Selective neurotoxic lesions of basolateral and central nuclei of the amygdala produce differential effects on fear conditioning
Abstract
In the fear conditioning literature, it is generally hypothesized that neurons in the basolateral amygdalar complex (BLA) (lateral and basal nuclei) support the formation of conditioned fear memory and project to neurons in the central nucleus (CeA) for the expression of conditioned fear responses. According to this serial processing-transmission view, damage to either BLA or CeA would comparably disrupt the expression of a variety of conditioned fear responses. In the present study, we further investigated the roles of BLA and CeA in fear conditioning by concurrently assessing freezing and 22 kHz ultrasonic vocalization (USV) as dependent measures of fear in rats. Selective neurotoxins, NMDA for the BLA and ibotenic acid for the CeA, were used to destroy intrinsic neurons [evidenced by thionin dye and NeuN (neuronal nuclei) antibody stainings] without damaging the fibers of passage (confirmed by myelin staining). During the 10 tone-footshock paired training, postshock freezing and USV responses were significantly impaired in BLA-lesioned animals, whereas CeA-lesioned animals exhibited only mild deficits. Similarly, conditioned fear responses assessed 24 hr after training were severely reduced in BLA-lesioned animals but not in...Continue Reading
Citations
The role of amygdala nuclei in the expression of auditory signaled two-way active avoidance in rats.
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