Prelimbic cortex bdnf knock-down reduces instrumental responding in extinction.

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Molecular Neuroscience

Background:

• Medial prefrontal cortex projections are known to regulate stimulus-reinforcement memory extinction.
• Mechanisms for instrumental response extinction for reward are less understood and may involve goal-directed action structures.

Purpose of the Study:

• To investigate the role of brain-derived neurotrophic factor (BDNF) in the prelimbic cortex (PL) and orbitofrontal cortex (OFC) in instrumental response extinction.
• To determine if PL cortex BDNF influences instrumental action, particularly under conditions of reward uncertainty.

Main Methods:

• Utilized knock-down techniques to reduce BDNF levels specifically in the PL cortex of mice.
• Assessed the impact of PL cortex BDNF reduction on the extinction of instrumental responding for food rewards.
• Examined the effect of providing alternative reinforcement options on extinction behavior in knock-down mice.

Main Results:

• Knock-down of BDNF in the PL cortex, but not the OFC, accelerated the initial extinction of instrumental responding for food.
• Striatal BDNF protein levels were reduced following PL cortex BDNF knock-down.
• When alternative response options were available, extinction of the previously reinforced response remained unaffected in knock-down mice.

Conclusions:

• The prelimbic cortex plays a critical role in promoting instrumental action, especially when reinforcement is uncertain or unavailable.
• BDNF in the prelimbic cortex is a key molecular mechanism regulating the extinction of instrumental reward-seeking behavior.