Alternative-based thresholding with application to presurgical fMRI

Functional magnetic reasonance imaging (fMRI) plays an important role in pre-surgical planning for patients with resectable brain lesions such as tumors. With appropriately designed tasks, the results of fMRI studies can guide resection, thereby preserving vital brain tissue. The mass univariate approach to fMRI data analysis consists of performing a statistical test in each voxel, which is used to classify voxels as either active or inactive—that is, related, or not, to the task of interest. In cognitive neuroscience, the focus is on controlling the rate of false positives while accounting for the severe multiple testing problem of searching the brain for activations. However, stringent control of false positives is accompanied by a risk of false negatives, which can be detrimental, particularly in clinical settings where false negatives may lead to surgical resection of vital brain tissue. Consequently, for clinical applications, we argue for a testing procedure with a stronger focus on preventing false negatives. We present a thresholding procedure that incorporates information on false positives and false negatives. We combine two measures of significance for each voxel: a classical p-value, which reflects evidence against the null hypothesis of no activation, and an alternative p-value, which reflects evidence against activation of a prespecified size. This results in a layered statistical map for the brain. One layer marks voxels exhibiting strong evidence against the traditional null hypothesis, while a second layer marks voxels where activation cannot be confidently excluded. The third layer marks voxels where the presence of activation can be rejected.     

Folk concepts and intuitions: from philosophy to cognitive science

Analytic philosophers have long used a priori methods to characterize folk concepts such as knowledge, belief and wrongness. Recently, researchers have begun to exploit social scientific methodologies to characterize such folk concepts. One line of work has explored folk intuitions with cases that are disputed within philosophy. A second approach, with potentially more radical implications, applies the methods of cross-cultural psychology to philosophical intuitions. Recent work in this area suggests that people in different cultures have systematically different intuitions surrounding folk concepts. A third strand of research explores the emergence and character of folk concepts in children. These approaches to characterizing folk concepts provide important resources that will supplement, and perhaps in some cases displace, a priori approaches.     

Comorbid Substance Use and Anxiety Disorders in Adolescents

To explore the coexistence of substance use disorders and anxiety disorders in adolescents, we assessed adolescents presenting for treatment to an inpatient substance abuse treatment facility (SUH), an inpatient psychiatric treatment facility (IPH), and a community-based psychiatric facility (CMHC) for comorbid substance use and psychiatric diagnoses. Thirty subjects from each facility (N=90) were interviewed using the revised Child Schedule for Affective Disorders and Schizophrenia (K-SADS) and the Structured Clinical Interview DSM-III-R (SCID-R) for substance use diagnoses. Overall, comorbidity (anxiety and substance use disorders) prevalence was 67% (20/30) of adolescents in the SUH group, 33% (10/30) of the CMHC adolescents, and 33% (10/30) of the IPH adolescents. Alcohol and marijuana were the most frequently abused substances. Anxiety disorders commonly coexist with substance use disorders in adolescents. Early identification and treatment of anxiety disorders may in fact prevent substance abuse in this population.