Brain Mechanisms in Blood Glucose Mobilization and Absorption: The Role of the Left and the Right Frontal Regions in the Regulatory Control of Blood Glucose Levels

Abstract

Citation DeVore BB, Harrison DW. Brain mechanisms in blood glucose mobilization and absorption: The role of the left and the right frontal regions in the regulatory control of blood glucose levels. With the ravaging effects of glucose related diseases (such as diabetes) on the rise, an increased understanding of the central mechanisms involved in glucose mobilization and absorption, and the potential development of the metabolic syndrome, is becoming increasingly important. Although, substantive efforts have been expended to better understand the peripheral mechanisms involved with the systemic processing of glucose, there remains a pau-city of research dedicated to the central neural aspects largely involved in the mobilization and absorption of blood glucose. Despite this lack of research, the relationship between emotional states of anger or fear and those oppositional processes associated with quiescent states or digestive uptake have been clearly related to blood glucose levels. 1-3 Moreover, and perhaps most relevant here, is that the differential emotional states just described have been established with origins in cerebral laterality and with regulatory control mechanisms largely relegated to the frontal lobes and executive brain systems. 4-6 We have provided evidence with the potential to bridge this gap between brain theory and research on peripheral mechanisms with specializations of the right brain for intense emotional states and sympathetic drive 7-10 and with somewhat oppositional specializations of the left brain for quiescent states and perhaps parasympathetic drive. Functional cerebral systems theory 11-14 demonstrates the regulatory control over sympathetic drive by the frontal lobe executive regions, where incremental blood pressure, heart rate, sweating, cholesterol levels, and blood glucose levels may provide the biological resources and reserves for the fight with relevance to insure success in meeting the potentially coercive threat or challenge. Furthermore , cerebral balance theory 7 supports oppositional mechanisms with quiescent states and the establishment of resource reserves largely by left cerebral systems. This brief review of current neuropsychological research will present a theoretical foundation, based upon Alexander Lu-ria's functional cerebral systems theory, for the preferential activation of glucose metabolism by the right cerebral hemisphere (Figure 1). Fundamental to the presented argument is the theoretical construct, that the majority of emotional processing, particularly intense emotions such as anger or fear, are lateralized to the right hemisphere. 15 Research in our lab looking at violent-prone individuals has consistently supported this theory by showing decreased frontal lobe regulation of right posterior anger and negative emotionally responsive brain regions. 4,16 Of further import to the theory of right hemi-spheric glucose mobilization is evidence showing sympathetic response is substantially under right hemispheric control and that overall cardiovascular recruitment is driven by right hemi-spheric activation. Current research efforts, 17 comparison studies of the left-versus-right sided cerebrovascular accidents, 18 and unilateral intracarotid sodium amobarbital injections (UISAI) [Wada technique] 18 all support the relative role of the right hemisphere in sympathetic response. Given the integral role of blood glucose as the major fuel source for the brain, it follows