Fearless!

August 19th, 2017| Topic: RaMbLeS | 0

We can become fearless!

So say researchers from the University of California, Riverside, Woong Bin Kim and Jun-Hyeong Cho, in “Encoding of Discriminative Fear Memory by Input-Specific LTP in the Amygdala,” published recently in Neuron.

Cho and Kim used genetically modified mice to study parts of the brain processing sounds and those dealing with emotional memories, the amygdala.

More and more studies seem to indicate that memories can be rewritten, modifying, or even obliterating, our remembered causes of fear and rendering us fearless.

Said Cho:

These mice are special in that we can label or tag specific pathways that convey certain signals to the amygdala, so that we can identify which pathways are really modified as the mice learn to fear a particular sound. It is like a bundle of phone lines. Each phone line conveys certain auditory information to the amygdala.”

Mice were exposed to high- and low-pitched sounds, with the former accompanied by a small electric shock to the feet of the animals. Thus they were conditioned to fear high-pitched sounds: they immediately froze in fear, but not to the low-pitched emissions.

But if the animals were subsequently exposed to high-pitched sounds with the fearsome shocks, the mice lost their fear—“fear extinction”—though the fear relapsed when they were tested a couple of weeks later.

Cho again:

Fear extinction is the psychological basis of exposure therapy used in [treating] post-traumatic stress disorder. But after exposure therapy, for example two weeks, the fear relapses or recurs spontaneously.”

So far so good. Nothing unexpected.

But then they manipulated the neurons involved in high-pitched fear pathway employing some nifty techniques of optogenetics. Via viruses, they introduced light-sensitive genes into those neurons of the high-pitched fear pathways. With light, they managed to turn on the production of proteins that weakens connections between those neurons. And once weakened, those nerve cells failed to participate in the high-pitched fear pathway, rendering the mice fearless. Basically, they turned off those nerve cells involved in generating fear to high-pitched sounds.

Declared Cho:

It permanently erases the fear memory. We no longer see the relapse of fear.”

Cho speculates that the findings could be used to diminish particular fearsome memories.

We can use same approach to selectively manipulate only the pathological fear memory while preserving all other adaptive fear memories which are necessary for our daily lives.”

Of course, these subjects were rodents, but still …

Noted Peter Giese, professor of neurobiology at King’s College London:

It is too soon to think of using the research to help those with psychopathologies; it would be unethical to use optogenetic techniques on people. Exactly how this can be applied to humans is a little bit unclear to me. But it is a big advance, not only in improving understanding of fear extinction, but also highlighting the importance of the strengthening of connections between neurons in forming memories. What’s more, it reveals a way to reverse the process. This is a true erasure of the memory.”

But there is a more natural—no, supernatural—way of tackling our fears.

I sought the LORD, and He answered me,
And delivered me from all my fears.
Psalm 34:4

Even though I walk through the valley of the shadow of death,
I fear no evil, for You are with me.
Psalm 23:4

Indeed!

For I am convinced that neither death, nor life, nor angels, nor principalities,
nor things present, nor things to come, nor powers,
nor height, nor depth, nor any other created thing,
will be able to separate us from the love of God, which is in Christ Jesus our Lord.
Romans 8:38–39