Slow phasic changes in nucleus accumbens dopamine release during fixed ratio acquisition: a microdialysis study
K N Segovia1, M Correa, J D Salamone
1Department of Psychology, University of Connecticut, Storrs, CT 06269-1020, USA.
Neuroscience
|September 3, 2011
Summary
Dopamine release in the nucleus accumbens is crucial for learning new behaviors. This study shows dopamine release patterns differ in brain regions during the acquisition of reinforcement schedules.
Area of Science:
- Neuroscience
- Behavioral Neuroscience
- Neurobiology
Background:
- Dopamine (DA) in the nucleus accumbens regulates reinforcement-seeking behavior.
- Previous research focused on established operant behaviors, not initial learning.
Purpose of the Study:
- Investigate nucleus accumbens dopamine release during the initial acquisition of operant schedules.
- Examine the transition from a fixed ratio 1 (FR1) to a fixed ratio 5 (FR5) schedule.
Main Methods:
- Microdialysis in rats during FR1, early FR5 training, and well-trained FR5 conditions.
- Compared DA release during operant tasks versus free food consumption.
Main Results:
- Well-trained rats showed increased nucleus accumbens DA on FR5.
- Early FR5 training induced significant DA release in the nucleus accumbens shell (day 1) and core (day 2).
- Free food consumption did not significantly increase DA, unlike initial exposure.
Conclusions:
- Transient nucleus accumbens dopamine increases occur during the acquisition of instrumental behavior.
- Distinct temporal patterns of dopamine release exist in nucleus accumbens core and shell during learning.
