Social Neuroscience Advances
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Social Neuroscience Advances
Understanding ourselves and how we interact
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Biochemical Mechanism Could Explain How Long-Term Memories Are Formed

Biochemical Mechanism Could Explain How Long-Term Memories Are Formed | Social Neuroscience Advances | Scoop.it

For a memory to endure, and not fade away, the synaptic connections must be kept strong. In a previous study, Kandel and Si identified CPEB as a synaptic protein that is responsible for maintaining the strength of these connections in the sea slug, a model organism used in memory research. In subsequent research at the Stowers Institute, Si and his team identified Orb2 as the fruit fly version of the CPEB synaptic protein.
Illustration of synapses.

In their latest study, Mohammed ‘Repon’ Khan, a predoctoral researcher in the Si Lab and first author of the Cell paper, determined that Orb2 exists in two distinct physical states, monomeric and oligomeric. Monomeric Orb2 is a single molecule capable of binding to other molecules. Like CPEB, oligomeric Orb2 is prion-like – that is, it’s a self-copying cluster. However, unlike disease-causing prions, oligomeric Orb2 and CPEB are not toxic.

The paper describes how monomeric Orb2 represses while oligomeric or prion-like Orb2 activates a crucial step in the complex cellular process that leads to protein synthesis. During this crucial step, messenger RNA (mRNA), which is a RNA copy of a gene’s recipe for a protein, is translated by the cell’s ribosome into the sequence of amino acids that will make up a newly synthesized protein.

“We propose that the monomeric form of Orb2 binds to the target mRNA, and the bound mRNA is kept in a repressed state,” explains Khan.

The Stowers scientists also determined that prion-like Orb2 not only activates translation but imparts its translational state to nearby monomer forms of Orb2. As a result, monomeric Orb2 is transformed into prion-like Orb2, and its role in translation switches from repression to activation. Si thinks this switch is the possible mechanism by which fleeting experiences create an enduring memory.

“Because of the self-sustaining nature of the prion-like state, this creates a local and self-sustaining translation activation of Orb2-target mRNA, which maintains the changed state of synaptic activity over time,” says Si.

The discovery that the two distinct states of Orb2 have opposing roles in the translation process provides “for the first time a biochemical mechanism of synapse-specific persistent translation and long-lasting memory,” he states.


Via Miloš Bajčetić
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Forgetting is key to learning

Forgetting is key to learning | Social Neuroscience Advances | Scoop.it
Forgetting is key to learning

Do you often feel overwhelmed with the amount of information coming at you? Forgotten your shopping list as soon as you've heard the sports results? Don't worry, it's all completely normal – and necessary – according to new research which shows that such forgetting is a key part of learning.

The study, by researchers from the University of Glasgow's Institute of Neuroscience and Psychology, is published today in Current Biology and has found that our inability to hold onto new memories is essential to the brain's learning process.

Researchers discovered that 'memory instability' – which prevents us from holding onto new memories – was key to the brain's ability to transfer experiences and skills to new situations. In contrast memories that were stable, or complete, prevented knowledge transfer. In short, forgetting your experience is essential to being able to transfer skills from one job to another.

Participants in the study learned one memory task at 9am followed quickly by another. They were then retested 12 hours later at 9pm on the initial memory task. The word-list was a repeating sequence of 12 simple words; while the skilled action was a new sequence of movements similar to that used when tapping out our PIN to get cash from an ATM.

The study found that learning transferred from actions to words, and vice versa. For example, learning a list of words helped participants learn a new skilled action. The information transferred between these diverse situations was on a 'higher abstract level', rather than simply transferring specific knowledge of each situation. Critically learning transferred only when a memory was unstable

Via Miloš Bajčetić
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Memory Specificity and Mindfulness Jointly Moderate the Effect of Reflective Pondering on Depressive Symptoms in Individuals With a History of Recurrent Depression

Memory Specificity and Mindfulness Jointly Moderate the Effect of Reflective Pondering on Depressive Symptoms in Individuals With a History of Recurrent Depression | Social Neuroscience Advances | Scoop.it

(Available in free full text) In previously depressed individuals, reflective thinking may easily get derailed and lead to detrimental effects. This study investigated the conditions in which such thinking is, or is not, adaptive. Levels of mindfulness and autobiographical memory specificity were assessed as potential moderators of the relationship between reflective thinking and depressive symptoms. Two hundred seventy-four individuals with a history of three or more previous episodes of depression completed self-report measures of depressive symptoms, rumination—including subscales for reflection and brooding—and mindfulness, as well as an autobiographical memory task to assess memory specificity. In those low in both mindfulness and memory specificity, higher levels of reflection were related to more depressive symptoms, whereas in all other groups higher levels of reflection were related to fewer depressive symptoms. The results demonstrate that the relation between reflective pondering and depressive symptoms varies depending on individual state or trait factors. In previously depressed individuals, the cognitive problem-solving aspect of reflection may be easily hampered when tendencies toward unspecific processing are increased, and awareness of mental processes such as self-judgment and reactivity is decreased.


Via Dr James Hawkins
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Dr James Hawkins's curator insight, July 4, 2015 7:06 PM

Very interesting ...

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The Type of Exercise That Most Benefits Memory, Reasoning and Mental Flexibility — PsyBlog

The Type of Exercise That Most Benefits Memory, Reasoning and Mental Flexibility — PsyBlog | Social Neuroscience Advances | Scoop.it
Study compared the mental effects of aerobic exercise, weight training and balance and co-ordination.

Via Luis Valdes
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Brain mapping reveals neurological basis of decision-making in rats

Brain mapping reveals neurological basis of decision-making in rats | Social Neuroscience Advances | Scoop.it

Scientists at UC San Francisco have discovered how memory recall is linked to decision-making in rats, showing that measurable activity in one part of the brain occurs when rats in a maze are playing out memories that help them decide which way to turn. The more they play out these memories, the more likely they are to find their way correctly to the end of the maze. (...) - by UCSF, ScienceBlog


Via Julien Hering, PhD
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A Molecular Basis for Memory

A Molecular Basis for Memory | Social Neuroscience Advances | Scoop.it
The brain still harbours many unknowns. Basically, it is assumed that it stores experiences by altering the connections between brain cells. This ability to adapt – which is also called “plasticity” – provides the basis for memory and learning, which is the ability to draw conclusions from memories. On a molecular scale these changes are mediated by modifications of expression of specific genes that as required strengthen or weaken the connections between the brain cells.

Via Miloš Bajčetić
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What happens in your brain when you make a memory?

What happens in your brain when you make a memory? | Social Neuroscience Advances | Scoop.it
You might imagine memory is a Santa’s sack of life events and the first half of jokes. You would be wrong. Neuroscientist Dean Burnett explains all in our new series, Use your head

Via Kasia Hein-Peters, Emre Erdogan
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New Neurons in Adult Brains Remodel Memory

New Neurons in Adult Brains Remodel Memory | Social Neuroscience Advances | Scoop.it
The brain is extremely dynamic, building and pruning connections in milliseconds with many different types of neuroplasticity simultaneously arising in large circuits all over the brain. The holy grail of neuroplasticity has been the creation of new brain cells in adults. Research looking for one cell in a region of the brain is much more difficult than a needle in a haystack. Despite, overwhelming odds, study shows new neurons arising in at least three, and possibly more, places in the adult brain—both humans and other animals.

Recent research shows that new neurons at least in the critical memory center of the hippocampus, are critical to learning and memory and rapidly become part of existing circuits. In fact, they remodel the circuit to take in new material in new ways. A previous post described that more than a thousand different types of neurons exist. Neurogenesis research shows that these new adult born neurons may be completely new types of cells with increased excitability, more widespread connections, a new window of opportunity, and increased neuroplasticity. New neurons in adult brains remodel memory circuits to make information more specific.

Via Miloš Bajčetić, Lynnette Van Dyke
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Rescooped by Jocelyn Stoller from Neuroscience_topics
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Very long-term memories may be stored in the pattern of holes in the perineuronal net

Very long-term memories may be stored in the pattern of holes in the perineuronal net | Social Neuroscience Advances | Scoop.it

A hypothesis and the experiments to test it propose that very long-term memories, such as fear conditioning, are stored as the pattern of holes in the perineuronal net (PNN), a specialized ECM that envelops mature neurons and restricts synapse formation. The 3D intertwining of PNN and synapses would be imaged by serial-section EM. Lifetimes of PNN vs. intrasynaptic components would be compared with pulse-chase 15N labeling in mice and 14C content in human cadaver brains. Genetically encoded indicators and antineoepitope antibodies should improve spatial and temporal resolution of the in vivo activity of proteases that locally erode PNN. Further techniques suggested include genetic KOs, better pharmacological inhibitors, and a genetically encoded snapshot reporter, which will capture the pattern of activity throughout a large ensemble of neurons at a time precisely defined by the triggering illumination, drive expression of effector genes to mark those cells, and allow selective excitation, inhibition, or ablation to test their functional importance. The snapshot reporter should enable more precise inhibition or potentiation of PNN erosion to compare with behavioral consequences. Finally, biosynthesis of PNN components and proteases would be imaged. (...) - By Roger Y. TsienPNAS July 23, 2013 vol. 110 no. 3012456-12461


Via Julien Hering, PhD
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Learning and reconsolidation implicate different synaptic mechanisms

Learning and reconsolidation implicate different synaptic mechanisms | Social Neuroscience Advances | Scoop.it

Synaptic mechanisms underlying memory reconsolidation after retrieval are largely unknown. Here we report that synapses in projections to the lateral nucleus of the amygdala implicated in auditory fear conditioning, which are potentiated by learning, enter a labile state after memory reactivation, and must be restabilized through a postsynaptic mechanism implicating the mammalian target of rapamycin kinase-dependent signaling. Fear-conditioning–induced synaptic enhancements were primarily presynaptic in origin. Reconsolidation blockade with rapamycin, inhibiting mammalian target of rapamycin kinase activity, suppressed synaptic potentiation in slices from fear-conditioned rats. Surprisingly, this reduction of synaptic efficacy was mediated by post- but not presynaptic mechanisms. These findings suggest that different plasticity rules may apply to the processes underlying the acquisition of original fear memory and postreactivational stabilization of fear-conditioning–induced synaptic enhancements mediating fear memory reconsolidation. - by Li Y. et al., PNASvol. 110 no. 12, 47984803



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