Tweaking non-neural brain cells can trigger memories to fade
Nerve cells and a 2nd cell type called an astrocyte work together to hold memories.
Astrocytes (identified in black) sit within a field of nerve cells. Credit: Ed Reschke
“If we return to the early 1900s, this is when the concept was very first proposed that memories are physically saved in some place within the brain,” states Michael R. Williamson, a scientist at the Baylor College of Medicine in Houston. For a very long time, neuroscientists believed that the storage of memory in the brain was the task of engrams, ensembles of nerve cells that trigger throughout a discovering occasion. It turned out this wasn't the entire photo.
Williamson's research study examined the function astrocytes, non-neuron brain cells, play in the read-and-write operations that go on in our heads. “Over the last 20 years the function of astrocytes has actually been comprehended much better. We've discovered that they can trigger nerve cells. The addition we have actually made to that is revealing that there are subsets of astrocytes that are active and associated with keeping particular memories,” Williamson states in explaining a brand-new research study his laboratory has actually released.
One effect of this finding: Astrocytes might be synthetically controlled to reduce or improve a particular memory, leaving all other memories undamaged.
Marking star cells
Astrocytes, otherwise referred to as star cells due to their shape, play numerous functions in the brain, and lots of are concentrated on the health and activity of their surrounding nerve cells. Williamson's group begun by establishing strategies that allowed them to mark picked ensembles of astrocytes to see when they trigger genes (consisting of one called c-Fos) that assist nerve cells reconfigure their connections and are considered vital for memory development. This was based upon the concept that the exact same path would be active in nerve cells and astrocytes.
“In basic terms, we utilize hereditary tools that enable us to inject mice with a drug that synthetically makes astrocytes reveal some other gene or protein of interest when they end up being active,” states Wookbong Kwon, a biotechnologist at Baylor College and co-author of the research study.
Those proteins of interest were primarily fluorescent proteins that make cells fluoresce brilliant red. In this manner, the group might find the astrocytes in mouse brains that ended up being active throughout finding out situations. When the tagging system remained in location, Williamson and his coworkers offered their mice a little scare.
“It's called worry conditioning, and it's an actually basic concept. You take a mouse, put it into a brand-new box, one it's never ever seen before. While the mouse explores this brand-new box, we simply use a series of electrical shocks through the flooring,” Williamson describes. A mouse treated in this manner remembers this as an undesirable experience and associates it with contextual hints like package's look, the smells and sounds present, and so on.
The tagging system illuminated all astrocytes that revealed the c-Fos gene in reaction to fear conditioning. Williamson's group presumed that this is where the memory is saved in the mouse's brain.
