Sunday, September 16, 2012

A chip to repair the brain

Researchers are working on an implant to restore lost mental capacity, writes Benedict Carey.

Scientists have designed a brain implant that sharpened decision making and restored lost mental capacity in monkeys, providing the first demonstration in primates of the sort of brain prosthesis that could eventually help people with damage from dementia, strokes or other brain injuries.

The device, though years away from commercial development, gives researchers a model for how to support and enhance fairly advanced mental skills in the frontal cortex of the brain, the seat of thinking and planning.

The new report appeared on Thursday in the Journal of Neural Engineering.

In just the past decade, scientists have developed brain implants that improve vision or allow disabled people to use their thoughts to control prosthetic limbs or move computer cursors. The new paper, led by researchers at Wake Forest Baptist Medical Center and the University of Southern California, describes a device that improves brain function internally, by fine-tuning communication among neurons.

Previous studies have shown that a neural implant can do this for memory in rodents, but the new report extends that work significantly, experts said - into brains that are much closer to those of humans.

In the study, researchers at Wake Forest trained five rhesus monkeys to play a picture-matching game. The monkeys saw an image on a large screen - of a toy, a person, a mountain range - and tried to select the same image from a larger group of images that appeared on the same screen a little while later. The monkeys got a treat for every correct answer.

After two years of practice, the animals developed some mastery, getting about 75 per cent of the easier matches correct and 40 per cent of the harder ones, markedly better than chance guessing.

The monkeys were implanted with a tiny probe with two sensors; it was threaded through the forehead and into two neighbouring layers of the cerebral cortex, the thin outer covering of the brain.

The two layers, called L-2/3 and L-5, are known to communicate with each other during decision making of the sort that the monkeys were doing when playing the matching game.

The device recorded the crackle of firing neurons during the animals' choices and transmitted it to a computer. Researchers at USC, led by Theodore Berger, analysed this neural signal, and determined its pattern when the monkeys made correct choices.

To test the device, the team relayed this ''correct'' signal into the monkeys' brains when they were in the middle of choosing a possible picture match, and it improved their performance by about 10 per cent.
The researchers then impaired the monkeys' performance deliberately, by dosing them with cocaine. Their scores promptly fell by 20 per cent.

''But when you turn on the stimulator, they don't make those errors; in fact, they do a little better than normal,'' said Robert E. Hampson of Wake Forest, a study author.

His co-authors were Sam A. Deadwyler, Ioan Opris and Lucas Santos, all of Wake Forest; Berger, Vasilis Marmarelis and Dong Song of USC; and Greg A. Gerhardt of the University of Kentucky.

The technology used in the study could easily be contained on an implantable chip, Deadwyler said, and it is possible to envision a system that could help people with brain damage.

''The whole idea is that the device would generate an output pattern that bypasses the damaged area, providing an alternative connection in the brain,'' he said.

Many hurdles remain. Decision making, like memory, is a multifaceted process that involves many neural circuits, depending on the decision being made.

A device focused on just one circuit is likely to be very limited. But not long ago, even a simple neural prosthesis would have seemed like science fiction.

Maha govt makes certification of brain death mandatory

Maha govt makes certification of brain death mandatory Mumbai: With a view to streamline procedures for coordinating organ transplant, the Maharashtra government has made it mandatory to declare `brain death` and certify it accordingly.

In the current situation, availability of organs for transplantation is falling woefully short of the demand, while organ transplantation is considered as the only treatment for end stage disease.

Considering the fact that a large number of brain deaths occur in non-transplant hospitals, an appropriate authority, as per the Transplantation of Human Organs Act, 1994, shall take the initiative to register those hospitals that fulfil the conditions as non-transplant organ retrieval centres, said the recent government resolution (GR) issued by the health department.

Whenever the medical condition (clinical and medical criteria prescribed) of a patient reaches a brain death stage, the certification will be done by the authorised medical personnel and immediately thereafter the details of it would be conveyed to zonal transplantation co-ordination committee for distribution of the organs, the GR said.

The order shall come in force in hospitals which are registered under Human Organ Transplant Act, 1994 and non transplant organ retrieval centres in the state with immediate effect, it mentioned.

Donor management and meticulous coordination is crucial in maintaining excellent outcomes in organ transplantation, the GR said.

The appropriate authority shall register all hospitals in the state that have an operation theatre and intensive care unit as non-transplant organ retrieval centres (NTORCs).

These hospitals are permitted to certify brain death
as per the procedures stipulated in the guidelines issued by the appropriate authority or state government and conduct organ retrieval for therapeutic purposes, but are not permitted to perform actual transplantation of human organs.

NTORCs can take assistance and support from any hospital registered with the appropriate authority as a transplant centre for maintaining the brain dead person in a stable condition until organ retrieval is carried out, the GR said.

Whenever a brain death occurs in an NTORC and the deceased donor`s family consents to the organ donation, the NTORC will contact the zonal transplant coordination committee or organ allocation as per norms. The organs shall be allocated following prioritisation norms for zonal transplant co-ordination committee in the state.

Hospitals which have been registered as transplant centres will maintain transplant surgery records for a minimum ten years. They shall ensure availability of a counselling department/ wing to whom the task of counselling individuals involved in organ transplant in entrusted.

The transplant centre hospital will not reveal identity of the recipient or attract any form of media publicity, the resolution said.

Also, all transplant centre hospitals that wish to benefit from the cadaver transplant programme are required to display the approximate range of cost of transplant surgery by specifying the organ type on the website of the hospital and the one designated for the purpose by the health department, it added.