Fig. 2

Glycogen accumulation in muscle fibers using infrared (IR) microspectroscopy. a: Representative raw IR spectra obtained from Tibialis anterior (TA) muscle fibers from Gaa^−/− and WT mice aged 1.5 and 9 mo (spectral range: 2000–800 cm^− 1). b: Principal component analysis (PCA) of IR spectra in the 1400–950 cm^− 1 range collected by mapping muscle fibers from Gaa^−/− and WT mice and corresponding loading plot (n = 100 spectra per mouse). c: Surface area under the curve of the glycogen peaks (spectral range: 1180–950 cm^− 1) normalized against the protein peak area (spectral range: 1720–1480 cm^− 1). Statistics: Two-way ANOVA with Sidak post hoc test; n = 3 animals per group; ****p < 0.0001