Hyperbaric Oxygen Therapy for Veterans With Combat-Associated Posttraumatic Stress Disorder: A Randomized, Sham-Controlled Clinical Trial.

Cumulative data indicate that new protocols of hyperbaric oxygen therapy (HBOT) may induce neuroplasticity and improve clinical symptoms of patients suffering from posttraumatic stress disorder (PTSD). The aim of the current study was to evaluate the effects of HBOT on veterans with combat-associated PTSD (CA-PTSD) in a randomized, sham-controlled trial. Male veterans aged 25-60 years with CA-PTSD, with a Clinician-Administered PTSD Scale for (CAPS-5) score above 20, were included.

Inhibitory mechanisms in the prefrontal-cortex differentially mediate Putamen activity during valence-based learning.

Learning from appetitive and aversive stimuli involves interactions between the prefrontal cortex and subcortical structures. Preclinical and theoretical studies indicate that inhibition is essential in regulating the relevant neural circuitry. Here, we demonstrate that GABA, the main inhibitory neurotransmitter in the central nervous system, differentially affects how the dACC interacts with subcortical structures during appetitive and aversive learning in humans.

The neurobehavioral correlates of exploration without learning: Trading off value for explicit, prospective, and variable information gains.

Exploration is typically motivated by gaining information, with previous research showing that potential information gains drive a "directed" type of exploration. Yet, this research usually studies exploration in the context of learning paradigms and does not directly manipulate multiple levels of information gain. Here, we present a task that isolates learning from decision-making and controls the magnitude of prospective information gains.

Irrelevant Threats Linger and Affect Behavior in High Anxiety.

Threat-related information attracts attention and disrupts ongoing behavior, and particularly so for more anxious individuals. Yet, it is unknown how and to what extent threat-related information leave lingering influences on behavior (e.g.

Average reward rates enable motivational transfer across independent reinforcement learning tasks.

Outcomes and feedbacks on performance may influence behavior beyond the context in which it was received, yet it remains unclear what neurobehavioral mechanisms may account for such lingering influences on behavior. The average reward rate (ARR) has been suggested to regulate motivated behavior, and was found to interact with dopamine-sensitive cognitive processes, such as vigilance and associative memory encoding. The ARR could therefore provide a bridge between independent tasks when these are performed in temporal proximity, such that the reward rate obtained in one task could influence performance in a second subsequent task.

A neural and behavioral trade-off between value and uncertainty underlies exploratory decisions in normative anxiety.

Exploration reduces uncertainty about the environment and improves the quality of future decisions, but at the cost of provisional uncertain and suboptimal outcomes. Although anxiety promotes intolerance to uncertainty, it remains unclear whether and by which mechanisms anxiety relates to exploratory decision-making. We use a dynamic three-armed-bandit task and find that higher trait-anxiety is associated with increased exploration, which in turn harms overall performance.

Prior Reward Conditioning Dampens Hippocampal and Striatal Responses during an Associative Memory Task.

Offering reward during encoding typically leads to better memory [Adcock, R. A., Thangavel, A.

Prediction errors bidirectionally bias time perception.

Time perception and prediction errors are essential for everyday life. We hypothesized that their putative shared circuitry in the striatum might enable these two functions to interact. We show that positive and negative prediction errors bias time perception by increasing and decreasing perceived time, respectively.

Interplay between midbrain and dorsal anterior cingulate regions arbitrates lingering reward effects on memory encoding.

Rewarding events enhance memory encoding via dopaminergic influences on hippocampal plasticity. Phasic dopamine release depends on immediate reward magnitude, but presumably also on tonic dopamine levels, which may vary as a function of the average accumulation of reward over time. Using model-based fMRI in combination with a novel associative memory task, we show that immediate reward magnitude exerts a monotonically increasing influence on the nucleus accumbens, ventral tegmental area (VTA), and hippocampal activity during encoding, and enhances memory.

Neurocomputational correlates of learned irrelevance in humans.

Inappropriate behaviors may result from acquiring maladaptive associations between irrelevant information in the environment and important events, such as reward or punishment. Pre-exposure effects are believed to prevent the expression of irrelevant associations. For example, learned irrelevance delays the expression of associations between conditioned (CS) and unconditioned (US) stimuli following their uncorrelated presentation.

Re-exploring Mechanisms of Exploration.

Deciding when to exploit what is already known and when to explore new possibilities is crucial for adapting to novel and dynamic environments. Using reinforcement-based decision making, Costa et al. (2019) in this issue of Neuron find that neurons in the amygdala and ventral-striatum differentially signal the benefit from exploring new options and exploiting familiar ones.

Trial-by-Trial Modulation of Associative Memory Formation by Reward Prediction Error and Reward Anticipation as Revealed by a Biologically Plausible Computational Model.

Anticipation and delivery of rewards improves memory formation, but little effort has been made to disentangle their respective contributions to memory enhancement. Moreover, it has been suggested that the effects of reward on memory are mediated by dopaminergic influences on hippocampal plasticity. Yet, evidence linking memory improvements to actual reward computations reflected in the activity of the dopaminergic system, i.

Correction: Linking Individual Learning Styles to Approach-Avoidance Motivational Traits and Computational Aspects of Reinforcement Learning.

[This corrects the article DOI: 10.1371/journal.pone.

Linking Individual Learning Styles to Approach-Avoidance Motivational Traits and Computational Aspects of Reinforcement Learning.

Learning how to gain rewards (approach learning) and avoid punishments (avoidance learning) is fundamental for everyday life. While individual differences in approach and avoidance learning styles have been related to genetics and aging, the contribution of personality factors, such as traits, remains undetermined. Moreover, little is known about the computational mechanisms mediating differences in learning styles.

The "Creative Right Brain" Revisited: Individual Creativity and Associative Priming in the Right Hemisphere Relate to Hemispheric Asymmetries in Reward Brain Function.

The idea that creativity resides in the right cerebral hemisphere is persistent in popular science, but has been widely frowned upon by the scientific community due to little empirical support. Yet, creativity is believed to rely on the ability to combine remote concepts into novel and useful ideas, an ability which would depend on associative processing in the right hemisphere. Moreover, associative processing is modulated by dopamine, and asymmetries in dopamine functionality between hemispheres may imbalance the expression of their implemented cognitive functions.

The left hemisphere learns what is right: Hemispatial reward learning depends on reinforcement learning processes in the contralateral hemisphere.

Orienting biases refer to consistent, trait-like direction of attention or locomotion toward one side of space. Recent studies suggest that such hemispatial biases may determine how well people memorize information presented in the left or right hemifield. Moreover, lesion studies indicate that learning rewarded stimuli in one hemispace depends on the integrity of the contralateral striatum.

Hemispheric Asymmetries in Striatal Reward Responses Relate to Approach-Avoidance Learning and Encoding of Positive-Negative Prediction Errors in Dopaminergic Midbrain Regions.

Some individuals are better at learning about rewarding situations, whereas others are inclined to avoid punishments (i.e., enhanced approach or avoidance learning, respectively).

Increased Reward-Related Behaviors during Sleep and Wakefulness in Sleepwalking and Idiopathic Nightmares.

Background: We previously suggested that abnormal sleep behaviors, i.e., as found in parasomnias, may often be the expression of increased activity of the reward system during sleep.

Trait anxiety and post-learning stress do not affect perceptual learning.

While it is well established that stress can modulate declarative learning, very few studies have investigated the influence of stress on non-declarative learning. Here, we studied the influence of post-learning stress, which effectively modulates declarative learning, on perceptual learning of a visual texture discrimination task (TDT). On day one, participants trained for one session with TDT and were instructed that they, at any time, could be exposed to either a high stressor (ice-water; Cold Pressor Test; CPT) or a low stressor (warm water).

Different types of feedback change decision criterion and sensitivity differently in perceptual learning.

In (perceptual) learning, performance improves with practice either by changes in sensitivity or decision criterion. Often, changes in sensitivity are regarded as the appropriate measure of learning while changes in criterion are considered unavoidable nuisances. Very little is known about the distinguishing characteristics of both learning types.

About similar characteristics of visual perceptual learning and LTP.

Perceptual learning is an implicit form of learning which induces long-lasting perceptual enhancements. Perceptual learning shows intriguing characteristics. For example, a minimal number of trials per session is needed for learning and the interleaved presentation of more than one stimulus type can hinder learning.

Perceptual learning, roving and the unsupervised bias.

Perceptual learning improves perception through training. Perceptual learning improves with most stimulus types but fails when certain stimulus types are mixed during training (roving). This result is surprising because classical supervised and unsupervised neural network models can cope easily with roving conditions.

Does perceptual learning suffer from retrograde interference?

In motor learning, training a task B can disrupt improvements of performance of a previously learned task A, indicating that learning needs consolidation. An influential study suggested that this is the case also for visual perceptual learning. Using the same paradigm, we failed to reproduce these results.

Anesthesia prevents auditory perceptual learning.

Background: An auditory perceptual learning paradigm was used to investigate whether implicit memories are formed during general anesthesia.

Methods: Eighty-seven patients who had an American Society of Anesthesiologists physical status of I-III and were scheduled to undergo an elective surgery with general anesthesia were randomly assigned to one of two groups. One group received auditory stimulation during surgery, whereas the other did not.