Discrimination of structure: I. Implications for connectionist theories of discrimination learning.

In each of 4 experiments animals were given a structural discrimination task that involved visual patterns composed of identical features, but the spatial relations among the features were different for reinforced and nonreinforced trials. In Experiment 1 the stimuli were pairs of colored circles, and pigeons were required to discriminate between patterns that were the mirror image of each other. A related task was given to rats in Experiment 2. Subjects solved these discriminations. For Experiment 3, some pigeons were given a discrimination similar to that used in Experiment 1, which they solved, whereas others received a comparable task but with 3 colored circles present on every trial, which they failed to solve. The findings from Experiment 3 were replicated in Experiment 4 using different patterns. The results are difficult to explain by certain connectionist theories of discrimination learning, unless they are modified to take account of the way in which compound stimuli are structured. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implications of computerized axial tomography for clinical neuropsychology.

Suggests that the development of computerized axial tomography (CT scanning) will alter the role of the clinical neuropsychologist working in a medical setting. The CT technique is rapid, noninvasive, and more accurate than traditional neurodiagnostic and neuropsychological measures. It is likely that the ability to isolate the suspected location of brain lesions on the basis of psychological test data will become increasingly an obsolete skill, while the ability to specify precise, functional deficits for purposes of litigation and/or rehabilitation counseling will become increasingly important. Finally, CT scanning will prove invaluable as an aid in mapping the functional geography of the brain. (13 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lesioning a connectionist model of visual search: Selective effects on distractor grouping.

Presents a connectionist model of visual search, Search via Recursive Rejection (SERR) by G. W. Humphreys and H. J. Muller (in press), in which search is determined by patterns of grouping between distractors and between simple form elements. The performance of SERR is examined after it is subject to various types of "lesion." Lesioning is produced either by increasing the internal noise on the activation functions governing the interactions between processing units or by eliminating processing units from different loci in SERR. Simulations demonstrate that (1) search processes can be disrupted by adding internal noise to search functions, (2) there can be selective effects on grouping processes, and (3) these selective effects can be associated with different types of lesion to different stages in SERR. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Graded semantic and phonological similarity effects in priming: Evidence for a distributed connectionist approach to morphology.

A considerable body of empirical and theoretical research suggests that morphological structure governs the representation of words in memory and that many words are decomposed into morphological components in processing. The authors investigated an alternative approach in which morphology arises from the interaction of semantic and phonological codes. A series of cross-modal lexical decision experiments shows that the magnitude of priming reflects the degree of semantic and phonological overlap between words. Crucially, moderately similar items produce intermediate facilitation (e.g., lately-late). This pattern is observed for word pairs exhibiting different types of morphological relationships, including suffixed-stem (e.g., teacher-teach), suffixed-suffixed (e.g., saintly-sainthood), and prefixed-stem pairs (preheat-heat). The results can be understood in terms of connectionist models that use distributed representations rather than discrete morphemes. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Women in multiple roles: Implications for school psychologists.

Reviews the literature on some selected aspects of women's lives in order to provide an orientation for school psychologists. Both qualitative and empirical literature in the 3 main areas: the meaning of work, the timing of parenthood, and the integration of multiple roles are discussed. The exploration of work and parenting roles has been chosen because they are 2 major foci around which, it is suggested, most adult women organize their lives. The 3rd area, the integration of multiple roles, is also of immediate relevance in light of the increasing number of women who are combining multiple roles. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Schizophrenia and the brain: Conditions for a neuropsychology of madness.

Describes 3 conditions for understanding schizophrenia as a kind of brain disease. First, the disorder must cohere as a clinical entity that is distinct from other disorders. Second, schizophrenia must be linked with an identifiable neuropathology. Third, implicated brain systems must have behavioral functions that fit the psychological characteristics actually seen in schizophrenia. In each case, the evidence is weak or equivocal. However, this does not mean that neurogenic interpretations are untenable. Instead, the primacy of problems associated with the 1st condition, the need to parse schizophrenia and reduce heterogeneity, must be recognized. Progress in understanding schizophrenia depends on a neurobehavioral approach to resolving the heterogeneity problem. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Prospects for a cognitive neuropsychology of autism: Hobson's choice.

A. M. Leslie (see record 1988-13495-001) proposed a new, metarepresentational model for the cognition of pretense. This model identified a cognitive component necessary for the normal development of a "theory of mind." In this article, the relation of the child's early affective sensitivities to this component is considered. Early affective sensitivities seem to be cognitively distinct from the metarepresentational component. Childhood autism provides an interesting opportunity to study this problem. Three theoretical possibilities for the pathogenesis of this condition are presented: (a) a basic affective disorder as proposed by R. P. Hobson (see record 1990-14380-001), (b) a basic affective disorder and a basic cognitive disorder jointly, and (c) a basic cognitive disorder. There is little evidence for Option a, and a growing body of evidence supports Option c. Option b is sidelined for the time being on grounds of parsimony. Leslie's original theoretical proposals are revised, and some resulting implications are presented for the future investigation of the cognitive neuropsychology of autism. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Implications from aphasia for the syntax of null-subject sentences: underlying subject slots in Bulgarian

Evidence for the existence of an underlying sentence-initial subject slot for Bulgarian null-subject personal constructions can be found in two aberrant tendencies by a Bulgarian patient with aphasia. In response to test sentences consisting of personal constructions that contained an object pronominal clitic and no lexical subject, the patient tended either to insert a superfluous sentence-initial pronominal subject, or to place the object pronominal clitic left-adjacent to the verb, in the position that it would have occupied had a sentence-initial overt subject been present.     

Recall as a function of single versus multiple trials: Implications for rehabilitation.

Objective: To empirically demonstrate that recall based on multiple presentations of material (i.e., "learning") is statistically distinct from recall based on singular presentations of material (i.e., "memory"). Participants: Two hundred ninety-one individuals referred to an outpatient neuropsychology laboratory, including 199 with a primary diagnosis of traumatic brain injury, 13 who experienced a cerebral vascular accident, 3 with progressive dementia, and 76 with an unknown etiology. Main Outcome Measures: Raw-standard scores from the Wechsler Memory Scale-Revised Logical Memory and Visual Reproduction subtests, the Rey Auditory Verbal Learning Test (RAVLT), the Tactual Performance Test (TPT), the Category Test, and indices of "learning" based on difference scores: RAVLT Trial 5 minus Trial 1; TPT Trial 3 minus Trial 1. Results: A promax factor analysis of 291 participants with cognitive dysfunction revealed a 4-factor solution (verbal memory, spatial memory, verbal learning, and tactile-motor learning), supporting the distinction between learning and memory constructs. Conclusions: Recall based on multiple presentations of information should be evaluated to provide the most functionally relevant assessments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The use of scattergrams for the representation and analysis of lateralized interference effects in neuropsychology.

Presents an approach and method for the representation and analysis of group differences in dual-task performance. Although designed to deal with complex data sets typically encountered in the analysis of lateralized interference effects in neuropsychology, it is, in principle, applicable to any dual-task paradigm in which variations in 1 performance measure are accompanied by variations in another. The use of scattergrams and the associated statistical analytic techniques discussed should facilitate communication and understanding of the complex sets of data typically generated with this paradigm. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Overconfidence effects in category learning: A comparison of connectionist and exemplar memory models.

Exemplar and connectionist models were compared on their ability to predict overconfidence effects in category learning data. In the standard task, participants learned to classify hypothetical patients with particular symptom patterns into disease categories and reported confidence judgments in the form of probabilities. The connectionist model asserts that classifications and confidence are based on the strength of learned associations between symptoms and diseases. The exemplar retrieval model (ERM) proposes that people learn by storing examples and that their judgments are often based on the first example they happen to retrieve. Experiments 1 and 2 established that overconfidence increases when the classification step of the process is bypassed. Experiments 2 and 3 showed that a direct instruction to retrieve many exemplars reduces overconfidence. Only the ERM predicted the major qualitative phenomena exhibited in these experiments. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

"Lesioning a connectionist model of visual search: Selective effects on distractor grouping": Erratum.

Reports an error in the original article by G. W. Humphreys et al (Canadian Journal of Psychology, 1992, Vol 46, 417–460). The figures in the article were printed in the wrong order. Figures 2 and 6 should be interchanged, as should Figures 3 and 5. (The following abstract of this article originally appeared in record 1993-24303-001.) Presents a connectionist model of visual search, Search via Recursive Rejection (SERR) by G. W. Humphreys and H. J. Muller (in press), in which search is determined by patterns of grouping between distractors and between simple form elements. The performance of SERR is examined after it is subject to various types of "lesion.' Lesioning is produced either by increasing the internal noise on the activation functions governing the interactions between processing units or by eliminating processing units from different loci in SERR. Simulations demonstrate that (1) search processes can be disrupted by adding internal noise to search functions, (2) there can be selective effects on grouping processes, and (3) these selective effects can be associated with different types of lesion to different stages in SERR. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Serial exhaustive models can violate the race model inequality: Implications for architecture and capacity.

Classical examples of simple architectures, ranked in terms of their relative efficiency or capacity from less to more, are standard serial (1-at-a-time) processes, followed by independent parallel (simultaneous) processes, followed by coactive (pooling of parallel channel information), and interactive parallel (e.g., mutually facilitory) processes. Violation of the race model inequality has been thought to rule out ordinary parallel and serial systems. Violation of the race model inequality does exclude many such processes. However, it is proven here that a variety of serial systems that is quite inefficient readily violates the race model inequality. In the Discussion, the authors indicate that the race model inequality still can be highly useful in the identification of mental architecture, when allied with other converging analyses of structure, process rules, and capacity. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dissociable effects of cingulate and medial frontal cortex lesions on stimulus-reward learning using a novel Pavlovian autoshaping procedure for the rat: Implications for the neurobiology of emotion.

The effects of quinolinic acid-induced lesions of the anterior cingulate, posterior cingulate, and medial frontal cortices on stimulus-reward learning were investigated with a novel Pavlovian autoshaping procedure in an apparatus allowing for the automated presentation of computer-graphic stimuli to rats (T. J. Bussey, J. L. Muir, & T. W. Robbins, 1994). White vertical rectangles were presented on the left or the right of a computer screen. One of these conditioned stimuli (the CS+) was always followed by the presentation of a sucrose pellet; the other, the CS–, was never followed by reward. With training, rats came to approach the CS+ more often than the CS–. Anterior cingulate cortex-lesioned rats failed to demonstrate normal discriminated approach, making significantly more approaches to the CS– than did sham-operated controls. Medial frontal cortex-lesioned rats acquired the task normally but had longer overall approach latencies. Posterior cingulate cortex lesions did not affect acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Simultaneous timing of multiple intervals: Implications of the scalar property.

Three experiments with pigeons are reported in which the scalar property in simultaneous timing tasks was studied. According to scalar expectancy theory, the scalar property should be maintained in simultaneous timing, but the behavioral theory of timing predicts that the scalar property should be evident only in independent timing. Experiment 1 showed that the appearance of distinct peaks at reinforcement times required about a 4:1 ratio between intervals. Experiment 2 (2-interval timing task) and Experiment 3 (3-interval timing task) used an individual trial analysis technique to examine high-rate responding segments bracketing the times of reinforcement. The standard deviations of the starting and stopping times of high-rate segments were linearly related to their means and to reinforcement time, supporting the scalar property in simultaneous timing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Excitotoxic lesions of the hippocampus leave sensory preconditioning intact: Implications for models of hippocampal functioning.

Learning about contextual cues is markedly disrupted in rats with hippocampal lesions. One analysis of this disruption is that it reflects a general failure to form associations between the elements of complex events. A straightforward prediction of this analysis is that sensory preconditioning will be disrupted by hippocampal lesions. This prediction was assessed by presenting rats with flavored solutions composed of 2 elements (A and X) before X was paired with an injection of the emetic, lithium chloride. A subsequent test revealed that rats were less willing to consume Solution A than they were to consume a control solution, B. This was true of rats with sham lesions and those with excitotoxic lesions of hippocampus. These findings fail to support the proposition that the hippocampus-dependent deficit in contextual conditioning is due to a general disruption to the process of associating the elements of complex events. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Decision-making effects on compensation surveys: Implications for market wages.

Compensation specialists made 2 survey-sample decisions in a simulated wage survey. Policy-capturing analyses indicate that most specialists relied extensively on 2 of the available cues and consistently applied that policy across judgments. They were not able to accurately estimate their own decision-making policies, as demonstrated by the fact that rationally generated assessments of cue importance were significantly different from their actual policies. Finally, meta-analyses demonstrate that the variation in policies across decision makers could not be attributed to statistical artifacts or any moderators (e.g., salary-survey experience or industry) associated with the demographic data. Thus, different compensation specialists are likely to select a different sample of employers even for the same wage survey. Implications for the relevance of market wages obtained from surveys are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Challenges for neuropsychology in the treatment and rehabilitation of brain-injured patients.

This article examines how the treatment of brain damage has evolved to its present form, and how neuropsychologists may be expected to deal with the challenges of providing it. This article describes how neuropsychology became involved in the treatment process. In this context, the authors considered historical factors that brought neuropsychological rehabilitation (NPR) from a purely psychotherapeutic enterprise into full participation in the direct-care process. The authors cover this process by which neuropsychologists put brain-behavior rehabilitation into practice in some detail. Prototypic research discussed in this article has served as a basis for consideration of parameters of measurement, estimation of the validity of treatment approaches, and projections about future study. The authors conclude that treatment approaches in NPR may remain unclear without development of a more cohesive, well-defined, and economically feasible role of the neuropsychologist in this clinical setting. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Age of acquisition effects in adult lexical processing reflect loss of plasticity in maturing systems: Insights from connectionist networks.

Early learned words are recognized and produced faster than later learned words. The authors showed that such age of acquisition effects are a natural property of connectionist models trained by back propagation when patterns are introduced at different points into training and learning of early and late patterns is cumulative and interleaved. Analysis of hidden unit activations indicated that the age of acquisition effect reflects a gradual reduction in network plasticity and a consequent failure to differentiate late items as effectively as early ones. Further simulations examined the effects of vocabulary size, learning rate, sparseness of coding, use of a modified learning algorithm loss of early items, acquisition of very late items, and lesioning the network. The relationship between age of acquisition and word frequency was explored, including analyses of how the relative influence of these factors is modulated by introducing weight decay. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Immunoregulatory effects of interferon-beta and interacting cytokines on human vascular endothelial cells. Implications for multiple sclerosis autoimmune diseases

BACKGROUND AND PURPOSE: Radiolabeled immunoglobulin therapy (RIT) can be a selective, effective, low-toxicity outpatient cancer therapy. A consensus on the best approach for the preclinical and clinical development of RIT reagents needs to be developed. We report the M.D. Anderson Cancer Center prior experience in translating RIT from laboratory to clinic for the treatment of Hodgkin's disease and propose a flow diagram for the development of RIT for other malignancies. MATERIAL AND METHODS: Three different animal models are described: nude mice bearing human tumor xenografts, normal beagle dogs, and normal rhesus monkeys. We produced and purified antibodies and prepared chelate-immunoconjugates reactive with six different human tumor-associated antigens. The Igs used were derived from rabbits, mice, and humans (human-derived RIT reagents being less immunogenic in human patients). Eighty patients with refractory Hodgkin's disease were treated with radiolabeled antiferritin. RESULTS: We recommend a two-injection scheme using, (1) an indium-111-labeled radioimmunoconjugate for diagnosis, pharmacokinetic studies, and dosimetry, and (2) a yttrium-90-labeled radioimmunoconjugate for therapy. The animal models provide useful data on tumor targeting, radiotoxicology, and undesirable biodistributions. A 70% response rate is obtained in patients with advanced recurrent Hodgkin's disease. More extensive preclinical testing allows for safer and more effective clinical RIT studies. CONCLUSIONS: We recommend, (1) preclinical optimization of chelation chemistry, Ig size, Ig origin, route of administration, and fractionation, (2) new clinical Phase I-III studies more appropriate for RIT development than the classical Phase I-III studies used for the development of chemotherapeutic agents, and (3) more extensive preclinical testing of RIT reagents.