Posts Tagged ‘mind’

Three Men Receive Bionic Hands Controlled With Their Minds

The outlook used to be pretty bleak for those who had lost movement in their limbs due to severe nerve damage, but over the last year or so, some incredible advances have been made that are restoring shattered hope for many.

The amazing breakthroughs include spinal cord stimulation that allowed paralyzed men to regain some voluntary control of their legs, a brain implant that enabled a quadriplegic man to move his fingers, and a system that allowed a paralyzed woman to control a robotic armusing her thoughts. Science has definitely been on a roll, but this winning streak isn’t showing any signs of slowing down. Now, the world’s first “bionic reconstructions” have been performed on three Austrian men to help them regain hand function. This technique enabled the newly amputated patients to control prosthetic hands using their minds, allowing them to perform various tasks that most people take for granted.

The men that underwent the procedure had all suffered serious nerve damage as a result of car or climbing accidents, which left them with severely impaired hand function. The nerves that suffered injury were those within a network of fibers supplying the skin and muscles of the upper limbs, known as the brachial plexus. As lead researcher Professor Oskar Aszmann explains in a news release, traumatic events that sever these nerves are essentially inner amputations, irreversibly separating the limb from neural control. While it is possible to operate, Aszmann says the techniques are crude and do little to improve hand function. However, his newly developed procedure is quite different, and is proving to be a success.

Before the men could be fitted with their prosthetic hands, the researchers had to do some preliminary surgical work in which leg muscle was grafted into their arms in order to improve signal transmission from the remaining nerves. After a few months, the fibers had successfully innervated the transplanted tissue, meaning it was time to start the next stage: brain training.

Using a series of sensors placed onto the arm, the men slowly began to learn how to activate the muscle. Next, they mastered how to use electrical nerve signals to control a virtual hand, before eventually moving on to a hybrid hand that was affixed to their non-functioning hand. After around nine months of cognitive training, all of the men had their hand amputated and replaced with a robotic prosthesis that, via sensors, responds to electrical impulses in the muscles.

A few months later, the men had significantly improved hand movement control, which was highlighted by a test of function known as the Southampton Hand Assessment Procedure. As reported in The Lancetbefore the procedure, the men scored an average of 9 out of 100, which soared to 65 using the prosthetic. Furthermore, the men reported less pain and a higher quality of life. For the first time since their injuries, they were able to perform avariety of tasks such as picking up objects, slicing food and undoing buttons with both hands.

“So far, bionic reconstruction has only been done in our center in Vienna,” said Aszmann. “However, there are no technical or surgical limitations that would prevent this procedure from being done in centers with similar expertise and resources.”

The above story is adopted from The Lancet and reprinted from materials provided by NewScientist.

Neural Networks Forget Information Quickly

December 16, 2012 Leave a comment

Researchers have figured out the speed that neural networks in the cerebral cortex can delete sensory information is a bit of information per active neuron per second. The activity patterns of the neural network models are deleted nearly as soon as they are passed on from sensory neurons.

The scientists used neural network models based on real neuronal properties for the first time for these calculations. Neuronal spike properties were figured into the models which also helped show that the cerebral cortex processes were extremely chaotic.

Neural networks and this type of research in general are all helping researchers better understand learning and memory processes. With better knowledge about learning and memory, researchers can work toward treatments for Alzheimer’s disease, dementia, learning disabilities, PTSD related memory loss and many other problems.

More details are provided in the release below. Read more…

Right and Left Brain

October 26, 2010 Leave a comment

The brain is divided physically into a left and right half is not a new discovery. The Egyptians knew that the left side of the brain controlled and received sensations from the right side of the body and vice versa.

It is only in the last two dozen years, however, that the true implication of the left/right split has gradually become apparent, through the work of a number of researchers. The most famous are probably Dr. Roger Sperry and Dr. Robert Ornstein of the California Institute of Technology. Their work has won them a Nobel prize.

Sperry and Ornstein noted that the left and the rig hemispheres are connected by an incredibly complex network of up to 300 million nerve fibres called the Corpus callosum. They were also able to show that the two halves of the brain tend to have different functions.

They (and other researchers) indicate that the left brain primarily appears to deal with language and mathematical processes and logical thought, sequences, analysis and what we generally label academic pursuits. The right brain principally deals with music, and visual impressions, pictures, spatial patterns, and colour recognition. They also ascribe to the right brain the ability to deal with certain kinds of conceptual thought – intangible ‘ideas’ such as love, loyalty, beauty.

The specialization of the two halves of the brain can result in some bizarre behaviour. Patients who, for medical reasons, have had their Corpus callosum severed, have effectively two semi-independent brains: two minds in one head.

If a ball is shown to the left visual field of such a person, i.e. registered to their right brain hemisphere, the speaking half of the brain, which is in the other, (left) brain will claim to have seen nothing. If, however, the patient is asked to feel in a bag of assorted shapes he will correctly pull out a ball. If he is asked what he has done he will say ‘nothing’. The ball has only been seen with the right brain, and felt with the right brain. The speech centre, which is located in the left brain, has registered nothing.

Even more delicate experiments have been performed on surgically split-brained patients. The word SINBAD was projected to such a patient while his eyes were focused on the precise spot between N and B. The first 3 letters went to his right brain, the last three to his left hemisphere. When asked to saywhat he had seen, he replied BAD. When asked to point with his left hand to what he had seen he pointed to the word SIN.

The specialisation of the two brains has also been demonstrated by measuring the electrical activity of the brain during various activities.

When the brain is relaxed in a state of rest, it tends predominantly to show an alpha brain wave rhythm – i.e. 8-12Hz waves. Ornstein found that a subject tackling a mathematical problem showed an increase in alpha in the right hemisphere. This indicated that the right side was relaxing whilst the left was active and, therefore, in a beta brain wave pattern. In contrast, when a subject was matching coloured patterns, the left showed alpha (i.e. was resting) and the right showed beta (i.e. was active).

The brain scans, show the varying levels of electrical brain activity in a subject listening to music, words and singing. The first activity (music) involved the right brain. The second (listening to words only) involved the left brain, but singing (words and music together) involved the whole brain.

The left brain is now thought to be the half that specialises in serial, sequential thought, i.e. analysing information in sequence in a ”logical” step by step approach. The left rationalises. The right brain seems to take in several bits of information ”at a glance” and process them into one overall thought. The right synthesises.

When you meet someone it seems to be the right brain that takes all the elements at once and synthesises the pattern into a whole to recognise the person instantaneously. If you were using your left brain only you would probably scan first the hair, then the forehead, then the eyes, nose, mouth and chin in sequence to ”build up” a picture. The right brain, however, recognises the pattern immediately.

It is the left brain that is dominant in, for example, mathematical calculations. It is the right brain that processes non-verbal signals.

We have come as a society to stress, and value more highly, the functions of the left brain. The analytical thinking of the physicist is usually valued higher (in money terms) than the artistic and intuitive ability of the musician or artist. Most schools relegate right brain dominant activities to two or three periods a week. Yet those schools who have tried increasing the proportion of arts subjects, have found that levels of all scholastic performance improved. Because, although the two halves of the brain may indeed be specialised, they are far from being isolated. Each compliments and improves the performance of the other.

Education that emphasises only analytical thinking is literally ”single minded”. As one psychologist put it »Such people’s brains are being systematically damaged. In many ways they are being de-educated.«