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PubMed1990

Knowledge-based representations of risk beliefs.

Beliefs about risks associated with two risk agents, AIDS and toxic waste, are modeled using knowledge-based methods and elicited from subjects via interactive computer technology. A concept net is developed to organize subject responses concerning the consequences of the risk agents. It is found that death and adverse personal emotional and sociological consequences are most associated with AIDS. Toxic waste is most associated with environmental problems. These consequence profiles are quite dissimilar, although past work in risk perception would have judged the risk agents as being quite similar. Subjects frequently used causal semantics to represent their beliefs and "% of time" instead of "probability" to represent likelihoods. The news media is the most prevalent source of risk information although experiences of acquaintances appear more credible. The results suggest that "broadly based risk" communication may be ineffective because people differ in their conceptual representation of risk beliefs. In general, the knowledge-based approach to risk perception representation has great potential to increase our understanding of important risk topics.

Acquired Immunodeficiency Syndrome↗

PubMed2004

Differential cognitive outcomes in the Hypertensive Old People in Edinburgh study.

Hypertension is associated with cognitive impairment in older adults. The Hypertensive Old People in Edinburgh (HOPE) study reported improved scores in two psychometric tests in those subjects with the greatest fall in diastolic blood pressure during a 24-week randomised, double-blind trial of captopril versus bendrofluazide in 81 elderly hypertensive people with mild cognitive impairment. Three hundred and eighty-seven of the original sample of 603 older people with and without hypertension and/or cognitive impairment from which the trial subsample was drawn were available for adequate psychometric testing 4 years later. Blood pressure was related prospectively to Raven's Progressive Matrices (RPM), a measure of fluid intelligence, but not memory differences. RPM scores were obtained at baseline, 6 weeks, 12 weeks and at the end of the randomised controlled trial. For subjects on captopril mean scores at each time point adjusted for blood pressure change were 27.6 (95% CI 25.5-29.6), 27.2 (95% CI 25.1-29.2), 28.4 (95% CI 26.6-30.3) and 28.9 (95% CI 26.9-30.9), and for bendrofluazide 27.1 (95% CI 25.1-29.0), 28.9 (95% CI 26.9-30.9), 28.9 (95% CI 27.2-30.7) and 28.7 (95% CI 26.8-30.6). There was a significant improvement in scores for those on bendrofluazide compared with captopril at week 6 (F=8.10, p=0.006, partial eta2=0.11). There were no significant effects for either drug or blood pressure at any time point for tests of memory. Future trials of the effects of antihypertensive therapy on cognition should focus more on outcomes other than memory. Early differential effects of therapeutic agents may not be maintained.

Aged↗

PubMed1997

The brain as a symbol-processing machine.

The knowledge accumulated about the biochemistry of the synapsis in the last decades completely changes the notion of brain processing founded exclusively over an electrical mechanism, toward that supported by a complex chemical message exchange occurring both locally, at the synaptic site, as well as at other localities, depending on the solubility of the involved chemical substances in the extracellular compartment. These biochemical transactions support a rich symbolic processing of the information both encoded by the genes and provided by actual data collected from the surrounding environment, by means of either special molecular or cellular receptor systems. In this processing, molecules play the role of symbols and chemical affinity shared by them specifies the syntax for symbol manipulation in order to process and to produce chemical messages. In this context, neurons are conceived as message-exchanging agents. Chemical strings are produced and stored at defined places, and ionic currents are used to speed up message delivery. Synaptic transactions can no longer be assumed to correspond to a simple process of propagating numbers powered by a factor measuring the presynaptic capacity to influence the postsynaptic electrical activity, but they must be modeled by more powerful formal tools supporting both numerical and symbolic calculations. It is proposed here that formal language theory is the adequate mathematical tool to handle such symbolic processing. The purpose of the present review is therefore: (a) to discuss the relevant and recent literature about trophic factors, signal transduction mechanisms, neuromodulators and neurotransmitters in order (b) to point out the common features of these correlated processes; and (c) to show how they may be organized into a formal model supported by the theory of fuzzy formal languages (d) to model the brain as a distributed intelligent problem solver.

Animals↗

PubMed2002

Fractionation of visual memory: agency detection and its impairment in autism.

It is known that the adult visual memory system is fractionable into functionally independent cognitive subsystems, selectively susceptible to brain damage. In addition, there have been hints from studies with individuals with autism that these cognitive subsystems can fractionate developmentally. However, there has been a paucity of systematic investigations. The present study involves the analysis of visual memory of a population of individuals with autism and age- and VIQ-matched comparison individuals. The individuals with autism presented selective impairments in face recognition in comparison to both the age- and VIQ-matched comparison populations. In addition, they were impaired relative to the age-matched comparison group on recognition memory for potential agents (i.e. objects capable of self-propelled motion) whether they were living (cats and horses) or non-living (motorbikes). In contrast, they were selectively superior relative to the VIQ-matched comparison group on recognition memory for such objects as topographical stimuli (buildings) and leaves that clearly do not have agency. The data is interpreted in terms of reduced sensitivity to agency cues in individuals with autism and general information processing capacity.

Adolescent↗

PubMed2001

Suicide and schizophrenia.

Suicide and suicide attempts occur at a significantly greater rate in schizophrenia than in the general population. Common estimates are that 10% of people with schizophrenia will eventually have a completed suicide, and that attempts are made at two to five times that rate. Demographically associated with suicidality in schizophrenia are being young, being early in the course of the illness, being male, coming from a high socioeconomic family background, having high intelligence, having high expectations, not being married, lacking social supports, having awareness of symptoms, and being recently discharged from the hospital. Also associated are reduced self-esteem, stigma, recent loss or stress, hopelessness, isolation, treatment non-compliance and substance abuse. Clinically, the most common correlates of suicidality in schizophrenia are depressive symptoms and the depressive syndrome, although severe psychotic and panic-like symptoms may contribute as well. This review specifically explores the issue of depression in schizophrenia, in relation to suicide, by organizing the differential diagnosis of this state and highlighting their potentially treatable or correctable causes. This differential diagnosis includes both acute and chronic disappointment reactions, the prodrome of an acute psychotic episode, neuroleptic induced akinesia and akathisia, the possibility of direct neuroleptic-induced depression, negative symptoms of schizophrenia, and the possible co-occurrence of an independent depressive diathesis. The potential beneficial roles of 'atypical' antipsychotic agents, including both clozapine and more novel agents, and adjunctive treatment with other psychopharmacological medications are considered, and the important roles of psychosocial factors and interventions are recognized.

Antipsychotic Agents↗

PubMed1977

Follow-up report on autism in congenital rubella.

A longitudinal study was conducted of 243 children with congenital rubella. In this sample a high rate of autism and a high rate of recovery were observed. Examination of the data suggested that the rubella virus was the primary etiologic agent. It is hypothesized that the course of autism was that of a chronic infection in which recovery, chronicity, improvement, worsening, and delayed appearance of the autistic syndrome all were found. Other rubella consequences such as blindness, deafness, and cardiac and neuromuscular defects remained present except as modified by operations and prostheses. Degree of mental retardation initially was related to the outcome of autism but shifts in mental retardation over time did not correlate significantly for the group with shift in the autistic symptoms.

Autistic Disorder↗

PubMed2004

The processing of verbs and nouns in neural networks: insights from synthetic brain imaging.

The paper presents a computational model of language in which linguistic abilities evolve in organisms that interact with an environment. Each individual's behavior is controlled by a neural network and we study the consequences in the network's internal functional organization of learning to process different classes of words. Agents are selected for reproduction according to their ability to manipulate objects and to understand nouns (objects' names) and verbs (manipulation tasks). The weights of the agents' neural networks are evolved using a genetic algorithm. Synthetic brain imaging techniques are then used to examine the functional organization of the neural networks. Results show that nouns produce more integrated neural activity in the sensory-processing hidden layer, while verbs produce more integrated synaptic activity in the layer where sensory information is integrated with proprioceptive input. Such findings are qualitatively compared with human brain imaging data that indicate that nouns activate more the posterior areas of the brain related to sensory and associative processing, while verbs activate more the anterior motor areas.

Algorithms↗

PubMed1997

Eco-grammar systems: a grammatical framework for studying lifelike interactions.

A formal framework for studying systems made up of a community of agents and their environment is proposed. The suggested model, technically based on the theory of formal grammars and called an eco-grammar system, captures some common features of ecological, economic, social, and collective robotic systems. The article contains an informal presentation as well as the formal definition of the model, presents some properties of variants of eco-grammar systems, and discusses the emergence of important lifelike features such as birth and death. Emphasis is put on results with relevance for artificial life. Some recent developments are also briefly reported.

Artificial Intelligence↗

PubMed2006

The folk psychology of souls.

The present article examines how people's belief in an afterlife, as well as closely related supernatural beliefs, may open an empirical backdoor to our understanding of the evolution of human social cognition. Recent findings and logic from the cognitive sciences contribute to a novel theory of existential psychology, one that is grounded in the tenets of Darwinian natural selection. Many of the predominant questions of existential psychology strike at the heart of cognitive science. They involve: causal attribution (why is mortal behavior represented as being causally related to one's afterlife? how are dead agents envisaged as communicating messages to the living?), moral judgment (why are certain social behaviors, i.e., transgressions, believed to have ultimate repercussions after death or to reap the punishment of disgruntled ancestors?), theory of mind (how can we know what it is "like" to be dead? what social-cognitive strategies do people use to reason about the minds of the dead?), concept acquisition (how does a common-sense dualism interact with a formalized socio-religious indoctrination in childhood? how are supernatural properties of the dead conceptualized by young minds?), and teleological reasoning (why do people so often see their lives as being designed for a purpose that must be accomplished before they perish? how do various life events affect people's interpretation of this purpose?), among others. The central thesis of the present article is that an organized cognitive "system" dedicated to forming illusory representations of (1) psychological immortality, (2) the intelligent design of the self, and (3) the symbolic meaning of natural events evolved in response to the unique selective pressures of the human social environment.

Attitude to Death↗

PubMed1986

Mental phenomena as changes of state in a finite-state machine.

This paper examines the classical functions of the psyche--cognition, affection and conation--from a phenomenological viewpoint and finds them to be defined each in terms of the other. It is held that this circularity of definition reflects the fundamental unity of conscious experience and, as a consequence, that the search for the biological substrate underlying individual functions too readily degenerates into a morphological and biochemical phrenology. An alternative approach, based on considerations from the field of artificial intelligence, is discussed. This approach provides a description of mental phenomena as changes of state in a finite-state machine, the next state being determined by both previous states and current inputs. This concept is shown to be compatible with the descriptions of conscious experience outlined in the phenomenology of Karl Jaspers. It is suggested that neurobiological investigations should be directed towards defining the processes by which state changes occur and further seeking to define mental pathology as aberrations of these dynamic processes.

Affect↗

PubMed1990

Identification of rodent carcinogens by an expert system.

CASE, an artificial intelligence method for identifying structural determinants responsible for biological activity was applied to the U.S. National Toxicology Program (NTP) cancer bioassay results. CASE identified structures which were significantly associated with rodent carcinogenicity. On the basis of these structural determinants CASE exhibited a sensitivity of 0.98 and a specificity of 1.00. CASE showed a similarly remarkable performance in predicting the carcinogenicity, or lack thereof, of chemicals not in the NTP data base. A comparison between the activating structures (biophores) responsible for mutagenicity in Salmonella and rodent carcinogenicity showed a significant overlap, verifying that there are structural commonalities between the two phenomena. CASE also identified biophores significantly associated with the activity of non-genotoxic carcinogens, thereby suggesting the unexpected possibility that there is a structural commonality among the chemicals included in this group. A comparison between the biophores responsible for carcinogenicity in mice and rats resulted in the identification of common ("universal") biophores. It is suggested that agents which contain "universal" biophores are more likely to present a risk to human than carcinogens that do not possess such biophores. CASE also permitted the recognition of species-specific carcinogenic biophores. While the former are primarily electrophiles or potential electrophiles, the latter represent non-electrophilic structures.

Animals↗

PubMed1996

The patient advocate: a cooperative agent to support patient-centered needs and demands.

Knowledge-based monitoring and therapy planning systems were mainly built for the convenience of health care providers. They neglected the consumers of health care, namely, the patients. Our approach is concentrated on the individual patients' demands and needs. We are designing, building, and demonstrating a cooperative agent to support patients' management of their own health-related behavior on a day-to-day basis at home. Clinical treatment protocols are represented in an intention-based time-oriented representation language to overcome the drawbacks of vague or ill-structured problem definitions (e.g., missing functional dependencies). These representations are used to guide the patients, to provide necessary explanations, and to observe and critique whether the patients obey the instructions of the health-care providers. We will present a prototype which supports women with gestational diabetes mellitus.

Ambulatory Care↗

PubMed1999

The cognitive and behavioural effects of clobazam and standard monotherapy are comparable. Canadian Study Group for Childhood Epilepsy.

PURPOSE: To compare the cognitive and behavioural effects of clobazam versus standard monotherapy in the treatment of childhood epilepsy. METHODS: A randomized, double-blind, prospective design was carried out at three Canadian pediatric epilepsy centres. This study was part of a larger multi-centre study on the efficacy of clobazam. Children with newly diagnosed epilepsy were assigned randomly to receive clobazam or carbamazepine. Children who had failed previous treatment with carbamazepine were assigned randomly to clobazam or phenytoin. Children who had failed on any other antiepileptic drug were assigned randomly to receive clobazam or carbamazepine. In a subset of patients neuropsychological assessments were carried out at 6 weeks and 12 months after initiation of medication. Intelligence, memory, attention, psychomotor speed, and impulsivity were assessed. RESULTS: There were no differences between the clobazam and standard monotherapy groups on any of the neuropsychological measures obtained at 6 weeks or 12 months. There was no evidence for a deterioration in performance for those children who remained on clobazam for the entire 12-month study period. CONCLUSION: The cognitive and behavioural effects of clobazam appear to be similar to those of standard monotherapy.

Adolescent↗

PubMed2007

Long-term effects of treatments for childhood cancers.

PURPOSE OF REVIEW: The late effects of current treatments for childhood cancer increase the risk of morbidity and mortality and diminish the quality of life in long-term survivors. We selectively review the negative late cardiac, endocrine, and neurological effects of childhood cancer and its treatments and comment on current research and recommendations for the care of long-term survivors of childhood cancer. RECENT FINDINGS: Progressive cardiotoxicity has been established. Late cardiac effects can be mitigated with the concomitant use of dexrazoxane with anthracycline. When radiotherapy is used multiple organ systems must be monitored for known late effects dependent on the location. Proper diet, physical activity, and obesity are topics that must be addressed in survivors. Late neurocognitive effects impact intelligence quotient, behavior, and achievement. Systematic follow-up with appropriate clinical screening and testing is important in diagnosing and potentially preventing late effects of cancer therapy. SUMMARY: The new paradigm for defining successful cancer therapy is the balance between oncologic efficacy and toxicity/late effects. The complexity of late effects necessitates a multidisciplinary approach to long-term care of these patients. The high frequency, delayed onset, and potential severity of late effects demand increased and lifelong monitoring of these individuals.

Adolescent↗

PubMed1997

The effects of clozapine on cognitive functioning in treatment-resistant schizophrenic patients.

This study examined the cognitive functioning of 10 treatment-resistant schizophrenic patients after a minimum of a 1-year trial on clozapine. Results indicated significant improvements on prorated Wechsler Adult Intelligence Scale-Revised (WAIS-R) Full Scale, Verbal, and Performance IQs and on the WAIS-R Similarities and Digit Symbol subtests. A trend was also found for improvement on the Wisconsin Card Sorting Test. It was concluded that clozapine treatment is associated with global cognitive improvements in patients with treatment-resistant schizophrenia. Clozapine treatment may also improve performance on the Wisconsin Card Sorting Test in a subset of patients. Improvement did not appear to be related to the reduction of any cognitive effects of the typical neuroleptics upon their discontinuation.

Adult↗

PubMed2005

Equilibria, prudent compromises, and the "waiting" game.

While evaluation of many e-negotiation agents are carried out through empirical studies, this work supplements and complements existing literature by analyzing the problem of designing market-driven agents (MDAs) in terms of equilibrium points and stable strategies. MDAs are negotiation agents designed to make prudent compromises taking into account factors such as time preference, outside option, and rivalry. This work shows that 1) in a given market situation, an MDA negotiates optimally because it makes minimally sufficient concession, and 2) by modeling negotiation of MDAs as a game gamma of incomplete information, it is shown that the strategies adopted by MDAs are stable. In a bilateral negotiation, it is proven that the strategy pair of two MDAs forms a sequential equilibrium for gamma. In a multilateral negotiation, it is shown that the strategy profile of MDAs forms a market equilibrium for gamma.

Algorithms↗

PubMed1995

Evolving mobile robots in simulated and real environments.

The problem of the validity of simulation is particularly relevant for methodologies that use machine learning techniques to develop control systems for autonomous robots, as, for instance, the artificial life approach known as evolutionary robotics. In fact, although it has been demonstrated that training or evolving robots in real environments is possible, the number of trials needed to test the system discourages the use of physical robots during the training period. By evolving neural controllers for a Khepera robot in computer simulations and then transferring the agents obtained to the real environment we show that (a) an accurate model of a particular robot-environment dynamics can be built by sampling the real world through the sensors and the actuators of the robot; (b) the performance gap between the obtained behaviors in simulated and real environments may be significantly reduced by introducing a "conservative" form of noise; (c) if a decrease in performance is observed when the system is transferred to a real environment, successful and robust results can be obtained by continuing the evolutionary process in the real environment for a few generations.

Algorithms↗

PubMed1978

Huntington's dementia. Clinical and neuropsychological features.

The neuropsychiatric syndrome of Huntington's disease is outlined in this report with an emphasis on the cognitive deficits that lend themselves to future neurobehavioral research. Eighteen patients without disabling cognitive or psychiatric symptoms were evaluated for a period of 3 to 15 weeks, with assessment of their cognitive disorder, psychiatric, and neurological symptoms. Neuropsychological examination included repeated mental status examination, the Wechsler Adult Intelligence Scale (WAIS), and, for some, parietal lobe testing. In addition to suffering from a loss of finely detailed memories, patients demonstrated impaired organizing, sequencing, planning, and recalling of information on request. On the WAIS, mean verbal and performance scores were not significantly different. Neuropsychological findings suggested that the Huntington's disease pattern of cognitive impairment is not initially diffuse and homogeneous, but characterized by a relative sparing of several higher cortical functions. Many patients had increased irritability and labile affect. The similarity of Huntington's disease to frontal lobe syndromes is also discussed.

Adult↗