The Patient, the Provider, and the TikTok Creator: Qualitative Analysis of the Content and Quality of Videos on Prenatal Genetic Screening.

Sensory cues experienced during goal-directed navigation serve as landmarks to direct appropriate adjustments in locomotor direction and speed (trajectory). Studies have implicated the striatum in landmark-based navigation strategies, which complement and compete with hippocampus and cortex dependent cognitive map-based strategies. Accurately adjusting behavior to an instructional cue requires information about whether the current trajectory is bringing an animal closer or further from the goal. For instance, seeing a sign for an ice cream store while driving in one direction may indicate successful approach, whereas seeing it driving in the opposite direction would indicate an incorrect trajectory. In this case, the correct response (continue or turn back) depends on the relative motion of the landmark and observer, calculated from self-motion or visual flow. While representations underlying cognitive map-based navigation have been widely studied, the striatal signals guiding landmark-based trajectory adjustments remain unresolved. Cues can trigger transient dopamine (DA) release in the striatum encoding a sudden change in the prediction of future reward, described in reinforcement learning models as ‘reward prediction errors’ (RPEs). Cue-evoked RPEs scale with the expected reward probability, magnitude, and timing, measures of the cue’s motivational value. Through bi-directional effects on striatal excitability and long-term plasticity, DA RPEs are positioned to influence motivation, associative learning, and the vigor of ongoing or future behavior. However, in landmark-based navigation, a cue-evoked RPE signaling nearby reward would be insufficient for guiding trajectory adjustments without incorporating movement direction and speed relative to the goal. Although RPE models can be adapted across contexts (or ‘state spaces’), whether signals needed for trajectory adjustments are represented in striatal DA release remains unknown. Most DA recordings come from instrumental tasks where animals are stationary at cue presentation, or Pavlovian tasks where cue and animal motion are irrelevant. In navigation tasks, ramping DA and place-value encoding reflect goal proximity, but in these tasks, animals always approached rewards along correct trajectories, preventing separation of trajectory accuracy from reward proximity.