Pharmacological studies of behavioral influences on cardiovascular function

Area of Science:

• Behavioral Neuroscience
• Cardiovascular Physiology
• Psychopharmacology

Background:

• Understanding the interplay between behavior and physiological responses is crucial in neuroscience.
• Squirrel monkeys exhibit complex behaviors under controlled experimental conditions.
• Cardiovascular changes during operant conditioning are not fully understood.

Purpose of the Study:

• To investigate cardiovascular changes associated with schedule-controlled behavior in squirrel monkeys.
• To determine if physiological responses are dependent on the type of reinforcement (food vs. shock termination).
• To explore the modulation of cardiovascular control systems by behavioral and environmental factors.

Main Methods:

• Squirrel monkeys were surgically prepared with chronic arterial and venous catheters.
• Operant responding was established under fixed-ratio schedules for food presentation or stimulus-shock termination.
• Cardiovascular parameters (heart rate, blood pressure) were monitored during behavioral tasks.
• Pharmacological challenges with 1-norepinephrine were employed to assess autonomic tone modulation.

Main Results:

• Pronounced, episodic elevations in heart rate and blood pressure occurred during and immediately after fixed-ratio responding.
• These cardiovascular changes were comparable whether the schedule involved food presentation or shock termination.
• 1-norepinephrine administration revealed a high baseline sympathetic tone, with reflex bradycardia being inhibited during responding.

Conclusions:

• Episodic cardiovascular changes are primarily driven by the performance of schedule-controlled behavior, not the specific reinforcer.
• Behavioral and environmental factors can significantly modulate fundamental cardiovascular control mechanisms, including autonomic reflexes.
• This study highlights the intricate relationship between behavioral engagement and physiological regulation in primates.