Neural Noise- Conventional miniscopes typically record one calcium indicator; a dual-color miniature endoscope allows simultaneous calcium imaging from two neuronal populations with spectrally distinct indicators.1
- In freely moving mice, the system has been used to record direct (dSPN) and indirect (iSPN) pathway striatal neurons simultaneously.1 1
Weekly enrichment (2026-07-20)
- The device is built on the open-source UCLA V3 Miniscope platform, redesigned with a dual-CMOS housing so two spectrally distinct indicators are imaged simultaneously through one gradient-index (GRIN) lens.2 3
- Two independent CMOS sensors and a T510lpxr excitation dichroic separate a blue LED (450–490 nm, for GCaMP6s) from a lime-green LED (547–572 nm, for jRCaMP1b), enabling true simultaneous two-channel capture rather than interleaved single-sensor switching.2
- The assembled miniscope weighs 6.6 g, offers 608 × 608-pixel resolution, a ~500–600 µm field of view, and 20× magnification, with the housing 3D-printed in Nylon PA12 by Multi-Jet Fusion for durability and low weight.2
- Both LEDs were tuned to deliver 2 mW/mm² beneath the GRIN lens; the blue LED is driven up to 30 mA and the lime-green LED up to 200 mA, the latter needing more power because of its broader spectrum and greater distance from the excitation lens.2
- Recordings used a chronically implanted GRIN lens (1.8 mm diameter, 4.3 mm length) in dorsal striatum, imaging at 20 frames per second; in the best mouse 180 GCaMP6s and 68 jRCaMP1b neurons were captured in a 600 × 600 µm field of view.2
- Signal quality was high: across four animals, 95% of GCaMP6s neurons (n = 500) and 99% of jRCaMP1b neurons (n = 180) had a signal-to-noise ratio above 20, with pixel-by-pixel flat-field correction used to remove minor LED crosstalk.2
- To label direct and indirect pathways separately, the team co-expressed Cre-dependent jRCaMP1b and Cre-off GCaMP6s in D1-Cre and A2A-Cre mice, confirming distinct expression by immunostaining.2 3
- In a two-spout switching task (spouts 50 mm apart, 12 µL sucrose every 600 ms), dSPN activity preceded iSPN activity by 110 ± 22 ms during contraversive turns, with dSPNs active during acceleration and iSPNs during deceleration.2
- This directly challenges the prior view (e.g., dual-color fiber photometry) that dSPNs and iSPNs are concurrently active during contraversive turning; the authors argue bulk photometry lacked the temporal and spatial resolution to see the lead-lag.2
- The peer-reviewed version appeared as Zhang et al., iScience 29(5):115514 (2026), from Henry Yin’s lab at Duke, offering a compact, low-cost tool for dissecting coordinated multi-population circuit dynamics in freely moving animals.4 3