i. OT males retrieved the banana more slowly than saline males, while OT females took it more quickly than saline females, suggesting OT heightened anxiety in males but reduced it in females. ii. OT males balked more frequently than saline males, while OT females balked less often than saline females. iii. The longest retrieval latencies were displayed at age 15 months, on day 1 of testing, and in response to more complex patterns.

1. T.A.R. Weinstein1, S.P. Mendoza1, W.A. Mason1, M. Solomon2, S. Jacob3, & K.L. Bales1
1California National Primate Research Center, UC Davis; 2MIND Institute, UC Davis; 3Department of Psychiatry, University of Minnesota.
Research Question
 We examined whether chronic treatment with oxytocin (OT)
affected male and female titi monkeys’ latency to retrieve a
preferred food item in the presence of novel visual patterns.
 Therapeutic OT is prescribed to increase approach and
social behavior and reduce anxiety in children with autism.
Age 12-18 months
 Subjects received once daily treatment with either 0.8 IU/kg
OT dissolved in 50μl of saline (n=8) or 50μl saline (n=7).
 We used a pipette to drip the treatment into alternate
nostrils in 25μl increments, then covered the nostril to
prevent the monkey from expelling the solution.
Habituation to baseline: Age 15 months
 A pattern presentation box containing a 2 cm piece of
banana in front of a white background was attached to the
subject’s home cage for 3-min trials.
 Trials were repeated up to 10x/day until banana retrieval
latency < 30 seconds for 10 consecutive trials.
Testing: Ages 15, 17, & 19 months
 We measured banana retrieval latency (sec) across six
30-sec trials: trials 1 & 6 were the baseline condition
(white background), and trials 2-5 contained backgrounds
of escalating pattern complexity.
 Test sessions occurred 1x/day for 4 days at each age:
 Days 1 & 3: subjects shown novel patterns.
 Days 2 & 4: subjects shown patterns from the day before.
 All habituation and testing took place in the subject’s home
cage while the family members were temporarily removed.
Pharmacological Treatment
 OT-treated females were quicker and more willing to retrieve
the banana than were saline-treated females, suggesting
reduced fearfulness/anxiety in response to novelty.
 In contrast, OT males were slower and less likely to take the
banana than saline males, suggesting heightened anxiety.
 The sex-specific effect of chronic OT on response to novelty
has vital clinical implications for its use as a therapeutic.
Pattern complexity predicted retrieval latencies.
 All subjects were more hesitant to reach for a preferred food
item in the presence of more complex visual patterns.
Subjects were slowest to take the banana when they were
youngest and on their first test day at every age.
 Over time, subjects became more habituated to the test
procedure and overall less fearful of novel visual stimuli.
Conclusions
Results
i. OT males retrieved the banana more
slowly than did saline males, while OT
females took the banana more quickly
than did saline females.
The longest retrieval latencies were displayed:
iii. At age 15 months iv. On day 1 of testing
Subjects
 15 juvenile coppery titi monkeys, Callicebus cupreus (8 ♂).
 Housed in indoor cages measuring 1.2 m × 1.2 m × 2.1 m
containing family groups of an adult pair and 1-4 offspring at
the California National Primate Research Center (CNPRC).
Treatment condition interacted with sex to predict banana
retrieval in the presence of novel visual stimuli.
Acknowledgements
Supported by NIH HD071998, P51OD011107, and the Good Nature Institute. We thank R. Arias Del
Razo, S. Carp, C. Blanz, E. Sahagun Parez, L. Goetze, C. Nuñez, B. Ragen, R. Larke, E. Rothwell, S.
Freeman, CNPRC husbandry and vet staff, and countless interns for their invaluable assistance.
Contact
Tamara A.R. Weinstein, California National Primate Research Center, University of
California, One Shields Ave, Davis, CA 95616. Email: tarweinstein@ucdavis.edu
Does chronic exposure to intranasal oxytocin affect
response to novelty in juvenile-adolescent titi monkeys?
F1,187 = 11.14, p = 0.001; Fisher’s LSD, *p < 0.05 **p < 0.01 * Χ2
df = 1 > 6.3, p ≤ 0.01
Oxytocin Saline
The effects of chronic intranasal oxytocin on response to novelty
in juvenile titi monkeys (Callicebus cupreus)
Novel Pattern Testing
Example pattern set
Trial: 1 2 3 4 5 6
Treatment
and
Testing
Pattern
presentation box
Perch bar
Not to scale
 A repeated measures linear mixed model tested the following
effects on banana retrieval latency:
 Treatment
 Sex
 Age
 Treatment * sex
 Treatment * age
Data Analysis
 A Χ2 test compared the # of trials in which subjects refused to take
the banana within 30 seconds (“balks”) by sex and treatment.
 Test day #
 Pattern complexity
ii. OT males balked more
frequently than saline males,
while OT females balked less
often than saline females.
v. In response to more complex patterns.
Males Females
0
2
4
6
8
10
Meanretrievallatency(sec)
** *
15 17 19
0
4
8
12
Age (months)
Meanlatency(sec)
a
b b
1 2 3 4
0
2
4
6
8
10
Test Day
Meanlatency(sec)
a
b b b
1 2 3 4 5 6
0
2
4
6
8
10
12
Trial
MeanLatency(sec)
a a,b
b a,b
c
c
F2,210 = 20.43, p < 0.001
a,b Fisher’s LSD,
p < 0.001
F3,333 = 3.79, p = 0.01
F5,555 = 14.23, p < 0.001 a,b,c Fisher’s LSD, p < 0.05
Males Females
0
25
50
75
100
*
*
%ofbalks