TY - JOUR
T1 - Neurochemical correlates of accumbal dopamine D2 and amygdaloid 5-HT1B receptor densities on observational learning of aggression
AU - Suzuki, Hideo
AU - Lucas, Louis R.
N1 - Funding Information:
The authors report no conflicts of interests. This work was supported by a Loyola University Chicago Research Support grant (to L.R.L). H.S.’s time was supported by NIH Grant Nos. MH090786 and MH098099.
Publisher Copyright:
© 2015, Psychonomic Society, Inc.
PY - 2015/6/22
Y1 - 2015/6/22
N2 - Social learning theory postulates that individuals learn to engage in aggressive behavior through observing an aggressive social model. Prior studies have shown that repeatedly observing aggression, also called “chronic passive exposure to aggression,” changes accumbal dopamine D2 receptor (D2R) and amygdaloid 5-HT1B receptor (5-HT1BR) densities in observers. But, the association between these outcomes remains unknown. Thus, in our study, we used a rat paradigm to comprehensively examine the linkage between aggression, D2R density in the nucleus accumbens core (AcbC) and shell (AcbSh), and 5-HT1BR density in the medial (MeA), basomedial (BMA), and basolateral (BLA) amygdala following chronic passive exposure to aggression. Male Sprague-Dawley rats (N = 72) were passively exposed to either aggression or nonaggression acutely (1 day) or chronically (23 days). When observer rats were exposed to aggression chronically, they showed increased aggressive behavior and reduced D2R density in bilateral AcbSh. On the other hand, exposure to aggression, regardless of exposure length, increased the 5-HT1BR density in bilateral BLA. Finally, low D2R in the AcbSh significantly interacted with high 5-HT1BR density in the BLA to predict high levels of aggression in observer rats. Our results advance our understanding of the neurobiological mechanisms in the observational learning of aggression, highlighting that dopamine–serotonin interaction, or AcbSh–BLA interaction, may contribute to a risk factor for aggression in observers who chronically witness aggressive interactions.
AB - Social learning theory postulates that individuals learn to engage in aggressive behavior through observing an aggressive social model. Prior studies have shown that repeatedly observing aggression, also called “chronic passive exposure to aggression,” changes accumbal dopamine D2 receptor (D2R) and amygdaloid 5-HT1B receptor (5-HT1BR) densities in observers. But, the association between these outcomes remains unknown. Thus, in our study, we used a rat paradigm to comprehensively examine the linkage between aggression, D2R density in the nucleus accumbens core (AcbC) and shell (AcbSh), and 5-HT1BR density in the medial (MeA), basomedial (BMA), and basolateral (BLA) amygdala following chronic passive exposure to aggression. Male Sprague-Dawley rats (N = 72) were passively exposed to either aggression or nonaggression acutely (1 day) or chronically (23 days). When observer rats were exposed to aggression chronically, they showed increased aggressive behavior and reduced D2R density in bilateral AcbSh. On the other hand, exposure to aggression, regardless of exposure length, increased the 5-HT1BR density in bilateral BLA. Finally, low D2R in the AcbSh significantly interacted with high 5-HT1BR density in the BLA to predict high levels of aggression in observer rats. Our results advance our understanding of the neurobiological mechanisms in the observational learning of aggression, highlighting that dopamine–serotonin interaction, or AcbSh–BLA interaction, may contribute to a risk factor for aggression in observers who chronically witness aggressive interactions.
KW - 5-HT1B receptor
KW - Aggression
KW - Amygdala
KW - Dopamine D2 receptor
KW - Nucleus accumbens
KW - Observational learning
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U2 - 10.3758/s13415-015-0337-8
DO - 10.3758/s13415-015-0337-8
M3 - Article
C2 - 25650085
AN - SCOPUS:84939969193
VL - 15
SP - 460
EP - 474
JO - Cognitive, Affective and Behavioral Neuroscience
JF - Cognitive, Affective and Behavioral Neuroscience
SN - 1530-7026
IS - 2
M1 - 15
ER -