Use of [14C]-2-deoxyglucose to detect regional brain activities associated with fearful behavior in wild Norway rats

Abstract

The 2-deoxyglucose method was used to compare regional brain activities of unrestrained wild Norway rats engaged in fear-based defensive behavior (n = 8), and that of solitary controls (n = 8). After infusion with 100 micrograms/kg of (14C)-deoxyglucose via jugular catheters, experimental rats spent the 45-min uptake period in flight, boxing, and defensive attack to painless threat stimuli. Coronal sections of brains were exposed to X-ray film, and the resultant global maps of regional brain activity for the two groups were quantitated by high-resolution fiber optic densitometry at 86 cerebral points and analyzed statistically by computer. Significant group differences in regional brain glucose uptake were found at 16 loci. The considerable agreement between these structures and those previously identified in the literature as involved in defensive behavior provides evidence for the potential of this method of investigation of brain correlates of specific behavioral patterns.