Cost Benefit Cingulate Croxson Oxford 2009

Jul 8, 2010 10:23 AM

free and online at

http://www.jneurosci.org/cgi/reprint/29/14/4531

Effort-Based Cost–Benefit Valuation and the Human Brain

Paula L. Croxson, Mark E.Walton, Jill X. O’Reilly,Timothy E. J. Behrens,

andMatthew F. S. Rushworth1,2all from Psych Dept Oxford.

J of Neurosci  2009.

animals’ preferences for one course of action over another reflect not just reward expectations but also

the cost in terms of effort that must be invested in pursuing the course of action.

The ventral striatum and dorsal anterior cingulate cortex (ACCd) are implicated  << ventr striatum = Nuc Accum>>

 in the making of cost–benefit decisions in the rat, but there is little information about how effort costs are

processed and influence calculations of expected net value in other mammals including humans

.We performed a magnetic resonance imaging  to determine where activity in the brain was available to guide effort-based cost–benefit valuation. Subjects were scanned while they performed a series of effortful actions to obtain secondary reinforcers. At the beginning of each trial, subjects were presented with one of eight different visual cues that they had learned indicated how much effort the course of

action would entail and howmuch reward could be expected at its completion.

Cue-locked activity in the ventral striatum and midbrain

reflected the net value of the course of action, signaling the expected amount of reward discounted by the amount of effort to be invested.

Activity in ACCd also reflected the interaction of both expected reward and effort costs.

Posterior orbitofrontal and insular activity, however, only reflected the expected reward magnitude.

The ventral striatum and anterior cingulate cortex may be the substrate of

effort-based cost–benefit valuation in primates as well as in rats.

INTRO

Animals choose a course of action not simply on the basis of the

expected reward but also on the actions’ potential costs (Hull,

A seminal series of experiments emphasized the importance of

dopamine, particularly in the ventral striatum, in mediating     <<ventral striatum =  NAC>>

effort-related behavior in the rat (Salamone et al., 1994, 2003).

More recently, the medial frontal cortex, particularly the Cg1 and

Cg2 fields of dorsal anterior cingulate cortex (ACCd), has also

been implicated in effort-based cost–benefit decision making in

the same species (Walton et al., 2002, 2003; Schweimer and

To investigate this, we scanned human subjects while they

performed a sequence of effortful actions to obtain secondary

reinforcers associated with of one of two amounts of money. The

effortful action entailed the repeated canceling of visual targets

using a trackball computer mouse. The number of targets to can-

cel, and hence effort, varied between four levels. Visual cues at the

beginning of each trial indicated the levels of reward and of effort

to be expected.  (high reward  and high effort  vs  low reward and low effort  etc.)

DISCUSSION:  4538

Before taking a course of action, BOLD activity in human 

ACCd, ventral striatum, and a region including the dopaminergic mid-

brain reflects not just the expected level of reward but also the

amount of effort that will be exerted to obtain reward. Activity in

these regions, particularly in striatum and midbrain, varied con-

tinuously as a function of the net cost–benefit value of the in-

tended course of action rather than only being present on trials

when subjects evaluated options in which reward followed small

effort expenditure (cf. Kable and Glimcher, 2007). These areas

are monosynpatically interconnected in other primate species

(Kunishio andHaber, 1994;Williams and Goldman-Rakic, 1998;

Haber et al., 2006), and diffusion weighted imaging and tractog-

raphy suggest similar connections exist in humans (Croxson et

al., 2005; Beckmann et al., 2009). The interconnected areas may

constitute a human brain system for the evaluation of effort-

related cost–benefit decisions about how hard it is worth working

and the value of persisting with a course of action given the ex-

pected rewards.

ACCd, striatum, and dopaminergic nuclei of the midbrain play  <<<ACCd =  Anter Cing Cortex, dorsal>>>

similar roles during effort-related valuation and decisionmaking   (ventral striatum = NAC = nucl accumbens>>

in rodents and primates such as humans, then it is tempting to

speculate that the circuit is important formany types of mammal.

 ACCd cells also rep-

resent likelihood information and ACCd region activated in this

study is close to that shown to be sensitive to reward probability

(Knutson et al., 2005). Together, this suggests that the role of  <Brain Knutson at Stfd>>

ACCd in action valuation reflects not just the level of reward and

likelihood associated with a course of action, but also the effort

costs intrinsic to the action.

Medial frontal cortex is important not just during reward-

guided action selection but also when actions are selected under

conditions of conflict (Botvinick et al., 2004). In the present

study, subjects had only one available option, meaning that

ACCd activation cannot just be caused by action conflict. 

Cost Benefit Cingulate Croxson Oxford 2009

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