Self-stimulation in the sheep: interactions with ingestive behaviour and light cycle

Area of Science:

• Neuroscience
• Animal Behavior
• Physiology

Background:

• Brain stimulation research often uses animal models to understand reward pathways.
• Sheep, as ruminants, offer a unique model for studying feeding behaviors distinct from monogastric species.

Purpose of the Study:

• To investigate the effects of brain self-stimulation on feeding and drinking in adult male sheep.
• To compare sheep responses to pigs regarding self-stimulation and feeding interactions.

Main Methods:

• Utilized a movable electrode system for self-stimulation in five adult male sheep.
• Manipulated current, food deprivation, and satiation to assess response rates.
• Conducted 5-day experiments under various conditions: operant feeding/drinking, self-stimulation with operant feeding/drinking, self-stimulation with ad libitum feeding/drinking, and with a light/dark cycle.

Main Results:

• Self-stimulation was successfully achieved in sheep.
• Response rates were affected by current intensity, food deprivation, and satiation.
• Interactions between self-stimulation, feeding, and drinking were observed over extended periods.
• Stimulation-bound feeding and drinking behaviors were confirmed in sheep.

Conclusions:

• Brain self-stimulation influences motivated behaviors like feeding and drinking in sheep.
• Sheep exhibit complex interactions between reward-seeking and consummatory behaviors.
• Findings in sheep provide comparative insights into brain reward mechanisms across different mammalian species.