Variable schedules of reinforcement do not reliably distinguish habit from goal-directed behavior.

Contemporary analyses of neurophysiological mechanisms of associative learning suggest that instrumental behavior can be controlled by separable action and habit processes. An increasingly broad range of human psychiatric and neurological disorders are now associated with maladaptive habit formation. The question of how the brain controls transitions into habit is thus relevant.

Free will: An Example of the Dopaminergic System.

Neuroscience has convinced people that much of their behavior is determined by causes unknown to them and beyond their control. However, are advances in neuroscience truly a prerequisite for such beliefs? Robert Kane's theory of ultimate responsibility is libertarian theory. Its innovative nature makes it possible to discuss the neurophysiological basis of its postulates.

Specific role of dopamine in striatum during instrumental learning.

Research of dopamine's role in behavior is seemingly in a state of permanent controversy over all major topics. The notion of 'prediction error' is a central component of current reward leaning models, but there are many caveats and contradictions in supporting data. In this paper we propose that the same dopamine signal can promote action and reinforce this action, and outline novel model of reward learning in which dopamine provides a kind of teaching signal with DA release starting well before and persisting beyond the to-be reinforced action.

[Neurobiology of addictive behavior].

Addictive behavior developes after repeated substance use and it typically include a strong desire to take the drug, difficulties in controlling its use, persisting in its use despite harmful consequences, a higher priority given to the drug use than to other activities. Relapse, the resumption of drug taking after periods of abstinence, remains the major problem for the treatment of addiction. The process of drug addiction shares striking commonalities with neural plasticity associated with natural reward learning and memory and is caused primarily by drug-induced sensitization in the brain mesocorticolimbic systems that attribute incentive salience to reward-associated stimuli.

[Mesocorticolimbic dopaminergic system in adaptive behavior].

A review. The midbrain dopaminergic system is traditionally considered as a 'common neural currency' for rewards of most kinds. There are several competing hypotheses of its precise contribution in behavior: 1) dopamine mediates the pleasure of rewards; 2) dopamine signals a reward prediction error and, thus, is involved in associative learning; 3) dopamine motivates the pursuit of rewards.