The lateral hypothalamus and orexinergic transmission in the paraventricular thalamus promote the attribution of incentive salience to reward-associated cues.

Rationale: Prior research suggests that the neural pathway from the lateral hypothalamic area (LHA) to the paraventricular nucleus of the thalamus (PVT) mediates the attribution of incentive salience to Pavlovian reward cues. However, a causal role for the LHA and the neurotransmitters involved have not been demonstrated in this regard.

Objectives: To examine (1) the role of LHA in the acquisition of Pavlovian conditioned approach (PavCA) behaviors, and (2) the role of PVT orexin 1 receptors (OX1r) and orexin 2 receptors (OX2r) in the expression of PavCA behaviors and conditioned reinforcement.

The paraventricular thalamus is a critical mediator of top-down control of cue-motivated behavior in rats.

Cues in the environment can elicit complex emotional states, and thereby maladaptive behavior, as a function of their ascribed value. Here we capture individual variation in the propensity to attribute motivational value to reward-cues using the sign-tracker/goal-tracker animal model. Goal-trackers attribute predictive value to reward-cues, and sign-trackers attribute both predictive and incentive value.

Transient inactivation of the paraventricular nucleus of the thalamus enhances cue-induced reinstatement in goal-trackers, but not sign-trackers.

Rationale: The paraventricular nucleus of the thalamus (PVT) has been shown to mediate cue-motivated behaviors, such as sign- and goal-tracking, as well as reinstatement of drug-seeking behavior. However, the role of the PVT in mediating individual variation in cue-induced drug-seeking behavior remains unknown.

Objectives: This study aimed to determine if inactivation of the PVT differentially mediates cue-induced drug-seeking behavior in sign-trackers and goal-trackers.

Manipulation of GABA in the ventral pallidum, but not the nucleus accumbens, induces intense, preferential, fat consumption in rats.

Injections of the GABAA antagonist bicuculline into the medial ventral pallidum (VPm) induce marked increases in food intake, but nothing is known about the way in which these injections alter the distribution of intake in a macronutrient selection situation. We investigated this topic by adapting rats to a diet containing independent sources of protein, carbohydrate and fat, and then examining the effects of intra-VPm bicuculline on diet selection. Under these conditions, bicuculline produced a massive, preferential increase in fat intake with subjects consuming a mean of 97% of their calories from fat.

Effects of muscimol in the nucleus accumbens shell on salt appetite and sucrose intake: a microstructural study with a comment on the sensitization of salt intake.

Previous work has demonstrated that injections of the γ-aminobutyric acidA (GABAA) agonist muscimol into the nucleus accumbens shell (AcbSh) induce pronounced increases in the intake of solid foods and sucrose solutions, but do not potentiate water intake. In order to clarify the range of situations in which inactivation of the AcbSh potentiates ingestive behavior, we examined the effects of muscimol injections on the intake of a 3% NaCl solution in sodium-depleted animals. Although sodium-depleted subjects avidly consumed this solution, muscimol injections had no effect either on the volume consumed or on a variety of microstructural licking parameters.

GABA(A) and dopamine receptors in the nucleus accumbens shell differentially influence performance of a water-reinforced progressive ratio task.

Several authors have shown that injections of the GABA(A) agonist muscimol into the medial shell region of the nucleus accumbens (AcbSh) result in large increases in food, but not water, intake. In previous studies we demonstrated that intra-AcbSh injections of either muscimol or of the indirect dopamine agonist amphetamine increase response output on a food-reinforced progressive ratio schedule. In the current experiment we extended these observations by examining the effects of muscimol and amphetamine injections on the performance of a water-reinforced progressive ratio task in mildly deprived animals.

Lower number of cerebellar Purkinje neurons in psychosis is associated with reduced reelin expression.

Reelin is an extracellular matrix protein synthesized in cerebellar granule cells that plays an important role in Purkinje cell positioning during cerebellar development and in modulating adult synaptic function. In the cerebellum of schizophrenia (SZ) and bipolar (BP) disorder patients, there is a marked decrease ( approximately 50%) of reelin expression. In this study we measured Purkinje neuron density in the Purkinje cell layer of cerebella of 13 SZ and 17 BP disorder patients from the McLean 66 Cohort Collection, Harvard Brain Tissue Resource Center.