Vision
grrlscientist | July 8, 2009tags: dragonfly vision, facets, opsin, compound eyes, insects, dragonflies, Dennis Paulson, David O'Carroll, Robert Olberg
Male Megaloprepus caerulatus, PANAMA, Rio Chico Masambi, near Gamboa,
11 August 2005; photo by Julie Craves, a Natural Science Research Associate
at the University of Michigan-Dearborn.
Color vision in humans depends upon three light-sensitive proteins, called opsins, that are present in our retinas. Each type of opsin absorbs one color of light in the spectrum. In humans, the colors absorbed by these opsins are red, green or blue. The many wavelengths of light…
sb admin | July 1, 2009I'm teaching about opponent processes in color vision today and thought I'd share one of my favorite examples. This is how you use the human visual system to turn a black and white photo into color. Try it out:
omnibrain | July 1, 2009I'm teaching about opponent processes in color vision today and thought I'd share one of my favorite examples. This is how you use the human visual system to turn a black and white photo into color. Try it out:
sb admin | June 16, 2009I'm in the middle of my qualification exams and ran across this interesting paper:
Liu, Z Kersten, D Knill, DC Dissociating stimulus information from internal representation--a case study in object recognition. Vision research. 1999; 39(3): 603-12.
However, I'm very confused about them calling the figure on the left an object. This is a collection of objects in 3D space - making it a scene. I'm not sure that this nullifies their model - but this is not object recognition.
People should really start using ideal observer analysis with scene perception...
neurophilosophy | June 8, 2009People who place an emphasis on positive things and are generally optimistic are sometimes said to "see the world through rose-tinted glasses". According to a new study by Canadian researchers, this is more than just an idiom. The study, which has just been published in the Journal of Neuroscience, provides the first direct evidence that the mood we are in affects the way we see things by modulating the activity of the visual cortex. Their findings show that putting on the proverbial rose-tinted glasses of a good mood is not so much about colour, but about the broadness of the view.
A number…
edyong | May 21, 2009In the forests of South America lives the unusual but aptly named owl monkey, or douroucouli. You could probably guess by looking at its large round eyes that it's nocturnal, and indeed, it is the only monkey to be mostly active at night. But its eyes have many adaptations for such a lifestyle, beyond a large size.
The owl monkey's retinas are 50% larger than those of a day-living monkey of similar size, like the brown capuchin. The proportions of different cells in their retina are also different. Owl monkeys have relatively few cone cells, which are responsible for colour vision and fewer…
neurophilosophy | May 11, 2009Music can be thought of as a form of emotional communication, with which the performer conveys an emotional state to the listener. This "language" is remarkably powerful - it can evoke strong emotions, and make your heart race or send tingles down your spine. And it is universal - the emotional content of a piece of music can be understood by anyone, regardless of cultural background.
Are the emotions evoked by piece of music similar to, and can they influence, other emotional experiences? The answer to these questions is unclear. But a new study, which has just been published in…
neurophilosophy | April 13, 2009If you look at a waterfall for about 30 seconds, and then shift your gaze to a nearby stationary object, such as a rock or a tree, that object will seem to drift slowly upwards. This well known optical illusion demonstrates a phenomenon called the motion after-effect, which is thought to occur as a result of adaptation - the brain compensates for movement in one direction, causing us to momentarily perceive a stationary objects to be moving in the other.
Although illusory motion can also be induced in the sense of touch, the brain is thought to process visual and tactile motion separately.…
sb admin | March 31, 2009I'm currently teaching Introduction to Psychology which has a number of university honors students who are required to do extra work in a certain number of their courses each semester in order to get 'honors credit.' The University leaves it up to me as to what they students should do to get this credit. I decided, along with my students, to let them explore the psychological literature through blogging. Each week they pick a relevant piece of literature (in this case - aggression, attractiveness, and political psychology) and write a short blog post about it.
I've found the blog to be a…
edyong | March 29, 2009Anyone who has played video games for too long is probably familiar with the sore, tired and dry eyes that accompany extended bouts of shooting things with rocket launchers. So it might come as a surprise that playing games could actually improve a key aspect of our eyesight.
Renjie Li from the University of Rochester found that intensive practice at shoot-em-ups like Unreal Tournament 2004 and Call of Duty 2 improved a person's ability to spot the difference between subtly contrasting shades of grey. In the real world, this "contrast sensitivity function" is reflected in the crispness of…
sb admin | March 20, 2009Funny!
From Jimmy Fallon:
Last night, Michael Showalter (from Stella, Wet Hot American Summer, The State, your dreams) made a cameo on the show. He and our head writer, A.D. Miles, played a couple of Columbia grad students on spring break. Things got pretty scandalous!
Really funny... but totally off base. It's more like Girls Gone Wild... I promise!
-via everyday scientist-
sb admin | March 20, 2009
Straight from XKCD...
I had this exact same reaction.
Now that we're on the topic. I don't like federal money going to pay bonuses but seriously... this money was promised long ago and it's already been given out. Using the tax code to take it back? Wow this is seriously a real cluster @#$!
zooillogix | February 24, 2009The barreleye has been known to science since 1939 but scientists have never understood why the fish had a see-through head. Well now researchers at MBARI have solved the mystery: the barreleyes' see-through heads allow them to read each others' thoughts!
OK not true. Actually, their see through heads allow their long tubular eyes to actually stare up through their own noggins. We strongly suggest you go visit the sea monkeys at Deep Sea News to get the whole story. But if you don't care about "facts", and just want pretty pictures and scintillating see-through fish video, well, we got that…
neurophilosophy | February 19, 2009Working memory refers to the process by which small amounts of information relevant to the task at hand are retained for short periods of time. For example, before cellular phones became so ubiquitous, calling someone usually involved first finding the number and then remembering it for a just few seconds by repeating it to oneself several times. Once the digits had been dialled, they are immediately forgotten.
Very little is known about the neural mechanisms underlying working memory, but very recently some advances have been made. Last month, a group from the University of Texas Medical…
neurophilosophy | December 12, 2008Recent advances in functional neuroimaging have enabled researchers to predict perceptual experiences with a high degree of accuracy. For example, it is possible to determine whether a subject is looking at a face or some other category of visual stimulus, such as a house. This is possible because we know that specific regions of the brain respond selectively to one type of stimulus but not another.
These studies have however been limited to small numbers of visual stimuli in specified categories, because they are based on prior knowledge of the neural activity associated with the conscious…
omnibrain | December 10, 2008In the never ending quest for death gadgets Mercedes has come up with a specialized screen that will show the driver one thing and the passenger another. Just think, now in addition to a driver watching a movie while they are going 70 mph they will be leaning all the way over into the passenger seat to see it. Unfortunately Mercedes hasn't created a system to keep stupid drivers from doing stupid things... like driving off a cliff while following the GPS directions on the screen they're allowed to see. Ok.. I jest - this seems like a pretty damn cool system and I totally want one. I'm…
neurophilosophy | November 4, 2008The Men's Final of the 1981 Wimbledon Tennis Championships is one of the most memorable events in sporting history. John McEnroe, who was playing against Bjorn Borg, famously challenged one of the referee's calls by throwing a tantrum, during which he shouted the immortal line "You cannot be serious!"
McEnroe's outburst was controversial, and he was almost eliminated from the championship because of it. But he may have been right to challenge the referee after all: according to a new study published in Current Biology, in such close calls, professional tennis referees consistently misjudge…
neurophilosophy | October 28, 2008The pioneering experiments performed by Hubel and Weisel in the late 1950s and early 60s taught us much about the development of the visual system. We now know, for example, that neurons in the visual cortex are organized into alternating ocular dominance columns which receive inputs from either the left or right eye and that groups of cells within these columns respond selectively to bars or edges of a specific orientation moving in a specific direction.
Hubel and Weisel also found that the proper development of these areas of the brain is dependent upon visual information from the eyes.…
neurophilosophy | October 1, 2008
Cataract 3, Bridget Riley, 1967.
In the 1960s, the British artist Bridget Riley began to develop a distinctive style characterised by simple and repetitive geometric patterns which create vivid illusions of movement and sometimes colour and often have a disorientating effect usually described by observers as "shimmering" or "flickering". With her explorations of the dynamic nature of optical phenomena, Riley became one of the most prominent exponents of what came to be known as Op Art.
Many optical illusions are generated by the brain, and studying them has provided us with a better…
neurophilosophy | August 8, 2008The classic Nobel Prize-winning studies of David Hubel and Torsten Weisel showed how the proper maturation of the developing visual cortex is critically dependent upon visual information received from the eyes. In what would today be considered highly unethical experiments, Hubel and Weisel sewed shut one eye of newborn kittens. They found that this monocular deprivation had dramatic effects on the visual part of the brain: the columns of cortical tissue that normally receive inputs from the closed eye failed to develop, while those that receive inputs from the other eye were significantly…