scholarly journals Selective deletion of the leptin receptor in dopamine neurons produces anxiogenic-like behavior and increases dopaminergic activity in amygdala

2011 ◽  
Vol 16 (10) ◽  
pp. 1024-1038 ◽  
Author(s):  
J Liu ◽  
S M Perez ◽  
W Zhang ◽  
D J Lodge ◽  
X-Y Lu
Keyword(s):  
Leptin Receptor ◽  
Dopamine Neurons ◽  
Dopaminergic Activity

scholarly journals Modeling Uncertainty-Seeking Behavior Mediated by Cholinergic Influence on Dopamine

2019 ◽  
Author(s):  
Marwen Belkaid ◽  
Jeffrey L. Krichmar
Keyword(s):  
Decision Making ◽  
Dopaminergic Neurons ◽  
Cholinergic System ◽  
Dopamine Neurons ◽  
Comprehensive Understanding ◽  
Dopaminergic Activity ◽  
Integrate And Fire ◽  
Major Implication ◽  
Seeking Behavior

AbstractRecent findings suggest that acetylcholine mediates uncertainty-seeking behaviors through its projection to dopamine neurons – another neuromodulatory system known for its major implication in reinforcement learning and decision-making. In this paper, we propose a leaky-integrate-and-fire model of this mechanism. It implements a softmax-like selection with an uncertainty bonus by a cholinergic drive to dopaminergic neurons, which in turn influence synaptic currents of downstream neurons. The model is able to reproduce experimental data in two decision-making tasks. It also predicts that i) in the absence of cholinergic input, dopaminergic activity would not correlate with uncertainty, and that ii) the adaptive advantage brought by the implemented uncertainty-seeking mechanism is most useful when sources of reward are not highly uncertain. Moreover, this modeling work allows us to propose novel experiments which might shed new light on the role of acetylcholine in both random and directed exploration. Overall, this study thus contributes to a more comprehensive understanding of the roles of the cholinergic system and its involvement in decision-making in particular.

A pair of dopamine neurons mediate chronic stress signals to induce learning deficit in Drosophila melanogaster

2021 ◽  
Vol 118 (42) ◽  
pp. e2023674118
Author(s):  
Jia Jia ◽  
Lei He ◽  
Junfei Yang ◽  
Yichun Shuai ◽  
Jingjing Yang ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Chronic Stress ◽  
Dopaminergic Neurons ◽  
Mushroom Body ◽  
Dopamine Neurons ◽  
Learning Deficit ◽  
Dopaminergic Activity ◽  
Output Neurons ◽  
Stress Signals ◽  
Underlying Mechanisms

Chronic stress could induce severe cognitive impairments. Despite extensive investigations in mammalian models, the underlying mechanisms remain obscure. Here, we show that chronic stress could induce dramatic learning and memory deficits in Drosophila melanogaster. The chronic stress–induced learning deficit (CSLD) is long lasting and associated with other depression-like behaviors. We demonstrated that excessive dopaminergic activity provokes susceptibility to CSLD. Remarkably, a pair of PPL1-γ1pedc dopaminergic neurons that project to the mushroom body (MB) γ1pedc compartment play a key role in regulating susceptibility to CSLD so that stress-induced PPL1-γ1pedc hyperactivity facilitates the development of CSLD. Consistently, the mushroom body output neurons (MBON) of the γ1pedc compartment, MBON-γ1pedc>α/β neurons, are important for modulating susceptibility to CSLD. Imaging studies showed that dopaminergic activity is necessary to provoke the development of chronic stress–induced maladaptations in the MB network. Together, our data support that PPL1-γ1pedc mediates chronic stress signals to drive allostatic maladaptations in the MB network that lead to CSLD.

scholarly journals Leptin Receptor Signaling in Midbrain Dopamine Neurons Regulates Feeding

Neuron ◽  
2006 ◽  
Vol 51 (6) ◽  
pp. 801-810 ◽  
Author(s):  
Jonathan D. Hommel ◽  
Richard Trinko ◽  
Robert M. Sears ◽  
Dan Georgescu ◽  
Zong-Wu Liu ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Dopamine Neurons ◽  
Receptor Signaling ◽  
Midbrain Dopamine ◽  
Midbrain Dopamine Neurons

scholarly journals Dichotomous dopaminergic and noradrenergic neural states mediate distinct aspects of exploitative behavioral states

2021 ◽  
Vol 7 (30) ◽  
pp. eabh2059
Author(s):  
Aaron C. Koralek ◽  
Rui M. Costa
Keyword(s):  
Dopamine Neurons ◽  
Calcium Dynamics ◽  
Noradrenergic Neurons ◽  
Dopaminergic Activity ◽  
Sustained Activity ◽  
Basal Activity ◽  
Behavioral Paradigm ◽  
Behavioral States ◽  
Sustained Inhibition ◽  
Action Choice

The balance between exploiting known actions and exploring alternatives is critical for survival and hypothesized to rely on shifts in neuromodulation. We developed a behavioral paradigm to capture exploitative and exploratory states and imaged calcium dynamics in genetically identified dopaminergic and noradrenergic neurons. During exploitative states, characterized by motivated repetition of the same action choice, dopamine neurons in SNc encoding movement vigor showed sustained elevation of basal activity that lasted many seconds. This sustained activity emerged from longer positive responses, which accumulated during exploitative action-reward bouts, and hysteretic dynamics. Conversely, noradrenergic neurons in LC showed sustained inhibition of basal activity due to the accumulation of longer negative responses in LC. Chemogenetic manipulation of these sustained dynamics revealed that dopaminergic activity mediates action drive, whereas noradrenergic activity modulates choice diversity. These data uncover the emergence of sustained neural states in dopaminergic and noradrenergic networks that mediate dissociable aspects of exploitative bouts.

scholarly journals Slowly evolving dopaminergic activity modulates the moment-to-moment probability of reward-related self-timed movements

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Allison E Hamilos ◽  
Giulia Spedicato ◽  
Ye Hong ◽  
Fangmiao Sun ◽  
Yulong Li ◽  
...  
Keyword(s):  
Dopaminergic System ◽  
Movement Time ◽  
Human Movement ◽  
The Self ◽  
Dopamine Neurons ◽  
Movement Initiation ◽  
Dopaminergic Activity ◽  
The Moment ◽  
The Relationship ◽  
Criterion Time

Clues from human movement disorders have long suggested that the neurotransmitter dopamine plays a role in motor control, but how the endogenous dopaminergic system influences movement is unknown. Here we examined the relationship between dopaminergic signaling and the timing of reward-related movements in mice. Animals were trained to initiate licking after a self-timed interval following a start-timing cue; reward was delivered in response to movements initiated after a criterion time. The movement time was variable from trial-to-trial, as expected from previous studies. Surprisingly, dopaminergic signals ramped-up over seconds between the start-timing cue and the self-timed movement, with variable dynamics that predicted the movement/reward time on single trials. Steeply rising signals preceded early lick-initiation, whereas slowly rising signals preceded later initiation. Higher baseline signals also predicted earlier self-timed movements. Optogenetic activation of dopamine neurons during self-timing did not trigger immediate movements, but rather caused systematic early-shifting of movement initiation, whereas inhibition caused late-shifting, as if modulating the probability of movement. Consistent with this view, the dynamics of the endogenous dopaminergic signals quantitatively predicted the moment-by-moment probability of movement initiation on single trials. We propose that ramping dopaminergic signals, likely encoding dynamic reward expectation, can modulate the decision of when to move.

scholarly journals What is dopamine doing in model-based reinforcement learning?

2020 ◽  
Author(s):  
Thomas Akam ◽  
Mark Walton
Keyword(s):  
Reinforcement Learning ◽  
Prediction Error ◽  
Dopamine Neurons ◽  
State Representation ◽  
Dopaminergic Activity ◽  
Model Based ◽  
Model Free ◽  
Reward Prediction ◽  
Predictive State Representation ◽  
Teaching Signal

Experiments have implicated dopamine in model-based reinforcement learning (RL). These findings are unexpected as dopamine is thought to encode a reward prediction error (RPE), which is the key teaching signal in model-free RL. Here we examine two possible accounts for dopamine’s involvement in model-based RL: the first that dopamine neurons carry a prediction error used to update a type of predictive state representation called a successor representation, the second that two well established aspects of dopaminergic activity, RPEs and surprise signals, can together explain dopamine’s involvement in model-based RL.

Expression and immunohistochemical localization of leptin and leptin receptor in normal and preeclamptic placenta

1998 ◽  
Vol 5 (1) ◽  
pp. 137A-137A
Author(s):  
J MCCARTHY ◽  
D MISRA ◽  
A KANBOURSHAKIR ◽  
L MINICH ◽  
D LYKINS ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Immunohistochemical Localization
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