Gregor Thut
Sep 13, 2006; 26:9494-9502
BehavioralSystemsCognitive

Italian translation of the Press Release on the pre-release of two special chapters of the Annual Economic Report of the BIS, 17 June 2018. Trust is the missing link in today's cryptocurrencies - Cryptocurrencies' model of generating trust limits their potential to replace conventional money, the Bank for International Settlements (BIS) writes in its Annual Economic Report (AER), a new title launched this year.

Italian translation of the BIS press release on the presentation of the Annual Economic Report 2018, 24 June 2018. Le autorità possono fare in modo che l'attuale ripresa economica si mantenga oltre il breve termine avviando riforme strutturali, ridando margine di manovra alle politiche monetarie e di bilancio per affrontare eventuali future minacce, e incoraggiando la pronta attuazione delle riforme regolamentari, scrive la Banca dei Regolamenti Internazionali (BRI) nella sua Relazione economica annuale. ...

Like conventional criminals, criminal hackers choose easy, lucrative targets. One group in the crosshairs is made up of companies that have data on millions of users, such as private sector entities with a Web presence. Why go after one user at a time when data is collected in one place? Criminal hackers also like to hunt small organizations that have modest capital but weak information security.

Pattern separation and completion are fundamental hippocampal computations supporting memory encoding and retrieval. However, despite extensive exploration of these processes, it remains unclear whether and how top-down processes adaptively modulate the dynamics between these computations. Here we examine the role of expectation in shifting the hippocampus to perform pattern separation. In a behavioral task, 29 participants (7 males) learned a cue-object category contingency. Then, at encoding, one-third of the cues preceding the to-be-memorized objects, violated the studied rule. At test, participants performed a recognition task with old objects (targets) and a set of parametrically manipulated (very similar to dissimilar) foils for each object. Accuracy was found to be better for foils of high similarity to targets that were contextually unexpected at encoding compared with expected ones. Critically, there were no expectation-driven differences for targets and low similarity foils. To further explore these effects, we implemented a computational model of the hippocampus, performing the same task as the human participants. We used representational similarity analysis to examine how top-down expectation interacts with bottom-up perceptual input, in each layer. All subfields showed more dissimilar representations for unexpected items, with dentate gyrus (DG) and CA3 being more sensitive to expectation violation than CA1. Again, representational differences between expected and unexpected inputs were prominent for moderate to high levels of input similarity. This effect diminished when inputs from DG and CA3 into CA1 were lesioned. Overall, these novel findings strongly suggest that pattern separation in DG/CA3 underlies the effect that violation of expectation exerts on memory.

SIGNIFICANCE STATEMENT What makes some events more memorable than others is a key question in cognitive neuroscience. Violation of expectation often leads to better memory performance, but the neural mechanism underlying this benefit remains elusive. In a behavioral study, we found that memory accuracy is enhanced selectively for unexpected highly similar foils, suggesting expectation violation does not enhance memory indiscriminately, but specifically aids the disambiguation of overlapping inputs. This is further supported by our subsequent investigation using a hippocampal computational model, revealing increased representational dissimilarity for unexpected highly similar foils in DG and CA3. These convergent results provide the first evidence that pattern separation plays an explicit role in supporting memory for unexpected information.

Priming refers to the influence that a previously encountered object exerts on future responses to similar objects. For many years, visual priming has been known as a facilitation and sometimes an inhibition effect that lasts for an extended period of time. It contrasts with the recent finding of an oscillated priming effect where facilitation and inhibition alternate over time periodically. Here we developed a computational model of visual priming that combines rhythmic sampling of the environment (attentional oscillation) with active preparation for future events (temporal expectation). Counterintuitively, it shows that both the sustained and oscillated priming effects can emerge from an interaction between attentional oscillation and temporal expectation. The interaction also leads to novel predictions, such as the change of visual priming effects with temporal expectation and attentional oscillation. Reanalysis of two published datasets and the results of two new experiments of visual priming tasks with male and female human participants provide support for the model's relevance to human behavior. More generally, our model offers a new perspective that may unify the increasing findings of behavioral and neural oscillations with the classic findings in visual perception and attention.

SIGNIFICANCE STATEMENT There is increasing behavioral and neural evidence that visual attention is a periodic process that sequentially samples different alternatives in the theta frequency range. It contrasts with the classic findings of sustained facilitatory or inhibitory attention effects. How can an oscillatory perceptual process give rise to sustained attention effects? Here we make this connection by proposing a computational model for a "fruit fly" visual priming task and showing both the sustained and oscillated priming effects can have the same origin: an interaction between rhythmic sampling of the environment and active preparation for future events. One unique contribution of our model is to predict how temporal contexts affects priming. It also opens up the possibility of reinterpreting other attention-related classic phenomena.

Theoretical models and experimental evidence have suggested that connections from the dentate gyrus (DG) to CA3 play important roles in representing orthogonal information (i.e., pattern separation) in the hippocampus. However, the effects of eliminating the DG on neural firing patterns in the CA3 have rarely been tested in a goal-directed memory task that requires both the DG and CA3. In this study, selective lesions in the DG were made using colchicine in male Long–Evans rats, and single units from the CA3 were recorded as the rats performed visual scene memory tasks. The original scenes used in training were altered during testing by blurring to varying degrees or by using visual masks, resulting in maximal recruitment of the DG–CA3 circuits. Compared with controls, the performance of rats with DG lesions was particularly impaired when blurred scenes were used in the task. In addition, the firing rate modulation associated with visual scenes in these rats was significantly reduced in the single units recorded from the CA3 when ambiguous scenes were presented, largely because DG-deprived CA3 cells did not show stepwise, categorical rate changes across varying degrees of scene ambiguity compared with controls. These findings suggest that the DG plays key roles not only during the acquisition of scene memories but also during retrieval when modified visual scenes are processed in conjunction with the CA3 by making the CA3 network respond orthogonally to ambiguous scenes.

SIGNIFICANCE STATEMENT Despite the behavioral evidence supporting the role of the dentate gyrus in pattern separation in the hippocampus, the underlying neural mechanisms are largely unknown. By recording single units from the CA3 in DG-lesioned rats performing a visual scene memory task, we report that the scene-related modulation of neural firing was significantly reduced in the DG-lesion rats compared with controls, especially when the original scene stimuli were ambiguously altered. Our findings suggest that the dentate gyrus plays an essential role during memory retrieval and performs a critical computation to make categorical rate modulation occur in the CA3 between different scenes, especially when ambiguity is present in the environment.

In some countries, mountains are considered deities. In others, mountains are peaks to climb. In others still, mountains, like volcanoes, are spirits that can be angered. In countries around the world though, mountains provide life-sustaining water, energy and food for over half the world’s population.

Growing crops, fishing, harvesting fruits and nuts from the forests are just some examples of the activities that millions of people do daily to get food to eat or to earn a living. But when their rights to that land or those natural resources aren’t recognized, livelihoods and food sources can disappear from one day to the next.    

Bombing ground targets from the air is tricky and not always accurate. But a new type of bomb creates an unimaginable level of destruction

The USS Barb had an unusual target in its sights in 1945 - one that wasn't even in the water. It was a Japanese supply train on the island of Karafuto

Two years before the Carthaginian general crossed the Alps, he won a decisive victory at the Battle of the Tagus

Over the past three years, the disease has claimed the lives of seven of the famously resilient ponies

The simultaneous mating calls of the male pug-nosed tree frog confuses bats but not female frogs

Helping health care workers treat patients and public safety officials contain the pandemic, these robots offer lessons for future disasters

Two lama are chatting on the middle of the road

Aubyn O'Grady, program director of the School of Visual Arts in Dawson City, seeks musical inspiration from some very interesting places.

A longstanding battle between an Alberta entrepreneur and a $50-million lottery winner is still raging after a new legal judgment, a securities investigation, allegations of harassment and even duelling ebooks.

Asylum seekers make up a large portion of the "guardian angels" Quebec Premier François Legault has praised in his daily COVID-19 briefings: the orderlies who have no guarantee they'll be allowed to stay in Canada.

Matt Keough, the former Oakland Athletics pitcher and special assistant, has died. He was 64. He was an American League all-star as a rookie in 1978 and two years later comeback player of the year.

Visit our four downtown locations where you can taste euphoria in our creative and delicious all natural ice-cream, yogurts and sorbets!

Bike the Sites of the Nation's Capital! It's the fun and easy way to get to get up close and personal with Washington's landmarks

Double Decker Tours offers the best experience. Our Double Decker buses have the most visible sights like US Capitol, White House, Museums and Memorials

Discover the real George Washington through his restored home and gardens, over 1,000 artifacts, and an immersive Revolutionary War "snow" experience

Voted "Washington's Best Tour" by Washingtonian Magazine. See the best of Washington aboard on our 2 hour tour with live narration

Take a bus tour to the sites of movies and TV shows. Your guide will entertain you as you visit over 30 locations used in West Wing, The Exorcist and more

Get up close to the DC sites on a Segway! Segs in the City offers daily guided 1 hour and 2 hour Segway tours and rentals. Join the fun!

The Best Museum Experience of All Things Washington, D.C. Experience the stories behind the people and events of the Nation's Capital.

Consumers and companies worldwide have ramped up online ordering for software products and digital goods as they struggle to improve productivity and security while working remotely and spending more time at home. The sharp spike in online commerce aligns with the timing of the current global pandemic. Software-based offerings accounted for the highest levels of growth.

As a farmer, spring means a fresh start, a chance for new life, hope and opportunities.

A sports writer covering the strange return of South Korea's baseball season says fans should brace for similarly odd experience in Toronto, if and when the 2020 season begins.

With proms cancelled across Canada, an online resource for kids called the Student Life Network has organized a national virtual prom.

This file contains the monthly total number of cattle and calves on feed, placements, marketings, and other disappearances; by class and feedlot capacity for selected states; number of feedlots and fed cattle marketings by size groups for selected states. Data is organized by state and by U.S.

The bonspiel took place in Edmonton March 11-14, starting the same day COVID-19 was declared a global pandemic.

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Apple is supposedly developing new mental health features for the Apple Watch line that allow the wearable to detect panic attacks, with the capability potentially slated for launch with a next-generation "watchOS 7" this fall.

A Thousand Moons

ANDY MURRAY has had a bumpy ride over the past couple of years, undergoing hip surgery, staging a comeback which saw him win his first title in two years before another injury setback has seen him sidelined since the tail-end of last year.

How UEFA has helped football development in Finland.

WHILE almost every athlete has been affected by the global shutdown of sport, it is perhaps the old and the young who are feeling it the most.

Dear Editor,Maybe I'm talking too soon, but when we see a spike in the numbers we become alarmists and when we see a dip in the numbers we downplay it. As of now we have 478 positive cases of the coronavirus in Jamaica.

EDINBURGH coach Richard Cockerill has taken two vital steps in rebuilding his squad for next season by signing stand-off Jono Lance from Worcester and centre Matt Gordon from London Scottish. With Simon Hickey and Matt Scott leaving at the end of the season, cover for both positions was a priority.

The Celtic Connections roots and traditional music festival recorded 100,000 visits this January.

I TOOK a bottle of Cot home the other day to share with a friend and his reaction got me thinking about the subject matter for this week's column, so here’s to wines and blends you may not have come across.

The National Labor Relations Board unanimously declined jurisdiction Monday in the case involving Northwestern University football players attempting to unionize.