Neural correlates of working memory deficits in schizophrenic patients. Ways to establish neurocognitive endophenotypes of psychiatric disorders

This article briefly reviews some methodological limitations of functional neuroimaging studies in psychiatric patients. We argue that the investigation of the neural substrates of cognitive deficits in psychiatric disorders requires a combination of functional neuroimaging studies in healthy subjects with corresponding behavioral experiments in patients. In order to exemplify this methodological approach we review recent findings regarding the functional neuroanatomy of distinct components of human working memory and provide evidence for selective dysfunctions of cortical networks that underlie specific working memory deficits in schizophrenia. This identification of subgroups of schizophrenic patients according to neurocognitive parameters may facilitate the establishment of behavioral and neurophysiological endophenotypes and the development of a neurobiological classification of psychiatric disorders.