Kenneth D. Brown

The facilitation of discrimination performance by physostigmine sulphate

In order to assess the effects of physostigmine sulphate on stable discrimination performance, a group of rats were trained on a simple brightness discrimination and injected with saline and three doses of the drug according to a latin square design. Improved performance was obtained with 0.05 and 0.10 mg/kg doses of the drug while the highest dose of 0.20 mg/kg impaired the discrimination responding. The effects of the highest dose were similar to the results obtained after injections of scopolamine hydrobromide into the same animals. A signal detection analysis revealed that physostigmine sulphate at the two low doses increased the stimulus sensitivity index without changes in the response bias index. These results were consistent with the hypothesis that physostigmine sulphate improved “attention” to the stimuli rather than response inhibition.A biochemical assay of brain cholinesterase activity showed that these two doses produced between 40% and 60% inhibition of activity, which is thought to be the critical levels for neural facilitation.

Food preference following acute or chronic chlordiazepoxide administration: Tolerance to an antineophobic action

Chlordiazepoxide (CDP) at 15 mg/kg produced two distinct actions in a food preference test firstly a general appetite-enhancing effect, and secondly an anti-neophobic effect. Following acute injection of CDP the rats changed from eating predominantly familiar food to a novel food. This may signify an anti-neophobic effect of CDP However, following 10 days of treatment with CDP, the anti-neophobic effect was abolished and the choice of familiar food was enhanced. This could be an indication of a more general appetite-enhancing effect. Hence some form of tolerance may develop to CDPs effects over 10 days of treatment which selectively abolishes anti-neophobic action whilst leaving the appetite effect further enhanced. There were no indications of tolerance developing to the actions of CDP in animals familiarized with all the test foods before the preference test was run. Hence the presence of food novelty may be critical to the observation of some form of selective tolerance.

Smoking, nicotine dose and the lateralisation of electrocortical activity.

The effects of cigarette smoking on the balance of activity of the cerebral hemispheres were studied in two experiments. Experiment 1 examined the effects of smoking on lateralisation of EEG alpha and beta power in six male smokers, and revealed a dose-related biphasic action. Low doses of nicotine as measured by residual butt analysis increased left hemisphere activity in a dose related manner, while higher doses (>1.1 mg) reversed this effect. Experiment 2 examined the time course of the changes in EEG alpha, beta, theta and delta lateralisation in 11 male smokers. During the initial period of smoking there was a reduction in EEG alpha, reflecting cortical activation, followed by an increase in alpha power towards the end of the cigarette. These changes were accompanied in smokers taking moderate nicotine doses, by an initial shift towards left hemisphere activation, followed by a reduction in left hemisphere activation relative to the right. Initial changes in delta and theta power were negatively correlated with nicotine dose. Higher nicotine doses were associated with greater shifts towards right hemisphere activation, as indicated by beta and delta lateralisation, and also with greater decreases in subjective arousal. These results were interpreted as supporting the hypothesis that the stimulant action of lower doses of nicotine involves the activation of a left hemisphere “Go” system, while the sedative effect of higher doses involves increased activation of the right hemisphere “NoGo” system.

Drugs as Research Tools in Psychology: Cholinergic Drugs and Aggression

A review of studies using cholinergic drugs as tools to investigate the neural mechanisms mediating affective and predatory aggressive behaviour reveals that the same two cholinergic systems are involved with both sorts of behaviour. There is a brain muscarinic system initiating aggression and a nicotinic system which inhibits aggressive behaviour. This evidence suggests that there could be two possible forms of cholinergic therapy for aggression, cholinolytics and nicotinic agonists. These possibilities are discussed.

Cholinergic Mechanisms in Aggressive Behavior

It has been suggested (Scott, 1958; Valzelli, 1967) that aggression is not a unitary concept. This premise is based on the fact that stimulus situations eliciting aggression are so diverse and hence there must be several types of behavior. It followed from this that there would be a variety of physiological substrates involved in the mediation of these different aggression types. Only recently, however, has any systematic attempt been made to list the types of aggression and indicate a basis for classification. Moyer (1968), suggested that if there were several forms of aggression, then progress in understanding the general phenomenon of this behavior could be made only when the various types were carefully and operationally defined. The definitional phase must then be followed by research in which experimental manipulations are applied to the subjects who are then tested in a variety of situations which define the various classes of aggression. A given manipulation may very well facilitate one kind of aggression, suppress another, and have no effect on a third (Moyer, 1968).

Shock-induced defensive fighting in the rat: Evidence for cholinergi mediation in the lateral hypothalamus

Bilateral microinjections of scopolamine into the lateral hypothalamus significantly reduced shock-induced defensive fighting, without altering jump threshold values. Further investigation of the lateral hypothalamus demonstrated that (1) fighting increased in response to bilateral microinjections of physostigmine and carbachol, (2) social attraction remained unaltered following scopolamine treatment, (3) neither motor co-ordination nor motor activity was significantly affected by any of the treatments.

The effects of two “anti-aggressive” compounds, an indenopyridine and benzothiazepin, on shock-induced defensive fighting in rats

1. An indenopyridine (YG19-256) and a benzothiazepin (thiazesim) were investigated in rats for possible effects on shock-induced defensive fighting, shock reactivity and locomotor activity. 2. YG19-256 significantly reduced aggression at the higher dose levels employed. Thiazesim produced no significant decrease in aggression at the dose levels used. 3. Neither compound produced any consistent effect on shock reactivity or locomotor activity.

Through a glass darkly: cost control in British industry: a case study

Between 1979 and 1984 the British toy industry was ravaged by business failure. One of the most notable casualties was Meccano Ltd, a major manufacturer dating from 1908, but twice taken over before its eventual closure in 1979. The survival of part of the companys records permits an empirical examination of the hypothesis that the toy industrys problems sprang mainly from an inability to monitor and control costs. In particular, this paper traces the unsuccessful attempts of new owners to impose more modern methods of cost control on a firm made complacent by past success.

A Social History of the Nonconformist Ministry in England and Wales, 1800-1930.

Protestant nonconformity was one of the most significant influences in nineteenth-century Britain, and has rightly received considerable attention from historians. At both local and national level much of its influence was channelled through, and inspired by, the activities and utterances of the professional minister. The names of the most successful were often household words in the Victorian period, and most have attracted a biographer. Yet neither the experiences nor the careers of these pulpit princes were necessarily those of the typical minister - almost nine thousand of them in 1900 - who served in the chapels of the main dissenting denominations. Using simple sampling and statistical techniques, Kenneth D. Brown sets out to recreate the lives, both private and professional, of this less celebrated but faithful and more representative body of men, rescuing them from the anonymity of the past.

College Principals — a Cause of Nonconformist Decay?

Nonconformity was one of the major formative influences on Victorian society in Britain. The census of 1851 revealed that of seven million worshippers attending service on census day roughly half were counted in a nonconformist chapel. Even the Victorian who failed to attend service regularly found it difficult to evade the influence of nonconformity — and the Evangelicalism with which it was most closely —identified — in a society whose very customs, attitudes and even political life were so largely moulded by it. The main physical manifestation of this pervasive influence was the ubiquitious chapel, its most obvious human expression the professional minister. Of the leading nonconformist denominations the Congregationals were served by some 1,400 full-time men in 1847 while the Wesleyan, Primitive, New Connexion and Association Methodists had respectively 1,125, 518, 83 and 91 ministers in 1851.