Hippocampus dysfunction may explain symptoms of fibromyalgia syndrome

In fibromyalgia (FM) a combination of symptoms frequently exists, including impaired cognition, memory changes, widespread pain, and disrupted sleep rhythm, with no sufficient explanations for these bizarre symptoms. Many theories have been developed and it is still not clear whether FM is a chronic stress syndrome caused by many factors, including society or just a part of the spectrum of chronic pain. FM is the second most common rheumatic disorder behind osteoarthritis and, though still widely a puzzling syndrome, is now considered to be a central nervous system disorder, which is responsible for amplified and intensive pain. Over the years, three main ideas of hippocampal function have dominated the literature: Response inhibition, episodic memory, and spatial cognition. Given that the hippocampus plays integral roles in memory, cognition, and sleep regulations the later functions may be influenced by prolonged stress know to exist in FM syndrome. Moreover the hippocampus is an integral component of the limbic system, and as such may contribute to the negative affect and avoidance motivation experienced during pain experience and chronic stress. The aim of the current review is to focus on the physiological roles of the hippocampus and its relation to symptoms production in FM syndrome.