Medial rostral prefrontal cortex and the neuroeconomics of mental time travel

Roland G. BenoitSam J. Gilbert

Paul W. BurgessUniversity College London

imagining the future

Addis, Wong, & Schacter, 2007

subjective value

Kable & Glimcher, 2007

metanalysis

Gilbert et al., 2006

* ImagineLunch Imagine

Lunch£ 27 in 360 days

£ 27 in 360 days1=yes; 2=no

Emotional?0=detach. … 4=highly

Experiencing?0=none … 4=highly

1s2s

14smax 4.5s

max 4s

max 4s

until 28.5 s

+

Task Episodic prospection

Semantic prospection

Arithmetic operations

Imagine Imagine the episode of spending the money in the scenario

X X X

Estimate Estimate what the money could buy you in the scenario

X X

Counting Count forwards (backwards) from the indicated number in steps of 3 (4)

X

5 amounts [£: 26;33;42;52;65] X 4 delays [days: 30;90;180;360]; 20 scenarios

£ 25 now

summary design

• 2 runs, each 10 trials of each task (Imagine, Estimate, Count)

• 28.5s * 30 trials = 855s (14.25min); 855s * 2 runs = 1710s (28.5 min)

• Instructions + practicing: ca. 60 min• Debriefing:

– Consideration of future consequences scale (Strathman et al., 1994)– Vividness of visual imagery questionnaire (Marks, 1973)– Given the money that you will probably have at those time points, how

much will £ 25 be worth to you [now; 30;90;180;360]?

• functional sequence:– 64 x 64; 3.5 x 3.5 mm pixels; 33 axial slices (3.5 mm thick, oriented to

the AC-PC plane)– TR: 2.5 s; TE: 40 ms;

• structural sequence: MPRAGE?• field maps