As animals learn novel behavioural responses, performance is maintained by two dissociable
influences. Initial responding is goal-directed and under voluntary control, but overtraining …

The amygdala has long been thought to be involved in emotional behaviour 1 , 2 , and its
role in anxiety and conditioned fear has been highlighted 3 , 4 . Individual amygdaloid nuclei …

Performance of instrumental actions in rats is initially sensitive to postconditioning changes
in reward value, but after more extended training, behavior comes to be controlled by …

Recent studies suggest new ways to interpret dopaminergic actions in goal-directed performance
and habitual responding. In the early stages of learning dopamine plays an essential …

Learning theory proposes that drug seeking is a synthesis of multiple controllers. Whereas
goal‐directed drug seeking is determined by the anticipated incentive value of the drug, …

The amygdala is a heterogeneous structure that has been implicated in a wide variety of
functions, most notably in fear conditioning. From this research, an influential serial model of …

Repeated exposure to the psychostimulant amphetamine has been shown to disrupt goal-directed
instrumental actions and promote the early and abnormal development of goal-…

Over the course of extended training, instrumental responding in rats shows a transition from
goal-dependent performance to goal-independent performance, as assessed by sensitivity …

A series of experiments examined the effects of 8 weeks of social isolation on spontaneous
locomotor activity, prepulse inhibition (PPI) of the acoustic startle response, latent inhibition (…

The amygdala is known to play a role in learning about motivationally significant events. We
investigated this role further by examining the effects of excitotoxic lesions of the basolateral …