The reward generated by social interactions is critical for promoting prosocial behaviors. Here we present evidence that oxytocin (OXT) release in the ventral tegmental area (VTA), a key node of the brain’s reward circuitry, is necessary to elicit social reward. During social interactions, activity in paraventricular nucleus (PVN) OXTneurons increased. Direct activation of these neurons in the PVN or their terminals in the VTA enhanced prosocial behaviors. Conversely, inhibition of PVN OXTaxon terminals in the VTA decreased social interactions. OXT increased excitatory drive onto reward-specific VTA dopamine (DA) neurons. These results demonstrate that OXTpromotes prosocial behavior through direct effects on VTA DA neurons, thus providing mechanistic insight into how social interactions can generate rewarding experiences.

Cognitive decline in Alzheimer's disease (AD) involves pathological accumulation of synaptotoxic amyloid-␤ (A␤) oligomers and hyperphosphorylated tau. Because recent evidence indicates that glycogen synthase kinase 3␤ (GSK3␤) activity regulates these neurotoxic pathways, we developed an AD therapeutic strategy to target GSK3␤. The strategy involves the use of copper-bis(thiosemicarbazonoto) complexes to increase intracellular copper bioavailability and inhibit GSK3␤ through activation of an Akt signaling pathway. Our lead compound Cu II (gtsm) significantly inhibited GSK3␤ in the brains of APP/PS1 transgenic AD model mice. Cu II (gtsm) also decreased the abundance of A␤ trimers and phosphorylated tau, and restored performance of AD mice in the Y-maze test to levels expected for cognitively normal animals. Improvement in the Y-maze correlated directly with decreased A␤ trimer levels. This study demonstrates that increasing intracellular copper bioavailability can restore cognitive function by inhibiting the accumulation of neurotoxic A␤ trimers and phosphorylated tau.Alzheimer's disease ͉ bioinorganic chemistry ͉ glycogen synthase kinase ͉ therapeutic ͉ animal model A lzheimer's disease (AD) is a neurodegenerative disorder characterized clinically by impaired cognitive performance and pathologically by cerebral deposition of extracellular amyloid plaques and intracellular neurofibrillary tangles. Amyloid plaques in AD contain aggregated forms of the 39-to 43-aa amyloid-␤ peptide (A␤) and A␤ is strongly implicated as a causative agent responsible for cognitive failure in AD. A diverse range of mechanisms for A␤ toxicity has been reported (1). A␤ is produced from the amyloid precursor protein (APP) (2-5) and readily aggregates to form insoluble, high-molecular-mass amyloid structures. Intermediates on the A␤ aggregation pathway, primarily low-molecular-mass oligomers such as dimers and trimers, exhibit the greatest neurotoxicity (6-8). In addition to A␤ oligomers, aberrantly phosphor ylated microtubuleassociated protein tau is also associated with cognitive decline in AD (9). Intracellular neurofibrillary tangles in the AD brain contain hyperphosphorylated tau, and A␤ induced cognitive deficits characteristic of AD transgenic mice are attenuated by decreasing levels of endogenous tau (10).It is now widely recognized that a truly effective therapeutic compound for treating AD needs to attenuate both the A␤-and tau-mediated pathologies. Recent positive outcomes for PBT2 in clinical and preclinical trials are therefore pertinent. Lannfelt et al.(11) demonstrated in phase IIa clinical trials that PBT2 lowers plasma A␤ levels and attenuates cognitive decline, and Adlard et al. (12) have shown that PBT2 decreases interstitial A␤ and phosphorylated tau in the brains of AD model mice. PBT2 is a secondgeneration 8-OH quinoline, which, unlike its predecessor clioquinol, lacks iodine and was selected for clinical development because of its easier chemical synthesis, higher solubility, and increased blood-brain barrier perme...

Mutations in the metallo-protein Cu/Zn-superoxide dismutase (SOD1) cause amyotrophic lateral sclerosis (ALS) in humans and