GCaMP6 plasmids at addgene
GCaMP6 variants are on addgene. Three flavors, fast kinetics or big signals. Bigger responses than OGB-1, some are MUCH bigger. The responses to drifting gratings in visual cortex are spectacular. Sorry no pics for now. Hopefully the reviewers will be nice so we can all read about it soon. Still work to be done getting true 1AP resolution when simultaneously imaging large populations of neurons, but for single neuron imaging in vivo, this has 1AP resolution. If you have been waiting for the GCaMPs that will blow your expectations away, these are them.
From the SfN abstract :
Using structure-guided mutagenesis and high-...
Source: Brain Windows - November 8, 2012 Category: Neurologists Authors: andrewhires Tags: Calcium in vivo gcamp6 GECI Source Type: blogs
Genetically-encoded intracellular EM stain for connectomics
The field of connectomics would greatly benefit from a genetically-encoded stain for specific proteins that works intracellularly. This could be used to provide positive contrast for axon tracts or to identify if a synapse is excitatory, inhibitory, or neuromodulatory. Horseradish peroxidase (HRP) is a classic approach to EM staining but does not work in reducing environments, such as inside cells. Several groups (Ting, Looger) have tried to engineer away the di-sulfide bonds of HRP, to allow it to work intracellularly, but all have failed to maintain activity after removing these bonds. An alternative approach, miniSO...
Source: Brain Windows - October 25, 2012 Category: Neurologists Authors: andrewhires Tags: circuit mapping connectomics Electron Microscopy neuroanatomy em stain Source Type: blogs
Drosophila visual system
By twitter request, click-thru for the original resolution of a fellow Janelian’s Nikon Small World 4th place prize winner. Ryan Williamson composed the image.
Drosophila melanogaster visual system halfway through pupal development, showing retina (gold), photoreceptor axons (blue), and brain (green) (1500x)Filed under: Imaging Tagged: drosophila, Imaging, rentia (Source: Brain Windows)
Source: Brain Windows - October 24, 2012 Category: Neurologists Authors: andrewhires Tags: Imaging drosophila rentia Source Type: blogs
G-CaMP5 is finally published!
The paper on G-CaMP5 has been published.
Optimization of a GCaMP Calcium Indicator for Neural Activity Imaging
Genetically encoded calcium indicators (GECIs) are powerful tools for systems neuroscience. Recent efforts in protein engineering have significantly increased the performance of GECIs. The state-of-the art single-wavelength GECI, GCaMP3, has been deployed in a number of model organisms and can reliably detect three or more action potentials in short bursts in several systems in vivo. Through protein structure determination, targeted mutagenesis, high-throughput screening, and a battery of in vitro assays, we ha...
Source: Brain Windows - October 3, 2012 Category: Neurologists Authors: andrewhires Tags: Uncategorized calcium imaging GCaMP GECI in vivo Source Type: blogs
Three ways of looking at touch coding
At SfN, a block of three posters by myself, Simon Peron and Daniel O’Connor will showcase three ways to approach the problem of touch coding.
My work on whisker force measurements, and single cell and silicon probe based cortical recordings during active objection localization :
Program#/Poster#:
677.18/KK18
Presentation Title:
Encoding whisking-related variables in the mouse barrel cortex during object localization
Location:
Hall F-J
Presentation time:
Tuesday, Oct 16, 2012, 2:00 PM – 3:00 PM
Authors:
*S. A. HIRES, D. O’CONNOR, D. GUTNISKY, K. SVOBODA;
Janelia Farm Res. Campus, ASHBURN, VA
...
Source: Brain Windows - September 20, 2012 Category: Neurologists Authors: andrewhires Tags: brain imaging Calcium circuit mapping in vivo Multiphoton Neuronal Control optogenetics Source Type: blogs
GCaMP6 candidate presentations
The first public presentation of data on candidates for GCaMP6 will be presented here. This is obviously a big deal for brain imaging.
Reliable detection of single action potentials and synaptic calcium signals using improved genetically-encoded calcium indicators
*T.-W. CHEN, J. YU, R. A. KERR, V. JAYARAMAN, L. L. LOOGER, K. SVOBODA, D. S. KIM
FFF77 / 927.08Oct 17 – 4:00pm/5:00pm
and here
Engineering next generation GCaMP calcium indicators using neuron-based screening
T.-W. CHEN, T. J. WARDILL, J. P. HASSEMAN, G. TSEGAYE, B. F. FOSQUE, E. R. SCHREITER, B. E. KIMMEL, R. A. KERR, V. JAYARAMAN, K. SVOBODA, L. L. ...
Source: Brain Windows - September 20, 2012 Category: Neurologists Authors: andrewhires Tags: Uncategorized Source Type: blogs
Where to get new BrainWindows content
It’s been pretty quiet around here lately and will likely continue that way for some time. BrainWindows is not dead, just resting. Experiments, paper writing, new baby, etc. However, if you still need a fix of BrainWindows analysis, please follow me, @AndrewHires, on Twitter. If you don’t have a Twitter account, get one! It’s the easiest way to get published in the Library of Congress. I’ll be honing the analysis to fit into 140 character snippets. There will also be a much broader range of topics. Hopefully we can continue a quality scientific discourse publicly, in near-real time.Filed under: Unca...
Source: Brain Windows - March 30, 2012 Category: Neurologists Authors: andrewhires Tags: Uncategorized Source Type: blogs
GCaMP5 is out
GCaMP3 is now officially old skool. GCaMP5 is available at addgene.
Plasmid 31788: pCMV-GCaMP5G, a.k.a. GCaMP3-T302L R303P D380Y
Dimmer baseline F, higher dF/F, picks up significantly more activity in vivo cortex. Still not holy grail level, but getting closer.Filed under: Calcium (Source: Brain Windows)
Source: Brain Windows - November 16, 2011 Category: Neurologists Authors: andrewhires Tags: Calcium Source Type: blogs
Cortical encoding of somatosensory input
Wednesday morning, I’m giving the first public presentation of my current work on sensory coding in the barrel cortex. The big picture question is, How does the cortex translate sensory input into perception and recognition of objects and their position?
To study this cortical function, we used a methodology with 3 critical components
1 – Goal-directed discrimination task
The activity of an awake cortex is profoundly different in character from an anesthetized cortex. There is also gathering evidence that the activity of sensory cortex when attending to and using its sensory input to perform a discrimiation is q...
Source: Brain Windows - November 16, 2011 Category: Neurologists Authors: andrewhires Tags: Uncategorized Source Type: blogs
Useful ChR2 mouse lines
Guoping Feng’s group has released what looks to be a very useful set of BAC transgenic Channelrhodopsin mice. The four lines specifically express YFP-tagged ChR2 in GABAergic, cholinergic, serotonergic and parvalbumin-expressing neurons.
They are well characterized and available from Jackson labs.
Filed under: Uncategorized (Source: Brain Windows)
Source: Brain Windows - August 19, 2011 Category: Neurologists Authors: andrewhires Tags: Uncategorized Source Type: blogs
