Detection of Visual Activation in the Rat Brain Using 2-deoxy-2-[18F]fluoro-d-glucose and Statistical Parametric Mapping (SPM)

Abstract

Purpose: This study was designed to assess changes in brain glucose metabolism in rats after visual stimulation. Materials and methods: We sought to determine whether visual activation in the rat brain could be detected using a small-animal positron emission tomography (PET) scanner and 2-deoxy-2-[ 18 F]fluoro-D-glucose (FDG). Eleven rats were divided into two groups: (a) five animals exposed to ambient light and (b) six animals stimulated by stroboscopic light (10 Hz) with one eye covered. Rats were injected with FDG and, after 45 min of visual stimulation, were sacrificed and scanned for 90 min in a dedicated PET tomograph. Images were reconstructed by a threedimensional ordered subset expectation maximization algorithm (1.8 mm full width at half maximum). A region-of-interest (ROI) analysis was performed on 14 brain structures drawn on coronal sections. Statistical parametric mapping (SPM) adapted for small animals was also carried out. Additionally, the brains of three rats were sliced into 20-μm sections for autoradiography. Results: Analysis of ROI data revealed significant differences between groups in the right superior colliculus, right thalamus, and brainstem (p≤0.05). SPM detected the same areas as the ROI approach. Autoradiographs confirmed the existence of hyperactivation in the left superior colliculus and auditory cortex. Conclusions: To our knowledge, this is the first report that uses FDG-PET and SPM analysis to show changes in rat brain glucose metabolism after a visual stimulus.

Progressive Metabolic and Structural Cerebral Perturbations After Traumatic Brain Injury: An In Vivo Imaging Study in the Rat

“…In contrast, SPM samples the whole brain in an unbiased fashion but has lower sensitivity in detecting changes. Few previous studies have applied SPM analysis to small-animal PET, and none involved models of TBI, despite the fact that the approach has been widely applied in human PET studies (15,28,29). Many of the brain regions that showed early hypometabolism on 18 F-FDG PET images later showed progressive atrophy on serial MRI scans, particularly the cortex and hippocampi.…”

Statistical Parametric Mapping reveals ligand and region-specific activation of G-proteins by CB1 receptors and non-CB1 sites in the 3D reconstructed mouse brain

“…SPM has previously been adapted for the analysis of reconstructed autoradiographic datasets mapping cerebral blood flow (Nguyen et al, 2004), and successfully applied to functionally map brain activity in small animals (Dubois et al, 2008; Holschneider et al, 2006; Soto-Montenegro et al, 2008; Yang et al, 2007). Applying SPM analysis to in vitro agonist-stimulated [ 35 S]GTPγS autoradiographic data offers unique advantages compared to conventional region of interest (ROI) analysis.…”

Sex Differences in Regional Brain Glucose Metabolism Following Opioid Withdrawal and Replacement

“…Images were overlaid onto an anatomical cryostat template with metabolic increases set as hot, and metabolic decreases set as winter in the color selection options. The color scale used represents all T distributions achieving statistical significance (Carrion et al, 2009;Nie et al, 2014;Soto-Montenegro et al, 2009). All corresponding brain areas are significant at a value of p ⩽ 0.001 (corrected) with a cluster-extent threshold of k = 0 voxels.…”