Tag Archives | Memory

Simple, Brainless Organisms Store Memories Externally

Barely-alive creatures, such as the slime mold at right, are able to produce “memories” — they just store them in their physical surroundings rather than a brain, Ars Technica has the latest news on the secret lives of simple beings:

Is it possible to know where you’ve been when you don’t have a brain? Depending on your definition of “know,” the answer may be yes. Researchers have shown that the slime mold, an organism without anything that resembles a nervous system (or, for that matter, individual cells), is capable of impressive feats of navigation. It can even link food sources in optimally spaced networks. Now, researchers have shown it’s capable of filling its environment with indications of where it has already searched for food, allowing it to “remember” its past efforts and focus its attention on routes it hasn’t explored.

In the course of studying the slime mold, some researchers noticed that the slime mold would avoid any areas covered in slime.

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Scientists Use Neural Prosthesis to Recover Monkeys’ Ability to Make Decisions

Picture: Unknown (PD)

Yes, but can they make the monkey vote Republican?

Via ScienceDaily:

Researchers have taken a key step towards recovering specific brain functions in sufferers of brain disease and injuries by successfully restoring the decision-making processes in monkeys.

By placing a neural device onto the front part of the monkeys’ brains, the researchers, from Wake Forest Baptist Medical Centre, University of Kentucky and University of Southern California, were able to recover, and even improve, the monkeys’ ability to make decisions when their normal cognitive functioning was disrupted.

The study, which has been published today (Sept. 14) in IOP Publishing’s Journal of Neural Engineering, involved the use of a neural prosthesis, which consisted of an array of electrodes measuring the signals from neurons in the brain to calculate how the monkeys’ ability to perform a memory task could be restored.

In the delayed match-to-sample task an image was flashed onto a screen and, after a delay, the monkeys were prompted to select the same image on the screen from a sampling which included 1-7 other images.

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Scientists Implant Short-Term Memories in Rat Brain tissue

Picture: Janet Stephens (PD)

Via ScienceDaily:

Evoking scenes from science fiction B-movies, (I’m looking at you, Battlefield Earth), scientists at Case Western Reserve University School of Medicine succeeded in implanting rudimentary memories in sections of puny rat-brains! rat brain tissue.

In their study, the researchers sought to better understand the mechanisms underlying short-term declarative memories such as remembering a phone number or email address someone has just shared.

Using isolated pieces of rodent brain tissue, the researchers demonstrated that they could form a memory of which one of four input pathways was activated. The neural circuits contained within small isolated sections of the brain region called the hippocampus maintained the memory of stimulated input for more than 10 seconds. The information about which pathway was stimulated was evident by the changes in the ongoing activity of brain cells.

The experiment will pave the way for a greater understanding of how short-term memories are formed, according to the article at ScienceDaily.… Read the rest

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Cell Phone Use in Pregnancy May Cause Behavioral Disorders in Offspring

Pregnant MouseVia ScienceDaily:

Exposure to radiation from cell phones during pregnancy affects the brain development of offspring, potentially leading to hyperactivity, Yale School of Medicine researchers have determined. The results, based on studies in mice, are published in the March 15 issue of Scientific Reports, a Nature publication.

“This is the first experimental evidence that fetal exposure to radiofrequency radiation from cellular telephones does in fact affect adult behavior,” said senior author Dr. Hugh S. Taylor, professor and chief of the Division of Reproductive Endocrinology and Infertility in the Department of Obstetrics, Gynecology & Reproductive Sciences.

Taylor and co-authors exposed pregnant mice to radiation from a muted and silenced cell phone positioned above the cage and placed on an active phone call for the duration of the trial. A control group of mice was kept under the same conditions but with the phone deactivated. The team measured the brain electrical activity of adult mice that were exposed to radiation as fetuses, and conducted a battery of psychological and behavioral tests.

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How Marijuana Impairs Short-Term Memory

UnrolledJointMo Costandi writes in the Guardian:

My latest news story for Nature describes a new study which explains how marijuana causes impairments in working memory, or the ability to retain information for short periods of time. This is a well known side effect of marijuana, which is unwanted with respect to medicinal use of the drug, but until now the underlying neurobiology was unknown.

The research shows that tetrahydrocanabinol (THC, the psychoactive ingredient in marijuana) impairs working memory by inducing a form of synaptic plasticity that weakens neuronal connections. This could lead to new THC-related drugs that have therapeutic value but do not cause this unwanted effect. More interestingly, though, the findings provide compelling evidence that hitherto neglected brain cells called astrocytes are critical for brain function and play a direct role in cognitive processes.

There are two different types of synapitc plasticity. One of these, called long-term potentiation, strengthens the connections between neurons so that neurotransmission – the process by which signals pass from one nerve cell to another – is more effective.

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Stereotypes Help Create False Memories

Illustration: J.J. (CC)

Illustration: J.J. (CC)

Via ScienceDaily:

A new study in Psychological Science, a journal of the Association for Psychological Science, published online October 26 addresses the influence of age-related stereotypes on memory performance and memory errors in older adults.

Ayanna Thomas, assistant professor of psychology and director of the Cognitive Aging and Memory Lab at Tufts University, and co-author Stacey J. Dubois, a former graduate student at Tufts, set out to investigate how implicitly held negative stereotypes about aging could influence memory performance in older adults.

Thomas and Dubois presented a group of older and younger adults with a list of semantically related words. A sample list participants would be presented with would be words associated with “sleep,” such as “bed,” “rest,” “awake,” “tired” and “night.” Though the word “sleep” itself was not actually presented, both the older and younger adults falsely indicated that they thought it had been included in the list, older adults more so than younger adults.

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Aging Brains Made Youthful?

Photo: Mieciu K2 (CC)

Photo: Mieciu K2 (CC)

Can we restore our “mental sketch pads” by renewing how our brain holds memory on the neurological level? The National Geographic reports:

You can’t teach an old brain new tricks—but you can restore its ability to remember the old ones, a new study in monkeys suggests.

Chemicals given to rhesus macaques blocked a brain molecule that slows the firing of the brain’s nerve cells, or neurons, as we age—prompting those nerve cells to act young again.

“It’s our first glimpse of what’s going on physiologically that’s causing age-related cognitive decline,” said study leader Amy Arnsten, a neurobiologist at Yale University.

“We all assumed, given there’s a lot of architectural changes in aged brains … that we were stuck with it,” Arnsten said.

But with the new results, “the hopeful thing is that the neurochemical environment still makes a big difference, and we might be able to remediate some of these things.”

[Continues at National Geographic]

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Google Is Ruining Your Memory

Columbia University Professor Betsy Sparrow says we just don't bother remembering anything anymore. From Columbia News:
The rise of Internet search engines like Google has changed the way our brain remembers information, according to research by Columbia University psychologist Betsy Sparrow published July 14 in Science. “Since the advent of search engines, we are reorganizing the way we remember things,” said Sparrow. “Our brains rely on the Internet for memory in much the same way they rely on the memory of a friend, family member or co-worker. We remember less through knowing information itself than by knowing where the information can be found.”...
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How Easy Is It to Falsify Memory? How Social Pressure Affects What We Remember

Total RecallFrom ScienceDaily:

New research at the Weizmann Institute shows that a bit of social pressure may be all that is needed. The study, which appears in the journal Science, reveals a unique pattern of brain activity when false memories are formed — one that hints at a surprising connection between our social selves and memory.

The experiment, conducted by Prof. Yadin Dudai and research student Micah Edelson of the Institute’s Neurobiology Department with Prof. Raymond Dolan and Dr. Tali Sharot of University College London, took place in four stages. In the first, volunteers watched a documentary film in small groups. Three days later, they returned to the lab individually to take a memory test, answering questions about the film. They were also asked how confident they were in their answers.

They were later invited back to the lab to retake the test while being scanned in a functional MRI (fMRI) that revealed their brain activity.

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Study: Advertising Plants Memories Of Experiences We Never Had

imagery-adOn the bright side, is it really such a bad thing to be implanted with false memories of, say, dancing with smiling, multicultural nu-ravers while drinking a refreshing Pepsi? Partial Objects explains:

A newly published study by two marketing professors suggests that advertising can create memories of experiences that never happened, simply by including sufficiently evocative imagery and descriptions in the ad:

Exposure to an imagery-evoking ad can increase the likelihood that consumer mistakenly believes that s/he has experience with the advertised product when in fact s/he does not. Moreover such a false belief produces attitudes that are as strong as attitudes based on true beliefs based on previous product experience, an effect that we label the false experience effect.

Advertising has always been an appeal to a fantasy, and this study seems to suggest that if the ad is created just right, that fantasy can be in the form of a desire to return to a previous wonderful experience (even if the previous experience never actually happened.) But this finding suggests something a bit more insidious.

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