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PubMed1986

Effects of video display character size, clarity, and color on P-300 latency.

The P-300 is a positive polarity electroencephalographic (EEG) signal occurring about 300 ms after a surprising, novel, or unique stimulus. The amplitude of the P-300 is dependent on the degree of attention and importance the subject has assigned to the stimulus and on its relative novelty. P-300 latency is dependent on the time it takes the subject to mentally process the stimulus and determine if the information it carries is novel. In Experiment I, the latencies of P-300's for 40 and 80 column size video display characters were compared. The effect of dioptric blur (mean add power +2.44 D) on latency was also determined. It was found that 40 column size characters could be interpreted more quickly than 80 column size characters and that blur increased the processing time equally for both character sizes. In Experiment II, P-300 latencies for green and amber display screens were compared. Display screen color did not significantly affect latency, neither did the addition of lens powers ranging from a mean of -1.15 D to a mean of +1.15 D over the subjects' habitual lenses. However, it was found that latencies significantly increased when a mean add of +2.29 D for the green display or a mean add of +2.57 D for the amber display were used. (Chromatic aberration accounted for the difference in lens power for the green vs. amber display.) These results demonstrate that character size and clarity are significant factors in determining the time required to mentally process a stimulus. They also demonstrate that there is no clear advantage to using an amber vs. a green screen when speed of mental processing (as measured by P-300 latency) is used as a criterion.

Adult↗
PubMed2004

Probabilistic pathway representation of cognitive information.

We present for mental processes the program of mathematical mapping which has been successfully realized for physical processes. We emphasize that our project is not about mathematical simulation of the brain's functioning as a complex physical system, i.e., mapping of physical and chemical processes in the brain on mathematical spaces. The project is about mapping of purely mental processes on mathematical spaces. We present various arguments--philosophic, mathematical, information, and neurophysiological--in favor of the p-adic model of mental space. p-adic spaces have structures of hierarchic trees and in our model such a tree hierarchy is considered as an image of neuronal hierarchy. Hierarchic neural pathways are considered as fundamental units of information processing. As neural pathways can go through the whole body, the mental space is produced by the whole neural system. Finally, we develop the probabilistic neural pathway model in that mental states are represented by probability distributions on mental space.

Cognition↗
PubMed1978

An alternative view of the neurobiology of dreaming.

The author critiques the recently proposed activation-synthesis hypothesis about the origin and formation of dreams. Many findings do not support the new hypothesis that specific pontine physiological processes, rather than mental processes, instigate dreams and produce their distortion. First, dreaming often occurs in the absence of the pontine processes. Second, forebrain activity (which can have mental correlates) is crucial to the instigation and maintenance of dreaming sleep. Finally, activity of the proposed pontine dream generator, which is claimed to cause dream distortion, is not reliably accompanied by dream distortion.

Diencephalon↗
PubMed2000

[Frequency and mean amplitude of spontaneous electrodermal fluctuations are not interchangeable indicators of psychological processes].

The study was concerned with the question of whether the frequency and the mean amplitude of spontaneous electrodermal fluctuations convey the same information about mental processes. In order to examine this, the content and the personal relevance of induced imaginations was varied experimentally. The experimental manipulations followed a 2 x 2 factorial design for independent groups (content of cells: 24 subjects each). Changes in electrodermal activity were measured as differences between the imagination and a resting phase. Results revealed that the two variables are not exchangeable indicators of mental processes. Although the two variables correlated significantly, they responded differently to the experimental manipulations. The imagination of death-related contents increased the frequency of spontaneous electrodermal fluctuations more than the imagination of neutral contents. High personal relevance enhanced the mean amplitude of these spontaneous fluctuations regardless of the imagined content. Therefore it was concluded that the two variables have something in common but, on the whole, do not depend on identical factors. Frequency of spontaneous electrodermal fluctuations seems to be a reflection of covert orienting processes, whereas their mean amplitude seems to reflect the activity of an appraisal system incorporating goals and past experiences. However, both variables, seem to be, in the same way, dependent on a kind of basal activation or vigilance.

Arousal↗
PubMed2005

Cerebral processes in mental transformations of body parts: recognition prior to rotation.

There is growing evidence that the visual processing of human body stimuli is particular and distinct from that of other objects. This is due to implicit knowledge of anatomical and biomechanical constraints of the human body. The question arises whether body stimuli in which biomechanical constraints are violated are processed in the same way as realistic bodies. This study investigated the neural mechanisms of anatomically plausible and implausible body stimuli. Event-related potentials (ERP) were recorded in healthy participants during mental rotation of body parts. Subjects were shown pictures of body parts or whole bodies in which one element (finger, arm) could be anatomically accurate or inaccurate (e.g., left forearm attached to right upper arm). Furthermore, the body parts were rotated in 7 different orientations, from 0 degrees to 180 degrees in 30 degrees increments, resulting in some possible and some impossible positions of the body parts. Analysis of the 123-channel ERPs was carried out by determining the successive segments of stable map topographies and comparing them between conditions. A particular segment appeared in the case of anatomically impossible postures at 190-230 ms followed by a segment reflecting mental rotation at 310-380 ms. Anatomically implausible positions are thus detected at a very early stage, before mental rotation occurs. Source estimations derived from the topographic data indicated that left occipital, bilateral frontal and two medial areas were activated in the case of impossible postures, whereas left parietal regions were strongly activated during mental rotation. This result contrasts with mental rotation of objects, which is considered to be a right parietal process.

Adult↗
PubMed2005

[Work process in mental health and the psychosocial area].

We present a theoretical reflection about determinants and constitutive elements of the nursing work process in the psychiatric and psychosocial areas, in the context of the Brazilian Psychiatric Reform. The aim is to offer theoretical and conceptual guidance with a view to mental health workers' reflexive action, particularly in nursing. The purpose of this article is to preserve the memory of nursing practice in psychiatry and to go beyond, with a view to constructing the psychosocial area, supporting teaching in all fields of health knowledge.

Brazil↗
PubMed1990

Connectionism and the problem of systematicity: why Smolensky's solution doesn't work.

In two recent papers, Paul Smolensky responds to a challenge Jerry Fodor and Zenon Pylyshyn posed for connectionist theories of cognition: to explain the existence of systematic relations among cognitive capacities without assuming that mental processes are causally sensitive to the constituent structure of mental representations. Smolensky thinks connectionists can explain systematicity if they avail themselves of "distributed" mental representation. In facts, Smolensky offers two accounts of distributed mental representation, corresponding to his notions of "weak" and "strong" compositional structure. We argue that weak compositional structure is irrelevant to the systematicity problem and of dubious internal coherence. We then argue that strong compositional (tensor product) representations fail to explain systematicity because they fail to exhibit the sort of constituents that can provide domains for structure sensitive mental processes.

Cognition↗
PubMed2002

The priority of primary process categorizing: experimental evidence supporting a psychoanalytic developmental hypothesis.

Earlier work has provided experimental evidence for the existence of the primary and secondary process mental organization posited by Freud and has demonstrated that primary process effects are the more active unconsciously (Brakel et al. 2000). Primary and secondary processes were assessed by a categorization test in which qualitatively different principles could be used. In new experiments using the same stimuli, another significant implication of Freud's model was tested: that primary process mental organization has developmental priority. In these experiments, which studied 559 participants ranging in age from 3 to 80, it was found (1) that primary process mentation predominates in preschoolers; (2) that it is not until around age 7 that primary process organization is supplanted by secondary process organization; and (3) that after age 7 the predominance of secondary process organization remains remarkably stable throughout the life span.

Adolescent↗
PubMed2006

Better quality of life with neuropsychological improvement on HAART.

BACKGROUND: Successful highly active antiretroviral therapy (HAART) regimens have resulted in substantial improvements in the systemic health of HIV infected persons and increased survival times. Despite increased systemic health, the prevalence of minor HIV-associated cognitive impairment appears to be rising with increased longevity, and it remains to be seen what functional outcomes will result from these improvements. Cognitive impairment can dramatically impact functional ability and day-to-day productivity. We assessed the relationship of quality of life (QOL) and neuropsychological functioning with successful HAART treatment. METHODS: In a prospective longitudinal study, subjects were evaluated before instituting HAART (naïve) or before changing HAART regimens because current therapy failed to maintain suppression of plasma viral load (treatment failure). Subjects underwent detailed neuropsychological and neurological examinations, as well as psychological evaluation sensitive to possible confounds. Re-evaluation was performed six months after institution of the new HAART regimen and/or if plasma viral load indicated treatment failure. At each evaluation, subjects underwent ultrasensitive HIV RNA quantitative evaluation in both plasma and cerebrospinal fluid. RESULTS: HAART successes performed better than failures on measures exploring speed of mental processing (p < .02). HAART failure was significantly associated with increased self-reports of physical health complaints (p < .01) and substance abuse (p < .01). An interesting trend emerged, in which HAART failures endorsed greater levels of psychological and cognitive complaints (p = .06). Analysis between neuropsychological measures and QOL scores revealed significant correlation between QOL Total and processing speed (p < .05), as well as flexibility (p < .05). CONCLUSION: Our study investigated the relationship between HIV-associated neurocognitive impairment and quality of life. HAART failures experienced slower psychomotor processing, and had increased self-reports of physical health complaints and substance abuse. Contrariwise, HAART successes experienced improved mental processing, demonstrating the impact of successful treatment on functioning. With increasing life expectancy for those who are HIV seropositive, it is important to measure cognitive functioning in relation to the actual QOL these individuals report. The study results have implications for the optimal management of HIV-infected persons. Specific support or intervention may be beneficial for those who have failed HAART in order to decrease substance abuse and increase overall physical health.

Adult↗
PubMed1999

Positive and sustained effects of highly active antiretroviral therapy on HIV-1-associated neurocognitive impairment.

OBJECTIVES: To determine whether highly active antiretroviral therapy (HAART) is effective in HIV-associated neurocognitive impairment. DESIGN: An open label, prospective, observational study. METHODS: Since April 1996, 116 patients with advanced HIV infection, reverse transcriptase inhibitor (nRTI) experienced but protease inhibitor (PI) naive, were screened for the presence of neurocognitive impairment. Ninety patients with confounding neurological illness, opportunistic infections or drug abuse were excluded. The remaining 26 patients underwent comprehensive neuropsychological testing, and laboratory measures before, after 6 and after 15 months of treatment with one PI plus two nRTI. RESULTS: The prevalence of neurocognitive impairment decreased from 80.8% (baseline) to 50.0% (P<0.05) (sixth month) and to 21.7% (P<0.001) (15th month). Among the functions explored, the impairment of concentration and speed of mental processing decreased from 65.4 to 21.7% (P<0.01) and of memory impairment from 50 to 8.7% (P<0.01). Comparing baseline with the sixth and 15th month raw scores, a statistically significant improvement was seen in measures exploring concentration and speed of mental processing (P<0.05), mental flexibility (P<0.05), memory (P<0.05), fine motor functions (P<0.05) and visuospatial and constructional abilities (P<0.01). After 6 months of HAART patients with a normal neuropsychological examination had lower mean plasma viraemia (2.95 versus 3.97 log copies/ml, P<0.05) and greater mean log plasma HIV RNA changes from baseline (-1.84 versus -0.83 log copies/ml, P<0.05) than neuropsychologically impaired subjects. CONCLUSION: HAART produces a positive and sustained effect on neurocognitive impairment in HIV-infected patients. A reduction of plasma viral load was associated with the regression of neuropsychological test abnormalities.

Adult↗
PubMed1998

A neurological dissociation between preserved visual and impaired spatial processing in mental imagery.

Studies on primates have shown that visual and spatial perceptual analysis depends on two separate neural pathways, associated with the processing of "what" and "where" an object is (visual characteristics and spatial coordinates, respectively). Similar dichotomies have been proposed by cognitive psychologists (e.g., the contrast between visual and spatial processing in working memory) and by neuropsychologists (e.g., the distinction between topographic agnosia and amnesia). In this paper we report the case of a patient with a severe spatial disorientation whose perceptual processing of visual and spatial information was normal, but in imagery tasks she had a dissociation between preserved visual and impaired spatial processing. While her ability to represent objects visually was intact, she failed in any task requiring mental rotation, recall of spatial position or execution of spatially based imagery operations. The case clearly demonstrates that visual and spatial imagery are functionally independent processes which must rely on different underlying neural systems. This pattern of impairment also explains the associated topographical amnesia as an inability to integrate spatial information in a mental map.

Aged↗
PubMed2005

Autonomic nervous system activity during actual and mentally simulated preparation for movement.

The aim of this study was to compare actual versus mentally simulated preparation for a complex motor skill. Two behavioral periods are observed during weightlifting: (i) an initial phase in which the subject standing behind the bar is thought to focus his attention on forthcoming execution and (ii) a second phase between hands/bar contact and execution during which the subject is thought to increase activation. Such mental processes accompanying behavioral sequences are correlated with autonomic nervous system activity, phasic responses corresponding to allocation of attentional resources, and tonic variations related to increasing general activation. To study mental processes during preparation for action, 12 subjects performed actual and imagined preparation phases of execution. Six autonomic variables were measured continuously. Skin potential (chi2 = 0.16), skin temperature amplitude (Z = -0.66) and duration (Z = -1.78), skin blood flow amplitude (Z = -0.56) and duration (Z = -1.51), respiratory frequency amplitude (Z = -0.14) and duration (Z = -0.13), and duration of heart rate response (Z = -1.25) were shown to be comparable (p > .05), whatever the modality of preparation. However, during mentally simulated preparation, skin resistance response was shorter than in actual preparation (Z = -2.12, p < .05), thus attesting to a weaker load, whereas lower decrease in heart rate was elicited (Z = -1.96, p < .05). This may be explained by this particular experimental condition because mental preparation would not lead to actual action. Such autonomic variables could be used as feedback to improve performance.

Adolescent↗
PubMed2000

Liveliness.

OBJECTIVE: The objective of this study is to explore the significance of the experience of liveliness in psychotherapeutic interactions and its relevance to the practice of psychotherapy. METHOD: Stern's notion of 'vitality affects' and Emde's concept of a 'primary affective core' are employed in developing a concept of liveliness, or an enlivening-deadening axis of experience. A critique of Freud's 'principles of mental functioning' is made in the light of this concept. Clinical examples are provided as illustrations of the relevance of considering the 'sense of liveliness', and its sustainability, in psychotherapy. RESULTS AND CONCLUSIONS: A sense of liveliness relates closely to activity within a system of interpersonal resonance with non-linear characteristics. The experience of, and responses to, vitality affects may be an important basis of a sense of liveliness. Sudden shifts towards experiences of deadness are a matter for concern in psychotherapy. This sphere of experience, although occurring largely outside verbal awareness, may constitute a distinct type of mental process. Three types of mental activity or process are postulated: (i) emergent, pre-representational activity characterised by the sense of liveliness; (ii) Play-related thought or activity typically experienced as enlivening; and (iii) work-related or adaptational thought or activity.

Affect↗
PubMed2005

Aripiprazole, a novel antipsychotic agent: dopamine D2 receptor partial agonist.

It is obvious that DA is an important neurotransmitter in vivo. It is involved in a variety of physiological processes such as mental processes, motor function and hormone regulation. In this context, it is quite understandable that a DA D2 receptor antagonist that inhibits the DA D2 receptor regardless of the state of activity of dopaminergic neurotransmission and inhibit the physiological function of DA can have a variety of adverse effects. In contrast to DA D2 antagonists, aripiprazole acts as an antagonist at the DA D2 receptor in the state of excessive dopaminergic neurotransmission, while it acts as an agonist at the DA D2 receptor in the state of low dopaminergic neurotransmission, and thus attempts to bring the state of dopaminergic neurotransmission to normal. This activity of aripiprazole to regulate dopaminergic neurotransmission is physiologically reasonable, and can be regarded as a stabilizing effect, for which aripiprazole is called a dopamine system stabilizer.

Animals↗
PubMed1989

What do we mean by 'phantasy'?

The term 'phantasy' may be used by psychoanalysts to mean an imaginative fulfillment of frustrated wishes, conscious or unconscious. This approximately condenses what is generally seen as Freud's main use of the term. It may also be used, inter alia, to denote the primary content of unconscious mental processes, as the mental representative and corollary of instinctual urges, and as based on or identical with Freud's postulated 'hallucinatory wish-fulfillment' and his 'primary introjection', which reflects Melanie Klein's extension of Freud's concept. The differences between the two notions were first clearly aired during the Controversial Discussions conducted by the British Psycho-Analytical Society during the war. This paper gives a necessarily abbreviated and incomplete account of some of the points made then, to give some detail of how widely the two notions differed. It then notes how the term 'phantasy' is still used for such widely differing notions: to indicate the problems that must exist, of what we mean and of how to communicate our ideas, if different people mean such different things by one technical term that is in constant use.

Anxiety↗
PubMed1995

The applicability of the Kaufman Assessment Battery for Children (K-ABC) with older adults (50+ years) with moderate, severe and profound intellectual impairment.

To define the intellectual characteristics of a population of older people (50+ years) with severe intellectual impairment who were the focus of a wider demographic study, participants were assessed on the Kaufman Assessment Battery for Children (K-ABC). Test material was modified to make it age-appropriate and culturally suitable. Of the 122 people in the population [chronological age (CA) = 63.5 years; range 50-90 years], 61 were successfully tested on the K-ABC (CA = 60.9 years; range 51-81 years). Factor analysis closely replicated the factorial structure demonstrated for younger children. Separate Sequential and Simultaneous Mental Processing factors were identified, with subtests from the Achievement Scale loading on these factors and not constituting a separate factor. Application of hierarchical cluster analysis confirmed the factor structures. Inferences in relation to cognitive development from a Piagetian perspective are drawn, and the utility of information on mental processing for educational intervention with older persons with severe intellectual impairment is noted.

Achievement↗