from the i-forgot-how-this-works dept.
Optogenetics has been used to activate neurons in mice with Alzheimer's-like symptoms, allowing them to remember the fear caused by an electric shock:
Memories banished by Alzheimer's can in theory be rescued by stimulating nerve cells to grow new connections, a study has shown. The research, conducted in mice, raises the possibility of future treatments that reverse memory loss in early stages of the disease. Scientists used a technique called optogenetics, which uses light to activate cells tagged with a special photo-sensitive protein. It was tested on mice with Alzheimer's-like symptoms that quickly forgot the experience of receiving a mild electric shock to their feet. After tagged cells in their brains were stimulated with light, their memory returned and they displayed a fear response when placed in the chamber where the shock had been applied an hour earlier.
The optogenetic treatment helped the neurons re-grow small buds called dendritic spines, which form synaptic connections with other cells. Although the same technique cannot be used in humans, the research points the way to future memory-retrieving therapies, say the researchers. Lead scientist Prof Susumu Tonegawa, from the Picower institute for learning and memory at the Massachusetts Institute of Technology (MIT) in the US, said: "The important point is, this a proof of concept. That is, even if a memory seems to be gone, it is still there. It's a matter of how to retrieve it."
The research, published in the journal Nature, specifically targeted memory cells in the hippocampus region of the brain previously identified by Tonegawa's team. Two different strains of mice, genetically engineered to develop Alzheimer's symptoms, plus a control group of healthy animals, were used in the experiment.
Memory retrieval by activating engram cells in mouse models of early Alzheimer's disease (DOI: 10.1038/nature17172)
Researchers have created a protein that breaks into two pieces when exposed to light:
Researchers at the University of Alberta have developed a new method of controlling biology at the cellular level using light. The tool -- called a photocleavable protein -- breaks into two pieces when exposed to light, allowing scientists to study and manipulate activity inside cells in new and different ways.
First, scientists use the photocleavable protein to link cellular proteins to inhibitors, preventing the cellular proteins from performing their usual function. This process is known as caging. "By shining light into the cell, we can cause the photocleavable protein to break, removing the inhibitor and uncaging the protein within the cell," said lead author Robert Campbell, professor in the Department of Chemistry. Once the protein is uncaged, it can start to perform its normal function inside the cell. The tool is relatively easy to use and widely applicable for other research that involves controlling processes inside a cell.
Optogenetic control with a photocleavable protein, PhoCl (DOI: 10.1038/nmeth.4222) (DX)
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