A previous review of the neuroimaging studies in obstructive sleep apnea (OSA) called for specific attention to longitudinal studies of the treatment effects of OSA on neuroimaging. This chapter focuses on those studies where treatment effects were considered. The structural studies suggest that there are some notable changes in the structure of the human brain when continuous positive airway pressure (CPAP) is used to correct OSA. Some of these changes are even associated with cognitive changes in the expected cognitive domains and are seen with as little as only three months of treatment. The functional imaging studies together suggest that changes in brain function associated with working memory are evident when comparing treatment with no-treatment conditions in patients with OSA. Specifically, treatment often results in the recruitment of fewer cognitive resources to perform at the same level or better.

This chapter reviews functional neuroimaging findings in the dorsal and ventral systems, as well as in other brain regions. Multiple functional imaging studies indicate basal ganglia dysfunction in bipolar disorder (BD). The chapter provides a more generalized review of functional abnormalities of the prefrontal cortex (PFC) in BD. Several functional magnetic resonance imaging (fMRI) studies have demonstrated primary motor cortex and supplementary motor area (SMA) dysfunction in BD. Functional imaging studies of pediatric BD to date have found evidence of abnormalities of the dorsal and ventral emotional control systems as well as other brain regions also implicated in adult BD. The studies reviewed in the chapter provide compelling evidence of dorsal and ventral system dysregulation in BD. The chapter provides considerable evidence of dysfunction in other brain regions including temporal, posterior cingulate, motor, parietal, occipital, and cerebellar regions. Most studies have examined medicated subjects, which introduce a significant potential confound.

Studies of glucose metabolism and blood flow have suggested a variety of global and focal brain abnormalities in autism. The accurate diagnosis and careful description of associated features of the subjects are essential criteria for obtaining meaningful functional imaging data. The majority of the functional imaging studies published to date have utilized clinical diagnoses of autism based upon DSM-III-R, DSMIV or ICD-10 criteria. This chapter presents a detailed discussion on functional imaging studies in autistic subjects. It is difficult to scan young children and to obtain appropriate age-matched controls; consequently, the majority of functional imaging studies of autistic subjects have employed adolescents and adults. The chapter discusses the problems that need to be addressed in future studies of autism. It is clear that functional imaging studies in young children, as well as new strategies for the assessment of developmental functional imaging data, are necessary to advance our understanding of autism.

This chapter discusses the numerous conflicting findings produced by a wide variety of functional imaging studies in Tourette's syndrome (TS) performed by different investigators under different experimental protocols over a large number of years. Superficially, the behavioral phenotypes of TS, obsessive-compulsive disorder (OCD), and attention-deficit hyperactivity disorder (ADHD) differ dramatically: one consists of motor and vocal tics. Another consists of obsessions and compulsions, and yet another consists of inattention, hyperactivity, and impulsivity. The phenomenology of TS introduces numerous potential confounds that can seriously impair our ability to interpret adequately the findings from functional imaging studies. The orbitofrontal cortex is interconnected with the anterior cingulate and other limbic structures. The cingulate cortex is a heterogeneous structure that probably is a component in most of the major cortico-striato-thalamo-cortical (CSTC) pathways: the supplementary motor area, orbitofrontal cortex and temporolimbic circuits.