Biomedical subjects

Susanne Neufang

Publications and source records attributed to Susanne Neufang.

4 recordsLinked to original sources

PubMed2006

Sex differences in neural mechanisms underlying implicit symmetry processing.

Some species, including humans, prefer symmetrical to asymmetrical patterns. Preferences for symmetrical stimuli could have arisen in both sexes because specialized systems developed to detect and identify symmetrical stimuli, which are more likely to be figure than background. Females, it has been suggested, prefer symmetry because it may provide a cue to biological fitness when choosing a mate. Using functional magnetic resonance imaging, we found sex differences in neural activity when subjects distinguished figure from ground in abstract patterns whose component shapes differed in colour, brightness, and symmetry/asymmetry. Although no participant explicitly reported using symmetry as a decision criterion, women showed more neural activity than men in visual processing areas when the display contained a symmetrical shape. This enhanced activity in occipital cortex (middle and superior occipital gyrus) occurred bilaterally in women irrespective of whether they chose the symmetrical element in the display as the figure. Contrariwise, men showed a significant neural response in right temporal (superior temporal gyrus) and left parietal cortex (inferior parietal cortex/temporo-parietal junction) only when they chose a symmetrical element as the figure. The female brain thus appears to register symmetry automatically as a stimulus attribute, while the differential neurophysiological response of the male brain is dependent upon an explicit behavioural response to symmetry (choosing the symmetrical part of the display as figure), even if the criterion for choice (symmetry) is not reported verbally.

Adult↗

PubMed2006

[Neuroimaging data of ADHD, tic-disorder and obsessive-compulsive-disorder in children and adolescents].

ADHD, Tic Disorder, Tourette's Syndrome, and Obsessive-Compulsive Disorder are all characterised by an impairment of executive functioning and often occur together. There are thus indications of a similar neurobiological basis. This review presents an overview of neuroimaging studies of these disorders in childhood and adolescence, focusing thereby on magnet resonance imaging data. Studies provide concurring data about structural changes in the basal ganglia and the prefrontal cortex, and abnormal activation in the fronto-striatal circuitry in patients as compared to healthy controls. ADHD and Tourette's Syndrome are both associated with prefrontal aberrations. However, variances in Tourette's Syndrome are less pronounced, which might be due to compensation mechanisms. ADHD children show small, but more global, morphological alterations in the cortex and cerebellum, while Tourette's Syndrome seems to be linked additionally to differences in the occipital cortex. Furthermore, structural and functional data for obsessive-compulsive disorder indicate aberrations in the amygdala and thalamus, and functional changes in the orbito-frontal cortex. By comparison, findings in children with ADHD point towards abnormal activity in the ventral prefrontal cortex. To summarise, the data display an impairment of cortico-striato-thalamic circuits which appears to be associated with dysfunctioning motor inhibition, and impulsive behaviour and objectionable thoughts. Since the majority of the studies reviewed are characterised by small and heterogeneous samples, and since the studies differ in their methods, comparability is limited and general conclusions can not be drawn.

Adolescent↗

PubMed2005

Dysfunctional attentional networks in children with attention deficit/hyperactivity disorder: evidence from an event-related functional magnetic resonance imaging study.

BACKGROUND: Although there is evidence for attentional dysfunction in children with attention deficit/hyperactivity disorder (ADHD), the neural basis of these deficits remains poorly understood. METHODS: We used event-related functional magnetic resonance imaging (fMRI) to investigate brain activations related to three particular aspects of attention: alerting, reorienting, and executive control. Sixteen medication-naive boys with ADHD and 16 healthy boys, aged 8 to 12 years, were studied. RESULTS: Behaviorally, children with ADHD showed a significant impairment only in their executive control system compared to healthy subjects. Neurally, children with ADHD (relative to controls) recruited deviant brain regions for all three attentional networks: less right-sided activation in the anterior cingulate gyrus during alerting, more fronto-striatal-insular activation during reorienting, and less fronto-striatal activation for executive control. ADHD symptom severity was associated with dysregulation of the blood oxygen level dependent (BOLD) signal within the putamen during reorienting and executive control. CONCLUSIONS: Our results demonstrated altered brain mechanism in ADHD associated with all three attentional networks investigated. For alerting and executive attention, our data indicate a deviant mechanism of cortical control, while ADHD children may have adopted altered strategies for reorienting of attention. Our results also stress the etiological role of functional abnormalities in the putamen in medication-naive ADHD.

Attention Deficit Disorder with Hyperactivity↗

PubMed2005

Development of attentional networks: an fMRI study with children and adults.

Data on the development of the attentional systems remain scarce. We used structural and event-related functional magnetic resonance imaging to investigate differences in the neural mechanisms associated with alerting, reorienting, and executive control of attention between children (ages 8 to 12 years) and adults, while controlling for effects of performance and brain morphology. Behaviorally, children exhibited a numerically smaller alerting effect and significantly larger invalidity (reorienting) and interference (executive control of attention) effects. Neurally, children showed significantly reduced brain activation in a priori defined regions-of-interest in right-sided frontal-midbrain regions during alerting, in the right-sided temporo-parietal junction during reorienting of attention, and in the dorsolateral prefrontal cortex during executive control of attention. In addition, children activated significantly more brain regions outside the a priori defined regions-of-interest, such as the superior frontal gyrus during reorienting and the superior temporal gyrus during executive control of attention. Functional group differences overlapped with structural group differences in gray matter volume in particular within the frontopolar areas. The data suggest that there is a transition from functional yet immature systems supporting attentional functions in children to the more definitive adult networks and that the differences observed may reflect both developmental changes in cognitive strategies and morphology.

Adult↗