When you step out on a winter day, halfway down the stairs, you suddenly realize that your ears are freezing because you forgot to wear a hat. Now, scientists have discovered that even if you occasionally space out, your brain never forgets what you’ve done.
Memory primarily operates through associations. For example, when you try to remember where you left your keys, you recall seeing them last in the living room, which leads you to remember a soap commercial on TV, and that reminds you that you’ve run out of soap… And as you head towards the door to buy soap, you suddenly remember that you left the keys on the kitchen counter.
Your brain always knows where the keys are, but it has to navigate through various thoughts to reach that specific memory.
Currently, scientists at the Salk Institute for Biological Studies in the U.S. are investigating associative memory in monkeys to understand how this complex process works.
First, the researchers trained a group of brown monkeys to remember pairs of arbitrary symbols. They then showed the monkeys one symbol (cold weather) and gave them a choice between two other symbols, one of which was related to the first symbol (the hat). When the monkeys chose correctly, they were rewarded with their favorite fruit juice.
The results showed that most of the monkeys performed perfectly on the test, but one monkey consistently made mistakes.
“We wondered what happens in the brain of the monkey that always gets it wrong, even though it seemed to remember the symbol pairs correctly,” said lead researcher Thomas Albright.
Albright and his team observed signals in the neurons of the inferior temporal cortex (ITC) of the monkeys, the region of the brain involved in visual recognition and storing such memories.
When the monkey decided which symbol to choose, a quarter of the brain’s activity occurred in the ITC. Meanwhile, more than half of the activity took place in a different group of neurons. The scientists believe this area of the brain is responsible for correctly recalling the symbol pairs. However, surprisingly, these neurons continued to be active even when the monkey made the wrong choice.
“Thus, these brain cells know more than the monkey itself – as shown by its actions. Therefore, behavior may change, but knowledge remains intact,” Albright noted.
M.T. (according to Livescience)
