Dopamine in the rodent tail of striatum regulates behavioral variability in response to threatening novel objects

The tail of the caudate is sensitive to both gain and loss feedback during information integration categorization

Although most category learning studies use feedback for training, little attention has been paid to how individuals utilize feedback implemented as gains or losses during categorization. We compared skilled categorization under three different conditions: Gain (earn points for correct answers), Gain and Loss (earn points for correct answers and lose points for wrong answers) and Correct or Wrong (accuracy feedback only). We also manipulated difficulty and point value, with near boundary stimuli having the highest number of points to win or lose, and stimuli far from the boundary having the lowest point value. We found that the tail of the caudate was sensitive to feedback condition, with highest activity when both Gain and Loss feedback were present and least activity when only Gain or accuracy feedback was present. We also found that activity across the caudate was affected by distance from the decision bound, with greatest activity for the near boundary high value stimuli, and lowest for far low value stimuli. Overall these results indicate that the tail of the caudate is sensitive not only to positive rewards but also to loss and punishment, consistent with recent animal research finding tail of the caudate activity in aversive learning.

Curiosity: primate neural circuits for novelty and information seeking

For many years, neuroscientists have investigated the behavioural, computational and neurobiological mechanisms that support value-based decisions, revealing how humans and animals make choices to obtain rewards. However, many decisions are influenced by factors other than the value of physical rewards or second-order reinforcers (such as money). For instance, animals (including humans) frequently explore novel objects that have no intrinsic value solely because they are novel and they exhibit the desire to gain information to reduce their uncertainties about the future, even if this information cannot lead to reward or assist them in accomplishing upcoming tasks. In this Review, I discuss how circuits in the primate brain responsible for detecting, predicting and assessing novelty and uncertainty regulate behaviour and give rise to these behavioural components of curiosity. I also briefly discuss how curiosity-related behaviours arise during postnatal development and point out some important reasons for the persistence of curiosity across generations.