Insight and non-insight problem solving: A heart rate variability study.

Occasionally, problems are solved with a sudden Aha! moment (insight), while the mundane approach to solving problems is analytical (non-insight). At first glance, non-insight appears to depend on the availability and taxation of cognitive resources to execute the step-by-step approach, whereas insight does not, or to a lesser extent. However, this remains debated. To investigate the reliance of both solution types on cognitive resources, we assessed the involvement of the prefrontal cortex using vagally mediated heart rate variability (vmHRV) as an index. Participants (N = 68) solved 70 compound remote associates word puzzles solvable with insight and non-insight. Before, during, and after solving the word puzzles, we measured the vmHRV. Our results showed that resting-state vmHRV (trait) showed a negative association with behavioural performance for both solution types. This might reflect inter-individual differences in inhibitory control. As the solution search requires one to think of remote associations, inhibitory control might hamper rather than aid this process. Furthermore, we observed, for both solution types, a vmHRV increase from resting-state to solution search (state), lingering on in the post-task recovery period. This could mark the increase of prefrontal resources to promote an open-minded stance, essential for divergent thinking, which arguably is crucial for this task. Our findings suggest that, at a general level, both solution types share common aspects. However, a closer analysis of early and late solutions and puzzle difficulty suggested that metacognitive differentiation between insight and non-insight improved with higher trait vmHRV, and that a unique association between trait vmHRV and puzzle difficulty was present for each solution type.

The natural history of terms describing functional (neurological) disorders in the medical literature of the last 60 years.

BACKGROUND: Functional neurological disorders (FND), a subtype of functional disorders (FD), are a frequent motive for neurology referrals. The various presentations and the unknown physiopathology of FD have led to the multiplication of terms describing these disorders over the years. METHODS: We examined the FD-related articles published from 1960 to 2020 in PubMed and PsycINFO databases. We searched for: psychogenic, somatization, somatoform, medically unexplained symptoms, hysteria, conversion disorder, dissociative, functional neurological disorder, and functional disorder. Use rates in the title, abstract, keyword, or MeSH fields were collected over successive 5-year periods. After correcting for off-topic results, we examined proportional distribution over time, term associations, and disciplinary fields (neurology and psychiatry). Term impact was estimated via H-index and number of citations. RESULTS: We found that none of the terms is prevailing in the recent medical literature. We observed three trends in the use rates: stability, increase, and decrease of use over time. While most of the terms were present in a stable proportion of the publications, hysteria and psychogenic lost popularity over time. We found a differential preference for terminology between disciplines. Functional neurological disorder showed the highest citation impact, yielding 10% of highly cited publications. CONCLUSION: We found a dynamic and evolving use of the different terms describing FD in the last 60 years. Despite the tendency to use the term functional in the recent highly cited publications, its low prevalence and coexistence with several other terms suggest that a precise, explanatory and non-offensive term remains yet to be found.

Pearls & Oy-sters: De Novo Seizure and Stroke in the Elderly: The Issue of Chicken and Egg.

Seizures immediately preceding the occurrence of an ischemic or hemorrhagic stroke are a rare but well-documented phenomenon, for which the term "heraldic seizure" has been proposed. Cerebrovascular disease is the most common cause of epileptic seizures in elderly patients; thus, screening and management of vascular risk factors should be performed systematically in cases of late-onset epilepsy. MRI may help to distinguish heraldic seizure from stroke-elicited seizure by showing abnormalities confined to the cortex that spare vascular territories, increased magnetic resonance angiography flow in the ipsilateral cerebral arteries, and enhancement of the leptomeninges on postcontrast MRI. We present a case report that illustrates the difficulty of making the diagnosis of a heraldic seizure at onset.