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Biomedical subjects

S C Hinton

Publications and source records attributed to S C Hinton.

8 recordsLinked to original sources
PubMed1998

Transdermal nicotine effects on attention.

Nicotine has been shown to improve attentiveness in smokers and attenuate attentional deficits in Alzheimer's disease patients, schizophrenics and adults with attention-deficit/hyperactivity disorder (ADHD). The current study was conducted to determine whether nicotine administered via transdermal patches would improve attentiveness in non-smoking adults without attentional deficits. The subjects underwent the nicotine and placebo exposure in a counterbalanced double-blind manner. Measures of treatment effect included the Profile of Mood States (POMS), Conners' computerized Continuous Performance Test (CPT) of attentiveness and a computerized interval-timing task. The subjects were administered a 7 mg/day nicotine transdermal patch for 4.5 h during a morning session. Nicotine significantly increased self-perceived vigor as measured by the POMS test. On the CPT, nicotine significantly decreased the number of errors of omission without causing increases in either errors of commission or correct hit reaction time. Nicotine also significantly decreased the variance of hit reaction time and the composite measure of attentiveness. This study shows that, in addition to reducing attentional impairment, nicotine administered via transdermal patches can improve attentiveness in normal adult non-smokers.

Administration, Cutaneous↗
PubMed1998

Scalar expectancy theory and peak-interval timing in humans.

The properties of the internal clock, temporal memory, and decision processes used to time short durations were investigated. The peak-interval procedure was used to evaluate the timing of 8-, 12-, and 21-s intervals, and analyses were conducted on the mean response functions and on individual trials. A distractor task prevented counting, and visual feedback on accuracy and precision was provided after each trial. Mean response distributions were (a) centered at the appropriate real-time criteria, (b) highly symmetrical, and (c) scalar in their variability. Analysis of individual trials indicated more memory variability relative to response threshold variability. Taken together, these results demonstrate that humans show the same qualitative timing properties that other animals do, but with some quantitative differences.

Adult↗
PubMed1997

The 'internal clocks' of circadian and interval timing.

Animals engage in a startlingly diverse array of behaviours that depend critically on the time of day or the ability to time short intervals. Timing intervals on the scale of many hours to around a day is mediated by the circadian timing system, while in the range of seconds to hours a different system, known as interval timing, is used. Recent research has illuminated some of the neural mechanisms underlying the 'internal clocks' of these two different timing systems in both animals and humans. Therapeutic applications for humans with impairments in either timing system may ultimately result from these endeavours.

Animals↗
PubMed1997

The 'internal clocks' of circadian and interval timing.

Animals engage in a startlingly diverse array of behaviours that depend critically on the time of day or the ability to time short intervals. Timing intervals on the scale of many hours to around a day is mediated by the circadian timing system, while in the range of seconds to hours a different system, known as interval timing, is used. Recent research has illuminated some of the neural mechanisms underlying the 'internal clocks' of these two different timing systems in both animals and humans. Therapeutic applications for humans with impairments in either timing system may ultimately result from these endeavours.

Animals↗
PubMed1996

Nicotine effects on adults with attention-deficit/hyperactivity disorder.

Several lines of evidence suggest that nicotine may be useful in treating the symptoms of Attention-Deficit/Hyperactivity Disorder (ADHD). The current study was an acute, placebo-controlled double-blind experiment to determine whether nicotine might be useful as an alternative treatment of adults with ADHD symptomatology. Six smokers and 11 nonsmokers who were outpatient referrals for ADHD were diagnosed by DSM-IV criteria. Measures of treatment effect included the Clinical Global Impressions (CGI) scale, Hopkins' symptom check list (SCL-90-R), the Profile of Mood States (POMS), Conners' computerized Continuous Performance Test (CPT), the Stroop test, and an interval-timing task. The smokers underwent overnight deprivation from smoking and were given a 21 mg/day nicotine skin patch for 4.5 h during a morning session. The nonsmokers were given a 7 mg/day nicotine skin patch for 4.5 h during a morning session. Active and placebo patches were given in a counter-balanced order approximately 1 week apart. Nicotine caused a significant overall nicotine-induced improvement on the CGI. This effect was significant when only the nonsmokers were considered, which indicated that it was not due merely to withdrawal relief. Nicotine caused significantly increased vigor as measured by the POMS test. Nicotine caused an overall significant reduction in reaction time (RT) on the CPT, as well as, with the smokers, a significant reduction in another index of inattention, variability in reaction time over trial blocks. Nicotine improved accuracy of time estimation and lowered variability of time-estimation response curves. Because improvements occurred among nonsmokers, the nicotine effect appears not to be merely a relief of withdrawal symptoms. It is concluded that nicotine deserves further clinical trials with ADHD.

Adult↗
PubMed1996

Nicotine and attention in adult attention deficit hyperactivity disorder (ADHD).

Nicotine, like the psychostimulants methylphenidate and dextroamphetamine, acts as an indirect dopamine agonist and improves attention and arousal. Adults and adolescents with attention deficit hyperactivity disorder (ADHD) smoke much more frequently than normal individuals or those with other psychiatric conditions, perhaps as a form of self-medication for ADHD symptoms. Nicotine might therefore have some value as a treatment for ADHD. The present study is an acute double-blind crossover administration of nicotine and placebo with smokers (n = 6) and nonsmokers (n = 11) diagnosed with adult ADHD. The drug was delivered via a transdermal patch at a dosage of 7 mg/day for nonsmokers and 21 mg/day for smokers. Results indicate significant clinician-rated global improvement, self-rated vigor and concentration, and improved performance on chronometric measures of attention and timing accuracy. Side effects were minimal. These acute results indicate the need for a longer clinical trial and a comparison with other stimulants in adult ADHD treatment.

Adult↗
PubMed1994

Oral stereotypy induced by amphetamine microinjection into striatum: an anatomical mapping study.

The ventrolateral striatum has been shown to specifically contribute to expression of psychostimulant-induced orofacial stereotypies. Adult male Sprague-Dawley rats were implanted with bilateral cannulae directed at one of eight striatal subareas, and were injected with saline or amphetamine (20 micrograms/0.5 microliter/side) in a counterbalanced order. Behaviors were observed and scored using a time-sampling procedure. In the middle ventrolateral striatum, amphetamine injections produced intense stereotypy, primarily consisting of bar biting, non-injurious self-biting and repetitive paw-to-mouth movements, while having no effect on locomotion or rearing. Amphetamine injections 2 mm medial or 1 mm dorsal produced no oral stereotypy, while injections 1 mm rostral or caudal to the effective site produced only low levels of stereotypy. Injections into the surrounding sites, particularly in the ventromedial region, also had stimulatory effects on locomotion and rearing. In a separate experiment, animals were given either unilateral or bilateral injection of amphetamine into the ventrolateral striatum. The unilateral injection produced stereotypy half as intense as that observed with bilateral injections. These results suggest that the ventrolateral striatum is a discrete neuroanatomical region which is primarily responsible for expression of psychostimulant-induced orofacial stereotypies, and which is likely to be the striatal region controlling normal oral motor function. Further investigation of this area may provide valuable insights concerning the etiology and treatment of orofacial dyskinesias associated with basal ganglia dysfunction.

Amphetamine↗
PubMedDate not supplied

The use of timing behaviors in animals and humans to detect drug and/or toxicant effects.

Behavioral paradigms applicable for use in both human and nonhuman subjects for investigating aspects of timing behavior are presented with a view towards exploring their strengths, weaknesses, and utility in a variety of experimental situations. Tri-peak, peak interval, differential reinforcement of low rate responding, and temporal response differentiation procedures are highlighted. In addition, the application of timing tasks in preclinical and clinical settings is discussed: pharmacological manipulations are providing information on the neurotransmitters involved and species differences; normative data for children are being developed; and noninvasive imaging procedures are being employed in adult human subjects to explore the involvement of specific brain areas.

Animals↗