Age differences in appetitive Pavlovian conditioning and extinction in rats

Area of Science:

• Neuroscience
• Comparative Psychology
• Developmental Psychology

Background:

• Adolescents show heightened reward sensitivity and impaired behavioral control.
• Adolescent reward processing differences are linked to increased risk-taking and impulsivity.
• Little is known about how adolescents learn reward-predictive cues.

Purpose of the Study:

• To investigate age-related differences in Pavlovian conditioning between adolescent and adult rats.
• To examine how reinforcement schedules influence learning and extinction in different age groups.
• To understand the developmental trajectory of learning about reward-predictive stimuli.

Main Methods:

• Pavlovian conditioning procedures were employed with adult and adolescent rats.
• Rats were trained under continuous (consistent) or partial (intermittent) reinforcement schedules.
• Extinction trials were used to assess the ability to update cue representations.

Main Results:

• Adolescent and adult rats acquired responses to continuously-reinforced cues similarly.
• Adolescents showed a faster increase in responding to partially-reinforced cues compared to adults.
• Adolescents exhibited less flexible updating of cue representations during extinction, with appetitive properties persisting longer.

Conclusions:

• Adolescence is characterized by enhanced associative learning under intermittent reinforcement conditions.
• Adolescents display deficits in flexibly updating learned associations during extinction compared to adults.
• These findings suggest developmental differences in learning and cognitive flexibility related to reward cues.