Journal: bioRxiv
Article Title: Long-term optical imaging of the spinal cord in awake, behaving animals
doi: 10.1101/2023.05.22.541477
Figure Lengend Snippet: a. Imaging a large spinal cord field is subject to several types of motion artifacts. b. Modular motion correction pipeline that addresses each of the issues outlined in a : features identified using deep learning followed by control point and rigid registration (large displacement motion correction method, LD-MCM ), deformation correction using displacement fields followed by rigid registration (non-rigid motion correction method, NR-MCM ), and manual or automated cross-session motion correction ( CS-MCM ). c. LD-MCM utilizes deep learning, here DeepLabCut (DLC), to identify vascular features after manual annotation and training. LD-MCM uses these features to transform and register frames to a reference frame’s features. Point clouds overlapping each feature in the reference frame show rostrocaudal and mediolateral extent of motion during each frame of an entire imaging session (2.31 mins, 20 Hz). Inset, zoomed in field of view shows overlap of markers with distinct vasculature features. Scale bar, 300 μm. d. Mean projection image across all movie frames for the raw movie and after TurboReg or LD-MCM demonstrates reduced motion with LD-MCM. Arrows indicate features seen only in LD-MCM (yellow) and others that are barely visible after TurboReg (white). Scale bar, 300 μm. e. Point clouds for rostrocaudal and mediolateral movement of feature #3 (as in c ) after motion correction with TurboReg, NoRMCorre, and LD-MCM. Each dot represents the location of that feature on an individual frame during an imaging session (2.31 min, 20 Hz). Arrow indicates location of LD-MCM points, showing negligible post-procedure motion. f. Boxplots show rostrocaudal displacement of the spinal cord relative to the mean location in the raw movie and after motion correction with TurboReg, NoRMCorre, and LD-MCM over all features, for each of 3 movies (n = 2 mice). Features for all methods identified with DLC. Arrow highlights negligible post-LD-MCM motion (as in e ). g. Synthetic image (116 × 77 px) before and after image alignment with NR-MCM. Vectors (red) indicate the displacement field orientation and magnitude at a given pixel location; the vector field is sub-sampled (5x) and magnitude scaled for display purposes. h. NR-MCM (as in g ) on an example frame from one-photon fluorescence imaging of spinal cord GCaMP-expressing neurons (same mouse as ). Yellow arrows highlight features that are aligned after registration. Scale bar, 300 μm. i. Mean projection images of the first 5,000 frames in a movie (~12.5 min, 20 Hz) show improved motion correction with NR-MCM compared to TurboReg and NoRMCorre. Yellow arrows highlight stable features in NR-MCM movies. Scale bar, 300 μm. j. 2D correlation coefficient of all frames to the mean frame of the movie (as in i ) for NR-MCM compared to raw, TurboReg, and NoRMCorre. All movies were spatially filtered to remove large magnitude, low-frequency changes in fluorescence, which artificially enhances correlations. Right inset: histogram of correlation coefficients across all frames; vertical axis is aligned to that in the main graph. k. Boxplots summarize results, as in j, over 3 movies (n = 2 mice). Boxplots in all figures display the 1st, 2nd, and 3rd quartiles with whiskers indicating 1.5*IQR; outliers are omitted.
Article Snippet: We imported feature locations from DeepLabCut CSV files into MATLAB using a custom CIAtah function.
Techniques: Imaging, Control, Plasmid Preparation, Fluorescence, Expressing