Biomedical subjects

K R Laurens

Publications and source records attributed to K R Laurens.

5 recordsLinked to original sources

PubMed2004

Changes in distributed neural circuitry function in patients with first-episode schizophrenia.

BACKGROUND: A number of functional brain abnormalities have been reported in schizophrenia, but it remains to be determined which of them represent trait and state markers of the illness. AIMS: To delineate regional brain dysfunctions that remain stable and those that fluctuate during the course of schizophrenia. METHOD: A cohort of patients with first-episode schizophrenia and a matched group of control participants underwent functional magnetic resonance imaging on two occasions 6-8 weeks apart during performance of a working memory task. The patients' disease was in partial remission at the second scan. RESULTS: Relative to control participants, the function of the left dorsolateral prefrontal cortex, left thalamus and right cerebellum remained disturbed in the people with schizophrenia, whereas the dysfunction of the right dorsolateral prefrontal cortex, right thalamus, left cerebellum and cingulate gyrus normalised, with significant reduction in symptoms. CONCLUSIONS: These results suggest that dysfunction of the left fronto-thalamo-cerebellar circuitry is a relatively stable characteristic of schizophrenia, whereas disturbance of the right circuitry and cingulate gyrusis predominantly a state-related phenomenon.

Adult↗

PubMed2001

The role of the anterior cingulate cortex in conflict processing: evidence from reverse stroop interference.

A recent theoretical account delineated the role of the anterior cingulate cortex (ACC) in cognitive control as the detection of conflict between competing information streams. Using functional magnetic resonance imaging, we examined the activity of this brain structure during different forms and degrees of conflict between the word and the color dimensions of Stroop stimuli. Overall, our results showed a dissociation between the degree of conflict and ACC activation. More specifically, although ACC activation was very extensive when print color interfered with word reading performance, the level of conflict, as measured by reaction time costs, was only moderate compared to other conditions. These results suggest that either the ACC is differentially sensitive to various types of conflict or its function should be extended to include other cognitive constructs, such as resolution of prior inhibition.

Adult↗

PubMed2001

Neural sources involved in auditory target detection and novelty processing: an event-related fMRI study.

We used event-related functional magnetic resonance imaging (erfMRI) techniques to examine the cerebral sites involved with target detection and novelty processing of auditory stimuli. Consistent with the results from a recent erfMRI study in the visual modality, target processing was associated with activation bilaterally in the anterior superior temporal gyrus, inferior and middle frontal gyrus, inferior and superior parietal lobules, anterior and posterior cingulate, thalamus, caudate, and the amygdala/hippocampal complex. Analyses of the novel stimuli revealed activation bilaterally in the inferior frontal gyrus, insula, inferior parietal lobule, and in the inferior, middle, and superior temporal gyri. These data suggest that the scalp recorded event-related potentials (e.g., N2 and P3) elicited during similar tasks reflect an ensemble of neural generators located in spatially remote cortical areas.

Acoustic Stimulation↗

PubMed1999

Early intervention and prevention of anxiety disorders in children: results at 2-year follow-up.

The Queensland Early Intervention and Prevention of Anxiety Project evaluated a child- and family-focused group intervention for preventing anxiety problems in children. This article reports on 12- and 24-month follow-up data to previously reported outcomes at posttreatment and at 6-month follow-up. A total of 1,786 7- to 14-year-olds were screened for anxiety problems using teacher nominations and children's self-report. After diagnostic interviews, 128 children were selected and assigned to either a 10-week school-based child- and parent-focused psychosocial intervention or a monitoring group. Both groups showed improvements immediately at postintervention and at 6-month follow-up; the improvement was maintained in the intervention group only reducing the rate of existing anxiety disorder and preventing the onset of new anxiety disorders. At 12 months, the groups converged, but the superiority of the intervention group was evident again at 2-year follow-up. Severity of pretreatment diagnoses, gender, and parental anxiety predicted poor initial response to intervention, whereas pretreatment severity was the only predictor of chronicity at 24 months. Overall, follow-up results show that a brief school-based intervention for children can produce durable reductions in anxiety problems.

Adolescent↗

PubMed1997

Prevention and early intervention for anxiety disorders: a controlled trial.

The Queensland Early Intervention and Prevention of Anxiety Project evaluated the effectiveness of a cognitive-behavioral and family-based group intervention for preventing the onset and development of anxiety problems in children. A total of 1,786 7- to 14-year-olds were screened for anxiety problems using teacher nominations and children's self-report. After recruitment and diagnostic interviews, 128 children were selected and assigned to a 10-week school-based child- and parent-focused psychosocial intervention or to a monitoring group. Both groups showed improvements immediately postintervention. At 6 months follow-up, the improvement maintained in the intervention group only, reducing the rate of existing anxiety disorder and preventing the onset of new anxiety disorders. Overall, the results showed that anxiety problems and disorders identified using child and teacher reports can be successfully targeted through an early intervention school-based program.

Adolescent↗