The present study was conducted to determine the degree to which impairments in attention accompany the memory deficits produced by scopolamine. Eighteen healthy young volunteers received scopolamine 0.6 mg subcutaneously on three experimental sessions and placebo on three others. On each session, prior to, and 60min after injection, the subjects underwent an automated computerized battery of 1 1 cognitive tasks. The study was run double-blind and the order of treatment conditions over successive visits was counterbalanced between subjects. Scopolamine produced marked and significant decrements on all major aspects of performance from the battery. The drug lowered the efficiency of the detection and processing of information in tests of visual vigilance, rapid information processing, choice reaction, letter cancellation and logical reasoning. These effects were accompanied by a lowering of critical flicker-fusion frequency and subjective alertness. Memory was also impaired on tests of immediate recall, delayed recall, recognition and memory scanning. These findings confirm and extend previous work, demonstrating that scopolamine impairs the selection and evaluation of enviroilmental information, as well as reducing the likelihood of information being subsequently recalled or recognized. Whether the former effects contribute to the latter is not known, but this must be considered a possibility. This potential role of processing deficits in memory loss associated with cholinergic blockade is briefly considered in relation to the cholinergic hypothesis of geriatric memory loss.KEY worn-Scopolamine, cholinergic system, human cognition, attention, information processing, memory, automated cognitive test battery, cholinergic hypothesis of geriatric memory loss.
The overriding principle of military surgery is the delayed primary suture of wounds. Therefore. by definition, battle casualties will receive more than one anaesthetic for the treatment of their injuries. The use of the Triservice anaesthetic apparatus (TSA) has bccii well tried and documented.',' It is a drawover system that uses ambient air iis the primary carrier gas, and halothane and trichlorocthylcnc a the volatile anaesthetic agcnts.However, in view of current opinions about liver damage due 10 repeated halothane it would be prcferablc if this agent were no1 used in the first instance. In addition, the manufacture of trichloroethylene has been threatened in the past and the future production of this agent cannot be guaranteed. The use of the newer inhalational agents, entlurane and isoflurane. has been rec o n~m c n d c d .~ Unfortunately. enflurane, which does have analgesic p r o p e r t i~s .~ has a high MAC and isoflurane, at present. is very expensive.We felt that ;I total intravenous technique is an obvious altcrnative in the treatment of battle casualties. This study was therefore designed to assess the suitability of such a technique using a mixture that contained ketamine, niidamlarn and vecuronium, ;iccuratcly dclivered intravenously by ineans of a syringe pump. Ketaminc has becn uscd widely as the induction and maintenance drug of choice for trauma cases but the high incidence of unpleasant side effects has limited its acceptance. Vecuronium bromide, one of the rnore recently introduced non-depolarising muscle relaxants. has been used because it is available as an anhydrous powder and therelhre stores well. Vccuronium is frcc of advcrsc circulatory effects and the incidence of release of histamine is minirnal.'j It is our contention that all battle casualties will have a full stomach, irrespective of the interviil between timc of injury and time of surgery. Therefore, tracheal intubation is mandatory and intermittent positive pressure venlilation can be iiscd for the duration of the surgical procedure. Another essential recluiremcnt for w x surgery is (hat patients should recover quickly and be able to maintain clear airway as soon as possible. MrriiorliOne hundred patients, 36 male and 64 Ccmale. age range 16-50 years. who presented for elective abdominal, thoracic or body surface surgery at this hospital wcre studied. All patients were in ASA classes 1 and 2. It MBS estimated that their operations would last at least 45 minutes. Patients with a past medical history of psychiatric illness. with hypertension and those with a history of ;I previous ccrcbrovascular iiccidcnt wcrc not studied. All patients were seen prc-operativcly. Thc following details were recorded: initials, sex, body weight. relevant medical history and physical findings. All were prcnicdicated with papavereturn and hyoscinc one hour preoperatively. Monitoring of the electrocardiogram a n d blood pressure (Dinamap) wis commenced on arrival in the anaesthetic room and a vein on thc dorsiun of the hand or forearm was cannulate...
Anorexia nervosa (AN) is a complex illness and highly challenging to treat. One promising approach to significantly advance our understanding of the underlying pathophysiology of AN involves developing a cognitive neuroscience model of illness. Cognitive neuroscience uses probes such as neuropsychological tasks and neuroimaging techniques to identify the neural underpinnings of behavior. With this approach, advances have been made in identifying higher order cognitive processes that likely mediate symptom expression in AN. Identification of related neuropathology is beginning. Such findings have led to the development of complex neurobehavioral models that aim to explain the etiology and persistence of AN. Future research will use these advanced tools to test and refine hypotheses about the underlying mechanisms of AN.
Correspondencediazepam will depress ventilation even more. Hypotension, due to its myocardial effect, may occur in severely wounded battle casualties and therefore it may not be the drug to use. Correction of mental aberrations would be the least of our worries.Ketamine, compared to thiopentone or other intravenous myocardial depressant agents, may still be the anaesthetic of choice for induction of anaesthesia. However, anaesthesiologists world wide must be aware of its adverse effects.
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