Song preferences predict the quality of vocal learning in zebra finches

In songbirds, learning to sing is a highly social process that likely involves social reward. Here, we hypothesized that the degree to which a juvenile songbird learns a song depends on the degree to which it finds that song rewarding to hear during vocal development. We tested this hypothesis by measuring song preferences in young birds during song learning and then analyzing their adult songs. Song preferences were measured in an operant key-pressing assay. Juvenile male zebra finches (Taeniopygia guttata) had access to two keys, each of which was associated with a higher likelihood of playing the song of their father or that of another familiar adult ("neighbor"). To minimize the effects of exposure on learning, we implemented a reinforcement schedule that allowed us to detect preferences while balancing exposure to each song. On average, the juveniles significantly preferred the father's song early during song learning, before they were themselves singing. At around post-hatch day 60, their preference shifted to the neighbor's song. At the end of the song learning period, we recorded the juveniles' songs and compared them to the father's and the neighbor's song. All of the birds copied father's song. The accuracy with which the father's song was imitated was positively correlated with the peak strength of the preference for the father's song during the sensitive period. Our results show that preference for a social stimulus, in this case a vocalization, predicted social learning during development.

Intelligence Predicts Sensory Discrimination Ability but not Implicit Reward Learning

Previous research has made use of sensory discrimination tasks that incorporate differential reinforcement schedules as a method for measuring individual differences in implicit reward learning. One such task utilizing a differential reinforcement schedule was popularized by Pizzagalli et al. (2005) with the intent of behaviorally assessing anhedonia and reward sensitivity. Various studies have examined implicit reward learning in relation to clinical symptoms and personality traits, including anhedonia, depression, and Extraversion. Despite extensive use of these tasks, they have not been extensively examined in relation to intelligence. Other research suggests positive associations of intelligence with sensory discrimination ability. The present study utilized a probabilistic reward task incorporating differential reinforcement in a large community sample to determine the relations among IQ, sensory discrimination ability, and implicit reward learning. Participants (N = 298) completed a sensory discrimination task, as well as an IQ test. IQ was not associated with participants’ levels of implicit reward learning but was positively associated with sensory discrimination ability. These findings provide further understanding of the complex relations among implicit learning, sensory discrimination ability, and intelligence.

Brief Training to Modify the Breadth of Attention Influences the Generalisation of Fear

Background Generalisation of fear from dangerous to safe stimuli is an important process associated with anxiety disorders. However, factors that contribute towards fear (over)-generalisation remain poorly understood. The present investigation explored how attentional breadth (global/holistic and local/analytic) influences fear generalisation and, whether people trained to attend in a global vs. local manner show more or less generalisation. Methods Participants (N = 39) were shown stimuli which comprised of large ‘global’ letters and smaller ‘local’ letters (e.g. an F comprised of As) and they either had to identify the global or local letter. Participants were then conditioned to fear a face by pairing it with an aversive scream (75% reinforcement schedule). Perceptually similar, but safe, faces, were then shown. Self-reported fear levels and skin conductance responses were measured. Results Compared to participants in Global group, participants in Local group demonstrated greater fear for dangerous stimulus (CS +) as well as perceptually similar safe stimuli. Conclusions Participants trained to attend to stimuli in a local/analytical manner showed higher magnitude of fear acquisition and generalisation than participants trained to attend in a global/holistic way. Breadth of attentional focus can influence overall fear levels and fear generalisation and this can be manipulated via attentional training.

The Partial-Reinforcement Extinction Effect Does Not Result from Reduced Sensitivity to Non-Reinforcement

Five experiments used a magazine approach paradigm with rats to investigate whether learning about non-reinforcement is impaired in the presence of a conditioned stimulus (CS) that had been partially reinforced (PRf). Experiment 1 trained rats with a PRf CS and a continuously reinforced (CRf) CS, then extinguished responding to both CSs presented together as a compound. Probe trials of each CS presented alone revealed that extinction was slower for the PRf CS than the CRf CS, despite being extinguished in compound. In Experiment 2, a CRf light was extinguished in compound with either a CRf CS or a PRf CS that had been matched for overall reinforcement rate. Responding to the light extinguished at the same rate regardless of the reinforcement schedule of the other CS. Experiment 3 replicated this result with a PRf light. Thus, we found no evidence that a PRf CS impairs extinction of another CS presented at the same time. Experiments 4 and 5 extended this approach to study the acquisition of conditioned inhibition by training an inhibitor in compound with either a PRf or CRf excitatory CS. The reinforcement schedule of the excitatory CS had no effect on the acquisition of inhibition. In sum, conditioning with a PRf schedule slows subsequent extinction of that CS but does not affect learning about the non-reinforcement of other stimuli presented at the same time. We conclude that the Partial Reinforcement Extinction Effect is not due to a decrease in sensitivity to non-reinforcement following presentation of a PRf CS.

Training protocol for touchscreen-based visual discrimination in mice

Automated touchscreen-based tasks are increasingly being used to explore a broad range of issues in learning and behavior in mice. Researchers usually report how they train mice before acquiring the target task concisely, and shaping protocols at this stage are typically flexible. In this report, we described a training protocol, developed in our laboratory, for mice acquiring a simultaneous discrimination performance using visual stimuli. C57BL/6N mice were first given magazine training. Nosepoke responses were then authoshaped and maintained on a continuous reinforcement schedule. Self-start response was then introduced in order to measure response time to complete each trial. The stimulus position was also varied across trials. We finally examined the contrast discrimination performance. Mice were tested with four different contrast ratios. Target stimuli were white and black targets and the brightness of distractors had values between targets and background. All mice successfully went through all training stages, confirming that this training protocol is promising for shaping appropriate discriminative behaviors in mice.

Opponent regulation of action performance and timing by striatonigral and striatopallidal pathways

The basal ganglia have been implicated in action selection and timing, but the relative contributions of the striatonigral (direct) and striatopallidal (indirect) pathways to these functions remain unclear. We investigated the effects of optogenetic stimulation of D1+ (direct) and A2A+ (indirect) neurons in the ventrolateral striatum in head-fixed mice on a fixed time reinforcement schedule. Direct pathway stimulation initiates licking, whereas indirect pathway stimulation suppresses licking and results in rebound licking after stimulation. Moreover, direct and indirect pathways also play distinct roles in timing. Direct pathway stimulation produced a resetting of the internal timing process, whereas indirect pathway stimulation transiently paused timing, and proportionally delayed the next bout of licking. Our results provide evidence for the continuous and opposing contributions of the direct and indirect pathways in the production and timing of reward-guided behavior.

Intolerance of uncertainty and novelty facilitated extinction: The impact of reinforcement schedule

Individuals who score high in Intolerance of Uncertainty (IU) display reduced threat extinction learning and retention. Recently, it was shown that replacing threat associations with novel associations (i.e. presenting a novel non-aversive tone 100% of the time vs. presenting nothing) can promote threat extinction retention in individuals with high IU. This effect could be driven by the tone’s novelty or reliability. Here we seek to address this question by adjusting the reliability via the reinforcement schedule of the novel tone. We propose to measure skin conductance response during an associative learning task in which participants (n = 90) will be assigned to one of three conditions; standard extinction, 100% reinforcement NFE or 50% reinforcement NFE. This work will further our understanding of the role novelty, reliability and IU in threat extinction. Ultimately, this research will inform future models of IU and clinical treatments of anxiety and stress disorders.