Published On: Mon, Jan 20th, 2020

The Biological Basis of Memory

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The Basis of Long-term Memory

Scientists believe that long-term memories are stored in groups of brain cells or “neurons” that are activated in response to particular experiences. How do you store a memory? The thought is that the initial experience triggers biochemical or structural changes in networks of neurons. These neurons are then more likely than other neurons to be activated during recall. In other words, memories are believed to leave traces.

Brain Regions Involved in Memory

It’s been difficult to study memory. Humans have about 100 billion neurons and each neuron can interact with thousands of others. And the cells involved in memory are distributed in different parts of the brain. For example, regions of the brain associated with memory include the cerebral cortex, cerebellum, striatum, hippocampus and amygdala.

Each of these regions is associated with a different type of memory. The hippocampus plays an important role in spatial learning, while the amygdala plays a role in learning during arousal (e.g., during a fear response). The different regions of the brain also work together to create memories. There’s no single region of the brain that functions as a “memory bank.”

With all these complicated interactions, how can we demonstrate that memory traces are real?

Transgenic Mice Provide Tools

In a recent study, scientists at the Scripps Research Institute genetically engineered mice to express a tag molecule (a bacterial enzyme called beta-galactosidase) in response to neuron activation. The mice were exposed to a stimulus and a light shock to their paws. Activation of neurons during the initial shocking experience signaled the activated neurons to express the beta-galactosidase tag molecule. When the mice were exposed to the stimulus three days later, they exhibited a “freezing behavior,” expecting to be shocked again. This time the expression of a different tag molecule (the product of a naturally expressed gene, egr) was triggered as the mice recalled the earlier unpleasant shock.

The scientists then examined the brains of the mice. They found both tag molecules in the same cells in a significant number (12%) of the reactivated neurons.

The take home? These results show that cells involved in remembering an experience include the same cells involved in learning. By showing that a neuron conditioned to respond to a fear stimulus is reactivated during recall, the study makes at least short-term memory traces a real possibility.

Genetic Engineering Opens Avenues for Drug Testing

The Biological Basis of Memory

The technique used in this study has some far-reaching applications. It gives researchers a powerful way to look at changes in individual neurons over any time period. For example, by looking at which neurons are active before and after treatment with a drug, you might be able to find which drug works best.

Although mice certainly aren’t human beings, by seeing how they respond to drugs, we’ve learned how to treat some very debilitating illnesses. There are a number of mouse models for mental diseases, including obsessive compulsive disorder, schizophrenia, and Alzheimer’s. This research makes it possible to investigate the impact of disease on memory in all of these models.

About the Author

- I am an internet marketing expert with an experience of 8 years.My hobbies are SEO,Content services and reading ebooks.I am founder of SRJ News andTech Preview.

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