Author(s): Carter F; Cossette MP; Trujillo-Pisanty I; Pallikaras V; Breton YA; Conover K; Caplan J; Solis P; Voisard J; Yaksich A; Shizgal P;

Phasic dopamine activity is believed to both encode reward-prediction errors (RPEs) and to cause the adaptations that these errors engender. If so, a rat working for optogenetic stimulation of dopamine neurons will repeatedly update its policy and/or action values, thus iteratively increasing its ...

Article GUID: 38039083

Author(s): Pallikaras V; Mac Cionnaith CE; Rosales VCF; Arvanitogiannis A; Pfaus JG;

Rationale: Exposure to rewards can alter behavioral reactivity to them. For example, stimulants sensitize locomotor activation, whereas sexual experience sensitizes copulatory behaviors. Moreover, rewards can cross-sensitize one another. Although stimulants are known to cross-sensitize locomotor effects, the evidence for cross-sensitization between stimul ...

Article GUID: 36544054

Author(s): Pallikaras V; Shizgal P;

Major depressive disorder is a leading cause of disability and suicide worldwide. Consecutive rounds of conventional interventions are ineffective in a significant sub-group of patients whose disorder is classified as treatment-resistant depression. Significant progress in managing this severe form of depression has been achieved through the use of deep b ...

Article GUID: 36009115

Author(s): Pallikaras V; Shizgal P;

Deep-brain stimulation of the medial forebrain bundle (MFB) can provide effective, enduring relief of treatment-resistant depression. Panksepp provided an explanatory framework: the MFB constitutes the core of the neural circuitry subserving the anticipation and pursuit of rewards: the "SEEKING" system. On that view, the SEEKING system is hypoactive in de ...

Article GUID: 35431828

Author(s): Pallikaras V; Carter F; Velazquez-Martinez DN; Arvanitogiannis A; Shizgal P;

Optogenetic experiments reveal functional roles of specific neurons. However, functional inferences have been limited by widespread adoption of a restricted set of stimulation parameters. Broader exploration of the parameter space can deepen insight into the mapping between selective neural activity and behavior. In this way, characteristics of the activa ...

Article GUID: 34864162