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Rubinsten O.,Haifa University | Tannock R.,Neuroscience and Mental Health Research Program | Tannock R.,University of Toronto
Behavioral and Brain Functions | Year: 2010

Background: Math anxiety, defined as a negative affective response to mathematics, is known to have deleterious effects on math performance in the general population. However, the assumption that math anxiety is directly related to math performance, has not yet been validated. Thus, our primary objective was to investigate the effects of math anxiety on numerical processing in children with specific deficits in the acquisition of math skills (Developmental Dyscalculia; DD) by using a novel affective priming task as an indirect measure.Methods: Participants (12 children with DD and 11 typically-developing peers) completed a novel priming task in which an arithmetic equation was preceded by one of four types of priming words (positive, neutral, negative or related to mathematics). Children were required to indicate whether the equation (simple math facts based on addition, subtraction, multiplication or division) was true or false. Typically, people respond to target stimuli more quickly after presentation of an affectively-related prime than after one that is unrelated affectively.Result: Participants with DD responded faster to targets that were preceded by both negative primes and math-related primes. A reversed pattern was present in the control group.Conclusion: These results reveal a direct link between emotions, arithmetic and low achievement in math. It is also suggested that arithmetic-affective priming might be used as an indirect measure of math anxiety. © 2010 Rubinsten and Tannock; licensee BioMed Central Ltd.

LeGris J.,University of Toronto | LeGris J.,McMaster University | Links P.S.,University of Toronto | Van Reekum R.,University of Toronto | And 3 more authors.
Psychiatry Research | Year: 2012

A range of executive function (EF) deficits have been associated with Borderline Personality (BPD), a disorder characterized by high rates of suicide. However, the role of EF and suicide risk in BPD has not been examined. This exploratory study compared working memory, Stroop interference, motor inhibition (SSRT) and Iowa Gambling Task (IGT) decision making performance in 42 women with BPD and 41 healthy controls. The sensitivity of EF to suicidal risk as assessed by the Suicide Behaviour Questionnaire-R (Osman et al., 2001) was also tested. Women with BPD performed similar to controls on all EF except decision making. Weaker Stroop interference control, however, was the only significant EF contributor to suicide risk, demonstrating near equivalent contributions to that of depression. EF and depression collectively explained 34% of the adjusted variance in total suicide risk. Contrary to expectations, IGT decision making and motor inhibition were not associated with overall suicide risk. Only Stroop interference control contributed significantly to lifetime suicide intent/attempt beyond depression or BPD severity. As prior suicide attempt remains the strongest predictor of future attempt (Soloff et al., 2003), the sensitivity of stroop performance to suicidal risk may be clinically important. Interference control may represent a "diathesis" for suicide that is independent of psychiatric diagnoses. © 2012 Elsevier Ltd.

Wheeler S.M.,Neuroscience and Mental Health Research Program | Wheeler S.M.,University of Toronto | McAndrews M.P.,University of Toronto | McAndrews M.P.,Krembil Neuroscience Center | And 3 more authors.
Journal of the International Neuropsychological Society | Year: 2012

Congenital hypothyroidism is a pediatric endocrine disorder caused by insufficient endogenous thyroid hormone production. Children with congenital hypothyroidism have difficulties with episodic memory and abnormalities in hippocampal structure, suggesting deficient hippocampal functioning. To assess hippocampal activation in adolescents with congenital hypothyroidism (N = 14; age range, 11.5-14.7 years) compared with controls (N = 15; age range, 11.2-15.5 years), a functional magnetic resonance imaging visuospatial memory task was used. In this task, participants had to decide if object pairings were novel or were previously studied or if object pairs were in the same location as they were at study or had switched locations. Despite no group differences in task performance, adolescents with congenital hypothyroidism showed both increased magnitude of hippocampal activation relative to controls and bilateral hippocampal activation when only the left was observed in controls. Furthermore, the increased activation in the congenital hypothyroidism group was correlated with the severity of the hypothyroidism experienced early in life. These results suggest that perinatal deprivation of thyroid hormone has longstanding effects on hippocampal function and may account for memory problems experienced by adolescents with congenital hypothyroidism. Copyright © 2011 INS. Published by Cambridge University Press.

Samadi A.,University of Toronto | Samadi A.,Neuroscience and Mental Health Research Program | Skocic J.,Neuroscience and Mental Health Research Program | Rovet J.F.,Neuroscience and Mental Health Research Program | Rovet J.F.,University of Toronto
Thyroid | Year: 2015

Background: Thyroid hormone (TH) is essential for the developing brain, and because the fetal thyroid develops relatively late in gestation, the maternal TH supply is critical for fetal brain development. However, if the mother has hypothyroidism during pregnancy, fetal brain and neuropsychological development may be compromised. Rodents experiencing maternal TH insufficiency show abnormal corpus callosum (CC) morphology, but it is not known if children born to women treated for hypothyroidism (HYPO) show similar effects. The purpose of the current study was to investigate HYPO for CC morphology and morphometry and to determine whether any specific CC abnormalities were associated aspects of maternal hypothyroidism and were correlated with reduced neuropsychological functioning in the children. Methods: ANALYZE software was used to trace CCs in archived magnetic resonance imaging scans from 22 HYPO and 22 matched controls. Areas of two sub-regions and six segments and different shape metrics (angles, lengths, ratios) were determined. CC parameters were correlated with maternal thyrotropin (TSH) values and number of hypothyroid trimesters as well as the child's neuropsychological test performance. Results: HYPO showed a smaller anterior CC and genu and larger posterior CC and splenium areas than controls as well as shape abnormalities in genu and splenium. Results were correlated with the duration of maternal hypothyroidism. Executive function skills were positively associated with genu size in HYPO, while verbal comprehension skills were negatively associated with splenium and overall posterior CC sizes. Conclusions: Maternal hypothyroidism contributes to CC abnormalities in the offspring, and effects differ for anterior versus posterior CC regions. © Mary Ann Liebert, Inc. 2015.

Wheeler S.M.,Neuroscience and Mental Health Research Program | Wheeler S.M.,University of Toronto | Willoughby K.A.,Neuroscience and Mental Health Research Program | Willoughby K.A.,University of Toronto | And 3 more authors.
Journal of Clinical Endocrinology and Metabolism | Year: 2011

Background: Despite early diagnosis and treatment of congenital hypothyroidism (CH) after newborn screening, selective and persistent neurocognitive weaknesses may be seen. One area of particular weakness is memory, especially on tasks known to be mediated by the hippocampus. However, the hippocampus has not been directly studied in this population. Objective: Our objective was to use magnetic resonance imaging to determine whether children and adolescents with CH have reduced hippocampal size and abnormal hippocampal growth patterns relative to peers and whether reduced hippocampal volumes in CH predict poor memory performance. Methods: Studied were 35 CH and 44 typically developing controls aged 9-15 yr. All were assessed using standardized tests of intelligence and verbal and visual memory and received an magnetic resonance imaging scan. Parents completed a questionnaire of their everyday memory functioning (EMF). Right and left hippocampal volumes were measured by manual tracing. Results: CH subjects scored significantly below controls on indices of verbal but not visual memory as well as aspects of EMF. CH subjects also had smaller hippocampal volumes, particularly on the left side. Unlike controls, who showed a positive relationship between age and hippocampal volumes, age was unrelated to hippocampal size in CH. Structure-function correlations revealed significant relationships between hippocampal volumes and EMF in controls and modest correlations between hippocampal volumes and memory test scores but not EMF in CH. Conclusions: Compromised hippocampal development in CH may contribute to some of the memory weaknesses observed in this population. Copyright © 2011 by The Endocrine Society.

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