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PubMed1987

Longitudinal studies of mental development.

Two longitudinal research projects--Individual Statistics and Evaluation through Follow-up of Students (UGU)--are presented. Their overriding aim is evaluation of the role of school in individual developmental processes. Mental development is one interest of study. The sequential design and data collected are briefly presented. Four representative samples of students born 1948, 1953, 1967 and 1972 are under study. Two smaller exemplifying studies are presented. The first is a cross-sectional comparison between thirteen-year-olds tested in 1961, 1966 and 1980 with identical tests. The average level of results on spatial and reasoning tests have risen since 1961. There were no changes in differences between students from white-collar and blue-collar background. Differences between boys and girls had changed, though. There was no verbal test difference in 1961 but in 1980 girls performed better than boys. Concerning spatial and reasoning ability, boys were clearly better 1961 but that difference had practically disappeared 1980. In the other study MMR students are defined within the 1967-born cohort. Some data on their school-experiences are presented. They face more difficulties and have more remedial teaching than other low ability students, but most of them complete compulsory schooling and 2/3 have plans for secondary education. Plans for future analyses are presented.

Adolescent↗
PubMed1992

Topographical changes in the ongoing EEG related to the difficulty of mental tasks.

An experiment was carried out to investigate the hypothesis that task difficulty is reflected in changes in the topographical distribution of the ongoing EEG. Subjects had to perform three different tasks at two difficulty levels each; the Sternberg memory scanning task in an auditory and in a visual mode and a task whose performance required mainly visual scanning. Task difficulty was verified by the measurement of response times. Using a commercial Brain Electrical Activity Mapping device, EEG was recorded from 19 scalp electrodes while the subjects performed the tasks. Spectral matrices of the EEG were calculated to investigate spatial relationships in the EEG. Compared to the lower level, higher task difficulty resulted in EEG changes that led to the identification of two factors. One was the reduction of parietal and occipital alpha activity due to the amount of visual scanning and the other an increase of theta activity in the left frontal electrodes which may be associated with the amount of general mental processing.

Adult↗
PubMed2001

Changes in neurocognitive performance in a cohort of patients treated with HAART for 3 years.

OBJECTIVES: To describe changes in HIV-associated neurocognitive impairment in patients treated with highly active antiretroviral therapy (HAART) for at least 3 years. METHODS: Prospective, observational study of comprehensive neuropsychologic (NP) testing, neurologic examination, and laboratory measures before HAART and after 6, 15 and 45 months of HAART, on 28 consecutive patients seen in our department since April 1996. RESULTS: At baseline, 16 patients were neurocognitively impaired and 12 were not. Among the 16 impaired patients, 5 patients failed to meet the criteria for impairment after 6 months and 9 patients after both 15 and 45 months of HAART, respectively. Statistically significant improvements ( p < or =.01) were seen in two of six measures exploring the concentration and speed of mental processing, two of three measures exploring mental flexibility, in one of five measures exploring memory, and in two of two measures exploring fine motor functions. Unimpaired study subjects performed better than impaired ones in 10 of 17 measures at baseline, in eight of 17 after 6 months, in six of 17 after 15 months, and in seven of 17 after 45 months of HAART. CONCLUSIONS: During the course of HAART, patients experienced a positive and sustained improvement in their neurocognitive performance. However, the presence of 7 of 16 (43.7%) patients with neurocognitive impairment, and the persistence of statistically significant differences in the neurocognitive performance between impaired and unimpaired patients after more than 3 years of HAART, suggests that ongoing HIV-related neurologic damage can occur even during potent antiretroviral treatment.

AIDS Dementia Complex↗
PubMed1987

Individual differences in cognitive arithmetic.

Unities in the processes involved in solving arithmetic problems of varying operations have been suggested by studies that have used both factor-analytic and information-processing methods. We designed the present study to investigate the convergence of mental processes assessed by paper-and-pencil measures defining the Numerical Facility factor and component processes for cognitive arithmetic identified by using chronometric techniques. A sample of 100 undergraduate students responded to 320 arithmetic problems in a true-false reaction-time (RT) verification paradigm and were administered a battery of ability measures spanning Numerical Facility, Perceptual Speed, and Spatial Relations factors. The 320 cognitive arithmetic problems comprised 80 problems of each of four types: simple addition, complex addition, simple multiplication, and complex multiplication. The information-processing results indicated that regression models that included a structural variable consistent with memory network retrieval of arithmetic facts were the best predictors of RT to each of the four types of arithmetic problems. The results also verified the effects of other elementary processes that are involved in the mental solving of arithmetic problems, including encoding of single digits and carrying to the next column for complex problems. The relation between process components and ability measures was examined by means of structural equation modeling. The final structural model revealed a strong direct relation between a factor subsuming efficiency of retrieval of arithmetic facts and of executing the carry operation and the traditional Numerical Facility factor. Furthermore, a moderate direct relation between a factor subsuming speed of encoding digits and decision and response times and the traditional Perceptual Speed factor was also found. No relation between structural variables representing cognitive arithmetic component processes and ability measures spanning the Spatial Relations factor was found. Results of the structural modeling support the conclusion that information retrieval from a network of arithmetic facts and execution of the carry operation are elementary component processes involved uniquely in the mental solving of arithmetic problems. Furthermore, individual differences in the speed of executing these two elementary component processes appear to underlie individual differences on ability measures that traditionally span the Numerical Facility factor.(ABSTRACT TRUNCATED AT 400 WORDS)

Cognition↗
PubMedDate not supplied

[The psychophysiological mechanisms of awareness: the hypothesis of self-identification].

A hypothesis is advanced concerning the neurophysiological mechanisms underlying the mental process of self-identification. It is assumed that a specific excitation pattern produced by a stimulus in one of several cortical areas is transmitted back to the neurons of the same cortical areas via massive parallel feedback pathways. The coincident (identical) excitation patterns--those produced by the stimulus and relayed by backward projections add together in the same neuronal structures thus inducing their intensive firing. This cyclic process amplifies the specificity and intensifies a representation of the stimulus thus creating the most favorable conditions for its categorization by distributed long-term memory. The result of categorization, a symbol or an image, is physiologically expressed by a pattern of neuronal activity, which is also included in the cycle of self-identification. This process underlies representation of subjective meaning of sensory characteristics of the stimulus. Symbolic representation of the stimulus signifies the transition of the perception process from the physiological (objective) to the mental (subjective) level. Theoretical analysis and experimental data show that the cyclic processes of self-identification and symbolic interpretation of sensory signals are likely to produce the phenomenon of awareness.

Awareness↗
PubMedDate not supplied

The theory of the organism-environment system: II. Significance of nervous activity in the organism-environment system.

The relation between mental processes and brain activity is studied from the point of view of the theory of the organism-environment system. It is argued that the systemic point of view leads to a new kind of definition of the primary tasks of neurophysiology and to a new understanding of the traditional neurophysiological concepts. Neurophysiology is restored to its place as a part of biology: its task is the study of neurons as living units, not as computer chips. Neurons are living units which are organised as metabolic systems in connection with other neurons; they are not units which would carry out some psychological functions or maintain states which are typical only of the whole organism-environment system. Psychological processes, on the other hand, are processes always comprising the whole organism-environment system.

Animals↗
PubMed1991

Mental, neuropsychic, and brain patterns of defense. Neuropsychic defense continua from psychopathology to the particularly human parallel networks that are problematic for artificial intelligence.

The synthesis of psychodynamic and neuroscientific data may be advanced by the study of similarly configured specific patterns of defense along continua from the normal and neurotic mental mechanisms of defenses, through what might be termed neuropsychiatric defenses influenced by the neurological state, to the more clearly neurological cortical reactions. These similar patterns and continua are the particularly human way brain adds its flavor of organism to mind, and the way in which all the psychodynamic mechanisms are specifically imbedded in brain. A purely psychological psychodynamics lacking this medical perspective fails to model human mental processes and reflects problems with artificial intelligence models that do not model brain. The pathological reactions that we address in psychiatry and neuropsychiatry interfere with and thereby reveal parallel processing features in (1) analogical and metaphorical thinking; (2) reduplication, redundancy, and repetitiveness; (3) self, person, and environmental recognition, including transference processes; (4) approximation and statistical inference; (5) spatiality and motor control; (6) affectivity, perception of sensations and sexuality; (7) projective mechanisms; and (8) problem solving by optimization, vectorial summation, and the mutual interaction of interconnected agencies. The new concepts in artificial intelligence built upon brainlike structures called neural nets portend great economies, emergent natural features that are more like human processes, and hierarchical and cyclic organizational demands. Medical psychoanalysts who comprehend dynamic and brain mechanisms and can describe them in terms that refer to both domains and their interaction should find increasing theoretical and practical convergence of their work with the emerging study and modeling of these processes by new forms of computers.

Adult↗
PubMed1993

Effects on response time of factors selectively influencing processes in acyclic task networks with OR gates.

The mental processes involved in performing some tasks can be represented as directed arcs in an acyclic network. A path directed from the head of one arc to the tail of another indicates that the process represented by the first arc must be executed prior to the process represented by the second arc. If there is no directed path from one arc to another, the corresponding processes can be executed concurrently. Information about the arrangement of processes in an acyclic network can be found from the effects on response times of factors selectively influencing the processes. The methodology was developed earlier for critical path networks, in which a process begins execution when all its immediate predecessors have finished. This paper considers shortest path networks, in which a process begins execution as soon as any immediate predecessor is finished. Results analogous to those for critical path networks are reported. New results are presented enabling investigators to distinguish sequential and concurrent processes in both critical path and shortest path networks. This information is sufficient to construct an acyclic network representing the processes. Further, by examining the effects of selectively influencing processes, one can determine whether a task network is a critical path network or a shortest path network.

Animals↗
PubMed1998

Mental-attentional capacity: does cognitive style make a difference?

There is currently no consensus on whether the difference between field-dependent and field-independent subjects on tasks of cognitive abilities result from different mental processing strategies, from true group differences in cognitive ability, or from both. School-age children (N = 239) were tested for field dependence/independence using the Children's Embedded Figures Test and for mental-attentional capacity using the Figural Intersection Task. Multigroup scaling models were used to separate the contributions of style from ability in children's performance on Figural Intersection items. Results show that field-dependent children have greater odds of success than field-independent children in Figural Intersection items when the task's mental-attentional demand is above the child's mental attentional capacity, as assessed in the same task. The contrary is true when the task's mental-attentional demand is below or equal to the mental-attentional capacity of the child. Overall, field-dependent children obtain lower estimates of mental-attentional capacity than field-independent children in this task. We discuss the implications of these results for the measurement of mental-attentional capacity and the conceptualization of field dependence/independence.

Adolescent↗
PubMed1997

Near-infrared optical detection of sequential brain activation in the prefrontal cortex during mental tasks.

To examine the spatiotemporal differences of brain activation during mental tasks, changes in the oxygenation and hemodynamics in two regions of the prefrontal cortex were measured simultaneously by near-infrared spectroscopy (NIRS). Subjects were eight healthy adults who attempted to solve three different mathematical problems. The behavior of concentration changes in oxy-, deoxy-, and total hemoglobin in one brain region varied with the time course (more than 10 min). This suggested that regional brain activity varied during the performance of the mental task. In each single subject, the pattern of these changes varied with each problem, and this variation differed from subject to subject. When NIRS traces in two regions were compared, it was seen that activated regions moved alternatively: when in one region total hemoglobin that had first increased returned to the resting level, in the other it started to increase. These region-dependent temporal variations of brain activity might reflect mental processes. It is thus concluded that NIRS has the potential for imaging the sequence of brain activation.

Adult↗
PubMed1999

Adaptive phase estimation and its application in EEG analysis of word processing.

Oscillations are a general phenomenon of neuronal activity during information processing. Mostly, widespread networks are involved in brain functioning. In order to investigate network activity coherence analysis turned out to be a useful tool for examining the functional relationship between different cortical areas. This parameter allows the investigation of synchronisation phenomena with regard to defined frequencies or frequency bands. Coherence and cross phase are closely connected spectral parameters. Coherence may be understood as a measure of phase stability. Whereas coherence describes the amount of information transfer, the corresponding phase, from which time delays can be computed, hints at the direction of information transfer. Mental processes can be very brief and coupling between different areas may be highly dynamic. For this reason a two-dimensional approach of adaptive filtering was developed to estimate coherence and phase continuously in time. Statistical and dynamic properties of instantaneous phase are discussed. In order to demonstrate the value of this method for studying higher cognitive processes the method was applied to EEG recorded during word processing. During visual presentation of abstract nouns an information transfer from visual areas to frontal association areas in the Alpha1 frequency band could be verified within the first 400 ms. The Alpha1 band predominately seems to reflect sensory processing and attentional processes. In addition to conventional coherence analyses during word processing phase estimations may yield valuable new insights into the physiological mechanisms during word processing.

Adult↗
PubMed2003

A paradigm for exploring what the mind does while deciding what it should do.

One widespread belief about automatic mental processes is that, among other characteristics, they are involuntary. No initial conscious intent is necessary because such processing is stimulus initiated. This claim was studied in the context of a novel task-choice procedure in which subjects were informed as to which of two tasks they should perform on a letter string either well in advance of a target, or when the target appeared. The hypothesis that initial processing of the target occurs without intent predicts that the effect of contrast reduction will be absent when the task cue appears synchronously with the target. This is because initial processing of the target should be completed during the time taken to decode the task cue. The results are inconsistent with this account. Instead, they support an account in which functional target processing is delayed until the subject knows what the task is. Some directions for future investigations are noted.

Attention↗
PubMed2005

Letter processing interferes with inhibition of return: evidence for cortical involvement.

Inhibition of return (IOR) refers to the finding that, when the time lag between a cue and a target is prolonged, the reaction to the target, when it eventually appears, is actually slower than with no cue. This phenomenon is thought to make visual search more efficient, and it is subserved by the left inferior parietal cortex and the supramarginal gyrus bilaterally. Interestingly, the very same brain structures are also involved in letter processing. Accordingly, we asked whether the two mental processes interfere with each other when simultaneously probed. The first experiment used a typical IOR procedure, but the cue/target placeholders were either simple geometric shapes or English letters. The results show that, although IOR is approximately the same across visual fields when shape placeholders are used, it is significantly lessened in the right visual field when letters are used as cue and target placeholders. To examine if this finding was due to potential spatial frequency differences between the placeholders, a second experiment using shapes and Japanese letters was conducted, and no differences in IOR were found. The supramarginal gyrus appears to be the most likely locus for the letter-IOR interference effect because it is active bilaterally in IOR, but only in the left hemisphere during letter processing. These findings provide support for the notion that IOR is not simply due to subcortical processes but also involves processing from cortical structures.

Analysis of Variance↗
PubMedDate not supplied

Learning style as a predictor of drug dosage calculation ability.

This study measured the learning style in mathematics of nursing students to determine if there was a correlation with their ability to calculate drug dosages. The results seem to indicate that instructors can improve the ability of their students to calculate drug dosages by integrating instructional methods that 1) reinforce the student's preferred learning style; and 2) require the student to use both sequential, step-by-step, paper and pencil processing and global, all-at-once mental processing.

Adult↗
PubMed1982

Discrimination of sleep onset stages: behavioral responses and verbal reports.

In a descriptive experiment on discrimination five human subjects were studied during the transitional period of sleep onset. Subjects were aroused by an abrupt auditory stimulus, attempted to discriminate the pre-arousal stage by a behavioral response, and answered a series of standardized questions. These questions focused on specific characteristics of private experience associated with sleep onset. Of 180 awakenings, subjects correctly identified 109 sleep-onset stages. Subjects' answers were analyzed to determine what criteria were used to make the discrimination among sleep-onset stages and to examine their self-awareness of changes in private experience. It was established that there are stage-related changes in mental processes and content and that these may aid subjects in making such discriminations. Implications of the methodological approach used in this study are discussed.

Adult↗
PubMed1984

[Effect of various factors on the rate of mental activity during training (the problem of aging)].

The author analyzes the effect of such factors as education, age and the health status on the rate of mental processes under training. Different educational levels are reflected in young and middle-aged individuals in clear-cut differences in terms of their capacity for work which is not so for the older age group. In conditions of training the overwhelming portion of the trainees show an identical level of progress, yet the proportion of individuals with psychophysical retardation tends to increase with age. In principle, the rate of learning may be trained in all age groups, yet in older individuals, the learning processes are less expressed and consistent. Patients with cerebral atrophy exhibit little progress in learning and irregularly changing parameters of the capacity for work.

Adult↗
PubMed1990

Knowledge and strategies for processing lexical metaphor after right or left hemisphere brain damage.

This study was designed to assess how unilateral right hemisphere brain damage (RHD) affects the knowledge and processing of metaphoric aspects of word meaning. Ambiguous adjectives that could convey either a metaphoric or a literal meaning were used as target words in auditory lexical decision tasks. Targets were preceded by primes that were valid (related to the target's metaphoric or literal meaning), neutral, or unrelated. Prime-target pairs were presented in two attention conditions, designed to favor either relatively automatic or relatively effortful mental processing, and reaction time data were gathered. RHD stroke patients performed similarly to left-brain-damaged and normal control subjects in the automatic condition, and when provided with specific processing strategies, indicating that they retained some knowledge of metaphoric word meanings. When left to glean strategies for themselves, however, both brain-damaged groups had difficulty. These results and others from the RHD literature are discussed in terms of attentional resource capacity and attentional allocation models.

Aged↗
PubMed2006

Gray and white matter brain atrophy and neuropsychological impairment in multiple sclerosis.

BACKGROUND: The relationship of gray and white matter atrophy in multiple sclerosis (MS) to neuropsychological and neuropsychiatric impairment has not been examined. METHODS: In 40 patients with MS and 15 age-/sex-matched normal controls, the authors used SPM99 to obtain whole brain normalized volumes of gray and white matter, as well as measured conventional lesion burden (total T1 hypointense and FLAIR hyperintense lesion volume). The whole brain segmentation was corrected for misclassification related to MS brain lesions. To compare the effects of gray matter, white matter, and lesion volumes with respect to brain-behavior relationships, the MS group (disease duration = 11.2 +/- 8.8 years; EDSS score = 3.3 +/- 1.9) underwent neuropsychological assessment, and was compared to a separate, larger group of age-/sex-matched normal controls (n = 83). RESULTS: The MS group had smaller gray (p = 0.009) and white matter volume (p = 0.018), impaired cognitive performance (verbal memory, visual memory, processing speed, and working memory) (all p < 0.0001), and greater neuropsychiatric symptoms (depression, p < 0.0001; dysphoria, p < 0.0001; irritability, p < 0.0001; anxiety, p < 0.0001; euphoria, p = 0.006; agitation, p = 0.02; apathy, p = 0.02; and disinhibition, p = 0.11) vs controls. Hierarchical stepwise regression analysis revealed that whole gray and white matter volumes accounted for greater variance than lesion burden in explaining cognitive performance and neuropsychiatric symptoms. White matter volume was the best predictor of mental processing speed and working memory, whereas gray matter volume predicted verbal memory, euphoria, and disinhibition. CONCLUSION: Both gray and white brain matter atrophy contribute to neuropsychological deficits in multiple sclerosis.

Atrophy↗