological status. Amalgam has been used since the 19th century and many countries are phasing out mercury within the amalgam. I have had amalgam composites in the past and unless there is sufficient evidence of them causing severe effects, which I have not encountered, fill 'er up!

Today, over 2 million people are suffering from Schizophrenia. The symptoms of Schizophrenia fall into three categories: positive symptoms, negative symptoms, and cognitive symptoms. Little is known about the neurobiology of this disease, particularly concerning circuits and molecules. Impairments within the various circuits and molecules affects cognition in the disease. A recent study published in the Journal of Neuroscience provided evidence that deficits in a brain chemical may be responsible for some of the debilitating cognitive effects such as poor attention, memory, and problem-solving skills. This is one of the first studies to explore the strong correlation between cognitive deficits and and a decrease in a particular neurotransmitter. Schizophrenia sufferers are subject to visual and auditory hallucinations as well as cognitive difficulties that interfere with everyday activities.

This study looked at the neurotransmitter, GABA, which has played a role in cognitive difficulties for people who have schizophrenia. Researchers GABA levels in the visual cortexes of 13 patients with the disorder and 13 patients without the disorder. Measurements were conducted with high-field magnetic resonance spectroscopy. Schizophrenic patients were found to have a deficit in GABA of about 10% to those without the disease. The second part of the study looked at the neurochemical deficit on cognitive behavior. GABA levels were assessed by showing patients a well-known illusion in which a presence of a high contrast surrounding region inhibits the ability to perceive information in the center of the visual field. Research showed that the surround-suppression illusion had a less effect on schizophrenia patients which was an unusual situation because they out performed healthy subjects. The researchers found that the lower levels of GABA in patients were responsible for the abnormal behavior.
This research provided support for targeting the GABA system for treatment of cognitive decline in schizophrenia.

http://www.sciencedaily.com/releases/2010/03/100310175130.htm