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PubMed1999

Response time distributions: some simple effects of factors selectively influencing mental processes.

When hypotheses about mental processing are tested with response times, inferences are often based on means, and occasionally on variance or skewness. Calculations on entire distributions of response times are more informative and can be conveniently carried out. Recently investigators have been updating procedures primarily based on means (such as additive factors tests) to procedures employing entire distribution functions. In one such advance, Nozawa and Townsend upgraded earlier tests of whether factors selectively influence serial or parallel processes, and whether parallel processes enter AND gates or OR gates. We discuss generalizations of the tests to complex arrangements of processes in networks. Results for a particularly difficult network, the Wheatstone bridge, are presented here. We use simulations to demonstrate the feasibility of the tests, and the possibility of mimicking.

Humans↗

PubMed2000

Topology and mental processes.

The study reported here considers the effect of rotation on the decision time taken to compare nonrigid objects, presented as like and unlike pairs of knots and unknots. The results for 48 subjects, 21 to 45 years old, support the notion that images which have a characteristic 'foundation part' are more easily stored and accessed in the brain. Also, there is evidence that the comparison of deformable objects is processed by mental strategies other than self-evident mental rotation.

Adult↗

PubMed2002

The impact of mental processing and pacing on spine loading: 2002 Volvo Award in biomechanics.

STUDY DESIGN: The impact of various levels of mental processing and pacing (during lifting) on spine loading was monitored under laboratory conditions. OBJECTIVES: To explore how mental demands and pacing influence the biomechanical response and subsequent spine loading and, to determine whether individual characteristics have a modifying role in the responses. SUMMARY OF BACKGROUND DATA: Modern work often requires rapid physical exertions along with demands of mental processing (both psychosocial stressors). While the effect of physical workplace factors on spine loading has been widely documented, few studies have investigated the impact that interaction of psychosocial factors and individual factors has on spine loads. METHODS: For this study, 60 subjects lifted boxes while completing two types of mental processing tasks: 1) series tasks with decisions occurring before the act of lifting, and 2) simultaneous tasks with decisions occurring concurrently with the lift. For both of these mental processing conditions, two intensities of mental load were evaluated: simple and complex. Task pacing was also adjusted under slow and fast conditions. Finally, individual characteristics (personality and gender) were evaluated as potential modifiers. An electromyographically assisted model evaluated the three-dimensional spine loads under the experimental conditions. RESULTS: Simultaneous mental processing had the largest impact on the spine loads, with the complex intensity resulting in increases of 160 N with lateral shear, 80 N with anteroposterior shear, and 700 N with compression. Increased task pace produced greater lateral shear (by 20 N), anteroposterior shear (by 60 N), and compression loads (by 410 N). Gender and personality also influenced loadings by as much as 17%. CONCLUSIONS: Mental processing stress acted as a catalyst for the biomechanical responses, leading to intensified spine loading. Mental stress appeared to occur as a function of time pressures on task performance and resulted in less controlled movements and increases in trunk muscle coactivation. These adjustments significantly increased spine loading. These results suggest a potential mechanism for the increase in low back pain risk resulting from psychosocial stress caused by modern work demands.

Adult↗

PubMed1997

Speed of mental processing in the middle of the night.

This study aimed to determine whether human mental processing actually slows down during the night hours, separately from the previously documented microsleeps, lapses in attention, and general slowing of motor responses. Eighteen healthy young adults were studied during 36 hours of constant wakeful bedrest. Every 2 hours, they performed a logical reasoning task. Items phrased in the negative voice took reliably longer to respond to than items phrased in the positive voice, indicating the need for more mental processing in those items. By subtracting "negative" from "positive" reaction times at each time of day, we were able to plot a circadian rhythm in the time taken for this extra mental processing to be done separately from microsleeps, psychomotor slowing, and inattention. The extra mental processing took longer at night and on the day following sleep loss than it did during the day before the sleep loss, suggesting that human mental processing slows down during the night under sleep deprivation.

Adult↗

PubMed1980

Critical-path scheduling of mental processes in a dual task.

Scheduling theory is used to extend the additive factors method of analyzing reaction times to tasks involving concurrent processing. Data indicate that mental processes in a double-stimulation experiment by Becker are executed in a critical-path network. A relationship predicted for the timing of the responses of the task is shown to hold.

Humans↗

PubMed1996

Queueing network modeling of elementary mental processes.

This article examines the use of reaction time (RT) to infer the possible configurations of mental systems and presents a class of queueing network models of elementary mental processes. The models consider the temporal issue of discrete versus continuous information transmission in conjunction with the architectural issue of serial versus network arrangement of mental processes. Five elementary but important types of queueing networks are described in detail with regard to their predictions for RT behavior, and they are used to re-examine existing models for psychological processes. As continuous-transmission networks in the general form, queueing network models include the existing discrete and continuous serial models and discrete network models as special cases, cover a broader range of temporal and architectural structures that mental processes might assume, and can be subjected to empirical tests.

Feedback↗

PubMed1999

Executive functions and speed of mental processing in elderly patients with frontal or nonfrontal ischemic stroke.

Impairments in executive functions have been related to aging and frontal lobe lesions. Aging also causes slowing of mental processing. We examined whether ischemic stroke in the frontal brain area results in dysexecutive syndrome, or whether the frontal stroke causes increased slowing of mental processing. Neurological, radiological and neuropsychological examinations were carried out 3 months post-stroke on 250 ischemic stroke patients (55-85 years) and on 39 healthy control subjects. Of the patients, 62 had frontal and 188 had nonfrontal lesions. The neuropsychological examination comprised several cognitive domains, including tests considered to measure executive functions. The frontal group was slower than the nonfrontal group in tasks measuring speed of mental processing which were time-limited (Trail Making A, Stroop dots and fluency). They were also inferior in the Digit Span backwards task. There were no differences between the groups in other cognitive domains, nor in some tests which are considered to be measures of executive functions (e.g. WCST). Impairments in executive functions were evident in both the frontal and the nonfrontal groups compared with the controls, but no dysexecutive syndrome specifically related to frontal lesions was found. Frontal stroke related mainly to the slowing of mental processing.

Age Factors↗

PubMedDate not supplied

[Interaction foci, informational synthesis and mental processes].

Brain organization of mental activity is based on the nervous integration, specialization of functions and combination of rigid and flexible connections. First of them are provided by structural changes in synapses, the second--by a coincidence of rhythmic characteristics and synchronization of the activity. These principles are realized in dynamic structures--interaction foci, revealed in the cortex during the process of mental activity by a method of mapping the intracortical interaction. Interaction foci are the centers of nervous connections. Each group has its appropriate frequency characteristics and is connected with the isorhythmic nervous elements at the periphery. Construction of the interaction focus provides the synthesis of the information coming from the sensory organs and the centers of motivations and that extracted from the memory. Informational synthesis is in the basis of the mental functions, having a rigid nucleus and a system of peripheral connections whose configuration can be changed, stipulating a unique character of experienced psychic feeling. Topography of interaction foci is different at different mental acts, realizing a principle of functional specialization. At perception the projection cortex is the center of integration, at thinking that are the cortical associative zones. Imaginable thinking is predominantly connected with the parieto-temporal, abstract--with the frontal cortical areas. Probably two basic functions of consciousness--integration of the "Self" including voluntary factor and communication-are also separated in space.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗

PubMed1993

White matter changes in healthy elderly persons correlate with attention and speed of mental processing.

OBJECTIVE: To evaluate the association between white matter changes (leukoaraiosis [LA]) seen on magnetic resonance imaging and cognitive functions. DESIGN: Survey of cohorts of neurologically healthy elderly subjects derived consecutively from a population-based random sample. SETTING: General community, the Helsinki (Finland) Aging Brain Study. SUBJECTS: Cohorts of neurologically healthy subjects aged 55, 60, 65, 70, 75, 80, and 85 years (n = 20, 18, 19, 18, 17, 17 and 11 subjects, respectively; total N = 120). MEASURES: Leukoaraiosis was rated in the periventricular areas (0 to 24) and the centrum semiovale (0 to 24); also, a total LA score was obtained (0 to 48). The neuropsychological test battery covered memory, verbal intellectual and constructional functions, language, speed and attention, and speed of mental processing, as well as simple psychomotor speed. RESULTS: Low age-related LA scores and deterioration of cognitive functions were obtained in the normal subjects. When controlling for age, we found that speed and attention, together with the speed of mental processing measured by the Trail Making A and the Stroop tests, correlated with the total LA score. However, there was wide variation between subjects. Comparing groups with and without LA proved the association of LA with Trail Making A time, Stroop test result (words/time and difference/time), and the compound score of speed and attention. Presence of periventricular LA was especially related to speed of mental processing. CONCLUSION: Leukoaraiosis could explain some of the intellectual impairment in the elderly, especially that of slowing of distinct motor and attentional functions, as well as slowing of mental processing. Mild LA in normal aged subjects could also signal brain at risk for further cognitive impairment.

Aged↗

PubMed1996

Cortical simplicity and mental processes.

The cerebral cortex can be looked upon as a non-linear system of coupled oscillators that tries to resist desynchronization and seeks to optimize the activity distribution of its elements. Cortical self-optimization can be disturbed by incoming nervous activity and the cortex will compensate for it by reorganizing the state of the soma, thus producing behavior. This simple concept would not explain mental processes that run within the cortex. It is proposed to relate mental processes to somatic behavior. Emotions, visual images, dreams, thoughts, memories, and anticipations could be perceived from the activity of respiratory, orofacial, and eye muscles. In their basic nature, mental processes may not differ from auditory, visual or visceral sensations. It is the peripheral soma that determines our mind and behavior; the task of the cortex is to line up somatic states. This philosophy could provide a new framework for data and results emanating from different fields of the neuroscience.

Afferent Pathways↗

PubMed1976

Meaning, memory structure, and mental processes.

Although people experience little difficulty in recognizing printed words and comprehending sentences, they cannot do it instantaneously. Experimental psychologists have recently measured the speed of these mental processes by applying a reaction-time method. The method provides new data concerning the organization and retrieval of familiar semantic information in human memory. It has been found that close relations between the meanings of words help people to recognize and pronounce the words faster, especially when the words are hard to see because of visual distortions. Close relations between word meanings also facilitate the comprehension of some sentences, as indicated by how long a person takes to decide whether the sentences are true or false. The facilitation is not universal, however. When the relation between the meanings of two words must be analyzed carefully, their proximity may actually inhibit mental processing. These results, along with additional findings, support the hypothesis that human memory includes a semantic network that represents various categories of objects at distinct locations linked to specify their relations with each other. The memory structure probably influences a number of different mental processes that use it. One possible access route to the network is through a set of detectors designed to accumulate sensory information and signal the presence of particular words. There also appear to be processes for searching and comparing pieces of knowledge after a person finds the memory locations of designated categories. Further research using the reaction-time method may provide a more detailed inventory of what facts are retrieved directly from memory and what are computed from other stored information (36).

Humans↗

PubMed1986

On the autonomy of mental processes: a case study of arithmetic.

We define a process as autonomous if it can begin without intention, and if it can run on to completion without intention. We develop empirical criteria for determining whether a process can begin without intention, for determining whether it begins in the same way without intention as it does with intention, and for determining whether it can run on to completion without intention once it begins. We apply these criteria to assess the autonomy of the processes underlying simple mental arithmetic--the addition and multiplication of single digits--and find evidence that simple arithmetic may be only partially autonomous: It can begin without intention, but does not begin in the same way without intention as with intention and does not run on to completion without intention. This conclusion suggests there may be a continuum of autonomy, ranging from completely autonomous to completely nonautonomous.

Association Learning↗

PubMed1982

Hemispheric functionality patterns between dextrals and sinistrals in tactile-visual tasks at lower or higher level of mental processes.

Two different patterns of unilateral tactile-visual recognition tasks with random shapes were administered to 64 subjects, 32 right-handed (16 males, 16 females) and 32 left-handed (16 males, 16 females). The main effects were found in the over-all performance: dextral subjects performed better than sinistral subjects; males performed better than females. On the task at a lower level of mental process dextral subjects performed better over-all than the sinistral subjects; however, neither group showed superiority of one hand over the other. On the task at a higher level of mental process performance of sinistral subjects improved to a level equivalent to that of the dextral subjects. Dextral subjects tended to perform better with their left hands, whereas the sinistral subjects scored equally with both hands. The findings are discussed in terms of quantitative and qualitative differences in patterns of hemispheric functionality between dextral and sinistral subjects, and the more specific cerebral activation for tasks at a higher level of mental process is hypothesized.

Adolescent↗

PubMed2001

Motor and visual imagery as two complementary but neurally dissociable mental processes.

Recent studies indicate that covert mental activities, such as simulating a motor action and imagining the shape of an object, involve shared neural representations with actual motor performance and with visual perception, respectively. Here we investigate the performance, by normal individual and subjects with a selective impairment in either motor or visual imagery, of an imagery task involving a mental rotation. The task involved imagining a hand in a particular orientation in space and making a subsequent laterality judgement. A simple change in the phrasing of the imagery instructions (first-person or third-person imagery) and in actual hand posture (holding the hands on the lap or in the back) had a strong impact on response time (RT) in normal subjects, and on response accuracy in brain-damaged subjects. The pattern of results indicates that the activation of covert motor and visual processes during mental imagery depends on both top-down and bottom-up factors, and highlights the distinct but complementary contribution of covert motor and visual processes during mental rotation.

Astrocytoma↗

PubMed2000

Beyond behaviorism: on the automaticity of higher mental processes.

The first 100 years of experimental psychology were dominated by 2 major schools of thought: behaviorism and cognitive science. Here the authors consider the common philosophical commitment to determinism by both schools, and how the radical behaviorists' thesis of the determined nature of higher mental processes is being pursued today in social cognition research on automaticity. In harmony with "dual process" models in contemporary cognitive science, which equate determined processes with those that are automatic and which require no intervening conscious choice or guidance, as opposed to "controlled" processes which do, the social cognition research on the automaticity of higher mental processes provides compelling evidence for the determinism of those processes. This research has revealed that social interaction, evaluation and judgment, and the operation of internal goal structures can all proceed without the intervention of conscious acts of will and guidance of the process.

Animals↗

PubMed1995

Inner connections within domain of dementia praecox: role of supervisory mental processes in schizophrenia.

Kraepelin's conclusion that there were underlying common features justifying the amalgamation of catatonia, hebephrenia and paranoia hallucinatoria to form a single illness is confirmed by factor analytic studies delineating the various dimensions of schizophrenic psychopathology. Neuropsychological studies reveal that the three cardinal dimensions reflect disorder of the supervisory mental processes responsible for initiation, selection and monitoring of self-generated mental activity. Brain-imaging studies indicate that the underlying neuropathology entails disordered functional connectivity within the neural networks in multimodal association cortex that are the substrate of the supervisory mental processes, consistent with Kraepelin's own speculation about the essential nature of the condition.

Humans↗

PubMedDate not supplied

[Mental processes in schizophrenia (based on data from neuropsychological studies)].

Features were studied of brain organization of mental processes in schizophrenic patients during the period of aggravation of the condition, using methods common in neuropsychological diagnosis. Faulty mental functions are analyzed in connection with clinical manifestations. Groups have been identified of patients having particular neuropsychological and clinical characteristics.

Adolescent↗

PubMedDate not supplied

[Cognitive mental processes and personality characteristics of socially unadjusted students].

Examination of 42 first-year students from the Pomor State University in Arkhangelsk has shown that 61.91% of them had obvious signs of social disadaptation and high reactive and personality anxiety and 38.09% had no social disadaptation with low and moderate anxiety. Examination was performed in the intersession period. Students with phenomena of social disadaptation displayed reduced functioning of basic cognitive mental processes: memory, thinking, attention. The individual properties predisposing to disadaptation were as follows: instability of central nervous system performance and the personality features were hypersensitivity, sensitiveness, emotional liability, some demonstrativeness in behavior, high anxiety, inclination to phobias. The detected changes in cognitive mental processes show it necessary to develop and to introduce comprehensive sociopsychological rehabilitative programmes for students of higher educational establishments for early assessment and adequate correction of social disadaptation phenomena.

Adjustment Disorders↗