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Google’s DeepMind is using AI to explore dopamine’s role in learning

In animals, dopamine is believed to reinforce behaviors by strengthening synaptic links in the prefrontal cortex. But the consistency of the neural network’s behavior suggests that dopamine also conveys and encodes information about tasks and rule structures, according to the researchers.

Often overlooked glial cell is key to learning and memory: Biomedical scientists offer simple advice: Keep the brain active -- ScienceDaily

In the lab, the researchers artificially increased levels of ephrin-B1 in mice and then tested them for memory retention. They found that the mice could not remember a behavior they had just learned. In cell culture studies, they added neurons to astrocytes that overexpressed ephrin-B1 and were able to see synapse removal, with the astrocytes "eating up" the synapses. "Excessive loss of synapses is a problem," Ethell said. "The hippocampus, the region of the brain associated primarily with memory, is plastic. Here, new neuronal connections are formed when we learn something new. But the hippocampus has a limited capacity; some connections need to go to 'make space' for new connections -- new memories. To learn, we must first forget." In contrast to an ephrin-B1 increase, when this protein decreases (or is down-regulated) it results in more synapses -- and better learning. The astrocytes, in this case, are not able to attach to the synapses. "But you don't want to remember everything," said Amanda Q Nguyen, a Neuroscience Graduate Program student working in Ethell's lab, and a co-first author of the research paper. "It's all about maintaining a balance: being able to learn but also to forget." Advice the researchers have for the public is simple: keep the brain -- that is, the neurons -- active. "Reading and solving puzzles is a good start," Ethell said.

Waves Move Across the Human Brain to Support Memory - Neuroscience News

“We also found that these traveling waves moved more reliably when subjects performed well while performing a working memory task,” says Joshua Jacobs, assistant professor of biomedical engineering and senior author of the paper. “This indicates that traveling waves are significant for memory and cognition–our findings show that these oscillations are an important mechanism for large-scale coordination in the human brain.”

Neurons ripple while brains rest to lock in memories: How quiet minds encode spatial maps while 'introspecting' -- ScienceDaily

"Animals encode a memory of an environment as they run around," said Kemere, an assistant professor of electrical and computer engineering who specializes in neuroscience. "They form a spatial map as individual neurons are activated in different places. When they're awake in our experiments, they're probably doing that exploration process 40 to 60 percent of the time. "But for the other 40 percent, they're scratching themselves, or they're eating, or they're sort of snoozing," he said. "They're not asleep, but they're paused; I like to call it introspecting." Those periods of introspection provided the critical data for the study that inverted the usual process of matching brain activity to movement while the animals were active. The primary data was gathered over the course of many experiments under the direction of Diba, an associate professor and leader of the Neural Circuits and Memory Lab at Michigan Medicine. As the animals explored either back-and-forth tracks or maze-like environments, electrodes in their brains sensed sharp wave-associated bursts of neural activity called population burst events (PBEs). In these events, between 50,000 and 100,000 neurons all fire within 100 milliseconds and send ripples throughout the brain that are not yet fully understood.

What people think they're doing and what they're doing are very different

They found that: Smartphone usage is repetitive and consistent for each person Future phone checking frequency can be predicted with very little data A standard survey was unable to predict these behaviours For example, the researchers found that if you check your phone 80 times today, you are likely to repeat this behaviour every day. Dr Tom Wilcockson from Lancaster University said: "Multiple checks could indicate an absent minded use of mobile phones, which is habitual and unconscious"

How Dopamine Neurons Contribute to Memory Formation in Humans - Neuroscience News

“What we discovered was that a subset of the dopaminergic neurons responded only when an image was novel, but not when it was familiar. In other words, it indicated if the image was new, but not if something was familiar,” said Jan Kaminski, PhD, first author of the study and a project scientist at Cedars-Sinai. “This is an important new scientific discovery, because it has so far remained unclear how the dopaminergic system contributes to episodic memory formation.”

A heavy working memory load may sink brainwave 'synch' -- ScienceDaily

They suggest that the "coupling," or synchrony, of brain waves among three key regions breaks down in specific ways when visual working memory load becomes too much to handle. "When you reach capacity there is a loss of feedback coupling," said senior author Earl Miller, Picower Professor of Neuroscience at MIT's Picower Institute for Learning and Memory. That loss of synchrony means the regions can no longer communicate with each other to sustain working memory.

People with depression have stronger emotional responses to negative memories: A study investigates the brain mechanisms underlying autobiographical memory disturbance in depression -- ScienceDaily

"This study provides new insights into the changes in brain function that are present in major depression. It shows differences in how memory systems are engaged during emotion processing in depression and how people with the disorder must regulate these systems in order to manage their emotions," said Cameron Carter, MD, Editor of Biological Psychiatry: Cognitive Neuroscience and Neuroimaging. The personal memories used to evoke emotion in the study help tap into complex emotional situations that people with MDD experience in their daily lives. The 29 men and women with MDD included in the study reported higher levels of negative emotions when bringing negative memories to mind than 23 healthy comparison people. Using brain imaging, senior author Kevin Ochsner, PhD, of Columbia University and colleagues traced the elevated emotional responses to increased activity in an emotional hub of the brain, called the amygdala, and to interactions between the amygdala and the hippocampus -- a brain region important for memory.

Russia’s only Gulag memorial is redesigned to celebrate the Gulag — Meduza

Viktor Shmyrov, the director of the nonprofit that until recently managed Perm-36, told the BBC that the museum is being maintained, but its public presentation is getting a complete overhaul. “Now it’s a museum about the camp system, but not about political prisoners. There’s nothing said about the repressions or about Stalin,” Shmyrov said.

Running helps brain stave off effects of chronic stress: Exercise protects vital memory and learning functions -- ScienceDaily

"Exercise is a simple and cost-effective way to eliminate the negative impacts on memory of chronic stress," said study lead author Jeff Edwards, associate professor of physiology and developmental biology at BYU. Inside the hippocampus, memory formation and recall occur optimally when the synapses or connections between neurons are strengthened over time. That process of synaptic strengthening is called long-term potentiation (LTP). Chronic or prolonged stress weakens the synapses, which decreases LTP and ultimately impacts memory. Edwards' study found that when exercise co-occurs with stress, LTP levels are not decreased, but remain normal.

Memories and recursion to the mean

The behavioral data revealed that as the rat awaited the second stimulus of the trial, the memory of the first stimulus shifted towards the mean of preceding stimuli. The experiment thus confirmed the sliding of memory towards the expected value, a phenomenon that earlier studies have termed 'contraction bias.'

Eating Salad Every Day Keeps Brains 11 Years Younger and Prevents Dementia, Study Shows

Nutritional epidemiologist Martha Clare Morris and her team at Rush University Medical Center in Chicago found that people who ate one to two servings of leafy green vegetables each day experienced fewer memory problems and cognitive decline compared to people who rarely ate spinach. In fact, Morris estimates that veggie lovers who included about 1.3 servings a day into their diets had brains that were roughly 11 years younger compared to those who consumed the least amount of foods like spinach or kale.

The Effects of Physical Exercise and Cognitive Training on Memory and Neurotrophic Factors | Journal of Cognitive Neuroscience | MIT Press Journals

This study examined the combined effect of physical exercise and cognitive training on memory and neurotrophic factors in healthy, young adults. Ninety-five participants completed 6 weeks of exercise training, combined exercise and cognitive training, or no training (control). Both the exercise and combined training groups improved performance on a high-interference memory task, whereas the control group did not. In contrast, neither training group improved on general recognition performance, suggesting that exercise training selectively increases high-interference memory that may be linked to hippocampal function. Individuals who experienced greater fitness improvements from the exercise training (i.e., high responders to exercise) also had greater increases in the serum neurotrophic factors brain-derived neurotrophic factor and insulin-like growth factor-1. These high responders to exercise also had better high-interference memory performance as a result of the combined exercise and cognitive training compared with exercise alone, suggesting that potential synergistic effects might depend on the availability of neurotrophic factors.

Your brain does not process information and it is not a computer | Aeon Essays

Worse still, even if we had the ability to take a snapshot of all of the brain’s 86 billion neurons and then to simulate the state of those neurons in a computer, that vast pattern would mean nothing outside the body of the brain that produced it. This is perhaps the most egregious way in which the IP metaphor has distorted our thinking about human functioning. Whereas computers do store exact copies of data – copies that can persist unchanged for long periods of time, even if the power has been turned off – the brain maintains our intellect only as long as it remains alive. There is no on-off switch. Either the brain keeps functioning, or we disappear. What’s more, as the neurobiologist Steven Rose pointed out in The Future of the Brain (2005), a snapshot of the brain’s current state might also be meaningless unless we knew the entire life history of that brain’s owner – perhaps even about the social context in which he or she was raised.

Human brain recalls visual features in reverse order than it detects them: Study challenges traditional hierarchy of brain decoding; offers insight into how the brain makes perceptual judgements -- ScienceDaily

The brain appeared to encode one line, then the other, and finally encode their relative orientation. But during decoding, when participants were asked to report the individual angle of each line, their brains used that the lines' relationship -- which angle is greater -- to estimate the two individual angles. "This was striking evidence of participants employing this reverse decoding method," said Dr. Qian. The authors argue that reverse decoding makes sense, because context is more important than details. Looking at a face, you want to assess quickly if someone is frowning, and only later, if need be, estimate the exact angles of the eyebrows. "Even your daily experience shows that perception seems to go from high to low levels," Dr. Qian added.

New insights into how sleep helps the brain to reorganize itself -- ScienceDaily

Dr Julie Seibt, Lecturer in Sleep and Plasticity at the University of Surrey and lead author of the study, said: "Our brains are amazing and fascinating organs -- they have the ability to change and adapt based on our experiences. It is becoming increasingly clear that sleep plays an important role in these adaptive changes. Our study tells us that a large proportion of these changes may occur during very short and repetitive brain waves called spindles. "Sleep spindles have been associated with memory formation in humans for quite some time but nobody knew what they were actually doing in the brain. Now we know that during spindles, specific pathways are activated in dendrites, maybe allowing our memories to be reinforced during sleep. "In the near future, techniques that allow brain stimulation, such as transcranial magnetic stimulation (TMS), could be used to stimulate dendrites with the same frequency range as spindles. This could lead to enhance cognitive functions in patients with learning and memory disorders, such as dementia."

When I left | The Passive Voice | A Lawyer's Thoughts on Authors, Self-Publishing and Traditional Publishing

I had a funny feeling as I saw the house disappear, as though I had written a poem and it was very good and I had lost it and would never remember it again.

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.