A selective and critical review of neuropsychological deficits and the frontal lobes

Presumptions about the functions of the frontal lobes, and the sensitivity and specificity of certain tests to measure frontal lobe functions, are having a substantial influence on both clinical and research conclusions. In this paper the authors examine the details of the studies that have contributed to these presumptions, and find that the evidence to support these conclusions is weak. A detailed evaluation of the evidence relating to the Wisconsin Card Sorting Test and the Thurstone Word Fluency Test is also presented. Finally, the development of the belief that frontal lobe functions can be specifically measured is reviewed. The authors of this paper conclude that the bewildering array of deficits attributed to frontal lesions still seems to prevail.     

Cognitive function after open-heart surgery: Are postoperative neuropsychological deficits caused by cardiopulmonary bypass?

Despite the many technological developments in arterial perfusion and cardiac surgical procedures, open-heart surgery is still believed to pose a significant risk for cerebral injury. There are several potential causes of brain damage during open-heart surgery, including prolonged or severe arterial hypotension, as well as emboli emanating from the cardiopulmonary bypass circuit or the operative field. This article reviews the available neuropsychological studies of outcome following cardiac valve replacement and coronary artery bypass grafting. Because both procedures are life-saving operations, the research in this area has been quasi-experimental and fraught with methodological problems. Nonetheless, the findings converge to suggest that cognitive dysfunction occurs after open-heart surgery, and that the deficits are attributable, at least in part, to factors specific to the operation or to the patient being maintained on cardiopulmonary bypass. Preliminary findings suggest that embolization is the primary cause of perioperative deficits in uncomplicated operations. Studies have also consistently found preoperative deficits in this population, suggesting that neuropsychological dysfunction is caused by severe chronic cardiac disease as well as open-heart surgery.     

The retention of nouns,adjectives, and verbs of sentences

This research compared the retention of nouns, adjectives and verbs of sentences. A model of the structure underlying the retention of sentences and in which deep structure constituent propositions are hierarchically related, was used to make predictions concerning the retention of these word classes. The model was not supported by the data and it was determined that latencies to recognize the words of a previously presented sentence were the same for all classes of words. This result indicated that for recognition (but not necessarily for other memory tasks), each word of a sentence is seperately or equally accessible (as long as inter-word imagery is the same). However, a further experiment showed that, although word class is not a variable, the image-arousing capacity of a word is. Latencies and error rates were much lower for high-imagery words than for low-imagery ones. The findings on error rates in recognizing words were interesting and pointed to a different model where the meaning representations and syntatic functions of words have an active role in sentence retention.     

An introduction to microcomputer networking concepts

This paper presents a brief history of the use of internal computer networks, an introduction to networking concepts and topology, and suggestions regarding a possible system for use in a psychology laboratory. Considerations about the design and use of a microcomputer network are discussed.     

Primary versus secondary rehearsal in imagined voices: Differential effects on recognition

Subjects were asked to rehearse word trigrams in a particular prefamiliarized male or female voice for 5, 10, or 15 sec. In Experiment 1, recognition performance improved with the amount of primary (maintenance) rehearsal only if the speaker's voice at test matched the rehearsal voice, but recognition performance improved with the amount of secondary (elaborative) rehearsal regardless of the sex of the speaker at test. With a visual testing procedure in Experiments 2 and 3, the amount of primary rehearsal given to a trigram had no effect on recognition performance unless the original voice context was reinstated mentally at test. These results suggest that: (a) Secondary rehearsal builds up semantic associations, whereas primary rehearsal serves to associate items with their physical characteristics at presentation. (b) There is an important memory search component in recognition as well as in recall. (c) Imaginal operations can yield a product in memory that is similar to that left by perceptual operations.     

Assessment of the relative importance of S+ and S− in rats using differential training on intercurrent discriminations

The present studies assessed the degree of stimulus control exerted by S+ and S? without confoundings of stimulus novelty and stimulus ambiguity. In Experiment 1, rats were trained on two intercurrent simultaneous discrimination problems with nine times more training given on one than the other. Then the animals were given transfer tests with re-paired stimuli. The results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination. Experiment 2 provided a test of the possibility that the relative degree of control by S? varies with different amounts of training. Three groups were trained on two intercurrent simultaneous discrimination problems; each group was given 7, 11, or 15 times more training on one problem than the other. Then transfer tests were given with re-paired stimuli. Again the results showed that S? exerts greater stimulus control than S+ in a two-choice simultaneous discrimination.     

Contextual potentiation of acquired behavior after devaluing direct context-US associations

In two experiments, water-deprived rats were exposed to tone-footshock pairings in a particular conditioning context. In Experiment 1, the training parameters were selected on the basis of parametric pilot data so as not to produce direct associations between the conditioning context and footshock. Despite independent evidence of no appreciable direct association between the conditioning context and footshock, animals tested in the conditioning context exhibited more lick suppression to the tone than other animals tested with the tone outside of the conditioning context. Thus, the conditioning context potentiated suppression to the tone in the absence of appreciable fear of the conditioning context. In Experiment 2, training parameters were used that permitted the formation of direct associations between the conditioning context and footshock; however, for half the animals, these associations to the context were then extinguished. With the tone absent, a comparison of extinguished animals tested either in the conditioning context or outside the conditioning context detected no differences in suppression, demonstrating the effectiveness of the extinction manipulation. However, other animals also subjected to extinction of direct context-footshock associations displayed greater suppression to the tone within the conditioning context than comparable animals tested outside the context. Collectively the data indicate that the superior retention-test performance seen within the training context can arise both from the commonly assumed direct associations between the training context and the unconditioned stimulus and from the potentiation by the training context of the associations between the nominal conditioned stimulus and unconditioned stimulus.     

The Pittsburgh Initial Neuropsychological Testing System (PINTS): A neuropsychological screening battery for psychiatric patients

This paper presents a new neuropsychological screening battery for psychiatric patients. It takes 1.5 to 2 hr to administer and briefly assesses general level of performance, memory, language skills, attention, and spatial-constructional abilities. Scoring and profiling are computerized. Initial validation based on discriminant analysis of a group of brain-damaged and non-brain-damaged psychiatric patients yielded a diagnostic accuracy level of 84.51%. Cross-validation on a different population led to a substantial attrition of classificatory accuracy, but cross-validation based on a comparison between two samples drawn from a homogeneous population yielded substantially less attrition. It was concluded that while the battery discriminates accurately in a homogeneous population, it is necessary to develop separate norms for populations varying in level of impairment.     

Assessment of social anxiety: a controlled comparison among social phobics,obsessive-compulsives,agoraphobics, sexual disorders and simple phobies

The construct validity of the Willoughby Personality Schedule (WPS) as an index of social anxiety was established in the present study. The WPS correctly identifies social phobics from controls in 88% of the cases.