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Neural systems underlying aversive conditioning in humans with primary and secondary reinforcers.

Delgado MR, Jou RL, Phelps EA - Front Neurosci (2011)

Bottom Line: The effectiveness of monetary reinforcers during aversive learning and associated neural basis, however, remains a topic of debate.In another session, a secondary reinforcer (loss of money) served as the US and was paired with one of two different CS.Taken together, these results suggest that learning about potential monetary losses may depend on reinforcement learning related systems, rather than on typical structures involved in more biologically based fears.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Rutgers University Newark, NJ, USA.

ABSTRACT
Money is a secondary reinforcer commonly used across a range of disciplines in experimental paradigms investigating reward learning and decision-making. The effectiveness of monetary reinforcers during aversive learning and associated neural basis, however, remains a topic of debate. Specifically, it is unclear if the initial acquisition of aversive representations of monetary losses depends on similar neural systems as more traditional aversive conditioning that involves primary reinforcers. This study contrasts the efficacy of a biologically defined primary reinforcer (shock) and a socially defined secondary reinforcer (money) during aversive learning and its associated neural circuitry. During a two-part experiment, participants first played a gambling game where wins and losses were based on performance to gain an experimental bank. Participants were then exposed to two separate aversive conditioning sessions. In one session, a primary reinforcer (mild shock) served as an unconditioned stimulus (US) and was paired with one of two colored squares, the conditioned stimuli (CS+ and CS-, respectively). In another session, a secondary reinforcer (loss of money) served as the US and was paired with one of two different CS. Skin conductance responses were greater for CS+ compared to CS- trials irrespective of type of reinforcer. Neuroimaging results revealed that the striatum, a region typically linked with reward-related processing, was found to be involved in the acquisition of aversive conditioned response irrespective of reinforcer type. In contrast, the amygdala was involved during aversive conditioning with primary reinforcers, as suggested by both an exploratory fMRI analysis and a follow-up case study with a patient with bilateral amygdala damage. Taken together, these results suggest that learning about potential monetary losses may depend on reinforcement learning related systems, rather than on typical structures involved in more biologically based fears.

No MeSH data available.


Related in: MedlinePlus

Depiction of aversive conditioning components of experimental paradigm. Participants are presented with two counterbalanced aversive conditioning sessions following a gambling game where they earn a monetary endowment. (A) In the first session, the unconditioned stimulus is a mild electric shock (primary reinforcer) which is paired with a colored square (sCS+). (B) In the second session, the unconditioned stimulus is a monetary loss (−$6.00), which is paired with a different colored square (mCS+) and detracted from the total sum earned during the gambling game.
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Figure 1: Depiction of aversive conditioning components of experimental paradigm. Participants are presented with two counterbalanced aversive conditioning sessions following a gambling game where they earn a monetary endowment. (A) In the first session, the unconditioned stimulus is a mild electric shock (primary reinforcer) which is paired with a colored square (sCS+). (B) In the second session, the unconditioned stimulus is a monetary loss (−$6.00), which is paired with a different colored square (mCS+) and detracted from the total sum earned during the gambling game.

Mentions: The experiment consisted of three experimental blocks (Figure 1). First, participants were exposed to a gambling session (adapted from Delgado et al., 2000) in order to acquire a financial endowment, or an “experimental bank.” Participants were then involved in two separate aversive conditioning sessions (adapted from Delgado et al., 2006) which were counterbalanced with respect to order of presentation across participants. In one block, referred to as the primary session due to the nature of the reinforcer, the US was a mild shock to the wrist and resembled traditional aversive conditioning human paradigms (e.g., Phelps et al., 2004). In another block, referred to as secondary session, a monetary loss served as the US and would be extracted from their experimental bank. In the gambling session, participants were told they were playing a “card-guessing” game, where the objective was to determine if the value of a given card was higher or lower than the number five. During each trial, a question mark was presented in the center of the “card,” indicating that participants had 2 s to make a response. Using a MRI compatible response unit, participants made a 50/50 choice regarding the potential outcome of the trial. The outcome was either higher (6, 7, 8, 9) or lower (1, 2, 3, 4) than five. The outcome was then displayed for 500 ms, followed by a feedback arrow (which indicated positive or negative feedback) for another 500 ms and an inter-trial interval of 13 s before the onset of the next trial. A correct guess led to the display of a green upward arrow indicating a monetary reward of $4.00 (reward trials), while an incorrect guess led to the display of a red downward arrow indication a monetary loss of −$2.00 (punishment trials). Each trial was 16 s and participants played one block of the game containing 17 trials for each condition (reward and punishment). Unbeknownst to participants, the outcomes were predetermined ensuring a 50% reinforcement rate and a fixed profit across participants. Participants were initially told they were guaranteed $25 for performance in the scanner and that anything they would earn in the game was theirs to keep. At the end of the gambling session, a screen appeared congratulating the participant for their total earnings of $59.00 ($25 guaranteed amount plus the additional sum of $34 earned during the game) and informing them that the second part was about to start.


Neural systems underlying aversive conditioning in humans with primary and secondary reinforcers.

Delgado MR, Jou RL, Phelps EA - Front Neurosci (2011)

Depiction of aversive conditioning components of experimental paradigm. Participants are presented with two counterbalanced aversive conditioning sessions following a gambling game where they earn a monetary endowment. (A) In the first session, the unconditioned stimulus is a mild electric shock (primary reinforcer) which is paired with a colored square (sCS+). (B) In the second session, the unconditioned stimulus is a monetary loss (−$6.00), which is paired with a different colored square (mCS+) and detracted from the total sum earned during the gambling game.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3101377&req=5

Figure 1: Depiction of aversive conditioning components of experimental paradigm. Participants are presented with two counterbalanced aversive conditioning sessions following a gambling game where they earn a monetary endowment. (A) In the first session, the unconditioned stimulus is a mild electric shock (primary reinforcer) which is paired with a colored square (sCS+). (B) In the second session, the unconditioned stimulus is a monetary loss (−$6.00), which is paired with a different colored square (mCS+) and detracted from the total sum earned during the gambling game.
Mentions: The experiment consisted of three experimental blocks (Figure 1). First, participants were exposed to a gambling session (adapted from Delgado et al., 2000) in order to acquire a financial endowment, or an “experimental bank.” Participants were then involved in two separate aversive conditioning sessions (adapted from Delgado et al., 2006) which were counterbalanced with respect to order of presentation across participants. In one block, referred to as the primary session due to the nature of the reinforcer, the US was a mild shock to the wrist and resembled traditional aversive conditioning human paradigms (e.g., Phelps et al., 2004). In another block, referred to as secondary session, a monetary loss served as the US and would be extracted from their experimental bank. In the gambling session, participants were told they were playing a “card-guessing” game, where the objective was to determine if the value of a given card was higher or lower than the number five. During each trial, a question mark was presented in the center of the “card,” indicating that participants had 2 s to make a response. Using a MRI compatible response unit, participants made a 50/50 choice regarding the potential outcome of the trial. The outcome was either higher (6, 7, 8, 9) or lower (1, 2, 3, 4) than five. The outcome was then displayed for 500 ms, followed by a feedback arrow (which indicated positive or negative feedback) for another 500 ms and an inter-trial interval of 13 s before the onset of the next trial. A correct guess led to the display of a green upward arrow indicating a monetary reward of $4.00 (reward trials), while an incorrect guess led to the display of a red downward arrow indication a monetary loss of −$2.00 (punishment trials). Each trial was 16 s and participants played one block of the game containing 17 trials for each condition (reward and punishment). Unbeknownst to participants, the outcomes were predetermined ensuring a 50% reinforcement rate and a fixed profit across participants. Participants were initially told they were guaranteed $25 for performance in the scanner and that anything they would earn in the game was theirs to keep. At the end of the gambling session, a screen appeared congratulating the participant for their total earnings of $59.00 ($25 guaranteed amount plus the additional sum of $34 earned during the game) and informing them that the second part was about to start.

Bottom Line: The effectiveness of monetary reinforcers during aversive learning and associated neural basis, however, remains a topic of debate.In another session, a secondary reinforcer (loss of money) served as the US and was paired with one of two different CS.Taken together, these results suggest that learning about potential monetary losses may depend on reinforcement learning related systems, rather than on typical structures involved in more biologically based fears.

View Article: PubMed Central - PubMed

Affiliation: Department of Psychology, Rutgers University Newark, NJ, USA.

ABSTRACT
Money is a secondary reinforcer commonly used across a range of disciplines in experimental paradigms investigating reward learning and decision-making. The effectiveness of monetary reinforcers during aversive learning and associated neural basis, however, remains a topic of debate. Specifically, it is unclear if the initial acquisition of aversive representations of monetary losses depends on similar neural systems as more traditional aversive conditioning that involves primary reinforcers. This study contrasts the efficacy of a biologically defined primary reinforcer (shock) and a socially defined secondary reinforcer (money) during aversive learning and its associated neural circuitry. During a two-part experiment, participants first played a gambling game where wins and losses were based on performance to gain an experimental bank. Participants were then exposed to two separate aversive conditioning sessions. In one session, a primary reinforcer (mild shock) served as an unconditioned stimulus (US) and was paired with one of two colored squares, the conditioned stimuli (CS+ and CS-, respectively). In another session, a secondary reinforcer (loss of money) served as the US and was paired with one of two different CS. Skin conductance responses were greater for CS+ compared to CS- trials irrespective of type of reinforcer. Neuroimaging results revealed that the striatum, a region typically linked with reward-related processing, was found to be involved in the acquisition of aversive conditioned response irrespective of reinforcer type. In contrast, the amygdala was involved during aversive conditioning with primary reinforcers, as suggested by both an exploratory fMRI analysis and a follow-up case study with a patient with bilateral amygdala damage. Taken together, these results suggest that learning about potential monetary losses may depend on reinforcement learning related systems, rather than on typical structures involved in more biologically based fears.

No MeSH data available.


Related in: MedlinePlus