Robin A. Hurley

Common data elements in radiologic imaging of traumatic brain injury.

Traumatic brain injury (TBI) has a poorly understood pathology. Patients suffer from a variety of physical and cognitive effects that worsen as the type of trauma worsens. Some noninvasive insights into the pathophysiology of TBI are possible using magnetic resonance imaging (MRI), computed tomography (CT), and many other forms of imaging as well. A recent workshop was convened to evaluate the common data elements (CDEs) that cut across the imaging field and given the charge to review the contributions of the various imaging modalities to TBI and to prepare an overview of the various clinical manifestations of TBI and their interpretation. Technical details regarding state‐of‐the‐art protocols for both MRI and CT are also presented with the hope of guiding current and future research efforts as to what is possible in the field. Stress was also placed on the potential to create a database of CDEs as a means to best record information from a given patient from the reading of the images. J. Magn. Reson. Imaging 2010;32:516–543.

White matter compromise in veterans exposed to primary blast forces.

Objective:Use diffusion tensor imaging to investigate white matter alterations associated with blast exposure with or without acute symptoms of traumatic brain injury (TBI). Participants:Forty-five veterans of the recent military conflicts included 23 exposed to primary blast without TBI symptoms, 6 having primary blast with mild TBI, and 16 unexposed to blast. Design:Cross-sectional case-control study. Main Measures:Neuropsychological testing and diffusion tensor imaging metrics that quantified the number of voxel clusters with altered fractional anisotropy (FA) radial diffusivity, and axial diffusivity, regardless of their spatial location. Results:Significantly lower FA and higher radial diffusivity were observed in veterans exposed to primary blast with and without mild TBI relative to blast-unexposed veterans. Voxel clusters of lower FA were spatially dispersed and heterogeneous across affected individuals. Conclusion:These results suggest that lack of clear TBI symptoms following primary blast exposure may not accurately reflect the extent of brain injury. If confirmed, our findings would argue for supplementing the established approach of making diagnoses based purely on clinical history and observable acute symptoms with novel neuroimaging-based diagnostic criteria that “look below the surface” for pathology.

Neuroanatomy of Dopamine: Reward and Addiction

Abnormalities of the physiological reward system are believed to play a major part in many serious psychiatric disorders, such as substance abuse, pathological gambling, and major depression. Motivation that involves liking, wanting, craving, and learning about pleasurable events and behavior is heavily influenced by the circuitry of the dopamine reward system, which plays a major role in both normal reward behavior and pathological behavior and addiction. In this Windows to the Brain article, the authors elucidate the mechanisms of this system.

The Differential Diagnosis of Pseudobulbar Affect (PBA): Distinguishing PBA Among Disorders of Mood and Affect

This monograph summarizes the proceedings of a roundtable meeting convened to discuss pseudobulbar affect (PBA). Two didactic lectures were presented followed by a moderated discussion among 11 participants. Post-meeting manuscript development synthesized didactic- and discussion-based content ad incorporated additional material from the neuroscience literature. A conceptual framework with which to distinguish between disorders of mood and affect is presented first, and disorders of affect regulation are then reviewed briefly. A detailed description of the most common of these disorders, PBA, is the focus of the remainder of the monograph. The prevalence, putative neuranatomic and neurochemical bases of PBA are reviewed, and current and emerging methods of evaluation and treatment of persons with PBA are discussed. The material presented in this monograph will help clinicians better recognize, diagnose, and treat PBA, and will form a foundation for understanding and interpreting future studies of this condition.

The Dynamic Brain: Neuroplasticity and Mental Health

This issues Windows to the Brain series describes the ways in which the adult brain, once thought to be “fixed and stable,” adapts to and recovers from various “brain-altering” conditions. The processes of neurogenesis, migration, and pruning do, in fact, occur in response to both learning and injury. These processes may include synapse-formation, axonal sprouting, and dendritic remodeling, which can be demonstrated with currently-available labeling techniques that highlight newly proliferated cells. Factors such as environmental enrichment, exercise, and learning, and treatment approaches such as ECT and long-term antidepressant administration have been associated with increased neurogenesis; whereas chronic stress, illness, and depression have been correlated with decreased neurogenesis.

Central Pontine Myelinolysis: A Metabolic Disorder of Myelin

This issues Windows to the Brain series describes this heterogeneous condition, in which demyelinization occurs because of nutritional or electrolyte stress, that is, imbalance due to overly-rapid correction of hyponatremia, often in the presence of alcoholism, liver disease, immunosuppression after transplantation, malnutrition, renal disease, cancer, pregnancy, and in high-endurance exercise. The authors describe evaluation procedures and the considerable variation in clinical course and outcome.

Oxytocin and Behavior: Evidence for Effects in the Brain

This installment of the Windows to the Brain series offers an overview of oxytocins many and varied effects, sites of action in the brain, and stimuli that are implicated in its actions. These include response to infant behavior, such as laughing or crying, “falling in love,” and abandonment.

Update on Mild Traumatic Brain Injury: Neuropathology and Structural Imaging

In this installment of the Windows to the Brain series, the authors present detailed, graphic representation of neuronal injury for all levels of traumatic brain injury (TBI), including mild. We see representation of the swollen axon profiles characteristic of the “diffuse axonal injury” that produces transient focal deformations resulting from applied forces such as angular acceleration, pressure, and ballistic trauma, and, over time, the localized swelling that can become sufficient to rupture the axon. A challenge for the clinical follow-up of mild TBI is the presence of considerable differences across patients in the anatomic distribution of affected areas.

Latent Toxoplasmosis gondii: Emerging Evidence for Influences on Neuropsychiatric Disorders

Toxoplasmosis gondii (T. gondii) an intracellular parasite discovered in 1908, is present in about one-third of the world’s population; once infected, hosts remain seropositive for life. (Known exposure risks are feline feces; raw or undercooked meat; raw oysters, clams, and mussels; and unwashed raw fruits and vegetables.) Various studies worldwide have found personality/adjustment difficulties, such as increased anxiety, in otherwise-healthy seropositive individuals, and seropositivity in schizophrenia patients was found to be almost three times that of a control population. Unlike the acute form, chronic latent T. gondii infection resides in intact neurons; and there is considerable variation in findings of structures affected, although there does appear to be a predilection for dopaminergic neurons.

Diagnosis and Treatment of Neuropsychiatric Disorders

Neuropsychiatry is the subspecialty of psychiatry that deals with disorders at the intersection of neurology and psychiatry. Neuropsychiatric disorders are complex and incompletely understood. Neuroscience research is beginning to elucidate the biological underpinnings of many of these disorders. These advances have the potential to improve diagnosis, inform treatment selection, and facilitate development of new and better interventions.