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Contrasting Roles for Orbitofrontal Cortex and Amygdala in Credit Assignment and Learning in Macaques.

Chau BK, Sallet J, Papageorgiou GK, Noonan MP, Bell AH, Walton ME, Rushworth MF - Neuron (2015)

Bottom Line: Recent studies have challenged the view that orbitofrontal cortex (OFC) and amygdala mediate flexible reward-guided behavior.A second experiment confirmed the existence of signals for adaptive stay/shift behavior in lOFC and reflecting irrelevant reward in the amygdala in a probabilistic learning task.Our data demonstrate that OFC and amygdala each make unique contributions to flexible behavior and credit assignment.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Psychology, University of Oxford, OX1 3UD, Oxford, UK; Department of Psychology, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: boltonchau@gmail.com.

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Win-Stay/Lose-Shift Signal in the lOFC(A) A whole-brain analysis showing a signal in the lOFC that was related to the occurrence of an outcome event.(B) A whole-brain analysis showing a signal in the lOFC that predicted win-stay/lose-shift behavior.(C) lOFC (16, 8, −4; green) BOLD activity was extracted for ROI analysis.(D and E) BOLD signal time course in the lOFC from an example session. The task events of win-stay, win-shift, lose-stay, and lose-shift are labeled in green, orange, red, and blue, respectively.(F) The BOLD signal was time locked at the outcome phase of the task and averaged across testing sessions and subjects.(G) The lOFC showed WSLS activity that ramped up after the onset of the outcome phase and peaked at around 4 s (green).(H) All four subjects consistently showed a WSLS signal after the outcome was revealed at 0 s.(I) The signal was extracted from the time window indicated by the bracket above the time course (which corresponds to the full-width half-maximum of the peak established using a leave-one-out procedure) and correlated with behavior. Testing sessions with larger WSLS signals in the lOFC were related to higher accuracies during the learning phase (first 9 trials in a block).(J) The sizes of the WSLS signal had no relationship with accuracies in the post-learning phase (after 30 trials in a block). Each type of marker symbol in (I) and (J) represents data from one animal.
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fig2: Win-Stay/Lose-Shift Signal in the lOFC(A) A whole-brain analysis showing a signal in the lOFC that was related to the occurrence of an outcome event.(B) A whole-brain analysis showing a signal in the lOFC that predicted win-stay/lose-shift behavior.(C) lOFC (16, 8, −4; green) BOLD activity was extracted for ROI analysis.(D and E) BOLD signal time course in the lOFC from an example session. The task events of win-stay, win-shift, lose-stay, and lose-shift are labeled in green, orange, red, and blue, respectively.(F) The BOLD signal was time locked at the outcome phase of the task and averaged across testing sessions and subjects.(G) The lOFC showed WSLS activity that ramped up after the onset of the outcome phase and peaked at around 4 s (green).(H) All four subjects consistently showed a WSLS signal after the outcome was revealed at 0 s.(I) The signal was extracted from the time window indicated by the bracket above the time course (which corresponds to the full-width half-maximum of the peak established using a leave-one-out procedure) and correlated with behavior. Testing sessions with larger WSLS signals in the lOFC were related to higher accuracies during the learning phase (first 9 trials in a block).(J) The sizes of the WSLS signal had no relationship with accuracies in the post-learning phase (after 30 trials in a block). Each type of marker symbol in (I) and (J) represents data from one animal.

Mentions: In this task, an optimal strategy is to stay with the same choice on the next trial after rewarded decisions but to shift to the alternative choice after non-rewarded decisions. In other words, monkeys should make use of the outcome feedback and follow a win-stay/lose-shift (WSLS) rule for guiding their behavior. Our first analysis, therefore, examined activity across the whole brain to identify regions that were sensitive to the occurrence of the outcome event of the task, regardless whether the outcome was a reward or not, using standard fMRI blood-oxygen-level-dependent (BOLD) imaging analysis procedures (see Experimental Procedures). Two example BOLD data volumes and mean BOLD data from two example sessions are shown in Figure S2A. We found that, bilaterally, lOFC became more active when the choice outcome was revealed (cluster-based thresholding z > 2.3, p < 0.05 cluster-corrected; Figure 2A). The lOFC signal was consistently found in all four animals (although in one subject the signal only exceeded the conservative threshold for significance in one hemisphere; Figure S2b). In addition, outcome-related activation was found in a number of other areas (Table S1).


Contrasting Roles for Orbitofrontal Cortex and Amygdala in Credit Assignment and Learning in Macaques.

Chau BK, Sallet J, Papageorgiou GK, Noonan MP, Bell AH, Walton ME, Rushworth MF - Neuron (2015)

Win-Stay/Lose-Shift Signal in the lOFC(A) A whole-brain analysis showing a signal in the lOFC that was related to the occurrence of an outcome event.(B) A whole-brain analysis showing a signal in the lOFC that predicted win-stay/lose-shift behavior.(C) lOFC (16, 8, −4; green) BOLD activity was extracted for ROI analysis.(D and E) BOLD signal time course in the lOFC from an example session. The task events of win-stay, win-shift, lose-stay, and lose-shift are labeled in green, orange, red, and blue, respectively.(F) The BOLD signal was time locked at the outcome phase of the task and averaged across testing sessions and subjects.(G) The lOFC showed WSLS activity that ramped up after the onset of the outcome phase and peaked at around 4 s (green).(H) All four subjects consistently showed a WSLS signal after the outcome was revealed at 0 s.(I) The signal was extracted from the time window indicated by the bracket above the time course (which corresponds to the full-width half-maximum of the peak established using a leave-one-out procedure) and correlated with behavior. Testing sessions with larger WSLS signals in the lOFC were related to higher accuracies during the learning phase (first 9 trials in a block).(J) The sizes of the WSLS signal had no relationship with accuracies in the post-learning phase (after 30 trials in a block). Each type of marker symbol in (I) and (J) represents data from one animal.
© Copyright Policy - CC BY
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4562909&req=5

fig2: Win-Stay/Lose-Shift Signal in the lOFC(A) A whole-brain analysis showing a signal in the lOFC that was related to the occurrence of an outcome event.(B) A whole-brain analysis showing a signal in the lOFC that predicted win-stay/lose-shift behavior.(C) lOFC (16, 8, −4; green) BOLD activity was extracted for ROI analysis.(D and E) BOLD signal time course in the lOFC from an example session. The task events of win-stay, win-shift, lose-stay, and lose-shift are labeled in green, orange, red, and blue, respectively.(F) The BOLD signal was time locked at the outcome phase of the task and averaged across testing sessions and subjects.(G) The lOFC showed WSLS activity that ramped up after the onset of the outcome phase and peaked at around 4 s (green).(H) All four subjects consistently showed a WSLS signal after the outcome was revealed at 0 s.(I) The signal was extracted from the time window indicated by the bracket above the time course (which corresponds to the full-width half-maximum of the peak established using a leave-one-out procedure) and correlated with behavior. Testing sessions with larger WSLS signals in the lOFC were related to higher accuracies during the learning phase (first 9 trials in a block).(J) The sizes of the WSLS signal had no relationship with accuracies in the post-learning phase (after 30 trials in a block). Each type of marker symbol in (I) and (J) represents data from one animal.
Mentions: In this task, an optimal strategy is to stay with the same choice on the next trial after rewarded decisions but to shift to the alternative choice after non-rewarded decisions. In other words, monkeys should make use of the outcome feedback and follow a win-stay/lose-shift (WSLS) rule for guiding their behavior. Our first analysis, therefore, examined activity across the whole brain to identify regions that were sensitive to the occurrence of the outcome event of the task, regardless whether the outcome was a reward or not, using standard fMRI blood-oxygen-level-dependent (BOLD) imaging analysis procedures (see Experimental Procedures). Two example BOLD data volumes and mean BOLD data from two example sessions are shown in Figure S2A. We found that, bilaterally, lOFC became more active when the choice outcome was revealed (cluster-based thresholding z > 2.3, p < 0.05 cluster-corrected; Figure 2A). The lOFC signal was consistently found in all four animals (although in one subject the signal only exceeded the conservative threshold for significance in one hemisphere; Figure S2b). In addition, outcome-related activation was found in a number of other areas (Table S1).

Bottom Line: Recent studies have challenged the view that orbitofrontal cortex (OFC) and amygdala mediate flexible reward-guided behavior.A second experiment confirmed the existence of signals for adaptive stay/shift behavior in lOFC and reflecting irrelevant reward in the amygdala in a probabilistic learning task.Our data demonstrate that OFC and amygdala each make unique contributions to flexible behavior and credit assignment.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Psychology, University of Oxford, OX1 3UD, Oxford, UK; Department of Psychology, The University of Hong Kong, Pokfulam Road, Hong Kong. Electronic address: boltonchau@gmail.com.

Show MeSH
Related in: MedlinePlus