[Neuroethics (II): moral pathways in disordered brain].

INTRODUCTION: Morality is made out of rules and values that guide human behavior. They barely change among different cultures and result in top social accomplishments. Specific moral pathways are available for this purpose in the brain. Their lesion or dysfunction will produce changes or alterations in moral behavior. AIM: To describe the process and mechanisms of moral dysfunctions under different lesions and neurological disorders. DEVELOPMENT: Moral pathologies are the result of either different structural lesions (destructive of the prefrontal cortex; microscopic involvement of the amygdala/prefrontal cortex in psychopathies), or neurochemical involvement (dopaminergic hyperfunction in Parkinson patients under certain treatments, or in some drug-dependences) or genetic alterations (point mutations of COMT or MAO enzymes in certain psychopathies). This activity is due to excitatory, inhibitory or mixed mechanisms. They operate at different levels of the moral circuits, as much emotional (temporal lobe) as cognitive ones (prefrontal lobe). The underlying topography and operating mechanisms can explain the different clinical expressivity. CONCLUSIONS: The knowledge of the disordered moral behaviors improves the background of information about the moral circuits that operate in healthy control groups, in anatomical and also in physiological terms. By this means, ethical variations among different cultures might be elucidated. This contribution is also paramount for the huge current progress of neuroethics, which is highly complex and influenced by distinct areas of the neuroculture.