Do you have a strategy? Multimodal brain signatures of social bargaining in neurodegeneration and frontal lesion

TORRALVA T; BILLEKE P; BAEZ S; HESSE E; DE LA FUENTE L; BIRBA A; GARCIA CORDERO I; GARCIA AM; SEDEÑO L; MANES F; IBANEZ A

Congreso; 0th International Conference on Frontotemporal Dementias (ICFTD); 2016

Recursive social decision making requires the use of contextual and flexible long-term strategies for negotiation. During successful social bargaining, participants must integrate the changing scenarios from self? and other?s perspectives (maximize self-benefits and adapt to the other?s preferences, respectively) in order to develop a successful long-run strategy (or self-other integration strategy, SOIS). Currently, the critical brain regions and related networks indexing SOIS are not well known. Here, we analyzed social bargaining behavior as well is structural neural correlates, ongoing brain dynamics (oscillations and related source space) and functional connectivity signatures in healthy subjects and patients offering contrastive lesion models of neurodegeneration and focal stroke: behavioral variant frontotemporal dementia (bvFTD), Alzheimer?s disease (AD), and frontal lesions (FL). All groups showed preserved basic bargaining indexes but compared to controls, impaired SOIS was found in bvFTD and FL suggesting that social bargaining depends critically of prefrontal preservation. At a structural level, voxel based morphometry [VBM] and voxel-based lesion-symptom mapping [VLSM]) revealed a critical role of prefrontal regions engaged in value integration and strategic decisions for SOIS. Task ongoing brain dynamics and related sources revealed that an anticipatory activity (alpha/beta oscillations with sources in fronto-temporal regions) associated with expectations about others? decisions predicted the SOIS, and in turn was reduced in all clinical groups (but more impaired in bvFTD and FL than in AD). Finally, fMRI connectivity analysis highlighted a fronto-temporo-parietal network involved in successful SOIS, with selective affectation of long-distance connections in frontal disorders (bvFTD and FL). This work provides unprecedented convergent behavioral and brain (structure, ongoing oscillations and functional connectivity) signatures of strategic social bargaining in different lesion models offers new insights regarding the critical roles of frontal hubs and its temporo-parietal networks for strategic social negotiation.