Cracking and Packing Information about the Features of Expected Rewards in the Orbitofrontal Cortex.

The orbitofrontal cortex (OFC) is crucial for tracking various aspects of expected outcomes, thereby helping to guide choices and support learning. Our previous study showed that the effects of reward timing and size on the activity of single units in OFC were dissociable when these attributes were manipulated independently ( Roesch et al., 2006).

Neuroscience: A bottom-up mechanism for cognitive control?

Cognitive control is often conceived of as occurring top-down, with prefrontal cortical areas exerting control over other parts of the brain. A new study demonstrates what might be considered a 'bottom-up' mechanism for cognitive control, involving the disinhibition of orbitofrontal cortex by subcortical regions.

Optogenetic Inhibition of Rat Anterior Cingulate Cortex Impairs the Ability to Initiate and Stay on Task.

Our prior research has identified neural correlates of cognitive control in the anterior cingulate cortex (ACC), leading us to hypothesize that the ACC is necessary for increasing attention as rats flexibly learn new contingencies during a complex reward-guided decision-making task. Here, we tested this hypothesis by using optogenetics to transiently inhibit the ACC, while rats of either sex performed the same two-choice task. ACC inhibition had a profound impact on behavior that extended beyond deficits in attention during learning when expected outcomes were uncertain.

Dopaminergic prediction errors in the ventral tegmental area reflect a multithreaded predictive model.

Dopamine neuron activity is tied to the prediction error in temporal difference reinforcement learning models. These models make significant simplifying assumptions, particularly with regard to the structure of the predictions fed into the dopamine neurons, which consist of a single chain of timepoint states. Although this predictive structure can explain error signals observed in many studies, it cannot cope with settings where subjects might infer multiple independent events and outcomes.

Neuroscience: Action history and the orbitofrontal cortex.

Decisions are often made in the absence of instructive cues, based instead on memories of previous actions and outcomes. A new study sheds light on how orbitofrontal cortex tracks action history to adjust actions over time.

Orbitofrontal State Representations Are Related to Choice Adaptations and Reward Predictions.

Animals can categorize the environment into "states," defined by unique sets of available action-outcome contingencies in different contexts. Doing so helps them choose appropriate actions and make accurate outcome predictions when in each given state. State maps have been hypothesized to be held in the orbitofrontal cortex (OFC), an area implicated in decision-making and encoding information about outcome predictions.

Prior Cocaine Use Alters the Normal Evolution of Information Coding in Striatal Ensembles during Value-Guided Decision-Making.

Substance use disorders (SUDs) are characterized by maladaptive behavior. The ability to properly adjust behavior according to changes in environmental contingencies necessitates the interlacing of existing memories with updated information. This can be achieved by assigning learning in different contexts to compartmentalized "states.

Dopamine neuron ensembles signal the content of sensory prediction errors.

Dopamine neurons respond to errors in predicting value-neutral sensory information. These data, combined with causal evidence that dopamine transients support sensory-based associative learning, suggest that the dopamine system signals a multidimensional prediction error. Yet such complexity is not evident in the activity of individual neurons or population averages.

Rat Orbitofrontal Ensemble Activity Contains Multiplexed but Dissociable Representations of Value and Task Structure in an Odor Sequence Task.

The orbitofrontal cortex (OFC) has long been implicated in signaling information about expected outcomes to facilitate adaptive or flexible behavior. Current proposals focus on signaling of expected value versus the representation of a value-agnostic cognitive map of the task. While often suggested as mutually exclusive, these alternatives may represent extreme ends of a continuum determined by task complexity and experience.

Expectancy-Related Changes in Dopaminergic Error Signals Are Impaired by Cocaine Self-Administration.

Addiction is a disorder of behavioral control and learning. While this may reflect pre-existing propensities, drug use also clearly contributes by causing changes in outcome processing in prefrontal and striatal regions. This altered processing is associated with behavioral deficits, including changes in learning.

Orbitofrontal neurons signal reward predictions, not reward prediction errors.

Neurons in the orbitofrontal cortex (OFC) fire in anticipation of and during rewards. Such firing has been suggested to encode reward predictions and to account in some way for the role of this area in adaptive behavior and learning. However, it has also been reported that neural activity in OFC reflects reward prediction errors, which might drive learning directly.

Effects of inference on dopaminergic prediction errors depend on orbitofrontal processing.

Dopaminergic reward prediction errors in monkeys reflect inferential reward predictions that well-trained animals can make when associative rules change. Here, in a new analysis of previously described data, we test whether dopaminergic error signals in rats are influenced by inferential predictions and whether such effects depend on the orbitofrontal cortex (OFC). Dopamine neurons were recorded from controls or rats with ipsilateral OFC lesions during performance of a choice task in which odor cues signaled the availability of sucrose reward in 2 wells.

Cholinergic Interneurons Use Orbitofrontal Input to Track Beliefs about Current State.

Unlabelled: When conditions change, organisms need to learn about the changed conditions without interfering with what they already know. To do so, they can assign the new learning to a new "state" and the old learning to a previous state. This state assignment is fundamental to behavioral flexibility.

Orbitofrontal lesions eliminate signalling of biological significance in cue-responsive ventral striatal neurons.

The ventral striatum has long been proposed as an integrator of biologically significant associative information to drive actions. Although inputs from the amygdala and hippocampus have been much studied, the role of prominent inputs from orbitofrontal cortex (OFC) are less well understood. Here, we recorded single-unit activity from ventral striatum core in rats with sham or ipsilateral neurotoxic lesions of lateral OFC, as they performed an odour-guided spatial choice task.

What the orbitofrontal cortex does not do.

The number of papers about the orbitofrontal cortex (OFC) has grown from 1 per month in 1987 to a current rate of over 50 per month. This publication stream has implicated the OFC in nearly every function known to cognitive neuroscience and in most neuropsychiatric diseases. However, new ideas about OFC function are typically based on limited data sets and often ignore or minimize competing ideas or contradictory findings.

Orbitofrontal neurons acquire responses to 'valueless' Pavlovian cues during unblocking.

The orbitofrontal cortex (OFC) has been described as signaling outcome expectancies or value. Evidence for the latter comes from the studies showing that neural signals in the OFC correlate with value across features. Yet features can co-vary with value, and individual units may participate in multiple ensembles coding different features.

Orbitofrontal neurons infer the value and identity of predicted outcomes.

The best way to respond flexibly to changes in the environment is to anticipate them. Such anticipation often benefits us if we can infer that a change has occurred, before we have actually experienced the effects of that change. Here we test for neural correlates of this process by recording single-unit activity in the orbitofrontal cortex in rats performing a choice task in which the available rewards changed across blocks of trials.

How did the chicken cross the road? With her striatal cholinergic interneurons, of course.

Recognizing when the world changes is fundamental for normal learning. In this issue of Neuron, Bradfield et al. (2013) show that cholinergic interneurons in dorsomedial striatum are critical to the process whereby new states of the world are appropriately registered and retrieved during associative learning.

Risk-responsive orbitofrontal neurons track acquired salience.

Decision making is impacted by uncertainty and risk (i.e., variance).

Reward prediction error signaling in posterior dorsomedial striatum is action specific.

Neural correlates of reward prediction errors (RPEs) have been found in dorsal striatum. Such signals may be important for updating associative action representations within striatum. In order that the appropriate representations can be updated, it might be important for the RPE signal to be specific for the action that led to that error.

The impact of orbitofrontal dysfunction on cocaine addiction.

Cocaine addiction is characterized by poor judgment and maladaptive decision-making. Here we review evidence implicating the orbitofrontal cortex in such behavior. This evidence suggests that cocaine-induced changes in orbitofrontal cortex disrupt the representation of states and transition functions that form the basis of flexible and adaptive 'model-based' behavioral control.

Neural correlates of stimulus-response and response-outcome associations in dorsolateral versus dorsomedial striatum.

Considerable evidence suggests that there is functional heterogeneity in the control of behavior by the dorsal striatum. Dorsomedial striatum may support goal-directed behavior by representing associations between responses and outcomes (R-O associations). The dorsolateral striatum, in contrast, may support motor habits by encoding associations between stimuli and responses (S-R associations).

A new perspective on the role of the orbitofrontal cortex in adaptive behaviour.

The orbitofrontal cortex (OFC) is crucial for changing established behaviour in the face of unexpected outcomes. This function has been attributed to the role of the OFC in response inhibition or to the idea that the OFC is a rapidly flexible associative-learning area. However, recent data contradict these accounts, and instead suggest that the OFC is crucial for signalling outcome expectancies.

The orbitofrontal cortex and ventral tegmental area are necessary for learning from unexpected outcomes.

Humans and other animals change their behavior in response to unexpected outcomes. The orbitofrontal cortex (OFC) is implicated in such adaptive responding, based on evidence from reversal tasks. Yet these tasks confound using information about expected outcomes with learning when those expectations are violated.

Cocaine exposure shifts the balance of associative encoding from ventral to dorsolateral striatum.

Both dorsal and ventral striatum are implicated in the "habitization" of behavior that occurs in addiction. Here we examined the effect of cocaine exposure on associative encoding in these two regions. Neural activity was recorded during go/no-go discrimination learning and reversal.