Archivio per 22 dicembre 2015

22
Dic
15

Biochemical Mechanism Could Explain How Long-Term Memories Are Formed

See on Scoop.itLearning & Mind & Brain

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.

See on neurosciencenews.com

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22
Dic
15

Verba Woland: la neuroeconomia e la corruzione politica.

See on Scoop.itBounded Rationality and Beyond

[Il Prof.Woland per La Città Invisibile]
La neuroeconomia è una scienza giovanissima che studia – soprattutto mediante la tecnica delle neuro immagini, come la risonanza magnetica funzionale (fMRI) –  i …
See on bruschi.blogautore.espresso.repubblica.it

22
Dic
15

Forbes Welcome

See on Scoop.itBounded Rationality and Beyond

At first glance, a neuroscientist and a business school might seem an odd fit. But in fact economists have been paying increasing attention to how the brain works.The children’s classic The Polar Express tells the fanciful story of a young boy’s journey to the North Pole on a train filled with chocolate and candy. But when Warner Brothers released a $165 million computer-animated version of the tale, many critics described the film not as a happy Christmas fantasy but as a horror movie. “This season’s biggest holiday extravaganza, ‘The Polar Express,’ should be subtitled ‘The Night of the Living Dead,’ ” groused CNN reviewer Paul Clinton. “ If I were a kid, I’d have nightmares,” wrote Geoff Pevere in the Toronto Star.The problem was that while the film’s characters appeared astonishingly human in many ways, their eyes looked lifeless. Viewers were creeped out.Humans are often delighted by objects with vaguely humanoid characteristics—think Pet Rocks, toy robots, or sock puppets. But there is a point at which an object looks almost human, yet not quite human enough, and the result is disturbing. It’s called the uncanny valley. And for Christine Looser, it’s the starting point for a line of research aimed at discovering how our brains detect life, and how we distinguish the cognizant from the mindless.“What I’m interested in is how and why the brain evolved to pay attention to other people,” says Looser, a fellow at Harvard Business School who sports a PhD in cognitive neuroscience.

See on forbes.com

22
Dic
15

Advanced Connectivity Analysis (ACA): a Large Scale Functional Connectivity Data Mining Environment – Online First – Springer

See on Scoop.itBounded Rationality and Beyond

AbstractUsing resting-state functional magnetic resonance imaging (rs-fMRI) to study functional connectivity is of great importance to understand normal development and function as well as a host of neurological and psychiatric disorders. Seed-based analysis is one of the most widely used rs-fMRI analysis methods. Here we describe a freely available large scale functional connectivity data mining software package called Advanced Connectivity Analysis (ACA). ACA enables large-scale seed-based analysis and brain-behavior analysis. It can seamlessly examine a large number of seed regions with minimal user input. ACA has a brain-behavior analysis component to delineate associations among imaging biomarkers and one or more behavioral variables. We demonstrate applications of ACA to rs-fMRI data sets from a study of autism.

See on link.springer.com

22
Dic
15

Cognitive Atlas

See on Scoop.itBounded Rationality and Beyond

The Cognitive Atlas is a collaborative knowledge building project that aims to develop a knowledge base (or ontology) that characterizes the state of current thought in cognitive science.

See on cognitiveatlas.org

22
Dic
15

Possum—A Framework for Three-Dimensional Reconstruction of Brain Images from Serial Sections – Online First – Springer

See on Scoop.itBounded Rationality and Beyond

AbstractTechniques based on imaging serial sections of brain tissue provide insight into brain structure and function. However, to compare or combine them with results from three dimensional imaging methods, reconstruction into a volumetric form is required. Currently, there are no tools for performing such a task in a streamlined way. Here we propose the Possum volumetric reconstruction framework which provides a selection of 2D to 3D image reconstruction routines allowing one to build workflows tailored to one’s specific requirements. The main components include routines for reconstruction with or without using external reference and solutions for typical issues encountered during the reconstruction process, such as propagation of the registration errors due to distorted sections. We validate the implementation using synthetic datasets and actual experimental imaging data derived from publicly available resources. We also evaluate efficiency of a subset of the algorithms implemented. The Possum framework is distributed under MIT license and it provides researchers with a possibility of building reconstruction workflows from existing components, without the need for low-level implementation. As a consequence, it also facilitates sharing and data exchange between researchers and laboratories.

See on link.springer.com




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