Until about 40 years ago it was only possible to study the workings of the brain of a living individual by their outward appearance and proposed symptoms. In 1977 the MRI (magnetic resonance imaging) scanner was developed and has since revolutionised the way in which we can investigate the anatomy and structure of the brain [1]. There are many unanswered questions in the field of neuroscience. One particular area is the aspect of memory and its storage – what physically happens and how it occurs.
An innovative new development in medical imaging is allowing scientists to observe the intricacies of the human brain including individual neurones. In San Diego California, a specialised facility has been established with resources to create detailed images of thin slices of brain in order to carry out research on brain mapping. Brain mapping allows scientists to see which areas of the brain are involved in particular activities. It is hoped that in the future these images can be used to find the source or cause of mental illnesses and conditions such as autism, Alzheimer’s and implications of brain damaging traumas subsequently, treatments can be developed. [2]
The aim of the project, led by Professor Jacopo Annese is to be able to navigate the entire brain. A particular focus currently is to determine how memory works by being able to follow networks formed in the brain between neurones. This is made possible by slicing a human brain into around 2400 micro-thin sections each which are then preserved chemically to keep the finest details of the neuro-anatomy to a cellular level. High resolution images of each slice are taken, allowing them to be examined in three dimensions where even single neurones are visible. This made this project the most precise attempt to be able to see the preserved human brain.
With the project in its initial experimental stages, the first brain used was that of Henry Molaison. Henry, or HM as he was known in the scientific community at the time to protect his identity, was studied greatly during his lifetime. The reason for this being that he lost the ability to be able to form new memories from the date of a disastrous operation initially intended to treat childhood epilepsy. The operating surgeon admitted afterwards that his patient was treated experimentally and wrongly so. During the procedure, Henry’s hippocampus was removed as well as inevitably parts of the surrounding regions. [3]
The hippocampus is a part of the brain that, as a result of this occurance, scientists now know is associated with the creation of new memories and specifically conscious memory. Consequently at the age of 27, henry lost the ability to remember events 30 seconds after they had occurred. He could however remember events leading up to the operation in 1953. Researcher Suzanne Corkin, a researcher, prominent in the study of Henry, recalls him fondly telling her of his childhood and was capable of recalling past significant events clearly, for example the Wall Street Crash. [4]
Over 100 different scientists had worked with Henry by the time of his death and more than 10,000 articles had been published which referenced research involving Henry. One particular experiment gave a particularly interesting discovery about our memory. The experimental task involved Henry looking in a mirror showing the image of the piece of paper with the outline of a shape in front of him. He had to look in the mirror and draw around the shape outline on the page. This was carried out over a number of days, by the end of which Henry had greatly improved at his proficiency at drawing the same shape despite his lack of recollection of having ever done it before.
This indicated to researchers that we not only have memories which we can consciously access but also memory and the ability to learn unconsciously which didn’t involve the hippocampus. Therefore Henry was forming new memories; however these were not memories that could be consciously accessed.
Professor Elizabeth Kensinger, who was one of the last researchers to work with henry claims that “Everything we know about memory began with the study of Henry.” Furthermore, since his death in 2008, scientists have been able to continue to study his brain by means of this new technology. The objective of Professor Jacopo’s development in neuro-technology is to find any physical traces of memories in neural circuitry using not only Henry’s brain but those of others. The overall aim is to discover how different types of memory form, how they are recalled and where they occur. It is appreciated that currently, we do not have sufficient technological capabilities of find such information and making such discoveries. However, researchers and scholars in the future this information collected and stored now might be an essential resource in eventually doing so. [3]
A similar procedure has since been carried out by a team of scientists from different scientists where a brain has been similarly sliced and preserved but in 7400 thinner sections, each about half the thickness of a single strand of hair. The slices were stained and converted into a three-dimensional digital model of the brain, capturing an estimated 80 billion neurons. The intention is for the digital “atlas” of the brain to be available to neuroscientists and researchers globally. It can be inputted with information from patients so neuronal circuitry can be tracked to create a database of information for anatomical comparison and possible root causes of mental illnesses can be detected. For example, a research team form the University of Cambridge intends to use the images to understand the mechanisms behind eating disorders in patients. [5]
The human ability and inclination to uncover their own inner workings is intriguing in itself. In addition, the potential capability of solving the mystery of these mechanisms and the complexities of the human brain is increasing with the development of these technologies but is proving that there is still much to discover in the field of neuroscience.
Bibliography
[1] http://www.teslasociety.com/mri.htm
[2] http://ucsdnews.ucsd.edu/feature/uc_san_diego_creates_center_for_brain_activity_mapping
[3] http://www.bbc.co.uk/iplayer/episode/b00xln23/the-brain-a-secret-history-3-broken-brains
[4] http://www.theguardian.com/science/2013/may/05/henry-molaison-amnesiac-corkin-book-feature
[5] http://www.bbc.co.uk/news/health-22977225