Hippocampal Prosthesis: Do Scientists Have the Ability to Mitigate Memory Loss?

Memory loss is a medical symptom that affects everyone at one time or another. It can come in the casual form of forgetting where you put your keys, or in the more severe form of forgetting who you are and those around you. Although there are differing degrees of memory loss, scientists around the world agree that we must regard the symptom as a serious matter. From a medical perspective, memory loss is very often seen as a symptom of dementia.

Unfortunately, given the number of people affected by dementia a year (running into the millions), according to BBC News, "...only a third of people with dementia receive a diagnosis" (1). Dementia is one of the most significant impediments to societal health in today's age, especially in the world's elderly population. Just three years ago, BBC noted that "There are 750,000 people living with dementia in the UK...in 15 years, one million people will be living with dementia" (1). Dementia is most definitely not an illness to take lightly. Dementia has been cited to greatly increase the chance of several types of anemia, depression, heart failure, and many infections. Most of these conditions result from the body's hindered cognitive ability and the suppression of several body systems (2). The problem is growing steadily each year, trying to hide in the shadow of other global medical issues. It's time that we take action. Unfortunately, negative effects related to memory don't stop at general dementia. Alzheimer's disease is a degenerative and often fatal memory disorder where cell-to-cell (neuron) connections in the brain rapidly diminish. Alzheimer's disease is one of the biggest issues concerning our future. According to the Alzheimer's Association:

"Alzheimer's disease is the sixth leading cause of death in the United States...1 in 3 seniors dies with Alzheimer's or another dementia... [and] more than 5 million Americans are living with the disease" (2).

The worst part is that unlike other leading causes of death, like breast cancer, heart disease, and HIV, death resulting from Alzheimer's is increasing every year (1,2). For decades scientists have been trying to curb such effects, yet to their dismay most measures have failed. Fortunately, some current glimmers of scientific discovery provide hope to those desiring a better future for our global society.

Hippocampal prosthesis. The National Institute of Health describes the process as "designed to restore the ability to form new long-term memories typically lost after damage to the hippocampus." Essentially, scientists use silicon neurons to replace damaged neurons in the hippocampus so that people with Alzheimer's and other dementias can remember things, stroke victims can speak better, and people with brain trauma can regain motor control. Unlike other devices that solely stimulate cerebral activity, the silicon chip can carry out the same operation as the destroyed part it is taking the place of (7).

A prosthesis is implanted into the brain to heal or replace damaged brain tissue vital to neuron gathering. The process involves delivering an electrical stimulation to the hippocampus through several electrodes (one electrode documents electrical information coming to the brain, while another sends out electrical "commands" out of the brain to the rest of the body), fostering the electrochemical interaction that occurs between neurons attempting to establish memories. The releasing of silicon neurons is necessary to stimulate the biological neurons of the brain, promoting activity.

It is very difficult, verging on the impossible, for scientists to record how the hippocampus encodes information. Acknowledging this challenge, scientists mimicked the coding behavior of the hippocampus itself. In one study, scientists stimulated a rat's hippocampus with millions of electrical signals, to determine what input led to certain outputs. Once the data was recorded, they were able to develop a mathematical formula of the whole hippocampus (7,8). They were soon able to program the formula unto a silicon chip, and implant the chip into the brain of a subject (for now, either a rat or a monkey).

The function of the hippocampus is to transform short-term memories into long-term memories. Damage to the hippocampus can come in several forms: physical blows to the head, strokes, ageing, etc. Damage to this vital part of the brain often leads to cognitive disorders in the form of dementia, Alzheimer's disease, and other memory-hindering illnesses. Hippocampal prosthesis's goal is to reverse the effects of such debilitating diseases, bringing memory back to those who have lost it. Not only does it bring back memory, it makes sure the memories stay there for the long term.

Some scientists argue that the procedure raises certain ethical issues. They say that controlling the brain's production of memory could fundamentally and permanently alter a person's identity (8). There are two problems with such a critique. First, experimentation with the prosthesis has shown that it only effectively stimulates the creation of a person's own memory, not altering how the neuron's gathered in the first place. Rather, it repairs the portion of the hippocampus necessary for such gathering to ensue. Second, even if a person's identity is slightly altered by the procedure, the ultimate benefits of a healthier brain outweigh the small costs. While the device has only been tested on monkeys and mice, it has shown considerable effectiveness. Scientists predict that they can begin full on human trials as early as 2015 (7,8).

The implications of solving issues involving memory loss and regeneration are huge. Memory degradation is something that affects the entire globe, harming humans more and more every year. Although it's not at the top of the list for leading causes of death, it has the largest scope--affecting more people than almost every disease.

Fortunately, the future looks bright. Not only have scientists discovered a method to create new memories, eliminate unwanted memories, and remember forgotten ones, but they have also developed a device successful at stimulating the regeneration of damaged brain tissue vital to the function of the brain. Avoiding the issue simply isn't an option. If left unchecked, memory disorders such as dementia, Alzheimer's disease, and post-traumatic stress syndrome will pose great threats to our longevity. To restrain the problem and to promote a healthier global society, it is of vital importance that we continue researching.

References

1. BBC News Health, "Memory loss 'should not be ignored.'" 23 August 2010.

2. Alzheimer's Association. Alz.org, "Alzheimer's Facts and Figures." 2013.

7. National Center for Biotechnology Information. T. W. Berger, et al, "A Hippocampal Cognitive Prosthesis: Multi-Input, Multi-Output Nonlinear Modeling and VLSI Implementation." National Institute of Health (2012).

8. New Scientist. D. Graham-Rowe, "World's first brain prosthesis revealed." March 2003.

Image Credit: US National Institute on Aging (Wikipedia), Garrondo (Wikipedia), Nrets (Wikipedia)