Journal: Current Research in Neurobiology
Article Title: Distinct functional cerebral hypersensitivity networks during incisional and inflammatory pain in rats
doi: 10.1016/j.crneur.2024.100142
Figure Lengend Snippet: Study design and analysis strategy. a Determination of mechanical paw withdrawal threshold was performed prior to (baseline), 24 h after pain model induction (plantar incision (INC), adjuvant/pathogen-induced inflammation induced by plantar injection of Complete Freund's Adjuvants (CFA)), or, as control, brief anesthesia (Isoflurane) only (CTR) in male Sprague-Dawley rats (N = 42). fMRI measurements were performed using two different stimulation modalities (electrical (ES) and mechanical (MS)) with low (1 mA/50g) and high (5 mA/95g) intensity, respectively. b Activated voxels, derived from standard general linear model (GLM) analysis, were assigned to specific brain structures by registration to a digital 3D rat brain atlas. The average time courses of activated voxels per brain structure were extracted, and after regression of their global mean, the residuals were subjected to pair-wise cross-correlation of all activated brain structures. The resulting symmetric correlation map was binarized to all significantly correlating connections (fdr, q = 0.05: network-size comparison) or the 7% strongest connections (topology comparison) and subsequently translated into networks with brain structures as nodes and their respective connections as edges. Edge weight, i.e. the correlation coefficient (Pearson's r), showed connectivity strength. c Global network characteristics were determined using average networks per group. Statistical analysis of specific connections and nodes was performed using single animal networks. NBS: network-based statistics, ANOVA: analysis of variance, LDA: linear discriminant analysis.
Article Snippet: Electrical stimulations (square wave pulses, DS5, Digitimer, Welwyn Garden City, UK) were applied subcutaneously between the second and fourth digit of the right hind paw with two intensities (first, 1 mA: low; second, 5 mA: high at a frequency of 9 Hz and with 2ms pulse duration).
Techniques: Adjuvant, Injection, Control, Derivative Assay, Comparison