Sara Karmi and Gholam ali Hamidi
Kashan University of Medical Sciences, Iran
Posters & Accepted Abstracts: J Neurol Neurophysiol
Introduction: The orexins are neuropeptide transmitters made exclusively in hypothalamic neurons that have extensive central
nervous system (CNS) projections. Orexin is mainly expressed by neurons located in the posterior of the hypothalamus.
Despite being small in number, these neurons release orexin through the CNS and affect a variety of physiological functions
including sleep, hunger, and drug abuse. Decision making is an adaptive behavior that takes into account several internal and
external input variables and leads to the choice of a course of action over other available and often competing alternatives. The
OFC plays a key role in processing reward and it is involved in delay based decision making. Hence, in the present study, we
conducted a series of experiments to clarify the role of orexin receptor 1 in the OFC regulate delayed-based decision making.
Material and methods: The rats had been trained in a delay-based form of cost-benefit T-maze decision making task. The twogoal arms were different in the amount of accessible reward. The animals could choose high reward arm (HR arm) and pay cost (waiting 20 sec) to achieve large reward or obtain a low reward in the other arm immediately (LR arm). Before surgery, all animals were selecting the HR arm on almost every trial. During test days, the rats received local injections of either DMSO 20% /0.5μl, a vehicle, or SB334867 (3, 30, 300 nM/0.5μl), as selective OX1-receptor antagonist, within the OFC.
Results: Our results demonstrate profound effects of OFC's OX1r on delay-based decision making, due to bilateral microinjection of SB334867, into the OFC, changed the animal's preference to a low reward.
Conclusion: These results imply that OX1-receptor has a crucial role in allowing the animal to pay a cost to acquire greater rewards.
Sara Karimi is a PhD student at Neuroscience Research Center in Shahid Beheshti University of Medical Sciences, Iran. She did her graduation from Shahid Beheshti University (one of the best university in Iran). She is major in Biology (Zoology). At master level she studied animal physiology in year 2006. She did her master’s research project under the supervision of Dr. Sahraei and Dr. Karami. The 2 year project was the investigation of the intra- central amygdale injection of Nitric Oxide agents on naloxone-induced place aversion in morphine conditioned rats. From year 2014, she is pursuing her PhD from Kashan University of medical sciences. Her PhD project is an investigation on “the role of orexin receptor 1 in the prefrontal cortex in cost and benefits decision makers in the rats” under the supervision of Dr. Haghparast, (famous physiologist in Iran).