Ruth Spinks

Cerebral cortex: a topographic segmentation method using magnetic resonance imaging

Remarkable developments in magnetic resonance imaging (MRI) technology provide a broad range of potential applications to explore in vivo morphological characteristics of the human cerebral cortex. MR-based parcellation methods of the cerebral cortex may clarify the structural anomalies in specific brain subregions that reflect underlying neuropathological processes in brain illnesses. The present study describes detailed guidelines for the parcellation of the cerebral cortex into 41 subregions. Our method conserves the topographic uniqueness of individual brains and is based on our ability to visualize the three orthogonal planes, the triangulated gray matter isosurface and the three-dimensional (3D) rendered brain simultaneously. Based upon topographic landmarks of individual sulci, every subregion was manually segmented on a set of serial coronal or transaxial slices consecutively. The reliability study indicated that the cerebral cortex could be parcelled reliably; intraclass correlation coefficients for each subregion ranged from 0.60 to 0.99. The validity of the method is supported by the fact that gyral subdivisions are similar to regions delineated in functional imaging studies conducted in our center. Ultimately, this method will permit us to detect subtle morphometric impairments or to find abnormal patterns of functional activation in circumscribed cortical subregions. The description of a thorough map of regional structural and functional cortical abnormalities will provide further insight into the role that different subregions play in the pathophysiology of brain illnesses.

Manual and Automated Measurement of the Whole Thalamus and Mediodorsal Nucleus Using Magnetic Resonance Imaging

The thalamus is an important relay structure in the brain that may be relevant to a variety of brain diseases. It is divided into multiple subnuclei with different cortical connections. The medial dorsal (MD) nucleus is particularly important because it forms key connections with the prefrontal cortex. The current study reports precise and efficient methods for measuring the whole thalamus and the MD with MRI that have a high degree of interrater reliability. A multispectral image acquisition and novel image processing technique were used to improve structure visibility. The tricolor image assigns a color to each of the T1, T2, and PD weighted images, represented by red, green, and blue, respectively. The manually defined regions were then used to train an artificial neural network (ANN) to automatically define both the whole thalamus and the MD. The ANN provides an efficient automated method, making studies using larger sample sizes more feasible.

Attachment as an organizer of behavior: implications for substance abuse problems and willingness to seek treatment

BackgroundAttachment theory allows specific predictions about the role of attachment representations in organizing behavior. Insecure attachment is hypothesized to predict maladaptive emotional regulation whereas secure attachment is hypothesized to predict adaptive emotional regulation. In this paper, we test specific hypotheses about the role of attachment representations in substance abuse/dependence and treatment participation. Based on theory, we expect divergence between levels of maladaptive functioning and adaptive methods of regulating negative emotions.MethodsParticipants for this study consist of a sample of adoptees participating in an ongoing longitudinal adoption study (n = 208). The Semi-Structured Assessment of the Genetics of Alcohol-II [41] was used to determine lifetime substance abuse/dependence and treatment participation. Attachment representations were derived by the Adult Attachment Interview [AAI; [16]]. We constructed a prior contrasts reflecting theoretical predictions for the association between attachment representations, substance abuse/dependence and treatment participation.ResultsLogistic regression was used to test our hypotheses. As predicted, individuals classified as dismissing, preoccupied or earned-secure reported the highest rates of substance abuse/dependence. Individuals classified as dismissing reported significantly lower rates of treatment participation despite their high rates of substance abuse/dependence. As expected, the continuous-secure group reported lowest rates of both substance abuse/dependence and treatment participation.ConclusionThe findings from this study identify attachment representations as an influential factor in understanding the divergence between problematic substance use and treatment utilization. The findings further imply that treatment may need to take attachment representations into account to promote successful recovery.

Globus pallidus volume is related to symptom severity in neuroleptic naive patients with schizophrenia

This study compares globus pallidus (GP) volume between neuroleptic naive patients with schizophrenia and healthy controls using structural MRI. The volume of the external segment of the GP (GPe) was positively correlated with the severity of global symptoms, as measured by the Scale for the Assessment of Negative Symptoms and Scale for the Assessment of Positive Symptoms (SANS/SAPS, Andreasen and Olsen, 1982). The volume for the GP, GPe, and internal segment (GPi) did not differ between groups.

IQ estimate smackdown: Comparing IQ proxy measures to the WAIS-III

Brief assessments of general cognitive ability are frequently needed by neuropsychologists, and many methods of estimating intelligence quotient (IQ) have been published. While these measures typically present overall correlations with the Wechsler Adult Intelligence Scale (WAIS) Full Scale IQ, it is tacitly acknowledged that these estimates are most accurate within 1 standard deviation of the mean and that accuracy diminishes moving toward the tails of the IQ distribution. However, little work has been done to systematically characterize proxy measures at the tails of the IQ distribution. Additionally, while these measures are all correlated with the WAIS, multiple proxy measures are rarely presented in one manuscript. The current article has two goals: (1) Examine various IQ proxies against Wechsler Adult Intelligence Scale (Third Version) scores, showing the overall accuracy of each measure against the gold standard IQ measure. This comparison will assist in selecting the best proxy measure for particular clinical constraints. (2) The sample is then divided into three groups (below, average, and above-average ability), and each group is analyzed separately to characterize proxy performance at the tails of the IQ distribution. Repeated measures multivariate analysis of variance compares the different proxy measures across ability levels. All IQ estimates are represented in tables so that they can be examined side by side.

Association of the HOPA12bp allele with a large X-chromosome haplotype and positive symptom schizophrenia

HOPA is a X‐chromosome gene that encodes an essential nuclear receptor co‐activator. Previously, we have demonstrated that an exonic polymorphism, termed HOPA12bp, in the Opa (Opposite Paired) domain of this gene that is critical for neuronal growth and differentiation is associated with a low risk for schizophrenia. But curiously, we have also noted that all HOPA12bp probands have the same haplotype immediately surrounding the HOPA12bp, and other investigators have found evidence of population stratification with the HOPA12bp allele. Since deleterious alleles are weeded from the population, and the HOPA12bp allele is not rare, these prior findings suggest the possibility that positive selection may be occurring with respect to the HOPA12bp allele and that unique phenotypic features may be associated with this allele. To test these hypotheses, we analyzed symptom data collected from schizophrenic probands and conducted haplotyping studies around the HOPA12bp polymorphism. Consistent with our hypotheses, genotyping studies of 43 unrelated HOPA12bp males and 137 HOPAwild males demonstrated that the HOPA12bp allele is associated with a large conserved DNA haplotype that extends over several genes known to be critical for human survival. Furthermore, ANOVA analysis of symptom data demonstrated that HOPA12bp schizophrenic probands (n = 14) have significantly lower severity of negative symptoms (P < 0.002) and better attention (P < 0.002) than matched controls (n = 30). Taken together, these findings further refine the behavioral endophenotype associated with the HOPA12bp allele and suggest that the sequence surrounding HOPA may need to be considered to fully understand the molecular basis of the phenotype associated with the HOPA12bp allele.

Lifetime Substance Misuse and 5-Year Incidence Rates of Emergent Health Problems Among Middle-Aged Adults

ABSTRACT Understanding the impact of prior substance misuse on emergent health problems is important to the implementation of effective preventive care. This study examined the 5-year incidence rates using a sample of middle-aged adult adoptees (N = 309, meanage = 44.32, standard deviationage = 7.28). Subjects reported on health problems at two waves of study. DSM-IV diagnoses of substance misuse were obtained using a semi-structured diagnostic interview. Finally, health services utilization and perceived health status were collected. Lifetime diagnoses of marijuana and other non-marijuana substance misuse significantly predicted new occurrences of cardiovascular and metabolic disease. Alcohol misuse predicted earlier onset of cardiovascular disease among men. Marijuana and other non-marijuana drugs predicted earlier onset of cardiovascular disease for men and women. Finally, marijuana and other non-marijuana drugs predicted earlier onset of metabolic disease among men. Substance misuse did not predict health services utilization despite higher rates of disease. These findings emphasize the need to assess lifetime substance misuse when evaluating health risks associated with use.

In vivo measurement of the thalamic subregions using contrast-enhanced MRI

1&duction: The thalamus is a major relay nucleus for much of the information processed in the brain; as such the thalamus is of interest to many areas of brain research including, normal development, various pathologies, and aging. The thalamus is a diverse structure, composed of numerous subnuclei serving distinct regions of the cortex. Examination of these subnuclei is necessary for a meaningful examination of deficit syndromes as well as normal functioning of specific cortical regions. The current study examines the major nuclear groups divided using the intramedullary lamina (the anterior, medial, lateral and geniculate nuclei as well as the pulvinar).