To GRIN or not to GRIN...
From Miniscope
To GRIN or not to GRIN...
I realize this is a very basic question, but should I use a GRIN lens or not when trying to image L5 of the motor cortex using a Miniscope V4? I am finding mixed information and would like to hear the feedback from people that have used a similar approach. L5, according to our measures, is 0.5-0.6 mm below the pia...thanks! Annalisa Scimemi (talk) 07:03, 7 September 2026 (PDT)
- Hi Annalisa, in my understanding, Miniscope is just 1photon imaging, which will not penetrate superficial layers, therefore L5 is not accessible through plain Miniscope. Usually you need larger power 2photon microscope to access deep layers. GRIN lens is also not ideal in my understanding, since it will damage the tissue above your image location. What you need is probably a right-angle prism that can reflect lights, like those in Mark Andermann 2013 neuron paper. Here's a more related work: https://doi.org/10.3791/55579, it's seems they can separate superficial and deep layer, but their best example image looks really crappy to me. It gotta to be a reason that people didn't normally access L5 cells in these way. There is also an alternative that image the apical dendrites of L5 cells instead of soma (check out some of Naoya Takahashi's work), but I doubt miniscope can reliably segregate L5 cell apical tufts. Let me know what u think. Xiaoyang Ma (talk) 12:12, 8 September 2026 (PDT)
- Thank you Xiaoyang Ma: fully agree that 2P or GRIN+prism is in order here. I will have to do some more digging for finding the right specs and fit all in the available budget. Thank you! Annalisa Scimemi (talk) 08:56, 9 September 2026 (PDT)
- Hi Annalisa, I found a few papers that might have relevant info for you on this.
- The two closest to what you're describing are from the Kullander lab. They imaged in L5 of M1 in freely moving mice with a one-photon miniscope, using a prism:
- Ciralli et al 2026 — doi:10.64898/2026.02.25.707928 (preprint). Pyramidal and Martinotti cells in M1 L5, open field.
- Malfatti et al 2025 — doi:10.7554/eLife.109286.2. L5 pyramidal cells during a single-pellet reaching task.
- Both have the full lens specs and surgical coordinates in their methods.
- Li et al 2024 (doi:10.7554/eLife.83897) used a Miniscope V4 over motor cortex for a reaching task but only imaged L2/3 using a cranial window. Samara Hecht (talk) 09:52, 9 September 2026 (PDT)