How rats see things

Rodents recognize objects using sophisticated perceptive strategies

2013-04-04

(Press-News.org) Sight is such a spontaneous activity that we are unaware of the complexity of the brain mechanisms it implies. For instance, we easily recognize objects, which appear to look always the same, without realizing that we observe them from ever-changing points of view and that their image – the luminance profile cast onto the retina –varies significantly each time we look at them.

To maintain such "invariance" in the shape, our brain performs procedures that extract from the two-dimensional image "key" visual information that enables us to recognize the object under any condition. Scientists believe that such ability belongs to humans and to other primates, but whether such ability may be applied also to other mammal species is still controversial.

In the experiments carried out at SISSA the rats observed objects under variable conditions regarding size, position, distance and points of view. The objects were covered with masks that exposed them only partially. The rats showed a great ability to evaluate whether two objects were identical or not.

Such experiments have shown that the recognition strategy employed by the rat's brain is based upon the gathering of the visual characteristics of the object which maximize the available information. In practice, the visual system of the rodent identifies and actively looks for the most typical features of the object which are subject to the smallest changes with each perspective variation.

The study, that has been just published in The Journal of Neuroscience, therefore confirms that rats can reveal plenty of information on the functioning of sight, also in humans. "Such observations suggest that the rats' visual system may act as a powerful model to study the neural basis of object recognition" Zoccolan commented.

### END

ELSE PRESS RELEASES FROM THIS DATE:

The equine Adam lived fairly recently: Close relationships among modern stallions

2013-04-04

In mammals, an individual's sex is determined by the chromosomes it inherits from its parents. Two X chromosomes lead to a female, whereas one X and one Y lead to a male. Y chromosomes are only passed from fathers to sons, so each Y chromosome represents the male genealogy of the animal in question. In contrast, mitochondria are passed on by mothers to all their offspring. This means that an analysis of the genetic material or DNA of mitochondria can give information on the female ancestry. For the modern horse, it is well known that mitochondrial DNA is extremely ...

National teen driving report finds safety gains for teen passengers

2013-04-04

PHILADELPHIA, April 4, 2013 – – A new report on teen driver safety released today by The Children's Hospital of Philadelphia (CHOP) and State Farm® shows encouraging trends among teen passengers. In 2011 more than half of teen passengers (54 percent) reported "always" buckling up. From 2008 to 2011, risky behaviors of teen passengers (ages 15 to 19 years) declined: the number of teen passengers killed in crashes not wearing seat belts decreased 23 percent; the number of teen passengers driven by a peer who had been drinking declined 14 percent; and 30 percent fewer teen ...

A model predicts that the world's populations will stop growing in 2050

2013-04-04

Global population data spanning the years from 1900 to 2010 have enabled a research team from the Autonomous University of Madrid to predict that the number of people on Earth will stabilise around the middle of the century. The results, obtained with a model used by physicists, coincide with the UN's downward forecasts. According to United Nations' estimates, the world population in 2100 will be within a range between 15.8 billion people according to the highest estimates –high fertility variant– and 6.2 billion according to the lowest –low fertility variant–, a figure ...

Wild mice have natural protection against Lyme borreliosis

2013-04-04

Springtime spells tick-time. Lyme borreliosis is the most common tick-borne disease in Switzerland: around 10,000 people a year become infected with the pathogen. The actual hosts for Borrelia, however, are wild mice. Like in humans, the pathogen is also transmitted by ticks in mice. Interestingly, not all mice are equally susceptible to the bacterium and individual animals are immune to the pathogen. Scientists from the universities of Zurich and Lund headed by evolutionary biologist Barbara Tschirren reveal that the difference in vulnerability among the animals is genetic ...

Power behind primordial soup discovered

2013-04-04

Researchers at the University of Leeds may have solved a key puzzle about how objects from space could have kindled life on Earth. While it is generally accepted that some important ingredients for life came from meteorites bombarding the early Earth, scientists have not been able to explain how that inanimate rock transformed into the building blocks of life. This new study shows how a chemical, similar to one now found in all living cells and vital for generating the energy that makes something alive, could have been created when meteorites containing phosphorus minerals ...

Hallucinations of musical notation: New paper for neurology journal Brain by Oliver Sacks

2013-04-04

Professor of neurology, physician, and author Oliver Sacks M.D. has outlined case studies of hallucinations of musical notation, and commented on the neural basis of such hallucinations, in a new paper for the neurology journal Brain. In this paper, Dr Sacks is building on work done by Dominic ffytche et al in 2000 [i], which delineates more than a dozen types of hallucinations, particularly in relation to people with Charles Bonnet syndrome (a condition that causes patients with visual loss to have complex visual hallucinations). While ffytche believes that hallucinations ...

Graduate glut spells underused skills and dissatisfaction for many

2013-04-04

Los Angeles, CA (April 04, 2013). Graduates are taking up jobs that don't fully use their skills and as a result are causing high turnover for employers, claims new research published today in the journal Human Relations, published by SAGE. The findings raise questions about today's high throughput in university education. Policy makers in many developed and developing countries envisioned high-value economies supported in part by a highly-skilled and well-paid workforce. As a result, many nations have increased higher education (HE) access, assuming that employers will ...

Study finds dementia care costs among highest of all diseases; comparable to cancer, heart disease

2013-04-04

ANN ARBOR, Mich. — The costs of caring for people with dementia in the U.S. are comparable to – if not greater than – those for heart disease and cancer, according to new estimates by researchers at the University of Michigan Health System and nonprofit RAND Corporation. Annual healthcare costs tied to dementia, including both formal and unpaid care, reach $159-$215 billion – rivaling the most costly major diseases – according to the findings that appear in The New England Journal of Medicine. "Our findings show why dementia is sometimes described as a 'slow-motion ...

New camera system creates high-resolution 3-D images from up to a kilometer away

2013-04-04

A standard camera takes flat, 2-D pictures. To get 3-D information, such as the distance to a far-away object, scientists can bounce a laser beam off the object and measure how long it takes the light to travel back to a detector. The technique, called time-of-flight (ToF), is already used in machine vision, navigation systems for autonomous vehicles, and other applications, but many current ToF systems have a relatively short range and struggle to image objects that do not reflect laser light well. A team of Scotland-based physicists has recently tackled these limitations ...

Online learning: It's different

2013-04-04

The number of online education offerings has exploded in recent years, but such "virtual" classes have also been plagued by one critical question – can classes offered online cut through the maze of distractions – email, the Internet, TV and more – that face students as they sit in front of a computer? The answer, Harvard researchers say, is to test students early and often. By interspersing online lectures with short tests, student mind wandering decreased by 50 percent, note-taking tripled and overall retention of the material improved, said Daniel Schacter, the ...

How rats see things

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: