24 research outputs found
Working Memory Overload: Fronto-Limbic Interactions and Effects on Subsequent Working Memory Function
Treatment of unstable sacral fractures with percutaneous reconstruction plate internal fixation
Lumbopelvic Fixation and Sacral Decompression for U-shaped Sacral Fractures: Surgical Management and Early Outcome
Abnormal medial prefrontal cortex activity in heavy cannabis users during conscious emotional evaluation
Below-elbow or above-elbow cast for conservative treatment of extra-articular distal radius fractures with dorsal displacement: a prospective randomized trial
Attention-deficit/hyperactivity disorder and impairment in executive functions: a barrier to weight loss in individuals with obesity?
Effects of nicotine and amphetamine on latent inhibition in human subjects
Latent inhibition (LI) is a phenomenon in which repeated non-reinforced exposure to a stimulus retards subsequent conditioning to that stimulus; it reflects a process whereby irrelevant stimuli become ignored, and has been the subject of study concerning attentional abnormalities in schizophrenia. Low doses of the indirect dopamine (DA) agonists, amphetamine and nicotine, disrupt LI in the rat. These drugs are believed to disrupt LI via DA release in the nucleus accumbens; LI in amphetamine- and nicotine-treated rats is reinstated by administration of the DA antagonist haloperidol. In human subjects, low doses of amphetamine abolish LI, and more recently haloperidol has been shown to potentiate LI. The present study investigated the effects of nicotine on LI in human subjects, and also attempted to replicate the abolition of LI by amphetamine. Nicotine failed to affect LI when administered either subcutaneously or by cigarette smoking. LI was, however, abolished in a group of subjects given 5 mg amphetamine 90 min before testing. Supplementary analyses of the data pooled from all three experiments showed that, in contrast to an earlier report, LI was no weaker in smokers than in nonsmokers