Reversal learning tasks assess behavioral flexibility by requiring subjects to switch from one learned response choice to a different response choice when task contingencies change. This requires both the processing of negative feedback once a learned response is no longer reinforced, and the capacity for flexible response selection. In 2-choice reversal learning tasks, subjects switch between ...

Behavior-based artificial systems, e.g. mobile robots, are frequently designed using (various degrees and levels of) biology as inspiration, but rarely modeled based on actual quantitative empirical data. This paper presents a data-driven behavior-based model of a simple biological organism, the hydra. Four constituent behaviors were implemented in a simulated animal, and the overall behavior o...

Dopamine neurons in the midbrain respond to behavioral events and environmental stimuli. Their different patterns of activation in turn modulate the activity of forebrain regions and modulate the expression of selective behavioral responses. However, their activity is closely dependent on the cholinergic systems in the brainstem. Ascending cholinergic projections from the pedunculopontine and l...

3 theoretical approaches to the origin and development o f the infant-mother relationship are reviewed: psychoanalytic theories of object relations, social learning theories of dependency (and attachment), and an ethologically oriented theory o f attachment. "Object relations," "dependency," and "attachment," although overlapping, are seen to differ substantially. Among the concepts in regard t...