ABSTRACT
Functional magnetic resonance imaging (fMRI) in conscious animals is evolving as a critical tool for neuroscientists. The present study explored the effectiveness of an acclimation procedure in minimizing the stress experienced by the animal as assessed by alterations in physiological parameters including heart rate, respiratory rate, and serum corticosterone levels. Results confirm that as the stress of the protocol is minimized, there is a significant decrease in head movements and enhancement in data quality. The feasibility of improving the quality of fMRI data acquired in alert rats by utilizing a relatively simple technique is presented.
Subject(s)
Acclimatization/physiology , Adaptation, Psychological/physiology , Hypothalamo-Hypophyseal System/metabolism , Magnetic Resonance Imaging/psychology , Stress, Psychological/prevention & control , Animals , Blood Pressure/physiology , Brain/physiology , Cerebrovascular Circulation/physiology , Corticosterone/blood , Magnetic Resonance Imaging/adverse effects , Male , Rats , Rats, Sprague-Dawley , Stress, Psychological/blood , Stress, Psychological/physiopathologyABSTRACT
Nursing has reciprocal benefits for both mother and infant, helping to promote maternal behavior and bonding. To test the "rewarding" nature of nursing, functional magnetic resonance imaging was used to map brain activity in lactating dams exposed to their suckling pups versus cocaine. Suckling stimulation in lactating dams and cocaine exposure in virgin females activated the dopamine reward system. In contrast, lactating dams exposed to cocaine instead of pups showed a suppression of brain activity in the reward system. These data support the notion that pup stimulation is more reinforcing than cocaine, underscoring the importance of pup seeking over other rewarding stimuli during lactation.
