Altered striatal dopaminergic neurotransmission is thought to be fundamental to schizophrenia. Increased presynaptic dopaminergic activity ([18F]-DOPA PET) may predate the onset of psychotic symptoms and correlates to clinical symptoms in subjects at Ultra High Risk (UHR) for developing psychosis. Postsynaptic dopaminergic neurotransmission has not been investigated yet in UHR patients. We hypo...

In constantly changing environments, it is crucial to adaptively respond to threatening events. In particular, painful stimuli are not only processed in terms of their absolute intensity, but also with respect to their context. While contextual pain processing can simply entail the repeated processing of information (i.e., habituation), it can, in a more complex form, be expressed through predi...

The dopaminergic mechanisms that control reward-motivated behavior are the subject of intense study, but it is yet unclear how, in humans, neural activity in mesolimbic reward-circuitry and its functional neuroimaging correlates are related to dopamine release. To address this question, we obtained functional magnetic resonance imaging (fMRI) measures of reward-related neural activity and [(11)...

In Parkinson disease (PD), alpha-synuclein aggregates called Lewy bodies often involve and sequester Septin4 (Sept4), a polymerizing scaffold protein. However, the pathophysiological significance of this phenomenon is unclear. Here, we show the physiological association of Sept4 with alpha-synuclein, the dopamine transporter, and other presynaptic proteins in dopaminergic neurons; mice lacking ...

Schizophrenia is a serious mental disorder that affects up to 1% of the population worldwide. Traditional models of schizophrenia have emphasized dopaminergic dysfunction. Over the last 20 years, however, limitations of the dopamine model have become increasingly apparent, necessitating development of alternative models. Glutamatergic models are based upon the observation that the psychotomimet...

A substantial amount of evidence has proposed an important role for Cyclooxygenase-2 (COX-2) enzyme in brain diseases and affiliate disorders. The purpose of this research was studying the effects of COX-2 selective inhibition on haloperidol-induced catatonia in an animal model of drug overdose and Parkinson's disease (PD). In this study, the effect of acute and Sub-chronic oral administration ...

Since the early days of physiological psychology it has been recognized that the behavioral effects of many manipulations often could not easily be attributed to impairments in learning because of possible changes in performance. Current psychopharmacological research concerned with evaluating the possible role of dopamine in reward-related learning is faced with the same problem. It is well kn...

Dopamine D(2) receptor partial agonist antipsychotic drugs can modulate dopaminergic neurotransmission as functional agonists or functional antagonists. The effects of antipsychotics on presynaptic dopaminergic functions, such as dopamine synthesis capacity, might also be related to their therapeutic efficacy. Positron emission tomography (PET) was used to examine the effects of the partial ago...

Obsessive-compulsive disorder (OCD) is a relatively common neuropsychiatric disorder affecting between 1.6 and 3.2% of the population. A number of studies have previously reported increased incidence of OCD, or exacerbation of preexisting symptoms in females during reproductive events. Since these periods are known to involve fluctuating levels of gonadal hormones, these steroids have been sugg...