Effort-related functions of nucleus accumbens dopamine and associated forebrain circuits

Background Over the last several years, it has become apparent that there are critical problems with the hypothesis that brain dopamine (DA) systems, particularly in the nucleus accumbens, directly mediate the rewarding or primary motivational characteristics of natural stimuli such as food. Hypotheses related to DA function are undergoing a substantial restructuring, such that the classic emphasis on hedonia and primary reward is giving way to diverse lines of research that focus on aspects of instrumental learning, reward prediction, incentive motivation, and behavioral activation. Objective The present review discusses dopaminergic involvement in behavioral activation and, in particular, emphasizes the effort-related functions of nucleus accumbens DA and associated forebrain circuitry. Results The effects of accumbens DA depletions on food-seeking behavior are critically dependent upon the work requirements of the task. Lever pressing schedules that have minimal work requirements are largely unaffected by accumbens DA depletions, whereas reinforcement schedules that have high work (e.g., ratio) requirements are substantially impaired by accumbens DA depletions. Moreover, interference with accumbens DA transmission exerts a powerful influence over effort-related decision making. Rats with accumbens DA depletions reallocate their instrumental behavior away from food-reinforced tasks that have high response requirements, and instead, these rats select a less-effortful type of food-seeking behavior. Conclusions Along with prefrontal cortex and the amygdala, nucleus accumbens is a component of the brain circuitry regulating effort-related functions. Studies of the brain systems regulating effort-based processes may have implications for understanding drug abuse, as well as energy-related disorders such as psychomotor slowing, fatigue, or anergia in depression

Fractionality in Homogeneity? Value differences and Cross-Cultural Conflict in Somalia

Despite the fact that intra-state conflict is a common feature of post-colonial African states, the seemingly endless nature of the Somali crisis has necessitated this study. The Somali case has proved immune to peace talks, military interventions, restructuring of governments by the international community, etc. The crisis had lingered, producing alarming figures of dead and displaced persons; a collapsed State, giving room for anarchy; unhindered militia presence on both land and sea; and persistently becoming a menace and threat to the peace of its immediate neighbours, the region and the world. All these visible manifestations of the Somali state can be regarded as convulsions of its internal value differences. Thus, this study seeks to examine the Somali value systems, the differences emanating from the jealous protection of such values, and how they have rendered conflict resolution attempts futile. With more emphasis on the structure of the Somali society, this study explores its unique stratifications that have kept the state collapsed. A descriptive-analytical approach is applied, while the data are basically collected from secondary sources. The findings of this research reveal the divisive characteristics of values which have manifested in segmentation, clannism, loyalty, among others. It has led to the endless violent struggle for dominance among the clans and social classes culminating in a total collapse of the state. It is therefore concluded that value differences have been detrimental to the peace of Somalia. This study recommends, among others, that genuine resolution efforts should thoroughly consider and engage these value differences. Keywords: clannism, conflict, loyalty, values, value differences