Effort Displayed During Appetitive Phase of Feeding Behavior Requires Infralimbic Cortex Activity and Histamine H1...

Area of Science:

• Neuroscience
• Behavioral Neuroscience
• Neuropharmacology

Background:

• Goal-directed behaviors, like seeking food, are enhanced by increased arousal.
• The appetitive phase of motivated behaviors involves excitation, with prefrontal cortical areas like the ventromedial prefrontal cortex being key decision-makers.

Purpose of the Study:

• To investigate if the infralimbic cortex (ILC) increases arousal during motivated feeding behavior.
• To determine if this arousal increase is mediated by the brain histaminergic system, thereby influencing motivation for food rewards.

Main Methods:

• Progressive ratio operant conditioning was used to assess motivation for food in rats.
• The histaminergic system was manipulated pharmacologically, and the ILC was inhibited using muscimol infusion.
• Extracellular histamine levels in the ILC were measured.

Main Results:

• ILC inhibition disrupted food-seeking behavior but not consumption.
• Blocking H1 histamine receptors or inducing satiety also impaired food-seeking behavior.
• Extracellular histamine levels in the ILC correlated positively with motivation, and ILC inhibition prevented this rise.

Conclusions:

• ILC activation and histamine release are necessary for motivated feeding.
• Histamine release during motivated behavior appears to be motivation-related, not solely due to arousal.
• Unlike histamine, serotonin levels did not change during the progressive ratio test.