Neurological soft signs (NSS) have received continuing interest in psychosis research, particularly schizophrenia. These signs have been shown with significant association with schizophrenia and related psychotic disorders and have been suggested to be the target features as well as one of the promising endophenotype markers linking genotypes and clinical phenotypes for schizophrenia. However, there are several unresolved issues concerning NSS in schizophrenia. One of the main issues is the definition in NSS. NSS have been conventionally considered as clinical neurological signs without localized brain regions. With the advance of neuroimaging technology, evidence has been suggested these NSS are partly localizable and may be associated with deficits in specific brain areas. In collaborating with international collaborators from UK and Australia, Dr. Raymond Chan’s team from the Neuropsychology and Applied Cognitive Neuroscience (NACN) Laboratory, Key Laboratory of Mental Health, Institute of Psychology has attempted to challenge the traditional view of NSS. In so doing, they conducted a meta-analysis of imaging studies to quantitatively review the neural bases of NSS, based on both structural and functional imaging findings, in patients with schizophrenia and related psychotic disorders.
Their findings showed that NSS were associated with atrophy of the precentral gyrus, the cerebellum, the inferior frontal gyrus and the thalamus. For the functional imaging data, their findings indicated that the NSS related task was significantly associated with altered brain activation in the inferior frontal gyrus, bilateral putamen, the cerebellum and the superior temporal gyrus. Taken together, their findings from both structural and functional imaging meta-analyses provide one of the very first evidence to support the conceptualization of NSS as a manifestation of the “cerebello-thalamo-prefrontal” brain network model of schizophrenia and related psychotic disorders. This new orientation of NSS will pave way for more rigorous and well-controlled studies for NSS, which finally helps link genotypes and phenotypes of the complex neuropsychiatric disorders such as schizophrenia.
This study was supported by a grant from the National Science Fund China Outstanding Investigator Award, the National Key Technologies R&D Programme, the Key Laboratory of Mental Health, and the Knowledge Innovation Project of the Chinese Academy of Sciences； the NHMRC Senior Principal Research Fellowship, NARSAD Distinguished Investigator Award, and a grant from the NHMRC Programme Grant.
The paper is now available online in Schizophrenia Bulletin: http://schizophreniabulletin.oxfordjournals.org/content/early/2013/05/13/schbul.sbt063.abstract?sid=e277ec2f-a03a-411d-9810-60e28eda50b7
