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Notes to our future selves

In other words, the true purpose of note-taking is transporting states of mind (not just information) through time. This is why pictures, sketches, and diagrams often work better than text. We don’t usually think of them as notes, but songs, smells, and tastes work even better. As HBR puts it: “A visual model becomes one of the most effective tools for minimizing alignment-attrition; a visualization formalizes an emergent idea and solidifies it at a moment in time.” Or as Craig Mod more eloquently says, “To return to a book is to return not just to the text but also to a past self. We are embedded in our libraries. To reread is to remember who we once were, which can be equal parts scary and intoxicating.”

Sleep, dopamine and memory

The study shows that increasing sleep, with either a sleep-promoting drug or by genetic stimulation of the neural sleep circuit, decreases signaling activity by dopamine, while at the same time enhancing memory retention. Conversely, increasing arousal stimulates dopamine signaling and accelerates forgetting. This signal activity isn’t constant but is tied directly to the animal’s arousal level. “Our findings add compelling evidence to support the model that sleep reduces the forgetting signal in the brain, thereby keeping memories intact,” Davis said. “As sleep progresses to deeper levels, dopamine neurons become less reactive to stimuli and this leads to more stable memories.

Neuroscientists identify brain circuit necessary for memory formation: New findings challenge standard model of memory consolidation -- ScienceDaily

The researchers labeled memory cells in three parts of the brain: the hippocampus, the prefrontal cortex, and the basolateral amygdala, which stores memories' emotional associations. Just one day after the fear-conditioning event, the researchers found that memories of the event were being stored in engram cells in both the hippocampus and the prefrontal cortex. However, the engram cells in the prefrontal cortex were "silent" -- they could stimulate freezing behavior when artificially activated by light, but they did not fire during natural memory recall. "Already the prefrontal cortex contained the specific memory information," Kitamura says. "This is contrary to the standard theory of memory consolidation, which says that you gradually transfer the memories. The memory is already there." Over the next two weeks, the silent memory cells in the prefrontal cortex gradually matured, as reflected by changes in their anatomy and physiological activity, until the cells became necessary for the animals to naturally recall the event. By the end of the same period, the hippocampal engram cells became silent and were no longer needed for natural recall. However, traces of the memory remained: Reactivating those cells with light still prompted the animals to freeze. In the basolateral amygdala, once memories were formed, the engram cells remained unchanged throughout the course of the experiment. Those cells, which are necessary to evoke the emotions linked with particular memories, communicate with engram cells in both the hippocampus and the prefrontal cortex.

Magical napping

I just want to add that we've done some studies looking at naps in terms of the memory processing and have been rather stunned, really, by the fact that in almost every experiment that we've tried, an hour-and-a-half nap seems to do as much good for memory processing as an entire night of sleep, and we continue to ponder that and sort of conclude that OK, we just don't get it yet. But in studies where six hours of sleep at night seems not enough to lead to consolidation of memory of a particular task, an-hour-and-a-half nap will. So there's something, at least from the memory perspective, rather magical and unusually efficient about napping as opposed to nocturnal sleep.

Hippocampal and prefrontal processing of network topology to simulate the future : Nature Communications

Here we tested the hypotheses that the hippocampus retrieves representations of the topological structure of the environment when new paths are entered in order to support goal-directed navigation and the lateral PFC performs path-planning via a BFS mechanism. We combined a graph-theoretic analysis of the city streets of London with functional magnetic resonance imaging (fMRI) data collected from participants navigating a film simulation of London’s streets. Our analysis reveals that the right posterior hippocampus specifically tracks the changes in the local connections in the street network, the right anterior hippocampus tracks changes in the global properties of the streets and the bilateral lateral prefrontal activity scales with the demands of a BFS. These responses were only present when long-term memory of the environment was required to guide navigation.

How the brain maintains useful memories -- ScienceDaily

there are specific groups of neurons in the medial prefrontal cortex (mPFC) of a rat's brain -- the region most associated with long-term memory. These neurons develop codes to help store relevant, general information from multiple experiences while, over time, losing the more irrelevant, minor details unique to each experience. The findings provide new insight into how the brain collects and stores useful knowledge about the world that can be adapted and applied to new experiences. "Memories of recent experiences are rich in incidental detail but, with time, the brain is thought to extract important information that is common across various past experiences," says Kaori Takehara-Nishiuchi, senior author and Associate Professor of Psychology at the University of Toronto. "We predicted that groups of neurons in the mPFC build representations of this information over the period when long-term memory consolidation is known to take place, and that this information has a larger representation in the brain than the smaller details."

Potential way to reduce drug cravings: Vagus nerve stimulation therapy -- ScienceDaily

"They still check a couple of times each session, thinking that maybe something will happen. They go from 60 lever presses down to something like 10 per session. They clearly haven't forgotten what the lever used to do and still have cravings for the drug," Kroener said. Eventually, the light and tone (but not the drug) were reinstated, causing intense cravings in the animals and a relapse to drug-seeking, which results in more lever presses. However, the animals that experienced VNS treatment during the extinction phase of the experiment pressed the lever less frequently, by nearly 40 or 50 percent which, Kroener said, means their craving was very much reduced. "That's what you want in addiction treatment," he said. "You want to have less craving and less responsiveness to the old cues and the old environment that previously signified drug taking.

Want to ace an exam? Tell a friend what you learned (and memories are a LOT bigger than we think)

"With a cue, suddenly, a lot of those details will come back," Sekeres said. "We don't permanently forget them, which would indicate lack of storage -- we just can't immediately access them. And that's good. That means our memories aren't as bad as we think." Much research on memory examines how brain damage or aging affects recall, but "we wanted to look at the normal course of forgetting in healthy brains -- and if anyone should have a good memory, it's healthy young adults," Sekeres said. "While the strategy of re-telling information -- known as 'the testing effect' -- has been shown to be a really effective study technique time and again, this study is novel in looking at how our memories change over time for a specialized group."

Catapult | You’ll Never Be Lovelier Than You Are Right Now: On Tennis, Grief, and Social Striving | Cody Delistraty

I was reminded of a line from Graham Greene’s Travels with My Aunt, where Greene writes, “it is well to have a few memories of extravagance in store for hard times.” And while this is certainly true, those memories now also conspired to make my current situation feel even more devastating—the gap between the once known and the currently lived expanding into an increasingly painful distance.

Scientist explains the psychological function of eulogizing the deceased

Thus, eulogizing the life of another after they die is almost like upholding our part of the bargain. We need to believe that others will carry on our memory after our death in order to allay our anxieties, and so we do for them what we hope they will do for us. When you think about it this way, you can see why the eulogy has become such an institutionalized aspect of the funeral ceremony. It satisfies our deeply rooted need to manage our own anxiety and sadness surrounding death and finitude.

Lots Of Fat And Sugar Can Take A Toll On Memory : Shots - Health News : NPR

Her researchers asked obese and lean people to do a memory task that's a virtual treasure hunt. The subjects had to hide something in a scene across various computer sessions, then they were asked what they hid, where they hid it and in which session. The Salt Aging Well: Keeping Blood Sugar Low May Protect Memory The obese people were 15 to 20 percent worse than lean ones in all aspects of the experiment. The finding confirmed what other researchers had already seen in rodents. "This really picks apart spatial, item and temporal memory, as well as, crucially, the ability to integrate them," which Cheke says is "one of the most fundamental aspects of memory." If you're obese, she says, you might just be "10 to 15 to 20 percent more likely to not quite remember where you put your keys."

Stress and hippocampus

Research in the neurological literature for years has shown changes in the hippocampus when one has experienced long stress – so a release of hormones such as cortisol actually causes damage to the hippocampus. But as it turns out, it may be that damage to the hippocampus also regulates one’s stress response – and that could contribute to the onset of depression. Again, it’s another one of these vicious cycles. We have a list of 100 potentially stressful events – divorce, moving house, losing loved ones, etc. We found that our group of depressed individuals had not experienced more stressful events in their lives – but they had experienced them as more stressful.

Imagination specificity helps pull people forward

[Research] has shown that people who can imagine future events in detail are more likely to go out and seek social support when they need it, they experience less worry about the upcoming event and they’re more likely to put good, successful behaviours into practice when they experience those events they’ve been thinking about.

Half of people believe fake facts, 'remember' events that never happened -- ScienceDaily

Over 400 participants in 'memory implantation' studies had fictitious autobiographical events suggested to them -- and it was found that around 50% of the participants believed, to some degree, that they had experienced those events. Participants in these studies came to remember a range of false events, such as taking a childhood hot air balloon ride, playing a prank on a teacher, or creating havoc at a family wedding. 30% of participants appeared to 'remember' the event -- they accepted the suggested event, elaborated on how the event occurred, and even described images of what the event was like. Another 23% showed signs that they accepted the suggested event to some degree and believed it really happened.

Rosemary really is herb of remembrance, as scent boosts memory by 15 per cent, say scientists | The Telegraph

A study of pensioners found that simply being in a room diffused with the smell of rosemary boosted memory test scores by 15 per cent.

Sugar can cause brain damage, claim scientists (but salmon reverses it)

The scientists fed a group of rats for six weeks with fructose-spiked water (the equivalent to about a litre of soft drinks a day for humans). Then they put them in a maze, alongside rats which had drank only water. The rats which had consumed fructose took twice as long to navigate the maze as the water-only group, despite the same level of training - suggesting that their memories had been impaired.

Neuronal structures associated with memory sprout in response to novel molecules: Drug candidates protect neurons against damage from substance implicated in Alzheimer's disease -- ScienceDaily

"Problems with learning and memory in many neurodegenerative and neurodevelopment disorders, such as Alzheimer's disease and certain forms of autism or mental retardation involve either loss or misregulation of dendritic spines," said Jerry Yang, a professor of chemistry and biochemistry who led the work. "The compounds we have developed may offer the possibility to compensate, or ideally preserve, neuronal communication in people suffering from problems with memory."

Scientists eliminate core symptom of schizophrenia in mice: Team uses chemical compound to restore affected brain regions; findings could lead to new treatment strategies -- ScienceDaily

"Schizophrenia affects about one in every 100 people, but for those with a 22q11.2 microdeletion, that chance jumps to one in three," said Dr. Gogos. "22q11.2 microdeletions remain the single greatest genetic risk factor for developing schizophrenia. This is why our model has proved invaluable in allowing us to trace schizophrenia back to its beginnings."

Muscle memory

when you strengthen your muscles, they generate more nuclei, or “little protein factories,” that contain DNA necessary for increasing muscle volume, says Kristian Gundersen, professor of physiology at the University of Oslo in Norway. A study led by Gundersen in 2010 confirms that even after you quit exercising, these nuclei stick around, meaning a runner is one step ahead when he decides to get back into it. “When you do an activity, the brain sends messages to your muscles in the form of electrical charges through pathways in the central nervous system, and the muscles send messages back,” says Matt Silvis, M.D., a primary-care sports-medicine physician at Penn State Milton S. Hershey Medical Center. It’s because of this constant feedback loop that the right muscles are activated, and at the right force, in order to perform a particular task. Do this task enough, and these nervous-system pathways become well-trodden, which is why you never forget how to ride a bike-or how to run.

Researchers reveal mechanisms of how body remembers, fights infections: Scientists find new evidence of immune system plasticity -- ScienceDaily

"It was once believed that effector and memory cells arose as two distinct populations, with some cells initially fated to be effector type and some to be memory," McDonald said. "We've now seen that there is much more fluidity between the cell types than originally thought." The presence of certain proteins can influence the cell's fate. Interleukin-2, for instance, is a highly inflammatory protein produced at the start of an infection.

Protein that boosts memory (and erases bad memories?) identified

In an earlier study, the Heidelberg scientists learned that there are reduced levels of Dnmt3a2 protein in the brains of older mice. When the elderly animals were injected with viruses that produce this protein, their memory capacity improved. "Now we have found that increasing the Dnmt3a2 level in the brains of younger mice also boosts their cognitive ability," explains Prof. Bading. In a number of different long-term memory tests, including classic Pavlovian conditioning, the scientists were able to demonstrate that mice with more Dnmt3a2 on board performed considerably better.

What is your memory style? Tndency to remember episodic details versus facts is reflected in intrinsic brain patterns -- ScienceDaily

Those who endorsed richly-detailed autobiographical memories had higher medial temporal lobe connectivity to regions at the back of the brain involved in visual processes, whereas those tending to recall the past in a factual manner (minus the rich details) showed higher medial temporal lobe connectivity to areas at the front of the brain involved in organization and reasoning.

Brain has internal ‘odometer’ and ‘stopwatch’

To prove the contrary, researchers put rats on treadmills and recorded the activity of grid cells, keeping either distance or duration of running unchanged, and only varying the speed. As a result, 92% of grid cells in rats emitted signals at specific moments: for instance, one cell would fire 8 seconds into the run, not taking into account speed or distance covered, and another cell would emit a signal every 400 cm, not depending on speed or duration of the run. 50 percent of the cells were affected by distance, another half by time, and around 40 percent by both factors. "Space and time are ever-present dimensions by which events can be organized in memory," senior study author Howard Eichenbaum, a psychologist and neuroscientist at Boston University, said in the official press release.

Archeologist Beheaded by ISIS After Refusing to Lead Them to Valuable Artifacts

Two theories of how neurons encode memories

There are two extremes of neural coding: Perceptions might be represented through the activity of ensembles of neurons, or they might be encoded by single neurons. The first strategy, called the dense code, would result in a huge storage capacity: Given N neurons in the brain, it could encode 2N items—an astronomical figure far greater than the number of atoms in the universe, and more than one could experience in many lifetimes. But it would also require high activity rates and a prohibitive energy budget, because many neurons would need to be active at the same time. The second strategy—called the grandmother code because it implies the existence of a cell that only spikes for your grandmother—is much simpler. Every object in experience would be represented by a neuron in the same way each key on a keyboard represents a single letter. This scheme is spike-efficient because, since the vast majority of known objects are not involved in a given thought or experience, most neurons would be dormant most of the time. But the brain would only be able to represent as many concepts as it had neurons.

Brain game 'improves lives of schizophrenia patients'

It asks players to enter rooms, find items in boxes and remember where they put them, testing their so-called episodic memory. Better-equipped Prof Barbara Sahakian, from the department of psychiatry at the University of Cambridge and who researched the impact of the game, said patients who played it made significantly fewer errors in tests afterwards on their memory and brain functioning. She said this was an indication that they were better prepared to function in the real world.