ABSTRACT
The effects of smoking cigarettes differing in nicotine content (0.14 vs 1.34 mg/cigarette) on the peak-to-peak amplitude and peak latency of the human averaged visual evoked response (AVER) were measured in 10 male smokers after a 2-hr smoking deprivation period. The AVER was obtained under five different flash intensities. Eight different peaks were involved in the amplitude and latency measurements. The nicotine dosage and flash intensity factors both had significant effects on peak-to-peak amplitudes while only the flash intensity factor affected peak latencies. The general enhancement of peak-to-peak amplitudes by the 1.34 mg cigarette, relative to the 0.14 mg cigarette, indicates that the effects of cigarette smoking on the AVER are predominantly due to nicotine's psychopharmacologic action, as opposed to other elements in tobacco smoke or as opposed to nonpharmacologic mechanisms involving learning processes. Past research, on an electrophysiological and behavioral level, indicating that nicotine, as administered via cigarette smoking, may have enhancing and/or restorative effects on visual attentional processes in the quiescent smoker was supported.
Subject(s)
Evoked Potentials, Visual/drug effects , Nicotine/pharmacology , Smoking , Adult , Animals , Attention/drug effects , Dose-Response Relationship, Drug , Humans , Male , Photic Stimulation , Reaction Time/drug effectsABSTRACT
Reaction times of 6 male and 6 female college students were used as a measure of arousal under different levels of ambient sensory stimulation. Subjects were tested under conditions of light-quiet, light-noise, dark-quiet and dark-noise with a non-signalled reaction-time task using a tactile stimulus. All sensory conditions were presented to each subject in a counterbalanced order and replicated in a second session 3 to 8 wk. later. Significant main effects were noise and replication. Improvement in performance across replication was related to the sex of the subject. White noise and level of illumination interacted to produce the typical U-shaped function. Results are discussed in terms of their relevance for research using behavioral and physiological measures of arousal.
Subject(s)
Arousal/physiology , Lighting , Noise , Touch/physiology , Acoustic Stimulation , Adaptation, Physiological , Adult , Female , Humans , Male , Photic Stimulation , Reaction Time , Sex FactorsABSTRACT
The interaction of altered activity levels by stimulants and brainstem lesions was examined. Lesions of the substantia nigra and red nucleus significantly increased activity over control levels in albino rats. The stimulant action of d-amphetamine and methylphenidate was additive with lesion effects. In addition, stimulants disrupted the normal light-dark relationship with activity while the lesions did not. It is suggested that there are two functionally separate systems regulating locomotor activity.
Subject(s)
Dextroamphetamine/pharmacology , Motor Activity/physiology , Red Nucleus/physiology , Substantia Nigra/physiology , Animals , Light , Male , Motor Activity/drug effects , RatsABSTRACT
The dose-response relationships for three stimulants have been explored. These drugs have been shown to differ in potency and, with successive doubling of doses, have been found to have dose-response curves of differing slopes. In addition, the relationship between dose and activity level was not the same for younger and older rats. The relationship between dosage of both d-amphetamine and methylphenidate and locomotor activity was not the same in the light and the dark. The latter finding suggests a difference between these two stimulants and the third stimulant studied, caffeine, whose effects where unaltered by ambient illumination level.
