Faculty Bibliography

Reelin is an extracellular matrix protein that is crucial for neural development and adult brain plasticity. While the Reelin signalling cascade has been reported to be associated with Alzheimer's disease (AD), the role of Reelin in this pathology is not understood. Here we use an in vitro approach to show that Reelin interacts with amyloid-β (Aβ42) soluble species, delays Aβ42 fibril formation and is recruited into amyloid fibrils. Furthermore, Reelin protects against both the neuronal death and dendritic spine loss induced by Aβ42 oligomers. In mice carrying the APP(Swe/Ind) mutation (J20 mice), Reelin overexpression delays amyloid plaque formation and rescues the recognition memory deficits. Our results indicate that by interacting with Aβ42 soluble species, delaying Aβ plaque formation, protecting against neuronal death and dendritic spine loss and preventing AD cognitive deficits, the Reelin pathway deserves consideration as a therapeutic target for the treatment of AD pathogenesis.

OBJECTIVE:The basal ganglia are implicated in the pathophysiology of attention-deficit/hyperactivity disorder (ADHD), but little is known of their development in the disorder. Here, we mapped basal ganglia development from childhood into late adolescence using methods that define surface morphology with an exquisite level of spatial resolution. METHOD/METHODS:Surface morphology of the basal ganglia was defined from neuroanatomic magnetic resonance images acquired in 270 youth with DSM-IV-defined ADHD and 270 age- and sex-matched typically developing controls; 220 individuals were scanned at least twice. Using linear mixed model regression, we mapped developmental trajectories from age 4 through 19 years at approximately 7,500 surface vertices in the striatum and globus pallidus. RESULTS:In the ventral striatal surfaces, there was a diagnostic difference in developmental trajectories (t = 5.6, p < .0001). Here, the typically developing group showed surface area expansion with age (estimated rate of increase of 0.54 mm(2) per year, standard error [SE] 0.29 mm(2) per year), whereas the ADHD group showed progressive contraction (decrease of 1.75 mm(2) per year, SE 0.28 mm(2) per year). The ADHD group also showed significant, fixed surface area reductions in dorsal striatal regions, which were detected in childhood at study entry and persisted into adolescence. There was no significant association between history of psychostimulant treatment and developmental trajectories. CONCLUSIONS:Progressive, atypical contraction of the ventral striatal surfaces characterizes ADHD, localizing to regions pivotal in reward processing. This contrasts with fixed, nonprogressive contraction of dorsal striatal surfaces in regions that support executive function and motor planning.

Previous work on peer victimization has focused primarily on academic outcomes and negative indicators of youth involved in bullying. Few studies have taken a strength-based approach to examine attributes associated with bullies and victims of bullying. As such, we examined developmental trajectories of moral, performance, and civic character components, and their links to bully status using data from 713 youth (63% female) who participated in Wave 3 (approximately Grade 7) through Wave 6 (approximately Grade 10) of the 4-H Study of Positive Youth Development. Latent growth curve analyses indicated that moral character was stable across waves, whereas civic character increased slightly by Wave 6. Trajectories for performance character varied; some youth alternatively displayed positive versus negative growth. Youth who reported bullying behavior reported lower initial levels of moral, performance, and civic character as compared to youth not involved in bullying. Bully-victims reported lower initial levels of moral and civic character as compared to youth not involved in bullying. Implications for future work examining character-related components in the context of peer victimization are discussed.

Trauma in childhood is a psychosocial, medical, and public policy problem with serious consequences for its victims and for society. Chronic interpersonal violence in children is common worldwide. Developmental traumatology, the systemic investigation of the psychiatric and psychobiological effects of chronic overwhelming stress on the developing child, provides a framework and principles when empirically examining the neurobiological effects of pediatric trauma. This article focuses on peer-reviewed literature on the neurobiological sequelae of childhood trauma in children and in adults with histories of childhood trauma.

Selective attention to phonology, i.e., the ability to attend to sub-syllabic units within spoken words, is a critical precursor to literacy acquisition. Recent functional magnetic resonance imaging evidence has demonstrated that a left-lateralized network of frontal, temporal, and posterior language regions, including the visual word form area, supports this skill. The current event-related potential (ERP) study investigated the temporal dynamics of selective attention to phonology during spoken word perception. We tested the hypothesis that selective attention to phonology dynamically modulates stimulus encoding by recruiting left-lateralized processes specifically while the information critical for performance is unfolding. Selective attention to phonology was captured by manipulating listening goals: skilled adult readers attended to either rhyme or melody within auditory stimulus pairs. Each pair superimposed rhyming and melodic information ensuring identical sensory stimulation. Selective attention to phonology produced distinct early and late topographic ERP effects during stimulus encoding. Data-driven source localization analyses revealed that selective attention to phonology led to significantly greater recruitment of left-lateralized posterior and extensive temporal regions, which was notably concurrent with the rhyme-relevant information within the word. Furthermore, selective attention effects were specific to auditory stimulus encoding and not observed in response to cues, arguing against the notion that they reflect sustained task setting. Collectively, these results demonstrate that selective attention to phonology dynamically engages a left-lateralized network during the critical time-period of perception for achieving phonological analysis goals. These findings suggest a key role for selective attention in on-line phonological computations. Furthermore, these findings motivate future research on the role that neural mechanisms of attention may play in phonological awareness impairments thought to underlie developmental reading disabilities.

Delusional misidentification syndromes may be superimposed on neurological or psychiatric disorders and include delusional beliefs that the people, objects, or places around the patient change or are made to change with one another. In this paper, an adolescent patient displaying Capgras syndrome, metamorphosis, reverse-intermetamorphosis, misidentification of reflection, and reduplicative paramnesia was presented. The findings that our patient struggled with visuospatial tests applied in the acute phase as well as the observation that she refused to meet her family face-to-face while accepting to speak on the phone may support the role of right hemisphere and visuospatial functions in the development of those syndromes. Further studies or case series evaluated more extensively are needed to reveal the relationship between right hemisphere functions and delusional misidentification syndromes.