Regional Fmri Activation in Response to Visceral Stimulation in Rats with Amygdala Implants of Corticosterone

INTRODUCTION: Visceral pain is clinically one of the most common complaints. Irritable bowel syndrome (IBS) is characterized by visceral pain and irregular bowel movements. It is estimated that IBS affects 10-22% adults, with a high female to male ratio. Frequently, episodes of visceral pain coincide with specific stressful event(s) or increased anxiety suggesting parallel activation of higher cognitive areas with pain processing circuits. The amygdala is thought to play a crucial role in the generation and propagation of fear and anxiety [1]. Furthermore, the central nucleus of the amygdala has been shown to facilitate activation of hypothalamic-pituitary-adrenal axis (HPA) in response to stress and increase corticotrophin release factor (CRF) [2]. The aim of this work was to examine brain activation in response to visceral pain and increased anxiety as modeled by corticosteroid implants delivered bilaterally to amygdale.