Zero the hero: Evidence for involvement of the ventromedial prefrontal cortex in affective bias for free items.

Recent evidence from psycho-economics shows that when the price of an item decreases to the extent that it becomes available for free, one can observe a remarkable increase of subjective utility toward this item. This phenomenon, which is not observed for any other price but zero, has been termed the zero-price effect (ZPE). The ZPE is attributed to an affective heuristic where the positive affect elicited by the free status of an item provides a mental shortcut biasing choice towards that item. Given that the ZPE relies on affective processing, a key role of the ventromedial prefrontal cortex (vmPFC) has been proposed, yet neuroscientific studies of the ZPE remain scarce. This study aimed to explore the role of the vmPFC in the ZPE using a novel, within-subject assessment in participants with either an acquired (lesion patients) or degenerative (behavioural-variant frontotemporal dementia patients) lesion of the vmPFC, and age-matched healthy controls. All participants were asked to make a series of choices between pairs of items that varied in price. One choice trial involved an equal decrease of both item prices, such that one of the items was priced zero. In contrast to controls, patients with both vmPFC-lesion and behavioural-variant frontotemporal dementia showed marked reductions in zero-related changes of preference in pairs of gift-cards, but not for pairs of food items. Our findings suggest that affective evaluations driving the ZPE are altered in patients with focal or degenerative damage to the vmPFC. This supports the notion of a key role of the vmPFC in the ZPE and, more generally, the importance of this region in value-based affective decision-making. Our findings also highlight the potential utility of affective heuristic tasks in future clinical assessments.

Social and emotional cognition in patients with severe migraine consulting in a tertiary headache center: A preliminary study.

Twenty-three severe migraine participants were studied to investigate social and emotional cognition features and explore their relationship with depression, anxiety and alexithymia. In comparison to normative data, 74% were under the norm for the Faux Pas subtest, 13% for the facial emotion recognition subtest and 52% for the overall composite score of the mini-SEA. Factor 1, Factor 3, and the total score of the TAS-20 were negatively correlated with the Faux Pas subtest. Our preliminary study shows that severe migraine patients present difficulties in inferring mental states, which could be related to alexithymia. It would be useful to identify these impairments in order to improve the quality of care provided. Clinical Trials registration number: NCT03577548.

Structural Connectivity and Cortical Thickness Alterations in Transient Global Amnesia.

BACKGROUND AND PURPOSE: Transient global amnesia (TGA) is a sudden onset of anterograde and retrograde amnesia. We aimed to assess differences in terms of cortical thickness and structural brain connectome between patients with TGA (at acute and delayed postrecovery stages) and matched controls. MATERIALS AND METHODS: We report on 18 consecutive patients with TGA who underwent 3T MR imaging, including DTI and MPRAGE sequences, at the acute (mean delay postonset: 44 hours) and delayed post-recovery (mean delay: 35 days) stages. Structural connectome was assessed in patients with TGA and in 18 age- and sex-matched controls by using probabilistic fiber- tracking and segmentation of 164 cortical/subcortical structures ("nodes"). Connectivity graphs were computed and global network metrics were calculated. Network-based statistical analysis (NBS) was applied to compare patients with TGA at each stage with controls. We also compared cortical thickness between patients with TGA and healthy controls. RESULTS: Global network metrics were not altered in patients with TGA. NBS-analysis showed structural connectome alterations in patients with TGA compared with controls, in core regions involving the limbic network, with 113 nodes and 114 connections (33 left intrahemispheric, 31 right intrahemispheric, and 50 interhemispheric connections) showing significantly decreased structural connectivity (P < .05 NBS corrected, t-values ranging from 3.03 to 8.73). Lower cortical thickness compared with controls was associated with these structural alterations in patients with TGA, involving the orbitofrontal, cingulate, and inferior temporal cortices. All the abnormalities were visible at both acute and delayed postrecovery stages. CONCLUSIONS: Our preliminary study suggests there are structural abnormalities of the limbic network in patients with TGA compared with controls, including decreased structural connectivity and cortical thickness.

Neural correlates of the mini-SEA (Social cognition and Emotional Assessment) in behavioral variant frontotemporal dementia.

Although Frontotemporal Dementia (FTD) is the second most common form of dementia after Alzheimer's disease, its diagnosis remains particularly challenging today. This is particularly true for the behavioral variant (bvFTD), the most common phenotype of FTD, which is characterised by dramatic changes in personal and social conduct. Novel clinical cognitive tests have been recently proposed to diagnose and assess these patients. Among them, the mini-SEA (Social cognition & Emotional Assessment) has shown promising results. This quick clinical tool evaluates emotion recognition and theory of mind deficits, both recognized as hallmark features of bvFTD. In this study, we investigated the neural correlates of the mini-SEA in twenty bvFTD patients, using single photon emission computed tomography (SPECT) and focusing on the mPFC. Results showed that detection of faux pas during a theory of mind evaluation was related to rostral mPFC perfusion (BA 10) while recognition of emotion involved more dorsal regions within the mPFC (BA 9). As significant and early dysfunction of the mPFC has been extensively described in bvFTD, this study supports the use of the mini-SEA in evaluation and diagnosis purposes in bvFTD.

A novel bedside task to tap inhibitory dysfunction and fronto-striatal atrophy in Parkinson's disease.

BACKGROUND: Given the heterogeneity of mild cognitive deficits in non-demented Parkinson's disease (PD), sensitive and anatomically specific behavioural measures are crucial when evaluating cognition in this patient group. Inhibitory dysfunction is one such deficit increasingly being recognised in non-demented PD; however, few clinical measures exist to detect it and its associated fronto-striatal pathology. METHODS: In 50 non-demented PD patients and 27 controls we employ a novel measure, the Excluded Letter Fluency (ELF) test, to objectively assess inhibitory dysfunction. ELF results were also contrasted with an established inhibitory measure (Hayling Test) and covaried against grey matter atrophy via voxel-based morphometry analysis in a subset of patients. RESULTS: The findings show that patients made significantly more rule-break errors than controls on the ELF and this measure was more sensitive than the Hayling in detecting inhibitory dysfunction, classifying over 76% of patients in logistic regression analysis. Importantly, ELF rule-break errors correlated with grey matter atrophy in known inhibitory-control regions (orbitofrontal cortex, inferior frontal gyrus and ventral striatum). CONCLUSIONS: The ELF is a brief bedside task that efficiently detects inhibitory dysfunction in non-demented PD. The utility of this novel behavioural measure is further substantiated by its anatomical specificity for fronto-striatal inhibitory control regions.