scholarly journals Firing patterns of serotonin neurons underlying cognitive flexibility

2016 ◽  
Author(s):  
Sara Matias ◽  
Eran Lottem ◽  
Guillaume P. Dugué ◽  
Zachary F. Mainen
Keyword(s):  
Cognitive Flexibility ◽  
Causal Structure ◽  
Dopamine Neurons ◽  
Prediction Errors ◽  
Firing Patterns ◽  
Learning Rates ◽  
Serotonin Neurons ◽  
Endogenous Role ◽  
Flexible Adaptation

Serotonin is implicated in mood and affective disorders1,2 but growing evidence suggests that its core endogenous role may be to promote flexible adaptation to changes in the causal structure of the environment3–8. This stems from two functions of endogenous serotonin activation: inhibiting learned responses that are not currently adaptive9,10 and driving plasticity to reconfigure them1113. These mirror dual functions of dopamine in invigorating reward-related responses and promoting plasticity that reinforces new ones16,17. However, while dopamine neurons are known to be activated by reward prediction errors18,19, consistent with theories of reinforcement learning, the reported firing patterns of serotonin neurons21–23 do not accord with any existing theories1,24,25. Here, we used long-term photometric recordings in mice to study a genetically-defined population of dorsal raphe serotonin neurons whose activity we could link to normal reversal learning. We found that these neurons are activated by both positive and negative prediction errors, thus reporting the kind of surprise signal proposed to promote learning in conditions of uncertainty26,27. Furthermore, by comparing cue responses of serotonin and dopamine neurons we found differences in learning rates that could explain the importance of serotonin in inhibiting perseverative responding. Together, these findings show how the firing patterns of serotonin neurons support a role in cognitive flexibility and suggest a revised model of dopamine-serotonin opponency with potential clinical implications.

scholarly journals Activity patterns of serotonin neurons underlying cognitive flexibility

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Sara Matias ◽  
Eran Lottem ◽  
Guillaume P Dugué ◽  
Zachary F Mainen
Keyword(s):  
Cognitive Flexibility ◽  
Causal Structure ◽  
Activity Patterns ◽  
Dopamine Neurons ◽  
Prediction Errors ◽  
Learning Rates ◽  
Serotonin Neurons ◽  
Endogenous Role ◽  
Flexible Adaptation

Serotonin is implicated in mood and affective disorders. However, growing evidence suggests that a core endogenous role is to promote flexible adaptation to changes in the causal structure of the environment, through behavioral inhibition and enhanced plasticity. We used long-term photometric recordings in mice to study a population of dorsal raphe serotonin neurons, whose activity we could link to normal reversal learning using pharmacogenetics. We found that these neurons are activated by both positive and negative prediction errors, and thus report signals similar to those proposed to promote learning in conditions of uncertainty. Furthermore, by comparing the cue responses of serotonin and dopamine neurons, we found differences in learning rates that could explain the importance of serotonin in inhibiting perseverative responding. Our findings show how the activity patterns of serotonin neurons support a role in cognitive flexibility, and suggest a revised model of dopamine–serotonin opponency with potential clinical implications.

scholarly journals A nonlinear relationship between prediction errors and learning rates in human reinforcement learning

2019 ◽  
Author(s):  
Erdem Pulcu
Keyword(s):  
Reinforcement Learning ◽  
Nonlinear Relationship ◽  
Prediction Errors ◽  
Learning Rates ◽  
The Face ◽  
In The Wild ◽  
Actual Outcome ◽  
Update Rules ◽  
Different Sources

AbstractWe are living in a dynamic world in which stochastic relationships between cues and outcome events create different sources of uncertainty1 (e.g. the fact that not all grey clouds bring rain). Living in an uncertain world continuously probes learning systems in the brain, guiding agents to make better decisions. This is a type of value-based decision-making which is very important for survival in the wild and long-term evolutionary fitness. Consequently, reinforcement learning (RL) models describing cognitive/computational processes underlying learning-based adaptations have been pivotal in behavioural2,3 and neural sciences4–6, as well as machine learning7,8. This paper demonstrates the suitability of novel update rules for RL, based on a nonlinear relationship between prediction errors (i.e. difference between the agent’s expectation and the actual outcome) and learning rates (i.e. a coefficient with which agents update their beliefs about the environment), that can account for learning-based adaptations in the face of environmental uncertainty. These models illustrate how learners can flexibly adapt to dynamically changing environments.

scholarly journals Rare Rewards Amplify Dopamine Learning Responses

2019 ◽  
Author(s):  
Kathryn M. Rothenhoefer ◽  
Tao Hong ◽  
Aydin Alikaya ◽  
William R. Stauffer
Keyword(s):  
Probability Distributions ◽  
Reaction Times ◽  
Neural Mechanism ◽  
Dopamine Neurons ◽  
Point Estimate ◽  
Prediction Errors ◽  
Average Value ◽  
Learning Rates ◽  
Behavioral Choices ◽  
Predicted Values

AbstractDopamine neurons drive learning by coding reward prediction errors (RPEs), which are formalized as subtractions of predicted values from reward values. Subtractions accommodate point estimate predictions of value, such as the average value. However, point estimate predictions fail to capture many features of choice and learning behaviors. For instance, reaction times and learning rates consistently reflect higher moments of probability distributions. Here, we demonstrate that dopamine RPE responses code probability distributions. We presented monkeys with rewards that were drawn from the tails of normal and uniform reward size distributions to generate rare and common RPEs, respectively. Behavioral choices and pupil diameter measurements indicated that monkeys learned faster and registered greater arousal from rare RPEs, compared to common RPEs of identical magnitudes. Dopamine neuron recordings indicated that rare rewards amplified RPE responses. These results demonstrate that dopamine responses reflect probability distributions and suggest a neural mechanism for the amplified learning and enhanced arousal associated with rare events.

scholarly journals Human midbrain precursors activate the expected developmental genetic program and differentiate long-term to functional A9 dopamine neurons in vitro. Enhancement by Bcl-XL

2012 ◽  
Vol 318 (19) ◽  
pp. 2446-2459 ◽  
Author(s):  
Emma G. Seiz ◽  
Milagros Ramos-Gómez ◽  
Elise T. Courtois ◽  
Jan Tønnesen ◽  
Merab Kokaia ◽  
...  
Keyword(s):  
Genetic Program ◽  
Dopamine Neurons ◽  
Developmental Genetic

scholarly journals Response dynamics of midbrain dopamine neurons and serotonin neurons to heroin, nicotine, cocaine, and MDMA

2018 ◽  
Vol 4 (1) ◽  
Author(s):  
Chao Wei ◽  
Xiao Han ◽  
Danwei Weng ◽  
Qiru Feng ◽  
Xiangbing Qi ◽  
...  
Keyword(s):  
Dopamine Neurons ◽  
Response Dynamics ◽  
Serotonin Neurons ◽  
Midbrain Dopamine ◽  
Midbrain Dopamine Neurons

scholarly journals Transient inhibition and long-term facilitation of locomotion by phasic optogenetic activation of serotonin neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Patrícia A Correia ◽  
Eran Lottem ◽  
Dhruba Banerjee ◽  
Ana S Machado ◽  
Megan R Carey ◽  
...  
Keyword(s):  
Motor Behavior ◽  
Motor Impairment ◽  
Long Term Effects ◽  
Strong Suppression ◽  
Serotonin Neurons ◽  
Short And Long Term ◽  
Rapid Kinetics ◽  
Long Term Facilitation ◽  
The Impact

Serotonin (5-HT) is associated with mood and motivation but the function of endogenous 5-HT remains controversial. Here, we studied the impact of phasic optogenetic activation of 5-HT neurons in mice over time scales from seconds to weeks. We found that activating dorsal raphe nucleus (DRN) 5-HT neurons induced a strong suppression of spontaneous locomotor behavior in the open field with rapid kinetics (onset ≤1 s). Inhibition of locomotion was independent of measures of anxiety or motor impairment and could be overcome by strong motivational drive. Repetitive place-contingent pairing of activation caused neither place preference nor aversion. However, repeated 15 min daily stimulation caused a persistent increase in spontaneous locomotion to emerge over three weeks. These results show that 5-HT transients have strong and opposing short and long-term effects on motor behavior that appear to arise from effects on the underlying factors that motivate actions.

scholarly journals Midbrain dopamine neurons signal aversion in a reward-context-dependent manner

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Hideyuki Matsumoto ◽  
Ju Tian ◽  
Naoshige Uchida ◽  
Mitsuko Watabe-Uchida
Keyword(s):  
Dopamine Neurons ◽  
Prediction Errors ◽  
Dependent Manner ◽  
Value Prediction ◽  
Signal Value ◽  
Aversive Events ◽  
High Reward ◽  
Midbrain Dopamine ◽  
Dopamine Signaling ◽  
Reward And Punishment

Dopamine is thought to regulate learning from appetitive and aversive events. Here we examined how optogenetically-identified dopamine neurons in the lateral ventral tegmental area of mice respond to aversive events in different conditions. In low reward contexts, most dopamine neurons were exclusively inhibited by aversive events, and expectation reduced dopamine neurons’ responses to reward and punishment. When a single odor predicted both reward and punishment, dopamine neurons’ responses to that odor reflected the integrated value of both outcomes. Thus, in low reward contexts, dopamine neurons signal value prediction errors (VPEs) integrating information about both reward and aversion in a common currency. In contrast, in high reward contexts, dopamine neurons acquired a short-latency excitation to aversive events that masked their VPE signaling. Our results demonstrate the importance of considering the contexts to examine the representation in dopamine neurons and uncover different modes of dopamine signaling, each of which may be adaptive for different environments.

scholarly journals The Tension Between Cognitive and Regulatory Flexibility and Their Associations With Current and Lifetime PTSD Symptoms

2021 ◽  
Vol 12 ◽  
Author(s):  
Shilat Haim-Nachum ◽  
Einat Levy-Gigi
Keyword(s):  
Cognitive Flexibility ◽  
Emotional Expression ◽  
Relative Effect ◽  
Ptsd Symptoms ◽  
Long Term Effects ◽  
Traumatic Exposure ◽  
Short And Long Term ◽  
Regulatory Flexibility ◽  
Personalized Intervention

In recent years, researchers have tried to unpack the meaning of the term flexibility and test how different constructs of flexibility are associated with various psychopathologies. For example, it is apparent that high levels of flexibility allow individuals to adaptively cope and avoid psychopathology following traumatic events, but the precise nature of this flexibility is ambiguous. In this study we focus on two central constructs: cognitive flexibility – the ability to recognize and implement possible responses to a situation– and regulatory flexibility – the ability to modulate emotional expression and experience across situations. We aim to explore the connection between cognitive and regulatory flexibility and evaluate their relative effect on PTSD symptoms. Trauma-exposed college students (N = 109, M age = 25.31, SD = 4.59) were assessed for cognitive and regulatory flexibility and current and lifetime PTSD symptoms. We predicted and found a relatively weak, yet significant, overlap between participants’ cognitive and regulatory flexibility. Importantly, while both cognitive and regulatory flexibility were associated with lifetime PTSD symptoms, only cognitive flexibility was associated with current PTSD symptoms. The findings illuminate the possible value of differentiating between constructs of flexibility in predicting short and long-term effects of traumatic exposure and may pave the ground for developing personalized intervention methods.

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