Abstract View
AMYGDALA-DEPENDENT LEARNING INCREASES THE NUMBER OF SPINOPHILIN-IMMUNOREACTIVE DENDRITIC SPINES IN THE LATERAL AMYGDALA.
L.R.Johnson1,3; J.J.Radley1,2*; J.Martino1,3; R.Lamprecht1,3; P.R.Hof1,2; J.E.LeDoux1,3; J.H.Morrison1,2
1. NIMH Ctr. for Fear and Anxiety, New York, NY, USA
2. Kastor Neurobiology of Aging Labs. and Fishberg Res. Ctr. for Neurobiology, Mount Sinai Sch. of Med., New York, NY, USA
3. Ctr. for Neural Sci., NYU, New York, NY, USA
During Pavlovian auditory fear conditioning a previously neutral auditory stimulus (CS) gains emotional significance through pairing with a noxious unconditioned stimulus (US). These associations are believed to be formed by way of plasticity at auditory input synapses on principal neurons in the lateral nucleus of the amygdala (LA). One proposed form of cellular plasticity involves structural changes in the number and morphology of dendritic spines. To this end, we examined the effect of fear conditioning on spine density and total number in the LA. Spines were identified immunohistochemically as small puncta containing spinophilin (a protein phosphatase highly enriched in spines). Male Sprague-Dawley rats were divided into 3 groups: a paired group (N=7) that received five presentations of a tone (CS) and foot-shock (US), an unpaired group (N=7) that received five random presentations of the CS and US, and a naive control group (N=7). 24 h following conditioning, rats were perfused and amygdala sections were immunohistochemically prepared with anti-spinophilin antibody, followed by silver-enhanced immunogold. Stereological analysis using the optical fractionator was performed for the assessment of the total spine number, and the volume of LA was determined using the Cavalieri principle. We found a statistically significant increase (25%) in the number of spinophilin puncta in the paired relative to the unpaired group. These results suggest that at least one type of plasticity underlying fear-conditioned memories is the formation of new dendritic spines in the LA.
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Citation:
L.R. Johnson, J.J. Radley, J. Martino, R. Lamprecht, P.R. Hof, J.E. LeDoux, J.H. Morrison. AMYGDALA-DEPENDENT LEARNING INCREASES THE NUMBER OF SPINOPHILIN-IMMUNOREACTIVE DENDRITIC SPINES IN THE LATERAL AMYGDALA. Program No. 623.7. 2003 Abstract Viewer/Itinerary Planner. Washington, DC: Society for Neuroscience, 2003. Online.