Abstract # 4473 Event # 146:

Scheduled for Friday, June 21, 2013 04:05 PM-04:20 PM: Session 20 (San Geronimo Ballroom C) Oral Presentation


NEONATAL AMYGDALA LESIONS IMPACT EMOTIONAL BEHAVIOR DEVELOPMENT IN RHESUS MONKEYS (MACACA MULLATTA) LIVING IN A SEMI-NATURALISTIC SOCIAL GROUP

J. Raper 1,2, M. M. Sanchez1,2, K. Wallen1,2 and J. Bachevalier1,2
1Yerkes National Primate Research Center, 954 Gatewood Rd NE, Atlanta, GA 30329, USA, 2Emory University
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     A hallmark study conducted at Cayo Santiago, reported that amygdala lesion differentially impacted socio-emotional behavior based on the animals’ age and social experience (Dicks et al., 1969). The younger the animal was at the time of the lesion the fewer changes in emotional behavior. However, this study only followed the animals for a few months and did not examine the longitudinal consequences of amygdala damage. Therefore, the current study examined the impact of neonatal amygdala lesions on the development of emotional behavior in rhesus monkeys living in a semi-naturalistic environment. Selective amygdala lesions (Neo-A: n=16) or sham-operation (n=15) were done at approximately 24 days of age. Subjects were tested at 2.5, 12, and 18months of age on the Human Intruder paradigm (HI), which measures the animals’ ability to modulate their emotional response based on the salience of the threat (Kalin & Shelton, 1989). As compared to controls, Neo-A animals exhibited few differences at 2.5 months of age, whereas at 12 & 18 months they exhibited less freezing, hostility, and anxious behaviors, demonstrating that behavioral alterations emerged with development. Discriminant analyses revealed that a combination of behaviors (i.e. freezing, cooing, hostility, anxious) accurately classified lesioned from non-lesioned animals in the juvenile stages, suggesting that a combination of behavioral responses may reflect an amygdalectomy syndrome which could be recognizable to other members in the animal’s social group.