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Subliminal instrumental conditioning demonstrated in the human brain.

Pessiglione M, Petrovic P, Daunizeau J, Palminteri S, Dolan RJ, Frith CD - Neuron (2008)

Bottom Line: Here, we formally test this by studying instrumental conditioning in a situation where we masked contextual cues, such that they were not consciously perceived.Behavioral data showed that subjects nonetheless developed a significant propensity to choose cues associated with monetary rewards relative to punishments.We conclude that, even without conscious processing of contextual cues, our brain can learn their reward value and use them to provide a bias on decision making.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for NeuroImaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N3BG, UK. mathias.pessiglione@gmail.com

ABSTRACT
How the brain uses success and failure to optimize future decisions is a long-standing question in neuroscience. One computational solution involves updating the values of context-action associations in proportion to a reward prediction error. Previous evidence suggests that such computations are expressed in the striatum and, as they are cognitively impenetrable, represent an unconscious learning mechanism. Here, we formally test this by studying instrumental conditioning in a situation where we masked contextual cues, such that they were not consciously perceived. Behavioral data showed that subjects nonetheless developed a significant propensity to choose cues associated with monetary rewards relative to punishments. Functional neuroimaging revealed that during conditioning cue values and prediction errors, generated from a computational model, both correlated with activity in ventral striatum. We conclude that, even without conscious processing of contextual cues, our brain can learn their reward value and use them to provide a bias on decision making.

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Neuroimaging DataLeft: ventral striatal regions isolated by regression of monetary values against BOLD responses to cue display. Right: visual cortical regions isolated by correlation of cue-value regression coefficients with individual payoffs. Slices were taken at global maxima of interest indicated by red pointers on the above axial glass brains. Areas shown in gray/black on glass brains and in orange/yellow on coronal slices showed significant effect. The [x y z] coordinates of the maxima refer to the Montreal Neurological Institute space.(A) Statistical parametric maps using conservative threshold (p < 0.05 after familywise error correction for multiple comparisons).(B) Statistical parametric maps using liberal threshold (p < 0.001 uncorrected).(C) Regression coefficients of Q values (QV) and prediction errors (PE) against BOLD responses to cue and outcome display, respectively. Bars are ± intersubjects standard errors of the mean.
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fig3: Neuroimaging DataLeft: ventral striatal regions isolated by regression of monetary values against BOLD responses to cue display. Right: visual cortical regions isolated by correlation of cue-value regression coefficients with individual payoffs. Slices were taken at global maxima of interest indicated by red pointers on the above axial glass brains. Areas shown in gray/black on glass brains and in orange/yellow on coronal slices showed significant effect. The [x y z] coordinates of the maxima refer to the Montreal Neurological Institute space.(A) Statistical parametric maps using conservative threshold (p < 0.05 after familywise error correction for multiple comparisons).(B) Statistical parametric maps using liberal threshold (p < 0.001 uncorrected).(C) Regression coefficients of Q values (QV) and prediction errors (PE) against BOLD responses to cue and outcome display, respectively. Bars are ± intersubjects standard errors of the mean.

Mentions: We recorded brain activity while subjects performed the subliminal conditioning task, using functional magnetic resonance imaging (fMRI). We first examined brain regions reflecting Q value at the time of cue onset, increasing their response to reward-predicting cues and decreasing their response to punishment-predicting cues, across learning sessions. After correction for multiple comparisons (family-wise error, p < 0.05), we noted significant correlated activity in ventral striatum bilaterally (Figures 3A and 3B, left). The same region was also significantly activated at the time of outcome in keeping with prediction errors being expressed at this time point (Figure 3C, left). In a second analysis, we computed regression coefficients for the different conditions at the time of cue and outcome onsets, separately for the first and second half of conditioning sessions. Contrasts with the neutral condition were then averaged over all ventral striatal voxels showing significant activation at the most conservative threshold in the first analysis. This confirmed that from the first to the second half of conditioning sessions, ventral striatal responses increased for reward cues and decreased for punishment cues (Figure 4A, left). At the time of outcome onset, the same ventral striatal region reflected positive prediction errors in the reward condition and negative prediction errors in the punishment condition. In keeping with the Q-learning model, both positive and negative prediction errors decreased from the first to the second half of conditioning sessions. Thus, across subliminal conditioning, the ventral striatal response was consistent with the expression of Q values (for unseen cues) and prediction errors (based on visible outcomes).


Subliminal instrumental conditioning demonstrated in the human brain.

Pessiglione M, Petrovic P, Daunizeau J, Palminteri S, Dolan RJ, Frith CD - Neuron (2008)

Neuroimaging DataLeft: ventral striatal regions isolated by regression of monetary values against BOLD responses to cue display. Right: visual cortical regions isolated by correlation of cue-value regression coefficients with individual payoffs. Slices were taken at global maxima of interest indicated by red pointers on the above axial glass brains. Areas shown in gray/black on glass brains and in orange/yellow on coronal slices showed significant effect. The [x y z] coordinates of the maxima refer to the Montreal Neurological Institute space.(A) Statistical parametric maps using conservative threshold (p < 0.05 after familywise error correction for multiple comparisons).(B) Statistical parametric maps using liberal threshold (p < 0.001 uncorrected).(C) Regression coefficients of Q values (QV) and prediction errors (PE) against BOLD responses to cue and outcome display, respectively. Bars are ± intersubjects standard errors of the mean.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2572733&req=5

fig3: Neuroimaging DataLeft: ventral striatal regions isolated by regression of monetary values against BOLD responses to cue display. Right: visual cortical regions isolated by correlation of cue-value regression coefficients with individual payoffs. Slices were taken at global maxima of interest indicated by red pointers on the above axial glass brains. Areas shown in gray/black on glass brains and in orange/yellow on coronal slices showed significant effect. The [x y z] coordinates of the maxima refer to the Montreal Neurological Institute space.(A) Statistical parametric maps using conservative threshold (p < 0.05 after familywise error correction for multiple comparisons).(B) Statistical parametric maps using liberal threshold (p < 0.001 uncorrected).(C) Regression coefficients of Q values (QV) and prediction errors (PE) against BOLD responses to cue and outcome display, respectively. Bars are ± intersubjects standard errors of the mean.
Mentions: We recorded brain activity while subjects performed the subliminal conditioning task, using functional magnetic resonance imaging (fMRI). We first examined brain regions reflecting Q value at the time of cue onset, increasing their response to reward-predicting cues and decreasing their response to punishment-predicting cues, across learning sessions. After correction for multiple comparisons (family-wise error, p < 0.05), we noted significant correlated activity in ventral striatum bilaterally (Figures 3A and 3B, left). The same region was also significantly activated at the time of outcome in keeping with prediction errors being expressed at this time point (Figure 3C, left). In a second analysis, we computed regression coefficients for the different conditions at the time of cue and outcome onsets, separately for the first and second half of conditioning sessions. Contrasts with the neutral condition were then averaged over all ventral striatal voxels showing significant activation at the most conservative threshold in the first analysis. This confirmed that from the first to the second half of conditioning sessions, ventral striatal responses increased for reward cues and decreased for punishment cues (Figure 4A, left). At the time of outcome onset, the same ventral striatal region reflected positive prediction errors in the reward condition and negative prediction errors in the punishment condition. In keeping with the Q-learning model, both positive and negative prediction errors decreased from the first to the second half of conditioning sessions. Thus, across subliminal conditioning, the ventral striatal response was consistent with the expression of Q values (for unseen cues) and prediction errors (based on visible outcomes).

Bottom Line: Here, we formally test this by studying instrumental conditioning in a situation where we masked contextual cues, such that they were not consciously perceived.Behavioral data showed that subjects nonetheless developed a significant propensity to choose cues associated with monetary rewards relative to punishments.We conclude that, even without conscious processing of contextual cues, our brain can learn their reward value and use them to provide a bias on decision making.

View Article: PubMed Central - PubMed

Affiliation: Wellcome Trust Centre for NeuroImaging, Institute of Neurology, University College London, 12 Queen Square, London WC1N3BG, UK. mathias.pessiglione@gmail.com

ABSTRACT
How the brain uses success and failure to optimize future decisions is a long-standing question in neuroscience. One computational solution involves updating the values of context-action associations in proportion to a reward prediction error. Previous evidence suggests that such computations are expressed in the striatum and, as they are cognitively impenetrable, represent an unconscious learning mechanism. Here, we formally test this by studying instrumental conditioning in a situation where we masked contextual cues, such that they were not consciously perceived. Behavioral data showed that subjects nonetheless developed a significant propensity to choose cues associated with monetary rewards relative to punishments. Functional neuroimaging revealed that during conditioning cue values and prediction errors, generated from a computational model, both correlated with activity in ventral striatum. We conclude that, even without conscious processing of contextual cues, our brain can learn their reward value and use them to provide a bias on decision making.

Show MeSH
Related in: MedlinePlus