Independent Component Analysis of the Effect of L-dopa on fMRI of Language Processing

L-dopa, which is a precursor for dopamine, acts to amplify strong signals, and dampen weak signals as suggested by previous studies. The effect of L-dopa has been demonstrated in language studies, suggesting restriction of the semantic network. In this study, we aimed to examine the effect of L-dopa on language processing with fMRI using Independent Component Analysis (ICA). Two types of language tasks (phonological and semantic categorization tasks) were tested under two drug conditions (placebo and L-dopa) in 16 healthy subjects. Probabilistic ICA (PICA), part of FSL, was implemented to generate Independent Components (IC) for each subject for the four conditions and the ICs were classified into task-relevant source groups by a correlation threshold criterion. Our key findings include: (i) The highly task-relevant brain regions including the Left Inferior Frontal Gyrus (LIFG), Left Fusiform Gyrus (LFUS), Left Parietal lobe (LPAR) and Superior Temporal Gyrus (STG) were activated with both L-dopa and placebo for both tasks, and (ii) as compared to placebo, L-dopa was associated with increased activity in posterior regions, including the superior temporal area (BA 22), and decreased activity in the thalamus (pulvinar) and inferior frontal gyrus (BA 11/47) for both tasks. These results raise the possibility that L-dopa may exert an indirect effect on posterior regions mediated by the thalamus (pulvinar)

Employment Outcomes for Young Adults With Autism Spectrum Disorders

This study investigated employment outcomes among young adults on the autism spectrum. Questionnaire responses indicated high job satisfaction and job retention. However, the majority were in low paid, part-time positions. Most found their job through a personal contact, and received a range of informal supports and accommodations on the job

Understanding embarrassment among those with autism: breaking down the complex emotion of embarrassment among those with autism

Scenarios manipulating various factors within the emotion of embarrassment, such as whether or not an audience was present when an embarrassing act was committed, the type of audience present, empathic embarrassment, etc., were presented to high-functioning participants with autism and comparison groups of those with learning difficulties and typically developing participants matched for verbal and nonverbal mental age. Participants were required to rate the level of embarrassment of the protagonist and justify their responses. It was predicted that those with autism would differ significantly from the comparison groups in their ratings and also their ability to provide justifications. The results showed those with autism to have difficulty with such concepts as empathic embarrassment but showed a surprisingly good understanding of other variables manipulated such as the presence of an audience

Lack of Noradrenergic Modulation of Indirect Semantic Priming

Norepinephrine and dopamine are both believed to affect signal-to-noise in the cerebral cortex. Dopaminergic agents appear to modulate semantic networks during indirect semantic priming, but do not appear to affect problem solving dependent on access to semantic networks. Noradrenergic agents, though, do affect semantic network dependent problem solving. We wished to examine whether noradrenergic agents affect indirect semantic priming. Subjects attended three sessions: one each after propranolol (40 mg) (noradrenergic antagonist), ephedrine (25 mg) (noradrenergic agonist), and placebo. During each session, closely related, distantly related, and unrelated pairs were presented. Reaction times for a lexical decision task on the target words (second word in the pair) were recorded. No decrease in indirect semantic priming occurred with ephedrine. Furthermore, across all three drugs, a main effect of semantic relatedness was found, but no main effect of drug, and no drug/semantic relatedness interaction effect. These findings suggest that noradrenergic agents, with these drugs and at these doses, do not affect indirect semantic priming with the potency of dopaminergic drugs at the doses previously studied. In the context of this previous work, this suggests that more automatic processes such as priming and more controlled searches of the lexical and semantic networks such as problem solving may be mediated, at least in part, by distinct mechanisms with differing effects of pharmacological modulation

Lack of noradrenergic modulation of indirect semantic priming

Abstract. Norepinephrine and dopamine are both believed to affect signal-to-noise in the cerebral cortex. Dopaminergic agents appear to modulate semantic networks during indirect semantic priming, but do not appear to affect problem solving dependent on access to semantic networks. Noradrenergic agents, though, do affect semantic network dependent problem solving. We wished to examine whether noradrenergic agents affect indirect semantic priming. Subjects attended three sessions: one each after propranolol (40 mg) (noradrenergic antagonist), ephedrine (25 mg) (noradrenergic agonist), and placebo. During each session, closely related, distantly related, and unrelated pairs were presented. Reaction times for a lexical decision task on the target words (second word in the pair) were recorded. No decrease in indirect semantic priming occurred with ephedrine. Furthermore, across all three drugs, a main effect of semantic relatedness was found, but no main effect of drug, and no drug/semantic relatedness interaction effect. These findings suggest that noradrenergic agents, with these drugs and at these doses, do not affect indirect semantic priming with the potency of dopaminergic drugs at the doses previously studied. In the context of this previous work, this suggests that more automatic processes such as priming and more controlled searches of the lexical and semantic networks such as problem solving may be mediated, at least in part, by distinct mechanisms with differing effects of pharmacological modulation

Beyond expectations: autism, understanding embarrassment, and the relationship with theory of mind

The ability of high-functioning individuals with autism to understand the complex emotion of embarrassment, and how this relates to an understanding of theory of mind, was investigated. Scenarios involving embarrassing and non-embarrassing situations were presented to a group with autism and three comparison groups. Participants were required to rate the level of embarrassment felt by the protagonist and to justify their choices. The results indicated that those with autism generally gave similar ratings of embarrassment as the comparison groups, but did show significant difficulty with non-embarrassing scenarios, and in providing appropriate justifications for embarrassment. In addition, a significant relationship between scores from false belief tasks and justification scores was found, supporting the proposed link between theory of mind skills and understanding embarrassment. Participants with autism did, however, show a higher than expected understanding of this complex emotion