Molecular and cellular mechanisms behind brain functioning

Research in functional brain mapping involves a series of procedures conducive to publishing of false findings. Statisticians and psychologists have warned that false findings are particularly common in research characterized by small sample size, undefined effect size, low prior probability of true findings, unsubstantiated assumptions, flexible data analyses, and confir-matory bias. I discuss how these factors can increase the probability of publishing false-positive findings in functional brain mapping and describe ways of reducing the likelihood that published findings in that field are false. Abstract: Structural changes in multiple brain regions have frequently been reported in first episode schizophrenic patients. Most studies have manually delineated the regions of interest. Few studies have used voxel-based morphometry (VBM) to test for groups differences in local gray matter concentration/volume throughout the brain. This study aimed to identify possible structural brain changes in 30 antipsychotic-na¨ıve first episode schizophrenic patients as compared to 17 matched healthy controls by means of optimized VBM. We hypothesized that the patients would have less whole brain and total gray matter volume, and have enlarged ventricles. Moreover, regionally we expected patients to exhibit reduced frontal (especially dorsolateral pre-frontal, DLPC), temporal (especially superior temporal, STG), and amygdala-hippocampal (AH) gray matter volumes. All subjects underwent MRI on a 3 Tesla TRIO Siemens scanner. Image processing largely followed optimized VBM procedures using SPM2. VBM analyses did not reveal any group differences in the a priori hypothesized brain regions and no group differences emerged in exploratory analyses. Our results do not seem to support the presence of global and (large) regional specific structural brain changes in antipsychotic-na¨ıve first episode schizophrenic patients. It is possible that VBM was not sensitive enough to detect the often subtle changes observed in studies that have used manual delineation. It should be emphasised that our results are based on preliminary data and that recruitment of subjects is still ongoing.