Biomedical subjects

Jessica Turner

Publications and source records attributed to Jessica Turner.

3 recordsLinked to original sources

PubMed2005

Parametric response surface models for analysis of multi-site fMRI data.

Analyses of fMRI brain data are often based on statistical tests applied to each voxel or use summary statistics within a region of interest (such as mean or peak activation). These approaches do not explicitly take into account spatial patterns in the activation signal. In this paper, we develop a response surface model with parameters that directly describe the spatial shapes of activation patterns. We present a stochastic search algorithm for parameter estimation. We apply our method to data from a multi-site fMRI study, and show how the estimated parameters can be used to analyze different sources of variability in image generation, both qualitatively and quantitatively, based on spatial activation patterns.

Algorithms↗

PubMed2004

Hostility differentiates the brain metabolic effects of nicotine.

The brain mechanisms underlying the cause of nicotine dependence are unknown, however, hostility traits are associated with increased susceptibility to nicotine dependence. We used FDG PET to measure brain metabolic response to nicotine administered by patch while the subject performed the Bushman aggression task in 86 high- and low-hostility subjects. Low-hostility trait subjects demonstrated no significant change in brain metabolic response to nicotine. In marked contrast, high-hostility non-smokers subjects demonstrated dramatic metabolic changes to low dose (3.5 mg patch) as did high-hostility smokers to high dose nicotine (21 mg patch) throughout the brain bilaterally (p<0.025). Correlational analyses demonstrated greater metabolic changes in response to nicotine in subjects with greatest hostility trait measures. The observed differences were not a consequence of plasma nicotine or cotinine levels. These metabolic changes were not observed when subjects performed a sustained attentional task (continuous performance task; CPT). Behaviorally, high-hostility subjects had higher ratings of anger, impatience, irritability and nervousness, and lower ratings of happiness, relaxation and curiosity than low-hostility subjects. Smokers had significantly greater scores on impatience and restlessness than non-smokers. This PET study demonstrates a conspicuous lack of the brain metabolic response to nicotine in low-hostility non-smokers in contrast to a dramatic brain response to nicotine in high hostility subjects. This biological difference in brain metabolic response to nicotine between high and low hostility trait subjects may explain differences in susceptibility to nicotine dependence.

Adolescent↗

PubMedDate not supplied

Sex-related hemispheric lateralization of amygdala function in emotionally influenced memory: an FMRI investigation.

The amygdala appears necessary for enhanced long-term memory associated with emotionally arousing events. Recent brain imaging investigations support this view and indicate a sex-related hemispheric lateralization exists in the amygdala relationship to memory for emotional material. This study confirms and further explores this finding. Healthy men and women underwent functional Magnetic Resonance Imaging (fMRI) while viewing a series of standardized slides that were rated by the subjects as ranging from emotionally neutral to highly arousing. Two weeks later, memory for the slides was assessed in an incidental recognition test. The results demonstrate a significantly stronger relationship in men than in women between activity of the right hemisphere amygdala and memory for those slides judged as arousing, and a significantly stronger relationship in women than in men between activity of the left hemisphere amygdala and memory for arousing slides. An ANOVA confirmed a significant interaction between sex and hemisphere regarding amygdala function in memory. These results provide the strongest evidence to date of a sex-related hemispheric lateralization of amygdala function in memory for emotional material. Furthermore, they underscore the view that investigations of neural mechanisms underlying emotionally influenced memory must anticipate, and begin to account for, the apparently substantial influence of sex.

Adult↗