Fat is a critical, highly preferred macronutrient and one of the major contributing factors to the current obesity epidemic. Although reducing the percentage of fat in the American diet is a high priority, this effort has been hindered by our poor understanding of fats sensory and rewarding properties. An appreciation for the central basis of oil reward awaits a better understanding of the sensory basis of fat and oil perception. Detection, discrimination, and even the appeal of fats and oils have been presumed to be within the purview of the somatosensory system, but the recent finding that fatty acids activate taste receptor cells suggests that the gustatory system plays a role as well. The experiments of Aim 1 will examine the ability of oils and oil/water emulsions to stimulate individual tactile, taste, and thermal fibers of the gustatory and somatosensory nerves that innervate the tongue.
Specific Aims 2 and 3 will identify the forebrain structures that mediate the hedonic value of oil. The experiments of Aim 2 will combine measurements of dopamine release within nucleus accumbens with central gustatory and trigeminal lesions to identify the central pathways involved in oil reward. The experiments of Aim 3 will use a functional dependent variable, c-Fos, to identify additional pathways and nuclei involved with oil reward. The proposed experiments are innovative because the sensorineural and rewarding properties of oil have never been investigated. This research is important because fats and oils represent a significant and increasing percentage of the American diet. In order to curtail our appetite for high fat foods, we must understand how fats and oils are detected by the orosensory apparatus and how this sensorineural information is used by the brain to determine the nature of oil reward. Resolution of these issues will permit us and other investigators in the fields of taste and nutrition to examine the effect of dietary fat and oil on brain areas involved with appetite and satiety.
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