Interesting paper: Characterization Of Neurite Outgrowth And Ectopic Synaptogenesis In Response To Photoreceptor Dysfunction

Gene heat map

Authors Stylianos Michalakis, Karin Schäferhoff, Isabella Spiwoks-Becker, Nawal Zabouri, Susanne Koch, Fred Koch, Michael Bonin, Martin Biel, and Silke Haverkamp have a new paper out that looks at the earliest gene microarray analysis results associated with neurite outgrowth in the degenerate retina.  The title is a overly broad, but the results focusing on gene expression changes in the A3B1 mouse retina (a CNGA3/CNGB1 double-knockout) are intriguing, particularly their proposal that Tp53, Smad and Stat3 signaling contribute to synaptic plasticity at least. Continue reading “Interesting paper: Characterization Of Neurite Outgrowth And Ectopic Synaptogenesis In Response To Photoreceptor Dysfunction”

Building Retinal Connectomes

Connectomics image

There has been quite a bit of discussion of connectomes in the last while with President Obama’s new BRAIN initiative.  It is important to consider some of the requirements of obtaining a true synapse level wiring map in the brain as many are articulating from this initiative.  While there are new technologies that will be required to undertake this initiative for mapping the entire brain, the NIH NEI has been funding an ongoing project to study retinal circuitry which guides the community in how to approach a true synapse level map of the nervous system.

An example of this work  in Current Opinion in Neurobiology titled Building Retinal Connectomes is a review that illustrates the importance of having a complete network graph of connectivities in the retina and by extension other neural systems.  Complete network graphs are what will be required to understand how retinal systems (and any neural system) is constructed.  Even though the retinal community understands how retinas are wired in broad strokes, the precise, fine details are critical and elucidating them requires a new level of complete annotation derived from advances in light and ultrastructural imaging, data management, navigation and validation.

Authors are Robert E. Marc, Bryan W. Jones, J. Scott Lauritzen, Carl B. Watt and James R. Anderson.


What Do Whales See?


This beautiful article in The Atlantic by Alexis Madrigal talks about the eyes of cetaceans or whales and has some beautiful imagery from photographer Bryant Austin.  More importantly, the article asks: “So, what does the world look like to a whale?” which is a fundamental question in comparative anatomy.

The really unusual thing about this article is that vision science gets very little coverage in the popular press and this particular article discusses some of the science of vision including retinal science, after interviews with Leo Peichl who studies comparative anatomy of the mammalian retina at Max Planck.  I’ve long admired Leo’s work and am pleased to see it covered in The Atlantic along with work by Sonke Johnsen, Michael Land and Dan-Eric Nilsson, particularly by one of my favorite writers, Alexis Madrigal.


Image of Ella the whale’s eye from Bryant Austin.

Interesting Paper: Precedence Of The Eye Region In Neural Processing Of Faces


Just seeing an eye… and only the eye is enough to establish the first components of neural facial recognition.  In this interesting paper by Elias B. Issa and James J. DiCarlo, the authors found using a combination of functional magnetic resonance imaging (fMRI) that the first stage in the primate visual/face processing circuitry is tuned to regions in images containing eyes.  Even a single eye is enough to trigger recognition pathways.

fMRI and electrophysiological recording work in facial processing has established that the facial processing network possesses six areas that are extensively interconnected and the anatomical analysis suggests a nested, hierarchical layout where signals progressing through the system become more established.  This of course begs for a true connectomics analysis which will be difficult at the large scale, but tractable at the mesoscale.  It turns out that this is an interesting computational problem as identification of isolated components of images that connate larger meaning is difficult.  Discovering how neural systems unravel this will have substantial importance to diverse applications.

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Visual Cortex Neuron


This is a fluorescently tagged primary visual cortex neuron from a light microscope capture of a brain slice preparation.  These data were focus stacked revealing a tremendous amount of detail including the spines.  Focus stacking is common method in confocal microscopy, but many folks do not realize that you can also do it with traditional light microscopy of just about anything using ImageJ or Adobe Photoshop.  See here for an example and discussion of focus stacking.

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Silicone Oil In Anterior Chamber


This image shows a slit lamp retro-illumination photograph through dilated pupil revealing silicone oil in anterior chamber following retinal re-attachment surgery.  Silicone oil is a commonly used approach for retinal tamponade during surgery in the vitreous or for retinal reattachment surgery.  While the silicone does assist with successful reattachment, often it causes optical complications resulting in followup surgeries to remove the silicone oil typically 2-8 months later.  Gas bubbles with SF6 or C3F8 are also used, with the advantage that there is no myopic shift post operation and no followup surgery is required.

This image was taken by Paula Morris of the Moran Eye Center using a  Zeiss photo slitlamp and a Nikon D-1S camera at and 24x magnification.  Notably, this image won Honorable mention in the Photo Slit Lamp Biomigraography Division in 2007.