Position emission tomography using 6-FDOPA as a marker of presynaptic dopaminergic activity was used to investigate the role of the dopamine system in stuttering. Three patients with moderate to severe developmental stuttering were compared with six normal controls. Stuttering subjects showed significantly higher 6-FDOPA uptake than normal controls in medial prefrontal cortex, deep orbital cortex, insular cortex, extended amygdala, auditory cortex and caudate tail. Elevated 6-FDOPA uptake in ventral limbic cortical and subcortical regions is compatible with the hypothesis that stuttering is associated with an overactive presynaptic dopamine system in brain regions that modulate verbalization.

No abstract

Although a hallmark of Alzheimer's disease (AD) is memory impairment, there is speculation that recall may be enhanced when an emotional component is associated with an event. The current study aims to assess whether patients with AD would recall emotionally laden material better than neutral stimuli. DSM-IV-diagnosed AD patients with mild to moderate dementia, as well as groups of young and elderly healthy controls, participated in this study. All subjects were administered three word lists for three trials each. The words were positive, negative, or neutral in valence and matched for concreteness, emotionality, and pleasantness. As expected, the controls performed significantly better than the AD patients. Importantly, the pattern of recall for the emotions was different, such that both control groups recalled all emotions equally, whereas the AD patients recalled significantly more negative words than positive or neutral. These findings of improved immediate memory for emotional material in AD lends support to the notion that mnemonic functions are differentially affected in the disease.