Individual differences in voluntary alcohol consumption are associated with conditioned fear in the fear incubation model

• Published in: Behavioural brain research 2019-04, Vol.362, p.299-310
• Main Authors: Pajser, Alisa, Limoges, Aaron, Long, Charday, Pickens, Charles L.
• Format: Article
• Language: English
• Subjects: Affect; Aggression - drug effects; Alcohol; Alcohol Drinking - physiopathology; Animals; Behavior, Animal - drug effects; Conditioning, Operant; Conditioning, Psychological - drug effects; Conditioning, Psychological - physiology; Cues; Disease Models, Animal; Ethanol - pharmacology; Extinction, Psychological - drug effects; Fear - drug effects; Fear conditioning; Incubation; Individual differences; Male; Rats, Long-Evans
• ISSN: 0166-4328; 1872-7549; 1872-7549
• DOI: 10.1016/j.bbr.2019.01.027

•Alcohol consumption in adolescence and adulthood did not affect conditioned fear.•In the adolescent alcohol group, high consumption was associated with lower fear.•High drinkers exhibited lower conditioned fear in the first conditioning session.•High drinking, low drinking and water-only groups all exhibited fear incubation.•High drinking rats exhibited lower fear in the day 2 and 1-month tests. Previous research in male Long Evans rats has shown a relationship between low voluntary alcohol consumption and high conditioned fear after a single training session. Here, we determined whether chronic intermittent access (CIA) to alcohol during adolescence/early adulthood or during adulthood would alter or be associated with auditory-cued conditioned fear levels using an extended training fear incubation procedure. This training procedure leads to low fear soon after training that grows over one month. Rats received 6 weeks of CIA to 20% alcohol or water from PND 26–66. Ten or eleven days later, the rats began behavioral testing that included 10 sessions of tone-shock pairings. Rats then received 4 weeks of CIA exposure during the 1-month fear incubation period and were tested for conditioned fear 6 days after the end of alcohol access. We found no evidence that voluntary alcohol consumption during adolescence/early adulthood or adulthood altered fear expression. However, we found that rats that consumed more alcohol during early adulthood (PND 54–66) had lower fear than low-consumption rats on day 1 of conditioned fear training and in the day 2 and 1-month tests. This extends associations we previously found between individual differences in alcohol consumption and conditioned fear to a different fear conditioning procedure. Combined with our previous data that show that the rate of instrumental extinction is associated with both alcohol consumption and conditioned fear, these data provide further support for the generality and reliability of a pair of phenotypes that encompass a wide variety of learning traits.