Topic: Dopamine (DA)

Dopamine (DA) in the nucleus accumbens (NAc) is a critical signal for both learning and motivation. While DA release dynamics are often associated with reward prediction errors, they also scale remarkably well with a state-value signal – expectations of reward from an animal’s current state. However, computing value in real-world environments poses a substantial computational problem. Expectations of future rewards from a given state depend on future actions and their reward likelihood. Computing state value, therefore, necessitates assumptions about future navigational choices. Furthermore, v

Dopamine (DA) ramps are gradual increases in DA concentration observed during motivated behavior, contrasting with phasic DA release typically associated with signaling reward prediction errors (RPE). While RPE-related DA transients align with traditional models of reinforcement learning, where DA encodes the difference between expected and received rewards, dopamine ramps are less understood. Previous research demonstrated that DA ramps occur both at the level of DA cell bodies in the ventral tegmental area (VTA) and at the axon terminals in the nucleus accumbens (NAc), specifically in the me

The striatum intricately regulates motor and cognitive functions through the dynamic interplay of dopamine (DA), acetylcholine (ACh), and intrinsic neuronal firing, bearing profound implications for disorders like Parkinson's. However, the interaction between striatal DA and ACh, and their collective impact on striatal neuron activity in health and disease, are not fully understood. This study aims to elucidate the complex interplay between ACh, DA, and neuronal activity in the striatum during sensory and motor events. Utilizing a specialized Delayed-Go reaching task for head-fixed mice, we re

Dopamine (DA) release in the striatum regulates reward, motivation, and locomotion. The release is considered to have a short-lived phasic and continuous tonic component. Recent studies, however, have challenged the existence of tonic DA and revealed major regional diversity in extracellular DA dynamics. Here we build a large-scale three-dimensional model of extracellular DA dynamics in the dorsal (DS) and ventral striatum (VS) based on experimentally determined biological parameters. The model predicts rapid dynamics in DS with little-to-no basal DA, whereas the lower uptake capacity in VS sl

Adaptive behavior in a dynamically changing environment requires learning the value of actions, and updating these values in response to changes in the environment. Several studies have investigated the role of the striatum, and its key neuromodulators, dopamine (DA) and acetylcholine (Ach), in this process. However, these studies usually investigated these neuromodulatory signals in animals which had undergone extensive pre-training, and were thus experts at flexibly adapting to new action values. In addition, most of these studies did not explore the dynamics of these signals simultaneously,