The Future of Prosthetics

Pavan Sreerama

Blog 2

Neuro 300

The Future of Prosthetics

There are around 2 million people living in the United States with missing limbs; this number increases by almost 200,000 people every year. This is just in the US, there are around 30 million amputees worldwide. According to several studies conducted by the Amputee Coalition group, 28 percent of amputees believe that they have discriminated against, (in employment, healthcare system, school, etc.).  Almost 30 percent of all amputees will be diagnosed with depression and/or anxiety. As of now most prosthetics are very clunky, restrict movements and do not allow for fine motor control (which are required for tasks such as playing instruments, writing, cooking, etc.). Another problem is that there are no commercially available prosthetics that have any form of sensory feedback. This is important because if one does not get sensory information back from a prosthetic limb they will not able respond accordingly to the environment. Fixing these problems will help amputees have a better quality of life.

Dr. Kuiken and his research team have developed a method using target muscle reinnervation (TMR) to improve the overall function of prosthetics limbs. TMR is a specialized surgical operation that helps improve the motor function of prosthetic limbs (upper limbs). First, surface electrodes are placed in the person’s prosthetic socket. Then the remaining neuronal cells in the patient's amputated limb are transferred to the chest (pectoral muscle). This is because the nerves cells will generate specific EMG signals which used to produce movements in the “elbow, wrist and hands”. They will act as an amplifier for which allows for more fine and overall motor control. Patients who received the TMR surgery showed a greater proficiency of control of the prosthetics arm in a shorter time frame. The patients were all able to perform basic tasks within the first day.

Ivan Owen is an American artist who created a metal mechanical arm for a cosplay convention and posted it online. A man from South Africa who lost his fingers in an accident and mother with a 5-year old born without fingers contacted him about creating a prosthetic arm. Owen eventually started a volunteer organization called Enabling the Future. This organization raises money for purchasing 3d printers which provide cheap prosthetics to people worldwide. As of today, the organization has over 7000 members and donated 2000 printers to dozens of countries. The organization’s 3-D templates are all open source, so anyone can use them or come up with useful modifications and re-upload them. These 3D printed limbs are especially useful for children because they are constantly growing and need new limbs every two years. Jorge Zuniga, a biomechanics scientist from the University of Nebraska in Omaha, heard about this program and after months of research, created an efficient cost-effective design called the cyborg beast. It only cost around 30 dollars to make and his design was downloaded almost 50 thousand times.

Dr. Kuiken’s cutting-edge research is extremely promising and can revolution prosthetics industry. However, there is no use increasing technological marvels when it is not accessible to the general population. According to a study financed by the Jordan Thomas Foundation, the cost of a prosthetic arm can be upwards of fifty thousand dollars. A child would need to replace their prosthetics every two years (because they are constantly growing), compared to adults who need to replace them every 2-5 years. This means an 8-year-old child’s cost of prosthetics replacement will be three hundred thousand dollars by the time they are 18 ($50,000 x 6 = $300,000). There are 30 million amputees (majority are from developing nations) and according to a Gallup metric, the worldwide median per capita household income is less than 3,000 dollars; most people cannot afford the financial burden required for these prosthetics.

On the other hand, organizations such as Enabling the Future provide very affordable prosthetics that anyone can buy. These prosthetics give some level of functionality to people who otherwise would never be able to access the more expensive ones.  But these prosthetics lack almost all of the features found in the higher end models (such as TMR). Hopefully, in the future, strides will be taken to bridge the gap between accessibility and functionality. Dr. Kuiken (and his team) and the workers of Enabling the Future have taken two different approach help make the lives of amputees better.

Works Cited

http://jama.ama-assn.org/cgi/content/full/301/6/619

https://accessprosthetics.com/15-limb-loss-statistics-may-surprise/

https://www.amputee-coalition.org/wp-content/uploads/2014/11/lsp_people-speak-out_120115-113243.pdf

https://jordanthomasfoundation.org/true-cost-prosthetic-limbs/

http://news.gallup.com/poll/166211/worldwide-median-household-income-000.aspx

Manipulating Memory

Manipulating Memory

By: Olajumoke Bamgbose

Memory is a key part of survival, especially fear learning. While being scared is not the ideal situation, our brain is still able to use that to learn and then later keep us away from harms way. Without fear learning, we would not know to run away from a tiger, which is important for survival. Fear is not the best emotion to feel at the time, but there is no doubt that most times having an appropriate fear response is necessary. While most fear memories are good for longevity some fear memories, like the ones seen in PTSD patients, can actually make life harder. According to a study done at the University of California: Riverside, researchers may have found a way to erase parts of fear memory that are not necessary for survival in mice while still keeping parts of that memory needed for survival in tact.

The researchers looked in the amygdala, which is responsible for fear learning and memory, and they saw that the fear conditioning training led to stronger connections in the synapses of neurons in the amygdala. The mice learned to fear different tones that were accompanied by a footshock and those tones began to have really strong synaptic connections in the amygdala. The researchers at UC-Riverdale then used optogenetics to manipulate this memory system. They were able to stimulate only the cells that responded to the sound by weakening the signal in the neurons, while leaving the fear response of the footshock alone. They were able to erase the fear of the tone from the mice without erasing the fear of a footshock. The researchers manipulated memory in a way that weakened connections in the amygdala which gave more insight on how fear memory is encoded.

 This is somewhat similar to the work of Joel Voss, who also manipulated memory but in an opposite direction. Voss’s work used TMS and MRI to strengthen communication between parts of the hippocampal network. TMS was used on the lateral parietal cortex and they found that the excitation of that area was able to indirectly stimulate the hippocampus, by waking up that network. This stimulation was able to cause an increase in performance of a memory task that participants took. Voss and his team were able to strengthen connections in the hippocampal network through rTMS and continual stimulation of the hippocampal network. They were able to improve memory by up to 30% which can be a big deal, especially for people with different types of memory deficits. Both studies give a lot of insight to memory and can both lead to changing the way we deal with different disorders that include memory deficits.  

References:

1.         University of California - Riverside. "How particular fear memories can be erased: Findings have therapeutic implications in PTSD and phobias." ScienceDaily, August 17, 2017 https://www.sciencedaily.com/releases/2017/08/170817131130.htm

2.         Jane X. Wang, Lynn M. Rogers, Evan Z. Gross, Anthony J. Ryals, Mehmet E. Dokucu, Kelly L. Brandstatt, Molly S. Hermiller, Joel L. Voss (2014) “Targeted enhancement of cortical-hippocampal brain networks and associative memory” Science, 345 pg. 1054-1057

3.         Woong Bin Kim, Jun-Hyeong Cho. “Encoding of Discriminative Fear Memory by Input-Specific LTP in the Amygdala” Neuron, 2017

Using Taste Buds to Regrow Nerves?

Dr. Rochlin's research at Loyola University Chicago focuses on the growth of nerves associated with taste. First, it is important to understand what his research is attempting to explain. In the tongue, nerves will grow in a specific manner and innervate the organ very predictability. But when a growing nerve from this tissue is to be removed and placed on a growth medium, the pattern of growth exhibits no discernable pattern whatsoever. This then leads to the belief that in the tissue there are various signals (both positive and negative) acting on the growing nerve which guides its growth.

So far Dr. Rochlin's lab has found that Semaphorin 3A is a chemical that is secreted by the tongue that repels the growth of a nerve. Dr. Rochlin and his lab are now studying the role of Eph/ephrin signals and how they can affect the growth of neurons. The long-term goal of this research is to develop treatments for those suffering from nervous system damage. The understanding of how various chemicals can influence the growth of neurons can be very key in nerve growth and regeneration.

While this research is very exciting, there is also some new research from the University of Wisconsin Madison that could go along with this. The Svaren lab has found a role of Schwann cells in nerve regeneration. First, it is important to understand what are Schwann cells. These are cells that are found in the peripheral nervous system, outside of the spinal cord and brain, that are responsible for myelination of axons. When the axons of nerves are myelinated, they are able to transmit their respective signals significantly faster than their unmyelinated counterparts. 

The Svaren lab has observed that in some instances, for a brief time period soon after nerve damage, the Schwann cells alter their function and aid in the regeneration of neurons. They are proposing that Schwann cells start to dissolve the myelin in the damaged nerves. Ironically, myelin is essential for optimal nerve signal transmission but is also detrimental to nerve regeneration. The Svaren lab has also stated that these alternatively functioning Schwann cells are simultaneously secreting signals that attract blood cells to aid in the clean up of damage, as well as repair and growth of the nerves.

            This new function of Schwann cells is an outstanding discovery on its own, but what really fascinates me about this is how the change in function is being done. The Svaren lab has found that the only process occurring in the Schwann cells is that activation of a different subset of genes. This is radically different than all other nerve regeneration research that is being done because all others rely on the use of stem cells, while this relies on the activation of different genes within an already mature nerve cell.

            Since the Schwann cells are the same, and the only change is the activation of genes within the cell itself, along with the fact that this process only occurs for a brief time period following nerve damage, I theorize that the damaged neurons must be releasing some sort of signal that is activating the repair function of Schwann cells. Then, if my assumption is correct, combining these findings with Dr. Rochlin’s work on nerve growth signaling, it could be possible in the near future to control the growth of neurons. Using Dr. Rochlin’s work on categorizing various signals as either growth promoting or inhibiting, in conjunction with these activated Schwann cells could make it possible to artificially manipulate the growth of axons in the human body. 

Although this is all very hypothetical, I believe if researchers are able to isolate the signal that damaged neurons are secreting, along with a methodical distribution of both growth promoting and inhibiting substances, we could selectively innervate parts of the human body that have lost nervous connection many years ago. This, in essence, could potentially give people back partial or even complete function of damaged tissues. 

To learn more about the University of Wisconsin Study, you can click the link below.

https://www.sciencedaily.com/releases/2016/09/160916132053.htm

It's Okay For Children to Be Scanned

Dr. Elizabeth Wakefield, an assistant professor in Developmental and Neuroscience, at Loyola University of Chicago is all for studying the development in children and finding ways that is more accurate to do so. Dr. Wakefield presented the struggles of studying children: 1. They don't always understand the task that was instructed to do 2. They are very squirmy, and that becomes difficult when using fMRI scanners or EEG since both are sensitive to movement 3. Their parents. This one is a huge barrier to doing research with children. Often times their parents are concerned about radiation from the machines that will be used. I'm here to tell you, there is no radiation, it is safe, and it is an expensive but useful tool in studying the brain development in children and can lead to important finding that may help us with diagnosis diseases prior to onset. 

Dr. Wakefield's area of study is, "How children and adults learn, generalize and retain information learned through action and gesture; how this differs based on an individual’s ability to interpret movement as meaningful; how this differs based on whether action and gesture are performed by a learner or teacher." Which is pretty cool, studying whether it is better to yourself do a gesture while learning or just seeing the gesture over and over. She and others in this field have noted that, if the learner has done the gesture before and then during a test hears the word, their motor cortex will activate as if they are the ones doing the motion. It would be pretty awesome if we could learn exactly how at different stages in development children are learning but we can only do this if parents are willing and children are cooperative. 

In 2016 Current Psychiatry published an article titled "Neuroimaging in children and adolescents: When do you scan? to inform the public about what each type of method of research can do. Neuroimaging when it was new was restricted to identifying structures in the brain , now it is being used for research and diagnosis, and there are many different types of imaging that can be done : CT, MRI, fMRI, and more. CT is less done with children but is the one that contains ionized radiation, but is used in emergency settings, more often with children MRI and fMRI are used, an MRI produces an image of the brain and is not using any type of radiation, it is completely safe, an fMRI is almost the same thing but it can show which areas of the brain are active by using the BOLD signal, this is the Blood Oxygenation Level Dependent signal, if the brain is using oxygen that is correlated to that areas function. 

            Now wouldn’t it be interesting to use this type of accurate imaging to see what effect technology is having on development? In a piece written in Time magazine: It's Official: iPads Are Sedatives for Kids, the effect of iPads on behavior was explored. They reported that a team in Hong Kong compared children’s behavior when using an iPad to people taking a sedative. They measured the children’s anxiety levels throughout the day and compared the results. It was found that they had the same levels, which is really terrible in an everyday sense, giving your child an iPad is giving your child drugs. The group in Hong Kong did have a positive answer, that instead of giving children drugs before surgery they can give them an iPad beforehand. Hopefully in years to come neuroimaging will be done on children at different stages in development to track the alterations in the brain, if any, due to iPads and other technology. A lot of research is yet to be done in the developmental field and it is exciting to see that it is becoming more accessible, hopefully one day it will be more affordable as well as parents more educated about the benefits of the studies and that they are not harming the children, just gathering information.