PMC

VBM of brain atrophy in behavioural variant FTD patients compared to controls (red), and in semantic variant PPA patients compared to controls (blue). Images are displayed according to neurological convention (right = right). bvFTD = behavioural variant FTD; svPPA = semantic variant PPA.

Neuroeconomic tasks to assess sensitivity to valence and time. (A) One of four choice titrators used in the loss aversion paradigm. (B) Choice condition of interest, and control conditions, in the delay discounting paradigm.

Abnormal decision-making is a central feature of both behavioural and semantic variants of frontotemporal dementia. Chiong et al. present evidence for a double dissociation in which the behavioural variant is associated with diminished loss aversion, while the semantic variant is associated with increased discounting of delayed rewards.

Neuroeconomic behaviour by diagnosis. (A) Distribution of lambda (win-loss ratio threshold) values in four cohorts. In the semantic variant PPA (svPPA) cohort, subjects with predominantly left-lateralized anterior temporal atrophy are represented in blue, while subjects with predominantly right-lateralized anterior temporal atrophy are represented in turquoise. Boxes represent interquartile range. (B) Distribution of ICR (the proportion of trials selecting the smaller immediate reward over the larger delayed reward) in four cohorts. Boxes represent interquartile range.

Two mechanisms for change in patients’ evaluation of action outcomes. (A) While healthy subjects are more strongly affected by prospective losses than gains (represented by the steeper slope of the grey curve on the negative side of the x-axis), this loss aversion may be diminished in patients (represented by the shallower slope of the dashed red curve). (B) While healthy subjects discount the value of rewards that occur later in time (represented by the downward slope of the grey curve), delay discounting may be increased in patients (represented by the steeper slope of the dashed blue curve).