Scientists capture memories being made

Scientists capture the first image of memories being made:

Scientists capture the first image of memories being made

The ability to learn and to establish new memories is essential to our daily existence and identity; enabling us to navigate through the world. A new study by researchers at the Montreal Neurological Institute and Hospital (The Neuro), McGill University and University of California, Los Angeles has captured an image for the first time of a mechanism, specifically protein translation, which underlies long-term memory formation. The finding provides the first visual evidence that when a new memory is formed new proteins are made locally at the synapse – the connection between nerve cells – increasing the strength of the synaptic connection and reinforcing the memory. The study published in Science, is important for understanding how memory traces are created and the ability to monitor it in real time will allow a detailed understanding of how memories are formed.

When considering what might be going on in the brain at a molecular level two essential properties of memory need to be taken into account. First, because a lot of information needs to be maintained over a long time there has to be some degree of stability. Second, to allow for learning and adaptation the system also needs to be highly flexible.

For this reason, research has focused on synapses which are the main site of exchange and storage in the brain. They form a vast but also constantly fluctuating network of connections whose ability to change and adapt, called synaptic plasticity, may be the fundamental basis of learning and memory.

“But, if this network is constantly changing, the question is how do memories stay put, how are they formed? It has been known for some time that an important step in long-term memory formation is “translation”, or the production, of new proteins locally at the synapse, strengthening the synaptic connection in the reinforcement of a memory, which until now has never been imaged,” says Dr. Wayne Sossin, neuroscientist at The Neuro and co-investigator in the study. “Using a translational reporter, a fluorescent protein that can be easily detected and tracked, we directly visualized the increased local translation, or protein synthesis, during memory formation. Importantly, this translation was synapse-specific and it required activation of the post-synaptic cell, showing that this step required cooperation between the pre and post-synaptic compartments, the parts of the two neurons that meet at the synapse. Thus highly regulated local translation occurs at synapses during long-term plasticity and requires trans-synaptic signals.”

Long-term memory and synaptic plasticity require changes in gene expression and yet can occur in a synapse-specific manner. This study provides evidence that a mechanism that mediates this gene expression during neuronal plasticity involves regulated translation of localized mRNA at stimulated synapses. These findings are instrumental in establishing the molecular processes involved in long-term memory formation and provide insight into diseases involving memory impairment.

This study was funded by the National Institutes of Health, the WM Keck Foundation and the Canadian Institutes of Health Research.

30 GM babies born

World’s first GM babies born:

World's first GM babies born

World’s first GM babies born

The world’s first genetically modified humans have been created, it was revealed last night. The disclosure that 30 healthy babies were born after a series of experiments in the United States provoked another furious debate about ethics. So far, two of the babies have been tested and have been found to contain genes from three ‘parents’. Fifteen of the children were born in the past three years as a result of one experimental programme at the Institute for Reproductive Medicine and Science of St Barnabas in New Jersey. The babies were born to women who had problems conceiving. Extra genes from a female donor were inserted into their eggs before they were fertilised in an attempt to enable them to conceive. Genetic fingerprint tests on two one-year- old children confirm that they have inherited DNA from three adults –two women and one man. The fact that the children have inherited the extra genes and incorporated them into their ‘germline’ means that they will, in turn, be able to pass them on to their own offspring. Altering the human germline – in effect tinkering with the very make-up of our species – is a technique shunned by the vast majority of the world’s scientists. Geneticists fear that one day this method could be used to create new races of humans with extra, desired characteristics such as strength or high intelligence. Writing in the journal Human Reproduction, the researchers, led by fertility pioneer Professor Jacques Cohen, say that this ‘is the first case of human germline genetic modification resulting in normal healthy children’. Some experts severely criticised the experiments. Lord Winston, of the Hammersmith Hospital in West London, told the BBC yesterday: ‘Regarding the treat-ment of the infertile, there is no evidence that this technique is worth doing . . . I am very surprised that it was even carried out at this stage. It would certainly not be allowed in Britain.’ John Smeaton, national director of the Society for the Protection of Unborn Children, said: ‘One has tremendous sympathy for couples who suffer infertility problems. But this seems to be a further illustration of the fact that the whole process of in vitro fertilisation as a means of conceiving babies leads to babies being regarded as objects on a production line. ‘It is a further and very worrying step down the wrong road for humanity.’ Professor Cohen and his colleagues diagnosed that the women were infertile because they had defects in tiny structures in their egg cells, called mitochondria. They took eggs from donors and, using a fine needle, sucked some of the internal material – containing ‘healthy’ mitochondria – and injected it into eggs from the women wanting to conceive. Because mitochondria contain genes, the babies resulting from the treatment have inherited DNA from both women. These genes can now be passed down the germline along the maternal line. A spokesman for the Human Fertilisation and Embryology Authority (HFEA), which regulates ‘assisted reproduction’ technology in Britain, said that it would not license the technique here because it involved altering the germline. Jacques Cohen is regarded as a brilliant but controversial scientist who has pushed the boundaries of assisted reproduction technologies. He developed a technique which allows infertile men to have their own children, by injecting sperm DNA straight into the egg in the lab. Prior to this, only infertile women were able to conceive using IVF. Last year, Professor Cohen said that his expertise would allow him to clone children –a prospect treated with horror by the mainstream scientific community. ‘It would be an afternoon’s work for one of my students,’ he said, adding that he had been approached by ‘at least three’ individuals wishing to create a cloned child, but had turned down their requests.