Laurie M McCormick | Search PubMed

PubMed2006

Anterior cingulate cortex: an MRI-based parcellation method.

OBJECTIVE: The anterior cingulate cortex (ACC) is an important part of the limbic system involved in emotions, cognition and executive function. The ACC has structurally distinct subregions, both microscopically and functionally, that have been implicated in several major psychiatric disorders. However, a structural analysis of these subregions with magnetic resonance imaging (MRI) has not been done. Our main purpose was to develop an MRI-based parcellation method of the ACC that permits us to explore plausible abnormalities in 4 functionally relevant subregions: dorsal, rostral, subcallosal and subgenual. METHODS: The reliability study for gray matter volume and surface area of each subregion was performed on 14 randomly selected MR scans by 3 different raters. Our method posits to conserve the topographic uniqueness of individual brains and is based on our ability to visualize both the 3-dimensional rendered brain and the 3 orthogonal planes simultaneously with BRAINS2 software. We developed rules to hand-trace regions of interest (ROI) to surround contiguous areas of gray matter for dorsal, rostral, subcallosal and subgenual regions. The ACC was then parcellated into these 4 distinct subregions (8 when both right and left hemispheres were measured). RESULTS AND DISCUSSION: The intraclass R coefficients for gray matter volume of each subregion ranged between 0.85 and 0.93. The current study describes a new highly reliable and reproducible topography-based parcellation method of the ACC into its dorsal, rostral, subcallosal and subgenual regions. CONCLUSIONS: This new parcellation method provides a new means of exploring the role of the functionally and structurally distinct subregions of the ACC in schizophrenia, depression and various other brain illnesses.

Cerebral Cortex↗

PubMed2005

Diagnosing schizophrenia circa 2005: how and why?

Since the introduction of the third edition of the Diagnostic and Statistical Manual of Mental Disorders, Third Edition in 1980, schizophrenia has been widely diagnosed with good to excellent levels of reliability. This is no small feat, as prior to the 1970s the reliability of this diagnosis over time and place was very poor. Although there have been some changes in the diagnostic algorithm for schizophrenia with subsequent revisions of the Diagnostic and Statistical Manual of Mental Disorders, there has been little change in the overall classification scheme. However, there has also been relatively little movement toward enhancing the validity of this diagnosis. Although there is broad consensus that what we now call schizophrenia is probably very heterogeneous with respect to underlying etiology and pathophysiology, attempts to identify more valid subtypes or dimensions have not progressed to the point that they are likely to be incorporated into diagnostic systems any time soon. The limited progress in defining more valid disease categories has increasingly important clinical implications as the field moves more and more to treatment by preset algorithms that are typically driven by diagnosis.

Algorithms↗