On the interplay between state-dependent reconfigurations of global signal correlation and BOLD fluctuations: An fMRI study.

BACKGROUND: The dynamics of global, state-dependent reconfigurations in brain connectivity are yet unclear. We aimed at assessing reconfigurations of the global signal correlation coefficient (GSCORR), a measure of the connectivity between each voxel timeseries and the global signal, from resting-state to a stop-signal task. The secondary aim was to assess the relationship between GSCORR and blood-oxygen-level-dependent (BOLD) activations or deactivation across three different trial-conditions (GO, STOP-correct, and STOP-incorrect). METHODS: As primary analysis we computed whole-brain, voxel-wise GSCORR during resting-state (GSCORR-rest) and stop-signal task (GSCORR-task) in 107 healthy subjects aged 21-50, deriving GSCORR-shift as GSCORR-task minus GSCORR-rest. GSCORR-tr and trGSCORR-shift were also computed on the task residual time series to quantify the impact of the task-related activity during the trials. To test the secondary aim, brain regions were firstly divided in one cluster showing significant task-related activation and one showing significant deactivation across the three trial conditions. Then, correlations between GSCORR-rest/task/shift and activation/deactivation in the two clusters were computed. As sensitivity analysis, GSCORR-shift was computed on the same sample after performing a global signal regression and GSCORR-rest/task/shift were correlated with the task performance. RESULTS: Sensory and temporo-parietal regions exhibited a negative GSCORR-shift. Conversely, associative regions (ie. left lingual gyrus, bilateral dorsal posterior cingulate gyrus, cerebellum areas, thalamus, posterolateral parietal cortex) displayed a positive GSCORR-shift (FDR-corrected p < 0.05). GSCORR-shift showed similar patterns to trGSCORR-shift (magnitude increased) and after global signal regression (magnitude decreased). Concerning BOLD changes, Brodmann area 6 and inferior parietal lobule showed activation, while posterior parietal lobule, cuneus, precuneus, middle frontal gyrus showed deactivation (FDR-corrected p < 0.05). No correlations were found between GSCORR-rest/task/shift and beta-coefficients in the activation cluster, although negative correlations were observed between GSCORR-task and GO/STOP-correct deactivation (Pearson rho=-0.299/-0.273; Bonferroni-p < 0.05). Weak associations between GSCORR and task performance were observed (uncorrected p < 0.05). CONCLUSION: GSCORR state-dependent reconfiguration indicates a reallocation of functional resources to associative areas during stop-signal task. GSCORR, activation and deactivation may represent distinct proxies of brain states with specific neurofunctional relevance.

Should perception of emotions be classified according to threat detection rather than emotional valence? An updated meta-analysis for a whole-brain atlas of emotional faces processing.

BACKGROUND: Human navigation of social interactions relies on the processing of emotion on faces. This meta-analysis aimed to produce an updated brain atlas of emotional face processing from whole-brain studies based on a single emotional face-viewing paradigm (PROSPERO CRD42022251548). METHODS: We conducted a systematic literature search of Embase, MEDLINE and PsycINFO from May 2008 to October 2021. We used seed-based d mapping with permutation of subject images to conduct a quantitative meta-analysis of functional neuroimaging contrasts between emotional (e.g., angry, happy) and neutral faces. We conducted agglomerative hierarchical clustering of meta-analytic map contrasts of emotional faces relative to neutral faces. We investigated lateralization of emotional face processing. RESULTS: From 5549 studies identified, 55 data sets (1489 healthy participants) met our inclusion criteria. Relative to neutral faces, we found extensive activation clusters by fearful faces in the right inferior temporal gyrus, right fusiform area, left putamen and amygdala, right parahippocampalgyrus and cerebellum; we found smaller activation clusters by angry faces in the right cerebellum and right middle temporal gyrus (MTG) and by disgusted faces in the left MTG. Happy and sad faces did not reach statistical significance. Clustering analyses showed similar activation patterns of fearful and angry faces; activation patterns of happy and sad faces showed the least correlation with other emotional faces. Emotional face processing was predominantly left-lateralized in the amygdala and anterior insula, and right-lateralized in the ventromedial prefrontal cortex. LIMITATIONS: Reliance on discretized effect sizes based on peak coordinate location instead of statistical brain maps, and the varying level of statistical threshold reporting from original studies, could lead to underdetection of smaller clusters of activation. CONCLUSION: Processing of emotional faces appeared to be oriented toward identifying threats on faces, from highest (i.e., angry or fearful faces) to lowest level (i.e., happy or sad faces), with a more complex lateralization pattern than previously theorized. Emotional faces may be processed in latent grouping but organized by threat content rather than emotional valence.

Amine Activation: "Inverse" Dipeptide Synthesis and Amide Function Formation through Activated Amino Compounds.

A copper(II)/HOBt-catalyzed procedure for the synthesis of dipeptides and "general" amides has been developed using microwave irradiation to considerably hasten the reaction. As an alternative to using traditional carboxylic acid activation, the method relies on the use of N-acyl imidazoles as activated amino partners. By doing so, a nonconventional way to reach dipeptides and amides has been proposed through the challenging and less studied N → C direction synthesis. A series of dipeptides and "general" amides have been successfully synthesized, and the applicability of the method has been illustrated in gram-scale syntheses. The mild reaction conditions proposed are completely adequate for couplings in the presence of sensitive amino acids, affording the products without detectable racemization. Furthermore, experimental observations prompted us to propose a plausible reaction pathway for the couplings.

Asymmetric Synthesis of Spirooxindoles via Nucleophilic Epoxidation Promoted by Bifunctional Organocatalysts.

Taking into account the postulated reaction mechanism for the organocatalytic epoxidation of electron-poor olefins developed by our laboratory, we have investigated the key factors able to positively influence the H-bond network installed inside the substrate/catalyst/oxidizing agent. With this aim, we have: (i) tested a few catalysts displaying various effects that noticeably differ in terms of steric hindrance and electron demand; (ii) employed α-alkylidene oxindoles decorated with different substituents on the aromatic ring (11a-g), the exocylic double bond (11h-l), and the amide moiety (11m-v). The observed results suggest that the modification of the electron-withdrawing group (EWG) weakly conditions the overall outcomes, and conversely a strong influence is unambiguously ascribable to either the N-protected or N-unprotected lactam framework. Specifically, when the NH free substrates (11m-u) are employed, an inversion of the stereochemical control is observed, while the introduction of a Boc protecting group affords the desired product 12v in excellent enantioselectivity (97:3 er).

The relationship between metaphor skills and Theory of Mind in middle childhood: Task and developmental effects.

Theoretical pragmatics in the post-Gricean tradition argued that metaphor requires understanding of how another person sees the world. Yet, it is unclear what role mindreading plays in developing metaphor skills. Here we examined the relationship between metaphor and Theory of Mind (ToM) in middle childhood by using two different tasks. In addition to the Physical and Mental Metaphors task (PMM), based on the verbal explanation of physical and mental metaphors, we revived the Referential Metaphors task for children (Noveck, Bianco, & Castry, 2001), where metaphorical and literal referents are presented in a narrative context. The sample included 169 8-, 9-, and 10-year-old children, assessed also for ToM (via the Strange Stories) and other linguistic and cognitive skills as control variables. In the PMM, ToM supported the understanding of mental (but not physical) metaphors in 9-year-olds only, whereas in the Referential Metaphors task ToM supported accuracy of understanding metaphors (but not literal items) in younger children as well. At age 10, ToM effects were negligible in both tasks. These findings suggest that ToM has a task-specific role in metaphor, linked to the characteristics of the items in the task at stake, being for instance greater for metaphors with mental (compared to physical) content and for non-literal (compared to literal) referents. The findings also suggest that the relationship between ToM and metaphor skills is developmental sensitive, as children start to capitalize on ToM earlier in development when the metaphor context is richer, and these effects fade with age. Theoretically, these data argue in favor of the relevance-theoretic account of metaphor, spelling out different ways in which ToM might support metaphor resolution across tasks, for instance by providing better access to the psychological lexicon (i.e., terms referring to mental states) and better context processing, serving as a springboard to achieve sophisticated pragmatic skills in middle childhood.