THE EFFECTS OF CAFFEINE ON MEMORY IN COMMON MARMOSET (Callitbrix jaccbus)

*Corresponding author e-mail: kathiane@gmail.com Introduction: We evaluated the effects of caffeine on memory in Callithrix jacchus , through the conditioned place preference task, and locomotor activity. Methods: We used 10 females and 10 males, between 3 and 9 years old, from Primate Center of UFRN (IBAMA no 1/24/92/0039- 0). This experiment comprised five phases: (1) Pre-exposure — 2 days; (2) Training, in which they were conditioned to discriminate between a non-rewarded context (NRC) and a rewarded context (RC) for 8 days; (3) Oral administration of caffeine or placebo (10 mg/kg - both substances) for 8 days, approximately 1,5 h before sleep, when the marmosets were distributed in groups: placebo (PL), acute (AC), repeated (RP), abstinence (AB); (4) One day of retraining, followed by administration of caffeine or placebo; (5) Test, without food. Each session had duration of 8 minutes, and began at 6:15 am for pre-exposure, training and test. The retraining began at 3:15 pm, because it should be a sleep-dependent task. For behavioral data, frequency of contacts, latency (seconds) and percent time spent in RC and NRC were registered. For locomotion, we registered the general activity, and locomotion in contact with apparatus and outside of it. Results: In training, the animals enter and stay more in RC versus NRC (percent time, frequency and latency; Wilcoxon test, p <0,001), and moved more in contact with apparatus than outside of it (test t , p <0,001). On test, marmosets under influence of caffeine percurred more quadrants than placebo group ( PL: 21,8 ± 0,9; AC: 30,2 ± 1,3; RP: 30,4 ± 1,3; AB: 32,4 ± 3,6). Moreover, the repeated and abstinence groups had a bad performance in task in relation to placebo and acute groups (percent time RC- PL: 53,4 ± 9,9%; AC: 78,3 ± 4,9%; RP: 10,3 ± 2,8%; AB: 20 ± 8,9%. Frequency RC- PL: 1,8 ± 0,3; AC: 2,2 ± 0,3; RP: 0,6 ± 0,2; AB: 0,8 ± 0,3. Latency RC- PL: 211,8 ± 49 s; AC: 141,4 ± 21 s; RP: 362,8 ± 38,3 s; AB: 396 ± 40,2 s). Additionally, the marmosets that ingested caffeine presented an increase in locomotor activity when compared with the placebo group. Conclusions: We suggest that prolonged administration of caffeine near to sleep, which is responsible for offline processing of memories, disrupts the memory for this specific task to marmosets in caffeine abstinence and taking repeated doses. Additionally, the results corroborate works that show caffeine increase the locomotion. Support: CNPq, FAPERN. Publication History Article published online: 16 June 2026 © 2009. Brazilian Sleep Academy. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/) Thieme Revinter Publicações Ltda. Rua Rego Freitas, 175, loja 1, República, São Paulo, SP, CEP 01220-010, Brazil