from the memories dept.
Imagine if we could enhance good memories for those suffering from dementia and wipe away bad memories for people with post-traumatic stress disorder.
Researchers have taken a step toward the possibility of tuning the strength of memory by manipulating one of the brain's natural mechanisms for signaling involved in memory, a neurotransmitter called acetylcholine.
Brain mechanisms underlying memory are not well understood, but most scientists believe that the region of the brain most involved in emotional memory is the amygdala. Acetylcholine is delivered to the amygdala by cholinergic neurons that reside in the base of the brain.
[...] For a new study published in the journal Neuron , researchers used a fear-based memory model in mice to test the underlying mechanism of memory because fear is a strong and emotionally charged experience. They used optogenetics, a newer research method using light to control cells in living tissue, to stimulate specific populations of cholinergic neurons during the experiments.
Two findings stand out. First, when they increased acetylcholine release in the amygdala during the formation of a traumatic memory, it greatly strengthened memory—making the memory last more than twice as long as normal. Then, when they decreased acetylcholine signaling in the amygdala during a traumatic experience, one that normally produces a fear response, they could actually wipe the memory out.
"This second finding was particularly surprising, as we essentially created fearless mice by manipulating acetylcholine circuits in the brain," Role says.
Sounds reminiscent of how they erased memories in the Philip K Dick film adaptation, Paycheck.
[Acetylcholine has been implicated in addiction to alcohol and nicotine; see, for example, Alcohol and nicotinic acetylcholine receptors (abstract) and full article (pdf) -Ed.]
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)
Related: With a Better Optogenetic Light Switch, Scientists Can Flip Neurons On and Off
Gene Therapy Human Trial Will Inject Virus Into the Retinas of the Legally Blind
Nerve Stimulation May Recover Memories in Alzheimer's Patients (Mice)
Scientists Test a Way to Erase Scary Memories
Mice Turned Violent by Photoactivation of Amygdala Neurons