Consciousness and its alterations in neuropsychology

The problem of consciousness has become important in many recent works on t he cognitive neurosciences and has always been present in the description o f the disorders resulting from brain lesions. In this article, the modifica tions of the states and contents of consciousness are examined in relation to the cognitive disorders resulting from brain lesions. Disorders of consc iousness are observed in anosognosia and when the subject is confronted wit h simultaneously occurring, incoherent or contradictory interpretations of the world or of his own actions. It is suggested that normal subjects are u sually only aware of the result of their cognitive processes. In neuropsych ology some disorders of consciousness can be interpreted either as lack of monitoring of the ongoing processes (anosognosia) or as reflecting the exis tence of contradictions between results of different processing components in a cognitive architecture (which result in fragmented conscious experienc es). Consciousness is also discussed in reference to goal-oriented behaviou r and dysexecutive functions as well as in relation to the functioning and the nature of episodic and autobiographical memory.