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Representation of reward feedback in primate auditory cortex.

Brosch M, Selezneva E, Scheich H - Front Syst Neurosci (2011)

Bottom Line: Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback.Correct identifications were rewarded with either a large or a small amount of water.Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institut für Neurobiologie Magdeburg, Germany.

ABSTRACT
It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1) the reward expectancy for each trial, (2) the reward-size received, and (3) the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

No MeSH data available.


Related in: MedlinePlus

Population responses in auditory cortex related to reward feedback. (A) Reward-size coding: Recruitment of the percentage of multiunits in each time bin in which the firing was significantly stronger (red) for at least one of the following three comparisons: (1) large and small reward trials (2) large and no-reward trials (3) small and no-reward trials. The blue curve shows the recruitment of multiunits whose firing was significantly stronger for reversed comparisons. See also Figure 5. (B) Reward mismatch coding: recruitment of the percentage of multiunits whose firing increased (red) with the size of the reward mismatch. For each time bin, the percentage of multiunits is shown whose firing was significantly stronger for at least one of the following three comparisons: (1) trials with large and small reward mismatch; (2) trials with large and no reward mismatch; (3) trials with small and no reward mismatch. Note that this curve closely matches the blue curve in (A). See also Figure 7. (C) Reward expectancy: recruitment of the percentage of multiunits whose firing was significantly stronger (red) or weaker (blue) when trials with large reward expectancy were compared to trials with small expectancy. Note the increasing separation of the two curves after bar grasp.
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Figure 4: Population responses in auditory cortex related to reward feedback. (A) Reward-size coding: Recruitment of the percentage of multiunits in each time bin in which the firing was significantly stronger (red) for at least one of the following three comparisons: (1) large and small reward trials (2) large and no-reward trials (3) small and no-reward trials. The blue curve shows the recruitment of multiunits whose firing was significantly stronger for reversed comparisons. See also Figure 5. (B) Reward mismatch coding: recruitment of the percentage of multiunits whose firing increased (red) with the size of the reward mismatch. For each time bin, the percentage of multiunits is shown whose firing was significantly stronger for at least one of the following three comparisons: (1) trials with large and small reward mismatch; (2) trials with large and no reward mismatch; (3) trials with small and no reward mismatch. Note that this curve closely matches the blue curve in (A). See also Figure 7. (C) Reward expectancy: recruitment of the percentage of multiunits whose firing was significantly stronger (red) or weaker (blue) when trials with large reward expectancy were compared to trials with small expectancy. Note the increasing separation of the two curves after bar grasp.

Mentions: In different multiunits, the increase in firing in the rewarded conditions compared with the no-reward condition was present at different times, resulting in varying percentages of active multiunits during the intertrial period, which we term “recruitment.” As shown in Figure 4A (red curve) the percentage of recruited multiunits that coded reward-size rapidly increased to a maximum of 25.7% at 700 ms after bar release, then slowly decreasing to near zero at ∼4 s. Figure 5 shows detailed comparisons between different reward-size conditions.


Representation of reward feedback in primate auditory cortex.

Brosch M, Selezneva E, Scheich H - Front Syst Neurosci (2011)

Population responses in auditory cortex related to reward feedback. (A) Reward-size coding: Recruitment of the percentage of multiunits in each time bin in which the firing was significantly stronger (red) for at least one of the following three comparisons: (1) large and small reward trials (2) large and no-reward trials (3) small and no-reward trials. The blue curve shows the recruitment of multiunits whose firing was significantly stronger for reversed comparisons. See also Figure 5. (B) Reward mismatch coding: recruitment of the percentage of multiunits whose firing increased (red) with the size of the reward mismatch. For each time bin, the percentage of multiunits is shown whose firing was significantly stronger for at least one of the following three comparisons: (1) trials with large and small reward mismatch; (2) trials with large and no reward mismatch; (3) trials with small and no reward mismatch. Note that this curve closely matches the blue curve in (A). See also Figure 7. (C) Reward expectancy: recruitment of the percentage of multiunits whose firing was significantly stronger (red) or weaker (blue) when trials with large reward expectancy were compared to trials with small expectancy. Note the increasing separation of the two curves after bar grasp.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 4: Population responses in auditory cortex related to reward feedback. (A) Reward-size coding: Recruitment of the percentage of multiunits in each time bin in which the firing was significantly stronger (red) for at least one of the following three comparisons: (1) large and small reward trials (2) large and no-reward trials (3) small and no-reward trials. The blue curve shows the recruitment of multiunits whose firing was significantly stronger for reversed comparisons. See also Figure 5. (B) Reward mismatch coding: recruitment of the percentage of multiunits whose firing increased (red) with the size of the reward mismatch. For each time bin, the percentage of multiunits is shown whose firing was significantly stronger for at least one of the following three comparisons: (1) trials with large and small reward mismatch; (2) trials with large and no reward mismatch; (3) trials with small and no reward mismatch. Note that this curve closely matches the blue curve in (A). See also Figure 7. (C) Reward expectancy: recruitment of the percentage of multiunits whose firing was significantly stronger (red) or weaker (blue) when trials with large reward expectancy were compared to trials with small expectancy. Note the increasing separation of the two curves after bar grasp.
Mentions: In different multiunits, the increase in firing in the rewarded conditions compared with the no-reward condition was present at different times, resulting in varying percentages of active multiunits during the intertrial period, which we term “recruitment.” As shown in Figure 4A (red curve) the percentage of recruited multiunits that coded reward-size rapidly increased to a maximum of 25.7% at 700 ms after bar release, then slowly decreasing to near zero at ∼4 s. Figure 5 shows detailed comparisons between different reward-size conditions.

Bottom Line: Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback.Correct identifications were rewarded with either a large or a small amount of water.Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

View Article: PubMed Central - PubMed

Affiliation: Leibniz Institut für Neurobiologie Magdeburg, Germany.

ABSTRACT
It is well established that auditory cortex is plastic on different time scales and that this plasticity is driven by the reinforcement that is used to motivate subjects to learn or to perform an auditory task. Motivated by these findings, we study in detail properties of neuronal firing in auditory cortex that is related to reward feedback. We recorded from the auditory cortex of two monkeys while they were performing an auditory categorization task. Monkeys listened to a sequence of tones and had to signal when the frequency of adjacent tones stepped in downward direction, irrespective of the tone frequency and step size. Correct identifications were rewarded with either a large or a small amount of water. The size of reward depended on the monkeys' performance in the previous trial: it was large after a correct trial and small after an incorrect trial. The rewards served to maintain task performance. During task performance we found three successive periods of neuronal firing in auditory cortex that reflected (1) the reward expectancy for each trial, (2) the reward-size received, and (3) the mismatch between the expected and delivered reward. These results, together with control experiments suggest that auditory cortex receives reward feedback that could be used to adapt auditory cortex to task requirements. Additionally, the results presented here extend previous observations of non-auditory roles of auditory cortex and shows that auditory cortex is even more cognitively influenced than lately recognized.

No MeSH data available.


Related in: MedlinePlus