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1.
Zootaxa ; 3972(2): 101-47, 2015 Jun 11.
Artículo en Inglés | MEDLINE | ID: mdl-26249486

RESUMEN

This paper provides details of 300 genus-group names in the suborder Uropodina, including the superfamilies Microgynioidea, Thinozerconoidea, Uropodoidea, and Diarthrophalloidea. For each name, the information provided includes a reference to the original description of the genus, the type species and its method of designation, and details of nomenclatural and taxonomic anomalies where necessary. Twenty of these names are excluded from use because they are nomina nuda, junior homonyms, or objective junior synonyms. The remaining 280 available names appear to include a very high level of subjective synonymy, which will need to be resolved in a future comprehensive revision of the Uropodina.


Asunto(s)
Ácaros/clasificación , Distribución Animal , Animales , Catálogos como Asunto , Femenino , Masculino
2.
Zootaxa ; 5280(1): 1-73, 2023 May 09.
Artículo en Inglés | MEDLINE | ID: mdl-37518754

RESUMEN

This paper reviews the state of knowledge of the feather mites of Australia (Arachnida: Acariformes: Astigmata). The known fauna includes 149 species arranged in 95 genera and 24 families, in the Superfamilies Analgoidea and Pterolichoidea. A checklist of the fauna is provided, including bibliographic details for every species and genus. The bird host and collecting localities are listed for every species, and taxonomic and nomenclatural problems are discussed where necessary. The total fauna may include as many as 800 undescribed species. The checklist is preceded by a brief review of some aspects of the biology of feather mites, which have not been studied in the context of the Australian fauna.The correct spelling for a family of respiratory tract parasites is confirmed as Kytoditidae. Dabertia indistincta (Dabert & Atyeo, 1993) comb. n. (Syringobiidae) and Hemialges australis (Trouessart, 1885) comb. n. (Analgidae) are new combinations proposed herein.


Asunto(s)
Arácnidos , Enfermedades de las Aves , Ácaros , Animales , Australia , Enfermedades de las Aves/parasitología , Aves
3.
Zootaxa ; 4061(4): 347-66, 2016 Jan 08.
Artículo en Inglés | MEDLINE | ID: mdl-27395506

RESUMEN

This paper reviews 47 names that have been used at the levels of Family, Subfamily and Tribe, for mites in the suborder Uropodina. Complete bibliographic references are provided for all of these names and the names of their type genera. The spelling and authorship of taxon names is corrected where necessary. Fifteen of these family-group names are unavailable, because they do not satisfy the requirements of the International Code of Zoological Nomenclature. However, some of these names represent taxonomic concepts that may be useful in future revisions of the group.


Asunto(s)
Ácaros/clasificación , Distribución Animal , Estructuras Animales/anatomía & histología , Estructuras Animales/crecimiento & desarrollo , Animales , Tamaño Corporal , Ecosistema , Femenino , Masculino , Ácaros/anatomía & histología , Ácaros/crecimiento & desarrollo , Tamaño de los Órganos
5.
Bone Joint J ; 98-B(6): 840-5, 2016 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-27235530

RESUMEN

AIMS: We wished to assess the feasibility of a future randomised controlled trial of parathyroid hormone (PTH) supplements to aid healing of trochanteric fractures of the hip, by an open label prospective feasibility and pilot study with a nested qualitative sub study. This aimed to inform the design of a future powered study comparing the functional recovery after trochanteric hip fracture in patients undergoing standard care, versus those who undergo administration of subcutaneous injection of PTH for six weeks. PATIENTS AND METHODS: We undertook a pilot study comparing the functional recovery after trochanteric hip fracture in patients 60 years or older, admitted with a trochanteric hip fracture, and potentially eligible to be randomised to either standard care or the administration of subcutaneous PTH for six weeks. Our desired outcomes were functional testing and measures to assess the feasibility and acceptability of the study. RESULTS: A total of 724 patients were screened, of whom 143 (20%) were eligible for recruitment. Of these, 123 were approached and 29 (4%) elected to take part. However, seven patients did not complete the study. Compliance with the injections was 11 out of 15 (73%) showing the intervention to be acceptable and feasible in this patient population. TAKE HOME MESSAGE: Only 4% of patients who met the inclusion criteria were both eligible and willing to consent to a study involving injections of PTH, so delivering this study on a large scale would carry challenges in recruitment and retention. Methodological and sample size planning would have to take this into account. PTH administration to patients to enhance fracture healing should still be considered experimental. Cite this article: Bone Joint J 2016;98-B:840-5.


Asunto(s)
Conservadores de la Densidad Ósea/uso terapéutico , Fracturas del Cuello Femoral/terapia , Curación de Fractura , Fracturas Osteoporóticas/terapia , Teriparatido/uso terapéutico , Anciano , Anciano de 80 o más Años , Femenino , Fijación Interna de Fracturas , Humanos , Inyecciones Subcutáneas , Masculino , Cumplimiento de la Medicación , Proyectos Piloto , Estudios Prospectivos , Autoadministración
6.
Arch Gen Psychiatry ; 40(11): 1243-8, 1983 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-6639294

RESUMEN

Hyperactivity in children has been attributed to underarousal, maturational lag, and both. Using event-related potentials (ERPs) and EEG spectra, we compared hyperactive children with age-matched normal controls. Neither underarousal nor maturational lag explained our findings, and we concluded that these explanations are now too simple to be useful. We found a number of differences in EEGs and ERPs between hyperactive subjects and controls. The best single measure was EEG power from 14 to 25 Hz, which was consistent with previous reports. Hyperactive children had lower beta power than normal controls.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/fisiopatología , Electroencefalografía , Potenciales Evocados Visuales , Factores de Edad , Ritmo alfa , Nivel de Alerta/fisiología , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Ritmo beta , Encéfalo/fisiología , Encéfalo/fisiopatología , Niño , Desarrollo Infantil/fisiología , Humanos , Metilfenidato/uso terapéutico , Ritmo Teta
7.
Neuropsychopharmacology ; 10(1): 9-19, 1994 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-8179796

RESUMEN

Human performance on a choice-reaction time task (Eriksen task) has been simulated by a neural network. In simulations, the network captures many features of normal performance. In addition, changing gain in different layers produces changes that simulate different drug-induced changes. Data from a similar choice-reaction time task have been reanalyzed to test some of the predictions derived from changing gain in different layers. Clonidine antagonizes norepinephrine and acetylcholine activities and changes speed-accuracy tradeoff (i.e., increased frequency of errors at any specified reaction time). That is predicted when gain is reduced in lower layers (attention layer and input layer) of the network. By contrast, manipulating dopamine activity (with pimozide and amphetamine) changes reaction time without changing speed-accuracy tradeoff functions. That is predicted when gain is changed in the output layer of the network.


Asunto(s)
Procesos Mentales/efectos de los fármacos , Psicotrópicos/farmacología , Humanos , Redes Neurales de la Computación , Desempeño Psicomotor/efectos de los fármacos , Tiempo de Reacción/efectos de los fármacos
8.
Am J Med ; 108(5): 359-65, 2000 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-10759091

RESUMEN

PURPOSE: We sought to determine whether propranolol has adverse effects on cognitive function, depressive symptoms, and sexual function in patients treated for diastolic hypertension. SUBJECTS AND METHODS: We performed a placebo-controlled trial among 312 men and women, 22 to 59 years of age, who had untreated diastolic hypertension (90 to 104 mm Hg). Patients were randomly assigned to treatment with propranolol (80 to 400 mg/day) or matching placebo tablets. Thirteen tests of cognitive function were assessed at baseline, 3 months, and 12 months. Five tests measured reaction time to, or accuracy in, interpreting visual stimuli; one test measured the ability to acquire, reproduce, and change a set of arbitrary stimulus-response sets; and seven tests measured memory or learning verbal information. Depressive symptoms and sexual function were assessed by questionnaires at baseline and 12 months. RESULTS: There were no significant differences by treatment assignment for 11 of the 13 tests of cognitive function at either 3 or 12 months of follow-up. Compared with placebo, participants treated with propranolol had slightly fewer correct responses at 3 months (33 +/- 3 [mean +/- SD] versus 34 +/- 2, P = 0.02) and slightly more errors of commission at 3 months (4 +/-5 versus 3 +/- 3, P = 0.04) and at 12 months (4 +/- 4 versus 3 +/- 3, P = 0.05). At 12 months, depressive symptoms and sexual function and desire did not differ by treatment assignment. CONCLUSIONS: Treatment of hypertension with propranolol had limited adverse effects on tests of cognitive function that were of questionable clinical relevance, and there were no documented adverse effects on depressive symptoms or sexual function. Selection of beta-blockers for treatment of hypertension should be based on other factors.


Asunto(s)
Antagonistas Adrenérgicos beta/efectos adversos , Antihipertensivos/efectos adversos , Cognición/efectos de los fármacos , Hipertensión/tratamiento farmacológico , Hipertensión/psicología , Propranolol/efectos adversos , Calidad de Vida , Antagonistas Adrenérgicos beta/uso terapéutico , Adulto , Anciano , Antihipertensivos/uso terapéutico , Depresión/inducido químicamente , Diástole , Femenino , Humanos , Hipertensión/fisiopatología , Masculino , Persona de Mediana Edad , Propranolol/uso terapéutico , Conducta Sexual/efectos de los fármacos
9.
Psychopharmacology (Berl) ; 99(4): 563-6, 1989.
Artículo en Inglés | MEDLINE | ID: mdl-2594924

RESUMEN

The effects of clonidine and yohimbine on human information processing were tested in six normal volunteers ages 18-30 years. Subjects were tested in a pre-post design with sessions conducted at weekly intervals. Three drug conditions were: Placebo (lactose), 0.2 mg clonidine, and 30 mg yohimbine. Two choice reaction time (RT) tasks were used. One was a stimulus evaluation-response selection task (SERS) that has been shown to be sensitive to d-amphetamine, methylphenidate and scopolamine. The other task was to assess stimulus pre-processing and used spatial frequency as a discriminative stimulus. The principle finding was that clonidine slowed RT; this effect was significant for both tasks. In contrast, yohimbine tended to speed RT, but the effects were significant only for the spatial frequency task on some analyses while not for others. RTs to high spatial frequency stimuli were speeded more than for low spatial frequency. The effects of these two NE drugs were compared with findings with d-amphetamine and scopolamine and interpreted within the framework of a serial information processing model proposed by Callaway (1983). Specifically, it is suggested that yohimbine and clonidine affect an early pre-processing stage.


Asunto(s)
Clonidina/farmacología , Procesos Mentales/efectos de los fármacos , Yohimbina/farmacología , Adolescente , Adulto , Emociones/efectos de los fármacos , Hemodinámica/efectos de los fármacos , Humanos , Masculino , Norepinefrina/farmacología , Tiempo de Reacción/efectos de los fármacos
10.
Psychopharmacology (Berl) ; 86(1-2): 90-5, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-3927371

RESUMEN

Models of information processing currently popular in cognitive psychology divide the reaction process into a series of discrete separable stages. The distinction between one stage and another is verified by the additive factors method (AFM) as defined by Sternberg (1969). Task factors that do not interact with each other are inferred to affect different stages. The distinction between stimulus evaluation stages and response selection stages has been supported by brain event related potential (ERP) studies. The latency of the P300 component of the ERP is sensitive to changes in stimulus complexity but not to to changes in response complexity. The focus of this research is to determine the effects of stimulant drugs on stages of information processing using both reaction time (RT) and P300 latency within an AFM framework. Four doses of methylphenidate (MP) were used in a within-subjects design to examine the effects of MP on stimulus and response processing. We found that MP speeds RT, and that this effect does not interact with the effect of stimulus complexity on RT. MP dose interacts with response complexity, the dose for optimal speeding varying with the level of complexity. The latency of P300 is increased by stimulus complexity, and not by response complexity, nor is it affected by MP. These results show that the stimulant drug acts on processes involved in response selection, rather than in stimulus evaluation. Individual differences in drug response are dose dependent, but also point to an effect on response processing.


Asunto(s)
Electroencefalografía , Procesos Mentales/efectos de los fármacos , Metilfenidato/farmacología , Adulto , Femenino , Humanos , Individualidad , Modelos Psicológicos , Práctica Psicológica , Tiempo de Reacción/efectos de los fármacos
11.
Psychopharmacology (Berl) ; 85(2): 133-8, 1985.
Artículo en Inglés | MEDLINE | ID: mdl-3925478

RESUMEN

In a previous study of the effect of age on information processing, both age and stimulus complexity slowed reaction time (RT) and the latency of the P300 component of the brain event-related potential (ERP). The aim of the present study was to compare the effects of scopolamine (an anticholinergic) with the previously noted effects of age. The choice of scopolamine was prompted by current hypotheses concerning decline in cholinergic function with age. Twelve adult women were studied on a battery of tasks before and after scopolamine in oral doses of 0.0 (placebo), 0.6 and 1.2 mg. Reaction times (RT) and event-related potentials (ERP) were measured. The principal task was one that combined two levels of stimulus complexity and two levels of response difficulty to provide four subtasks. Scopolamine slowed RT and P300 as had age, but scopolamine slowed responses to simple stimuli more than responses to complex stimuli. Scopolamine effects on other tasks in the battery were small but consistent with an action of scopolamine on an early stimulus preprocessing stage that is independent of a stimulus evaluation stage that is also affected by age.


Asunto(s)
Encéfalo/efectos de los fármacos , Electroencefalografía , Procesos Mentales/efectos de los fármacos , Escopolamina/farmacología , Adulto , Discriminación en Psicología/efectos de los fármacos , Femenino , Humanos , Memoria/efectos de los fármacos , Desempeño Psicomotor/efectos de los fármacos , Tiempo de Reacción/efectos de los fármacos , Percepción Visual/efectos de los fármacos
12.
Psychopharmacology (Berl) ; 114(4): 628-34, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-7855225

RESUMEN

Many studies have found that cigarette smoking or nicotine improves mental functioning in abstinent smokers. An unresolved issue is whether this improvement is due primarily to a direct facilitation of performance or to relief of the impairment caused by nicotine withdrawal. We evaluated the performance of 12 non-smokers before and twice (15 and 45 min) after a subcutaneous injection of 0.8 mg nicotine, 0.8 ml saline, and a control no treatment, on a choice reaction time (RT) task. Each treatment was given on a separate day; the control day was given on the first session. The order of nicotine and saline was balanced between subjects, and injections were given double-blind. The RT task manipulated stimulus and response processing. These manipulations consisted of two levels of stimulus complexity and two levels of response complexity, resulting in four task conditions. These manipulations along with latency measures of the event-related potential were used to identify the components of processing that mediated nicotine's effects on performance. During each active drug session blood nicotine levels, cardiovascular, and subjective responses were measured before and after each of the three tests (pre-drug, 15 min and 45 min post-drug). For the information processing measures only the comparisons of the pre- and 15-min post-test showed significant drug effects. Nicotine compared to saline significantly increased the number of responses at the fast end of the RT distribution. However, there were no changes in accuracy. Nicotine also speeded mean RT compared with saline or the control day, but the effects were only significant for the control-nicotine comparison.(ABSTRACT TRUNCATED AT 250 WORDS)


Asunto(s)
Procesos Mentales/efectos de los fármacos , Nicotina/farmacología , Fumar/psicología , Adulto , Algoritmos , Presión Sanguínea/efectos de los fármacos , Cognición/efectos de los fármacos , Método Doble Ciego , Electroencefalografía/efectos de los fármacos , Frecuencia Cardíaca/efectos de los fármacos , Humanos , Inyecciones Subcutáneas , Masculino , Nicotina/administración & dosificación , Nicotina/sangre , Desempeño Psicomotor/efectos de los fármacos , Tiempo de Reacción/efectos de los fármacos
13.
Psychopharmacology (Berl) ; 135(2): 127-32, 1998 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-9497017

RESUMEN

Cotinine, the major proximate metabolite of nicotine, is present in smokers in higher concentrations and for a longer time than nicotine, yet its effects on information processing have not previously been reported. We studied the cognitive effects of cotinine in non-smokers. Sixteen subjects were tested on three doses of cotinine (0.5, 1.0, and 1.5 mg cotinine base/kg), and placebo, on a choice reaction time (RT) task and on a verbal recall task with short and long lists. Cotinine significantly impaired recall on the long list and displayed non-significant but generally consistent dose-related slowing of RT and N100 latency. The acute effects of cotinine were small, and probably do not account for the cognitive deficits observed in tobacco withdrawal, although the cognitive effects of chronic cotinine administration need to be investigated.


Asunto(s)
Cognición/efectos de los fármacos , Cotinina/farmacología , Memoria/efectos de los fármacos , Adulto , Cotinina/metabolismo , Método Doble Ciego , Potenciales Evocados/efectos de los fármacos , Femenino , Humanos , Masculino , Nicotina , Saliva/metabolismo
14.
Brain Res ; 242(1): 165-77, 1982 Jun 17.
Artículo en Inglés | MEDLINE | ID: mdl-7201879

RESUMEN

A syndrome of "contralateral sensory neglect' was induced by hypothalamic knife cuts in 6 of 10 cats in which quiet biting attack behaviour could be elicited by lateral hypothalamic stimulation. The contralateral sensory neglect in the 6 affected cats was accompanied by a loss on the "neglected' side of the body of the patterned reflexes which mediate positioning of the head to bite and the jaw-opening component of biting. As a result, when these cats were stimulated in the lateral hypothalamus, although they continued to approach and even make tactile contact with the rat, they generally failed to bite it. Analysis of the histological and behavioural data suggested that damage to the nigrostriatal and/or striato/pallidonigral fibre systems provided the likely basis for both the induction of the contralateral sensory neglect and the lateralized patterned reflex loss. It was suggested, with respect to these specific patterned reflex components of the attack, that an important contribution may be made by the striatum.


Asunto(s)
Conducta Apetitiva/fisiología , Cuerpo Estriado/fisiología , Hipotálamo/fisiología , Conducta Predatoria/fisiología , Reflejo/fisiología , Sensación/fisiología , Animales , Mapeo Encefálico , Gatos , Dopamina/fisiología , Humanos , Trastornos de la Percepción/fisiopatología , Sustancia Negra/fisiología , Ácido gamma-Aminobutírico/fisiología
15.
Neurosci Lett ; 21(2): 231-6, 1981 Jan 20.
Artículo en Inglés | MEDLINE | ID: mdl-6971420

RESUMEN

Following unilateral transection of the medial forebrain bundle (MFB) within the anterior hypothalamic-preoptic region of cats, the biting attack upon a rat elicited by ipsilateral posterior hypothalamic or ventral midbrain stimulation is eliminated, although the cat continues to approach from 2.8 metres away to within several centimetres of the rat. In contrast, both the approach to and biting attack upon a rat elicited by contralateral posterior hypothalamic and ventral midbrain stimulation are unchanged. The results suggest that specific agents (biting, approach) of the elicited behaviour may be mediated by neural effects which proceed along anatomically distinct components of the ascending as well as the descending MFB.


Asunto(s)
Conducta Apetitiva/fisiología , Hipotálamo Posterior/fisiología , Hipotálamo/fisiología , Haz Prosencefálico Medial/fisiología , Mesencéfalo/fisiología , Vías Nerviosas/fisiología , Conducta Predatoria/fisiología , Animales , Gatos , Estimulación Eléctrica , Haz Prosencefálico Medial/cirugía
16.
Artículo en Inglés | MEDLINE | ID: mdl-1749827

RESUMEN

1. Humans have been tested on a choice reaction time task designed to disclose interactions between stimulus complexity and drug effect. 2. Tests were carried out using oral scopolamine (1.2 mg) and clonidine (0.2 mg). 3. Reaction times and event related potentials were measured. 4. Both drugs slowed reaction time and the N1 component of the ERP. 5. SCOP slows RTs to easy-to-discriminate stimuli more than RTs to harder stimuli. Its effect on P3 is the same for both types of stimuli. 6. CLON tends to slow P3 latencies to easy stimuli more than P3 latencies to harder stimuli, while the RT slowing is almost identical for both types of stimuli.


Asunto(s)
Clonidina/farmacología , Procesos Mentales/efectos de los fármacos , Escopolamina/farmacología , Adulto , Cognición/efectos de los fármacos , Método Doble Ciego , Potenciales Evocados/efectos de los fármacos , Humanos , Masculino , Tiempo de Reacción/efectos de los fármacos
17.
Biol Psychol ; 33(1): 1-22, 1992 May.
Artículo en Inglés | MEDLINE | ID: mdl-1599996

RESUMEN

In humans, close relationships are found between cholinergic activity and constraints placed on information processing operations. This is true for all operations where the effects of cholinergic activity have been studied. Studies of vigilance, memory, problem solving, stimulus processing and response processing are cited as illustrations. These studies suggest the hypothesis that cholinergic activity controls constraints in all information processing operations. Alternative hypotheses are proposed and experimental tests are suggested.


Asunto(s)
Acetilcolina/fisiología , Nivel de Alerta/fisiología , Atención/fisiología , Encéfalo/fisiología , Procesos Mentales/fisiología , Receptores Colinérgicos/fisiología , Adulto , Nivel de Alerta/efectos de los fármacos , Atención/efectos de los fármacos , Encéfalo/efectos de los fármacos , Electroencefalografía/efectos de los fármacos , Femenino , Humanos , Masculino , Procesos Mentales/efectos de los fármacos , Tiempo de Reacción/efectos de los fármacos , Tiempo de Reacción/fisiología , Receptores Colinérgicos/efectos de los fármacos , Escopolamina/farmacología
18.
Psychiatry Res ; 7(3): 299-308, 1982 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-6962438

RESUMEN

The latency of the visual evoked potential N1 component evoked by nontarget stimuli increases with an increased attention to nontarget stimuli. The latency increase seems related to a general effort at processing, rather than any early filtering. This phenomenon is illustrated in one study of hyperactive children and another of normal young adults. The literature of this phenomenon is reviewed, and various explanations are considered. It does not appear to be a result of a slow negative wave, but rather a genuine effect of one aspect of attention on N1.


Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/diagnóstico , Atención , Electroencefalografía , Tiempo de Reacción , Percepción Visual , Adolescente , Nivel de Alerta/efectos de los fármacos , Atención/efectos de los fármacos , Trastorno por Déficit de Atención con Hiperactividad/tratamiento farmacológico , Niño , Relación Dosis-Respuesta a Droga , Potenciales Evocados Visuales/efectos de los fármacos , Humanos , Masculino , Metilfenidato/uso terapéutico , Tiempo de Reacción/efectos de los fármacos , Percepción Visual/efectos de los fármacos
19.
Ann Clin Biochem ; 19(Pt 2): 83-8, 1982 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-6176174

RESUMEN

A simple method which uses 100 microliter serum has been developed to measure the binding of somatomedin B (SMB) to protein in serum from normal children, adults, and patients with growth hormone deficiency. 125I-labelled SMB was used as binding ligand. The correlation between the binding of label by the proposed procedure and by an immunoelectrophoretic technique was acceptable (r = 0.73; P less than 0.02). The mean percentage of label bound to protein in serum from patients with deficiencies of growth hormone or other trophic hormones was significantly (P less than 0.001) lower than that for controls. The physicochemical characteristics of a specific binding-protein suggested that a protein with low capacity (160 pmol/l) and low Ka (4.37 X 10(6) l/mol was present in serum, in addition to a high concentration of alpha globulin(s) which also bound 125I SMB.


Asunto(s)
Proteínas Portadoras/sangre , Hipopituitarismo/sangre , Somatomedinas/sangre , Adolescente , Niño , Preescolar , Femenino , Hormona del Crecimiento/deficiencia , Humanos , Proteínas de Unión a Factor de Crecimiento Similar a la Insulina , Masculino
20.
Acta Psychol (Amst) ; 73(1): 35-54, 1990 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-2180255

RESUMEN

Several studies have shown that d-amphetamine (DAMP) speeds mean reaction time (RT). However, the use of mean RT may obscure important aspects of the drug response. Therefore we applied the Poisson-Erlang (PE) stochastic model of choice reaction time proposed by Pieters (1985) to the RT distribution. This model proposes that the RT distribution is generated by two states: Processing (P) and Distraction (D). RT represents the sum of the time spent in each of these states. P is the time taken to complete a set of cognitive operations which are required to give a correct response. D represents the time taken by all other activities. RTs were collected using a task (SERS) in which stimulus and response complexity each had two levels, easy and hard. Subjects were tested pre- and postdrug. Drug conditions were: placebo, 10 mg d-amphetamine (DAMP), 4 mg of the dopamine agonist, pimozide, and a combination of DAMP and pimozide (COMBO). Parameters of the model were derived using methods described by Pieters. Four measures were analyzed: Processing Time (PT); Mean Time per distraction (XTD); Distraction Rate (DR); and Total Distraction Time per trial (TDT). Mean RT is also presented. Analyses of the effects of task conditions on the parameters of the model were made using the predrug sessions. Mean RT was increased by both stimulus and response complexities as was PT. TDT was increased by the task conditions. The PE measures did not change over days. DAMP speeded mean RT. However, this effect did not interact with the task factors. DAMP speeded processing and reduced distraction. Processing was speeded only in the hard response condition, distraction time was reduced only in the easy response condition. The results indicate that the PE model can be successfully applied to fast RT tasks. More importantly, the parameters of the model revealed important pharmacological effects that were not apparent in mean RT. DAMP speeds cognitive operations related to motor preparation and reduces the effects of distraction. Consistent with past studies there are no indications that DAMP interacted with stimulus processing. The distraction effect appears to be mediated by an increase in the rate of distraction and a decrease in the average time of these distractions.


Asunto(s)
Nivel de Alerta/efectos de los fármacos , Atención/efectos de los fármacos , Cognición/efectos de los fármacos , Dextroanfetamina/farmacología , Tiempo de Reacción/efectos de los fármacos , Adulto , Ensayos Clínicos como Asunto , Método Doble Ciego , Humanos , Masculino , Reconocimiento Visual de Modelos/efectos de los fármacos , Pimozida/farmacología , Desempeño Psicomotor/efectos de los fármacos
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