Joseph Hilferty

Ventro-Striatal Reductions Underpin Symptoms of Hyperactivity and Impulsivity in Attention-Deficit/Hyperactivity Disorder

BACKGROUND Models of attention-deficit/hyperactivity disorder (ADHD) classically emphasize the relevance of executive processes and, recently, reward circuits. The neural bases of reward processes have barely been explored in relation to this disorder, in contrast to extensive neuroimaging studies that examine executive functions in patients with ADHD. To our knowledge, no previous studies have analyzed the volume of the ventral striatum, a key region for reward processes in ADHD children. METHODS We used a manual region-of-interest approach to examine whether there were volumetric differences in the ventral striatum of ADHD children. Forty-two children/adolescents with ADHD (ages 6-18), and 42 healthy control subjects matched on age, gender, and handedness were selected for the study. RESULTS The ADHD children presented significant reductions in both right and left ventro-striatal volumes (t = 3.290, p = .001; and t = 3.486, p = .001, respectively). In addition, we found that the volume of the right ventral striatum negatively correlated with maternal ratings of hyperactivity/impulsivity (r = -.503, p = .003). CONCLUSIONS Our study provides neuroanatomical evidence of alterations in the ventral striatum of ADHD children. These findings coincide with previous explicative models as well as with recent reports in behavioral and functional neuroimaging studies. Furthermore, the negative correlations we observed strongly uphold the relation between the ventral striatum and symptoms of hyperactivity/impulsivity.

Quantitative MR analysis of caudate abnormalities in pediatric ADHD: Proposal for a diagnostic test

Most morphometric magnetic resonance imaging (MRI) studies of pediatric attention-deficit/hyperactivity disorder (ADHD) with appropriate sample sizes reveal a decreased right caudate nucleus volume. Recently, our group reported that this decrease is mainly due to a diminished right caudate body volume (rCBV). Here, we hypothesize that, employing either the total bilateral caudate volume (tbCV) or the bilateral caudate body volume (bCBV) as scaling variables, the rCBV/tbCV and rCBV/bCBV ratios could be found diminished and used as a basis of an imaging diagnostic test. Volumetric caudate nucleus data were obtained from a case-control morphometric MRI study with 39 ADHD subjects and 39 handedness- and IQ-matched controls, using a novel semi-automated caudate segmentation procedure. Student t-tests comparing each relevant ratio were conducted between the two samples. After splitting the samples into two groups, a receiving operator characteristic (ROC) analysis was conducted on the training group to determine the optimal cut-off. Its performance was then examined on the test group. The rCBV/bCBV ratio was found to be statistically different. For a value equal or inferior to 0.48, the specificity was 95.00%. We propose using the rCBV/bCBV ratio to assist in the diagnosis of ADHD in children.

The neuroimaging of sacred values

Sacred (or protected) values (SVs) constitute core beliefs that define primary reference groups. There is significant research on SVs at a behavioral level, but their neural underpinnings are just beginning to be discovered. In this paper, we highlight the current state of neuroimaging research concerning SVs. Given that SVs are considered to be strongly motivated by moral principles, we first provide an outline of the neural circuits that have been found to be involved in moral cognition. We then review various neuroimaging studies that have explored the notion of SVs. Specifically, we concentrate on neuroimaging studies dealing with intergroup bias and those that focus on social norms, since these are two basic dimensions of SVs that have been studied with neuroimaging techniques. Finally, we review two studies that have directly addressed SVs with neuroimaging techniques, and we offer suggestions for further avenues of study.

The neuroanatomical basis of panic disorder and social phobia in schizophrenia: a voxel based morphometric study.

Objective It is known that there is a high prevalence of certain anxiety disorders among schizophrenic patients, especially panic disorder and social phobia. However, the neural underpinnings of the comorbidity of such anxiety disorders and schizophrenia remain unclear. Our study aims to determine the neuroanatomical basis of the co-occurrence of schizophrenia with panic disorder and social phobia. Methods Voxel-based morphometry was used in order to examine brain structure and to measure between-group differences, comparing magnetic resonance images of 20 anxious patients, 20 schizophrenic patients, 20 schizophrenic patients with comorbid anxiety, and 20 healthy control subjects. Results Compared to the schizophrenic patients, we observed smaller grey-matter volume (GMV) decreases in the dorsolateral prefrontal cortex and precentral gyrus in the schizophrenic-anxiety group. Additionally, the schizophrenic group showed significantly reduced GMV in the dorsolateral prefrontal cortex, precentral gyrus, orbitofrontal cortex, temporal gyrus and angular/inferior parietal gyrus when compared to the control group. Conclusions Our findings suggest that the comorbidity of schizophrenia with panic disorder and social phobia might be characterized by specific neuroanatomical and clinical alterations that may be related to maladaptive emotion regulation related to anxiety. Even thought our findings need to be replicated, our study suggests that the identification of neural abnormalities involved in anxiety, schizophrenia and schizophrenia-anxiety may lead to an improved diagnosis and management of these conditions.

The availability of cues for word segmentation and vocabulary acquisition in Catalan child-directed speech

Varios estudios previos han senalado ya la utilidad del tipo de lenguaje que las madres utilizan para dirigirse a sus hijos en el aprendizaje de lenguas, ya que dicho lenguaje ha demostrado ser de ayuda en varias de las tareas a las que los aprendices de primeras lenguas se enfrentan. En concreto, investigaciones recientes sugieren que el tipo de simplificaciones estructurales y lexicas a las que los ninos estan expuestos (es decir, la longitud de los enunciados maternos y la redundancia lexica en su discurso) son particularmente utiles para una segmentacion inicial de palabras en el discurso oral. Mientras que la mayoria de los estudios se centran en el ingles, se sabe poco acerca de las caracteristicas y los efectos que el discurso materno puede tener en otras lenguas. El presente estudio tiene como objetivo aportar evidencia de la utilidad del discurso materno en catalan a partir del analisis de fragmentos del lenguaje dirigido a ninos aprendices de esta lengua.

Mothers, lies, and bachelors: A brief reply to Wierzbicka (1990)

AbstractAnna Wierzbickas work on semantics is well known not only for her genuinely insightful analyses, but also for her harsh criticisms. This note contests some of Wierzbickas claims of alleged “prototype abuse” in her controversial article, ‘“Prototypes save’: On the uses and abuses of the notion of ‘prototype’ in linguistics and related fields” (Wierzbicka 1990). In particular, I argue that the criticisms Wierzbicka levels at the cognitive-model approach to meaning are largely unfounded and that the definition-based account she presents as superior is actually the less-convincing alternative.