Seeing Vision in a New Light

first_imgThe eye is like a camera, right?  That picture is way too simplistic.  The eye-brain visual system does image processing and gleans information from photons in diverse and remarkable ways.  Here are some recent findings by scientists:Upward mobility:  A team of Harvard scientists found some retinal ganglion cells that sense upward motion.  Writing in Nature,1 they began,The retina contains complex circuits of neurons that extract salient information from visual inputs.  Signals from photoreceptors are processed by retinal interneurons, integrated by retinal ganglion cells (RGCs) and sent to the brain by RGC axons.  Distinct types of RGC respond to different visual features, such as increases or decreases in light intensity (ON and OFF cells, respectively), colour or moving objects.  Thus, RGCs comprise a set of parallel pathways from the eye to the brain….    ….Here we show, by means of a transgenic marking method, that junctional adhesion molecule B (JAM-B) marks a previously unrecognized class of OFF RGCs….  These cells have asymmetric dendritic arbors aligned in a dorsal-to-ventral direction across the retina.  Their receptive fields are also asymmetric and respond selectively to stimuli moving in a soma-to-dendrite direction; because the lens reverses the image of the world on the retina, these cells detect upward motion in the visual field.  Thus, JAM-B identifies a unique population of RGCs in which structure corresponds remarkably to function.Got your number:  The retina can also respond to a quality called “numerosity” – a nonverbal, visual sense of number.  David Burr and John Ross, writing in Current Biology,2 summarized this unusual ability of the eye:Evidence exists for a nonverbal capacity for the apprehension of number, in humans (including infants) and in other primates.  Here, we show that perceived numerosity is susceptible to adaptation, like primary visual properties of a scene, such as color, contrast, size, and speed.  Apparent numerosity was decreased by adaptation to large numbers of dots and increased by adaptation to small numbers, the effect depending entirely on the numerosity of the adaptor, not on contrast, size, orientation, or pixel density, and occurring with very low adaptor contrasts.  We suggest that the visual system has the capacity to estimate numerosity and that it is an independent primary visual property, not reducible to others like spatial frequency or density of texture.Go with the flow:  Many photographs and videos are taken with the camera fixed on a tripod.  What happens to the visual scene in a movie when the camera is mounted on a galloping horse, train engine or race car?  It certainly becomes more dynamic and much more difficult to process the information.    We saw that dragonflies are masters of optic flow, and that scientists are keen to imitate their special visual organ that processes the information from rapid forward direction (08/13/2004).  Frank Bremmer summarized some new findings in Current Biology that says human eyes also have some of this ability.3  This gives us processing powers beyond the simple interpretation of an image coming through a lens.Optic flow is a key signal for heading perception.  A new study has shown that the human brain can dissociate between consistent (natural) and inconsistent flow, revealing what is likely a new hierarchy in visual motion processing.He reported on recent “surprising findings” that showed certain areas of the visual cortex, labeled MST, VIP and CSv, appear to be processing stations for optic flow information.Taken together, these new results suggest that area MST may be a preprocessing stage acting like a tuned filter for visual self-motion signals.  Areas VIP and CSv, on the other hand, could be seen as downstream processing stages judging the ecological validity of the self-motion signals.  This interpretation would indicate a previously unknown hierarchy within the human visual cortical motion system.Color me blue:  Brian Wandell, Stanford psychologist, wrote in Current Biology about another stimulating fact: the colors activated by the cones that react to red, green or blue when those colors come through the lens (or are transmitted from video pixels) also “see” the corresponding colors when the neurons themselves are stimulated.4  Commenting on a study of a patient that had electrodes implanted into the visual cortex, he said:Directly stimulating certain cortical neurons can produce a color sensation; a case is reported in which the color perceived by stimulation is the same as the color that most effectively excites the cortical circuitry….These results teach us that even the simplest stimulation is capable of stirring up a perceptually meaningful response from the cortical circuitry.  One possibility is that the complex molecular and neural circuitry that serves this portion of the brain is tolerant of a wide range of potential inputs, and that nearly any stimulation of this circuitry evokes a characteristic (resonant) response.  The resonant response of these specific circuits is the experience of color. To avoid human chauvinism, let’s look into the eyes of some animals living underwater that can, in certain ways, outperform our own visual tricks.  The winner in both cases is among the humblest creatures you would ever suspect to find such abilities: the mantis shrimp.Polar opposites:  For the first time, scientists found an animal with the ability to discern circularly polarized light: the mantis shrimp.  An international team of scientists reported this in Current Biology5 with some obvious pride at being #1 to discover this feat:We describe the addition of a fourth visual modality in the animal kingdom, the perception of circular polarized light.  Animals are sensitive to various characteristics of light, such as intensity, color, and linear polarization.  This latter capability can be used for object identification, contrast enhancement, navigation, and communication through polarizing reflections.  Circularly polarized reflections from a few animal species have also been known for some time.  Although optically interesting, their signal function or use (if any) was obscure because no visual system was known to detect circularly polarized light.  Here, in stomatopod crustaceans, we describe for the first time a visual system capable of detecting and analyzing circularly polarized light.  Four lines of evidence—behavior, electrophysiology, optical anatomy, and details of signal design—are presented to describe this new visual function.  We suggest that this remarkable ability mediates sexual signaling and mate choice, although other potential functions of circular polarization vision, such as enhanced contrast in turbid environments, are also possible.  The ability to differentiate the handedness of circularly polarized light, a visual feat never expected in the animal kingdom, is demonstrated behaviorally here for the first time.Super sight:  In the latest issue of Creation magazine (March-May, 2008),6 Jonathan Sarfati described one amazing feature of the mantis shrimp, its Guinness-level power punch: it can flick its snapper at 51 mph, generating an acceleration of 10,600 g.  But that’s not all.  In a sidebar, he talked about another Guinness-level ability: the shrimp’s “super sight.”  Would you believe this little crustacean has one of the world’s most complex color vision systems?While humans have three different types of colour receptor (red, green and blue), the shrimp has 12.  Four of these can see in the ultraviolet, which we can’t.  Furthermore, they can tune their vision with special transparent colour filters to compensate for the way water absorbs different colours differently. None of the above articles mentioned evolution once.1.  Kim, Zhang, Yagamata, Meister and Sanes, “Molecular identification of a retinal cell type that responds to upward motion,” Nature 452, 478-482 (27 March 2008) | doi:10.1038/nature06739.2.  David Burr and John Ross, “A Visual Sense of Number,” Current Biology, Vol 18, 425-428, 25 March 2008, http://dx.doi.org/10.1016/j.cub.2008.02.052.3.  Frank Benner, “Visual Neuroscience: The Brain’s Interest in Natural Flow,” Current Biology, Volume 18, Issue 6, 25 March 2008, Pages R263-R265, http://dx.doi.org/10.1016/j.cub.2008.01.023.4.  Brian Wandell, “Colour Vision: Cortical Circuitry for Appearance,” Current Biology, Volume 18, Issue 6, 25 March 2008, Pages R250-R251, doi:10.1016/j.cub.2008.01.045.5.  Chou, Kleinlogel, Cronin, Caldwell, Loeffler, Siddiqi, Goldizen and Marshall, “Circular Polarization Vision in a Stomatopod Crustacean,” Current Biology, Volume 18, Issue 6, 25 March 2008, Pages 429-434, doi:10.1016/j.cub.2008.02.066.6.  Jonathan Sarfati, “Shrimpy superboxer,” Creation magazine, Volume 30, Issue 2, Published March 2008, pp. 12-13.Isn’t this terrific?  What amazing things are found in nature.  The eye gave Darwin cold shudders, but now we know that it is far more complex than he knew.  And some of the most remarkable capabilities reside in the humblest of creatures.  Shrimp are crustaceans – a subphylum of arthropods, whose members extend all the way back to the Cambrian.  This means that the lowest fossil layers containing multicellular animals already display these technologies (10/04/2007).    This circuitry and the complex processing software did not emerge by chance.  Each of these capabilities are systems involving hardware and software.  They require programmed analysis and response to sensory inputs.  Eyes are able to extract all kinds of interesting information from light, much more than you would think from the simple diagram in most textbooks of an inverted camera-like image on a retina.    The research done to find these abilities was done in intelligently-designed labs by intelligent scientists using reverse-engineering principles.  Intelligent design is present de facto from beginning to end.  Evolution is blind, they say; well, evolutionary theory is also blind.  Take off the blinders and see the creation through created eyes.(Visited 38 times, 1 visits today)FacebookTwitterPinterestSave分享0last_img read more

“Zero Emission” GC234PG Geocache of the Week – March 14, 2011

first_imgNear the geocache “Zero Emission”The icy, austere beauty of Antarctica is home to one of the most remote geocaches on the globe. “Zero Emission” (GC234PG) challenges adventurers to brave a journey to the bottom of the world to find the traditional cache. Leovinci81 placed the small geocache in January of 2010 outside a Belgian research station.Leovinci81 explains the story on the cache page for Zero Emission: “I created this geocache for people to find in one of the greatest places I ever visited. During the first quarter of 2010 I visited the Belgian research station on Antarctica.“After the first explorers Adrienne de Gerlache & A. Cook, 110 years later, Belgium returned to the South Pole with the team of Alain Hubert.   It’s the first zero emission research station on South Pole, running on solar and wind power.”Belgium research stationThe difficulty three, terrain five cache waits patiently in its extreme environment for the next geocacher. Could it be you?Continue your exploration of some of the most engaging geocaches from around the world. Explore all the Geocaches of the Week on our blog or view the Bookmark List on Geocaching.com.Share with your Friends:More SharePrint RelatedNo Further South From Here — Geocache of the WeekJanuary 31, 2018In “Community”Getting warmer… — Fire and Ice (GC4TXB2) — Geocache of the WeekJanuary 8, 2015In “Geocache of the Week”Selfie Letterbox — Geocache of the WeekMay 23, 2018In “Community”last_img read more

Ebondo drops 31 as CEU holds off Marinerong Pilipino

first_imgBrace for potentially devastating typhoon approaching PH – NDRRMC MOST READ PBA IMAGESCentro Escolar University rode Rod Ebondo’s big performance to kickstart its campaign with a 104-93 win over Marinerong Pilipino in the 2018 PBA D-League Aspirants’ Cup Monday at Ynares Sports Arena in Pasig.Ebondo flirted with a double-double, posting 31 points and nine rebounds.ADVERTISEMENT NEXT BLOCK ASIA 2.0 introduces GURUS AWARDS to recognize and reward industry influencers 2 ‘newbie’ drug pushers fall in Lucena sting Don’t miss out on the latest news and information. LATEST STORIES CEU 104 — Ebondo 31, Fuentes 20, Manlangit 19, Wamar 11, Arim 9, Guinitaran 8, Cruz 4, Aquino 2, Caballero 0, Intic 0, Saber 0, Veron 0.MARINERONG PILIPINO 93 — Ayonayon 24, Subido 17, Robles 17, Toth 10, Tratter 6, Iñigo 6, Paredes 6, Banal 5, Pasaol 2, Babilonia 0, Lopez 0, Terso 0.Quarters: 20-21, 55-41, 83-75, 104-93. Kammuri turning to super typhoon less likely but possible — Pagasa Philippines marks anniversary of massacre with calls for justice PLAY LIST 01:44Philippines marks anniversary of massacre with calls for justice01:27Filipino athletes get grand send-off ahead of SEA Games01:29DOH kicks off nationwide polio vaccination drive01:29Police teams find crossbows, bows in HK university01:35Panelo suggests discounted SEA Games tickets for students02:49Robredo: True leaders perform well despite having ‘uninspiring’ boss02:42PH underwater hockey team aims to make waves in SEA Games01:19Fire erupts in Barangay Tatalon in Quezon City Slow and steady hope for near-extinct Bangladesh tortoises John Lloyd Cruz a dashing guest at Vhong Navarro’s wedding The Congolese, however, wasn’t the lone hero for the Scorpions as Judel Fuentes went 3-of-8 from three to finish with 20 markers, five of which coming in the last 1:22 to stave off the late uprising from the Skippers.Joseph Manlangit also got eight of his 19 points in the payoff period, and had seven rebounds, while Orlan Wamar tallied 11 markers, four rebounds, and three dimes.FEATURED STORIESSPORTSWATCH: Drones light up sky in final leg of SEA Games torch runSPORTSLillard, Anthony lead Blazers over ThunderSPORTSMalditas save PH from shutoutCEU saw its 19-point lead, 62-43, dissipate as Marinerong Pilipino rallied back to knot the score at 75 late in the third quarter.But the Scorpions quickly restored order, ending the third frame on an 8-0 run to regain the upperhand. Globe Business launches leading cloud-enabled and hardware-agnostic conferencing platform in PH CEU was also buoyed by its 12-of-30 sniping from three while lording the boards, 55-44.“It’s all credit to the players. They gave their best,” said coach Yong Garcia. “We had a good first half, but in the third quarter, we relaxed. I’m just glad that we followed the gameplan and recovered in the fourth.”Marinerong Pilipino stumbled to its second straight defeat and dropped to 1-2.Rian Ayonayon captained the Skippers with 24 points, eight rebounds, and two assists, while Renzo Subido and Billy Robles both got 17.The Scores:ADVERTISEMENT Read Next Typhoon Kammuri accelerates, gains strength en route to PH View comments Former champ Francisco loses to Ortega in Mexicolast_img read more