Image the visual cortex with V4

[JIAXIN FU]

Hi all, 

We're trying to visualise individual neurons with the UCLA miniscope V4 in the visual cortices (the postrhinal cortex and V1) under a 3mm cranial window. 

After a few trials, we could only see general fluorescence in the FOV (please see: https://drive.google.com/file/d/1WB_TVA84JZrkxN5NVZTXakdF8RWiJne1/view?usp=drive_link). Could anyone share some experience for your successful attempts? I'm wondering the combination of parameters you use and how you troubleshoot to arrive at it.

We've tried with: 

1. pGP-AAV9-hsyn-jfCaMP8m; titre in the range of 10^12; inject in at least 3 sites (non-overlapping) of 30nl/site; injection speed of 1nl/s; with/without dura removal

2. AAV1-HSyn1-GCAMP6f-P2A-nls-dTomato with the same parameters as above

Apart from the difficulty of visualising individual neurons, we saw frequent bone regrowth and tissue damage even with dura removal. 

On a different note, if anyone has tried retrograde tracing from another brain region, specifically the ACC/amygdala, to the visual cortices, could you share which virus you use for that? 

Thank you very much for your suggestions in advance!!

[Somoday Hazra]

Hi,

I’m currently trying to image PPC L2/3–L5 neurons in a GCaMP6 transgenic line, but I haven’t been able to detect any fluorescence (see attached image).

I’m also planning to target V1 L5 in the same transgenic line and was wondering if you might have any insights or suggestions regarding this.

Additionally, do you have any recommendations for GRIN lens options other than Inscopix?

Thanks in advance for your help!