Naoyuki Hironaka

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Dopamine (DA) plays roles in circuits that are important for brain reward and in striatal brain regions that are important for certain types of habit learning. These processes in wildtype, heterozygous, and homozygous dopamine transporter knockout (DAT-KO) mice, which were mildly food deprived and allowed to make nose-poke responses for food reinforcement,(More)
Prepulse inhibition (PPI) of acoustic startle reflex has been suggested as a neurophysiologic measure of information processing abnormalities in schizophrenia. However, there has been little information on PPI and related measures in Asian patients with schizophrenia. We examined startle response to acoustic stimuli, its habituation, and PPI in 20 Japanese(More)
named Component I, II and III. The former was found to be the major mucopolysaccharide in white bile having slower mobility than hyaluronic acid and was present in all white bile samples examined. In contrast , Component II and III were by far the minor components and were absent in half of the white bile samples. Component II had similar mobility to(More)
The assessment of drug effects on attention is important in non-clinical pharmacology, for both evaluation of safety and therapeutic efficacy of medicinal products. In the present study, we have developed a two-lever choice behavioral test to assess drug effects on attentional performance in monkeys. In each trial of this experiment, one of two lamps in(More)
Ifenprodil is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist which prefers NR2B-containing NMDA receptors to NR2A-containing NMDA receptors. It has been reported that ifenprodil suppresses morphine-induced place preference in mice. In this study, the effects of ifenprodil on the discriminative stimulus effects of cocaine were examined in(More)
Nicotine dependence and its neural mechanisms have been well documented by pharmacological, behavioral and neuroscience studies. In this review, we introduce recent new findings in this theme, particularly on the role of nicotine -associated stimuli as non-pharmacological factors affecting maintaining/reinstating nicotine seeking. By using the techniques of(More)
To investigate the relationship between the prefrontal and hippocampal acetylcholine (ACh) systems and working memory, an in vivo microdialysis study was conducted. A group of rats was trained to perform a working memory task, delayed alternation, in an operant chamber for food reinforcement. The rats had to choose one of two response levers in an(More)