This male common yellowthroat (Geothlypis trichas) was seen at Ft. Jefferson in Dry Tortugas National Park.  While I have never seen one of these birds before, or perhaps just not taken notice of them, my friend Michael Redmond (his laboratory here) helped identify this bird as he notes: “It is one of the most widespread warblers in N. America. It is less common in the desert SW as it like wetter brushy areas, though I’ve seen it in a riparian area in central AZ. Riparian areas would be perfect for them there.”

Camera: Canon 1D MkIV
Exposure: 1/500
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

A great blue heron (Ardea herodias) seen on the beach in Dry Tortugas National Park.  There were several great blue herons on the island, one of which gave me quite a start at 2am.  I had always thought that birds slept at night, but given the calls from above me in the night sky as well as bumping into a great blue heron walking on the beach towards me in the moonlight corrected my beliefs.  I suppose their retinas have rods as well as cones and it sure would be fun to examine such a retina in the future…

Camera: Canon 1D MkIV
Exposure: 1/8000
Aperture: f/5.0
Focal Length: 200mm
ISO: 800

Heron footprints always looked so alien to me…

Camera: Canon 1D MkIV
Exposure: 1/4000
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

A male American redstart (Setophaga ruticilla) seen in Dry Tortugas National Park.  I’ve previously photographed American redstarts in the Dry Tortugas, but the photos from this trip were easier to get given the number of birds that were in and around our camp site.  I also had the luxury of time as we were camping out with not nearly as much time pressure as we had last year to return to the ferry in time.

Camera: Canon 1D MkIV
Exposure: 1/100
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

Camera: Canon 1D MkIV
Exposure: 1/640
Aperture: f/5.6
Focal Length: 244mm
ISO: 1600

Camera: Canon 1D MkIV
Exposure: 1/400
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

Camera: Canon 1D MkIV
Exposure: 1/320
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

Camera: Canon 1D MkIV
Exposure: 1/400
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

A red shouldered hawk (Buteo lineatus) diving out of a tree in Everglades National Park. Years ago, I made a lousy shot of a red shouldered hawk and have yet to get a really good technical exposure on one of these birds, but this shot is definitely better than the last one.

Camera: Canon 1D MkIV
Exposure: 1/5000
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

This Black-throated Green Warbler (Setophaga virens) was seen at Ft. Jefferson, Dry Tortugas National Park, USA.

Camera: Canon 1D MkIV
Exposure: 1/2500
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

Camera: Canon 1D MkIV
Exposure: 1/640
Aperture: f/5.6
Focal Length: 300mm
ISO: 800

This abstract was presented today at the Association for Research in Vision and Opthalmology (ARVO) meetings in Ft. Lauderdale, Florida by Robert E. Marc, J. Scott Lauritzen, Bryan W. Jones, Carl B. Watt and James R. Anderson.

Purpose: Transitions between scotopic and photopic switch seem smooth, but psychophysical dissection reveals that it is underpinned by mutual rod-cone suppression processes. Further, rod and cone signals mix to generate shifted spectral percepts. The neural architecture supporting these processes has resisted discovery.

Methods: Multiple amacrine cell (AC) networks connecting 70 rod and >100 cone bipolar cells (BCs), 30 A-II and 20 A-I ACs were traced in the ultrastructural rabbit retinal connectome RC1, annotated with the Viking viewer, and explored by 3D rendering and graph visualization of connectivity (Anderson et al. 2011. The Viking Viewer. J Microscopy). RC1 contains embedded small molecule signals, enabling complete cellular classification independent of network identity.

Results: Multiple GABAergic AC pathways connect rod and cone BCs. (1) Certain wide-field GABAergic ACs are reciprocal feedback elements at every ON cone BC they encounter, but also collect rod BC input enabling rod suppression of cone signals. (2) Conversely, A-I(S2) ACs are reciprocal feedback ACs at rod BCs but are also presynaptic to some ON cone BCs, also enabling rod suppression of cone signals. (3) Every rod BC receives inhibitory input from GABAergic ACs driven directly by ON or OFF cone BCs. Instances of ON glycinergic AC > rod BC inhibition also exist. (4) Every A-I AC receives massive inhibition via OFF cone BC > OFF cone AC > A-I chains (Fig. 1). (5) Every A-II AC receives inhibitory input from multiple cone BC driven ACs. (6) A-II amacrine cells collect ribbon input signals from wide-field ON cone BCs.

Conclusions: The mammalian retina appears to use ACs to create a winner-take all architecture for rod and cone bipolar cells. When rod responsivity exceeds cones, multiple inhibitory networks further suppress the cone pathway output, and vice versa.

Four primary synaptic chains support this process:
Rod BCs > GABAergic ACs > ON and OFF Cone BCs
ON and OFF Cone BCs > GABAergic ACs > Rod BCs
ON and OFF Cone BCs > GABAergic ACs > A-II ACs
OFF Cone BCs > GABAergic ACs > A-I ACs > Rod BCs

Rod signals directly mix with cone signals via A-II cells potentially driving color shifts. If the wide-field BCs of the rabbit retina are blue-dominated, this may explain blue-biased hue shifts near rod threshold.

Image Credit: Robert E. Marc

This abstract was presented today at the Association for Research in Vision and Opthalmology (ARVO) meetings in Ft. Lauderdale, Florida by  J. Scott Lauritzen, Bryan W. Jones, Carl B. Watt, Shoeb Mohammed, James R. Anderson, Robert E. Marc.

Purpose: Current tenets assert that the mono-stratified bipolar cells (BCs) of the mammalian retina require multi-stratified amacrine cells (ACs) to mediate ON-OFF crosstalk, since ON and OFF cone bipolar cell (ON CBC and OFF CBC) axonal arbors putatively occupy distinct domains in the inner plexiform layer (IPL). Nonetheless, recent studies demonstrated the capacity of BCs to violate the mammalian IPL stratification rules, manifest as a subset of ON CBCs with synapses in the OFF IPL, and a subset of OFF CBCs with primary axons longer than some ON CBC primary axons (Dumitrescu et al. 2009. Ectopic retinal ON bipolar cell synapses in the OFF IPL. J Comp Neurol; Hoshi et al. 2009. ON inputs to the OFF layer. J Neurosci; Anderson et al. 2011. Exploring the retinal connectome. Mol Vis). Our goal was to identify a suspected population of diffusely-stratified OFF CBCs (dsOFF CBCs) that infiltrate the canonical ON IPL, confirm the comingling of ON and OFF CBC synapses in the ON IPL with automated transmission electron microscopy (ATEM), and identify the targets of the dsOFF CBC synapses in ON territory.

Methods: BC networks in the ultrastructural rabbit retinal connectome RC1 were annotated with the Viking viewer, and explored via graph visualization of connectivity and 3D rendering (Anderson et al. 2011. The Viking Viewer. J Microscopy). Small molecule signals embedded in RC1, e.g. 4-aminobutyrate (y), glycine (G), and L-glutamate (E), combined with morphological reconstruction and connectivity analysis allow for robust BC classification.

Results: A subset of glycine-negative OFF CBCs diffusely arborize more proximally into the IPL than their OFF CBC cohorts, where they comingle with ON CBC axonal arbors. These dsOFF CBCs form reciprocal synapses with mono- and multi-stratified GABAergic ACs (γACs) and glycinergic ACs (GACs) at the same IPL depth as synapses formed by nearest-neighbor ON CBCs. γAC and GAC targets of dsOFF CBCs also form reciprocal synapses with glycine-positive ON CBCs.

Conclusions: dsOFF CBCs establish regions of mixed ON-OFF processing within the canonical ON IPL, where mono- and multi-stratified γACs and GACs facilitate within- and cross-channel inhibitory feedback. These results ambiguate the traditional IPL strata, legitimize partial dissolution of ON and OFF IPL segregation, and establish multi-stratified BCs as an additional means by which to achieve ON-OFF crosstalk in mammalian retina.

Image Credit: J. Scott Lauritzen

This abstract was presented today at the Association for Research in Vision and Opthalmology (ARVO) meetings in Ft. Lauderdale, Florida by Alexandra D. Butler, William D. Ferrell, Alex Woodell, Carl Atkinson, Bärbel Rohrer, Robert E. Marc and myself. 

Abstract:

Presented today at the Association for Research in Vision and Opthalmology (ARVO) meetings in Ft. Lauderdale, Florida by W. Drew Ferrell, Lloyd Williams, Carl B. Watt, James R. Anderson, Robert E. Marc and Bryan William Jones.  Full size (almost) poster can be seen here.

This paper in the Current Opinion in Neurobiology outlines the fundamental approach for the creation of retinal connectomes and justifies why they need to be constructed at nominally 2nm resolution with complete annotation of connectivity with molecular tags defining class membership of cells in the connectome volume.  Completeness of any connectome requires extensive descriptions of all participating objects in the volume to complete an adjacency matrix of that neural system.

Notably, this approach is also extensible to any connectome project.  Authors were Robert E. Marc, myself, J. Scott Lauritzen, Carl B. Watt and James R. Anderson.

I ran down to Torrey, Utah to visit with Robert and Ann and help plant an apple orchard, appropriately enough on Earth Day.  This first image is a nighttime capture of a newly installed apple orchard with each tree lit up under a night sky.  More on the apple orchard below…

Robert and Ann have a newly acquired bit of property down in Torrey, Utah called the Stray Arrow Ranch and it is a beautiful piece of land.  In a surprising turn of events, they decided to bring back apple ranching to Torrey for the first time in something like 100 years.  This sounded like an adventure, so off I went to Torrey to help them put in an apple orchard.  Ann covered the event in Four Minutes a Tree along with a most excellent cover of American Gothic with Scott and Lisa.  I promised Ann that I’d grab a few photographs as well, so here they are…

Ann has been reading a book by Michael Phillips called The Holistic Orchard where he advocates coating the tree roots with a bio-sludge to help them build a mycological symbiotic environment at the root structure.

Lisa and Scott came down from their place in Teasdale to help out.  Again, I am always amazed at how small the world is.  Scott is a long time photographer in the Salt Lake valley (Scott, thanks for the G11 and UW housing man) and his wife Lisa will be taking Julia Kleinschmidt’s position at the Moran Eye Center in the very near future.  They are good peeps and I look forward to more interactions with them in the future.

Slate… my man (cat), Slate.  What can I say?  I’ll miss seeing you and your sister as often with you guys down in Torrey.  I’ll visit.  Promise.

The thing about Torrey is that its a small town, but amazingly beautiful.  Torrey was founded some time in the 1880s and it has not grown much then with the last official census putting the population at 171.  Its a few more now I suspect, but not much more.  That said, there are places to stay and really nice places to eat.  The last night of my visit, we strolled up to Cafe Diablo for a most *excellent* meal by Chef Gary Pankow.  (Aside:  Its a crazy small world, but even smaller with friends like Maggie who has known Gary for years.  maggie is one of those 6 degrees nodal points where you can take a shortcut through to just about anyone else on the planet).  Try the empanadas and the duck mariachi.  Wow.  Also, the Elder Tequila made with elderberry juice is phenomenal.  I had two of them before ambling back to the ranch for some night photography.

Night photography down there is wonderful, though the town could do with some better/less bright lights or lights with shades that don’t blow out the night skies.  I’ve been told that is a discussion that several of the townsfolk have had.  Hope it happens…

The drive back had to happen all too quickly as I had to get back to work to finish preparing for the rapidly upcoming ARVO meetings, finish a couple of manuscript reviews and much more.  However, the back roads through Utah are some of the most beautiful drives ever with amazing Western vistas across beautifully desolate country filled with deer.  Thank goodness for good brakes and reliable vehicles.

Grabbed this iPhone shot of the Fish Lake National Forest on my way down to help friends plant an orchard. More pics coming of the tree planting including some night shots to test settings in preparation for an upcoming photographic opportunity where there are no lights for miles and miles around…

Many things have been written already about the new Retina Display in the iPad and it is indeed truly amazing. My friend Duncan has posted about how amazing photographs are on the iPad as have a number of others. Its hard to express how beautiful images are on the new iPad without actually looking at one as the display you will be reading this on is the limiting factor. That said, I was interested in “how beautiful it was”.

Given the level of interest in the new iPad Retina Display, I am surprised that nobody has made any quantitative imagery of the new iPad display yet. So, in the spirit of the previous Retina Display post back when Apple first announced a “Retina Display”, I grabbed a couple of quick images on the microscope this afternoon. The first two images are from the iPad Retina Display and an iPhone 4 under a Olympus SZX16 Stereomicroscope with a Canon 1D Mk III attached. The scale bar in the lower right of the iPad image above is ~82 micrometers in length giving a size comparison with the pixels in other iOS devices.

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Interestingly, this seems fractionally larger than the pixels in the iPhone which are ~78 micrometers in size which slightly alters the Retina Display equation. Though the moniker holds as from what I’ve informally observed, folks don’t hold their iPads as close to their face as the iPhones and what qualifies as a “Retina Display” will depend upon how close one holds the display to their eye combined with some optical characteristics that we covered before. I am sure that somebody, somewhere has looked at statistics of how close people hold devices to their faces.

I also find it interesting that the iPad sub-pixels are chevron shaped. This is as it was with the original iPad, so perhaps there is something about the shape of the pixels and how they relate to distance held from the eye as all iPhone sub-pixels seem to be orthogonal.

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A point of reference, just so you can appreciate how small these pixels are… This is the original pixel size from the first iPhone.

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We celebrated our traditional Easter get together with family and homemade dyed eggs, cinnamon rolls, breakfast/brunch casserole, sausages and fruits.  Its always good to see everyone and get together to sip coffee and visit and we had a glorious day to do it on.

I promised everyone pics, so here they are…

I’ve never been to a cat show…  But when visiting family and friends up in Portland a while ago, we took the opportunity to stop by a local cat show as I thought there could be some interesting photography there… cats *and* people and this is what came out.

This take of photos was the subject of a photo critique tonight by the Utah Photojournalism community as I wanted to present something different from the typical military assignments that most people in this community know me for.  I opted for the take no prisoners critique and got some wonderful, honest feedback from folks that culled a few photos from the take and ended up cropping a couple of others.  It was a wonderful experience and I look forward to more of our photo critique get togethers in the future.  If you are local, keep an eye out on the Utah Photojournalism website for future announcements.

Enjoy…