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Nature Neuroscience | Voume 26 | September 2023 | 1575–1583 1575
nature neuroscience
https://doi.org/10.1038/s41593-023-01407-3
Article
Value dynamics affect choice preparation
during decision-making
Zuzanna Z. Balewski1,3, Thomas W. Elston1,3, Eric B. Knudsen1
& Joni D. Wallis 1,2
During decision-making, neurons in the orbitofrontal cortex (OFC)
sequentially represent the value of each option in turn, but it is unclear how
these dynamics are translated into a choice response. One brain region that
may be implicated in this process is the anterior cingulate cortex (ACC),
which strongly connects with OFC and contains many neurons that encode
the choice response. We investigated how OFC value signals interacted with
ACC neurons encoding the choice response by performing simultaneous
high-channel count recordings from the two areas in nonhuman primates.
ACC neurons encoding the choice response steadily increased their ring
rate throughout the decision-making process, peaking shortly before
the time of the choice response. Furthermore, the value dynamics in OFC
aected ACC ramping—when OFC represented the more valuable option,
ACC ramping accelerated. Because OFC tended to represent the more
valuable option more frequently and for a longer duration, this interaction
could explain how ACC selects the more valuable response.
A wealth of evidence demonstrates the necessity of the orbitofron-
tal cortex (OFC) for value-based decision-making. Patients with OFC
damage show specific deficits in value-based decision-making
1
, while
electrical microstimulation of OFC in humans
2
and monkeys
3,4
selec-
tively impairs value-based decision-making. Despite this, there is less
evidence that OFC is involved in selecting the correct response to real-
ize the decision. OFC only weakly connects with motor areas
5
and its
neurons only weakly encode the choice response
6–8
. At the population
level, although OFC alternately represents the value of each available
option9,10, it does not appear to represent a specific option at the time
that the choice response occurs.
One area that could have an important role in translating
value-based decisions into actions is the anterior cingulate cortex
(ACC). Like OFC, ACC neurons strongly encode the value of antici-
pated outcomes, but unlike OFC, they also often encode the choice
response
7,11–15
. In addition, ACC strongly connects with both OFC
5,16
and motor areas in the medial frontal cortex, such as the cingulate
motor area
17,18
. Stimulation of ACC in humans evokes movements
19
and an urgency to act
20
. ACC seems to be particularly important when
the cost of action must be factored into the decision. Lesions of ACC
impair effort-based decisions21,22 and neuronal tuning in ACC reflects
the value of anticipated outcomes, discounted by the effort necessary
to obtain them23.
We, therefore, aimed to determine whether the dynamics of OFC
value signals influenced neurons in ACC that encoded the choice
response. One clue as to how this might occur is that more valuable
options tend to be represented more frequently and for longer dura-
tion
9,10
. Consequently, a downstream area that integrated the OFC
value dynamics would be able to select the more valuable option.
ACC neurons that encoded the choice response tended to increase
their firing rate throughout the decision, peaking shortly before the
choice response. To determine whether this ramping was affected by
the value dynamics in OFC, we carried out high-channel count record-
ings simultaneously from OFC and ACC while monkeys performed a
value-based decision-making task.
Results
We taught two monkeys (subjects C and G) to use a bidirectional
lever to select either one (forced choice trials) or between two (free
choice trials) available pictures for the corresponding juice outcome
Received: 20 June 2022
Accepted: 17 July 2023
Published online: 10 August 2023
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1Helen Wills Neuroscience Institute, University of California at Berkeley, Berkeley, CA, USA. 2Department of Psychology, University of California at Berkeley,
Berkeley, CA, USA. 3These authors contributed equally: Zuzanna Z. Balewski, Thomas W. Elston. e-mail: wallis@berkeley.edu
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