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  • 1
    Electronic Resource
    Electronic Resource
    Functional properties of neurons in the temporo-parietal association cortex of awake monkey (1980)
    Springer
    Experimental brain research 39 (1980), S. 203-215 
    Details
    ISSN: 1432-1106
    Keywords: Parietal lobe ; Temporal lobe ; Association cortex ; Audition ; Microelectrode recording
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The temporo-parietal association cortex around the caudal end of the Sylvian fissure was studied with the single cell recording technique in three awake behaving Macaca speciosa-monkeys. Of the 197 cells isolated, 5% were active only during the monkey's own movements, mostly during head rotation, and 95% were responsive to sensory stimulation: 54% to auditory stimuli, 24% to somatosensory stimuli, 13% to both of these and 4% to visual stimuli. Some cells, classified as responsive to somatosensory stimuli, were activated only by passive rotation of the head on the cervical axis; it is possible that they were driven by vestibular stimuli. Half of the cells were activated by stimuli on both sides of the monkey, and almost all the rest, only by stimuli on the side contralateral to the hemisphere recorded. Of the acoustically drivable cells, 95% responded to natural sounds, such as, rubbing hands together, rustle of clothes, clicks or jingles (sounds with noise spectrum and rapid intensity transitions). Most of these neurons were also examined with pure tones of 0.2–20 kHz: various inhibitory or excitatory responses were elicited in half of them, usually over a wide range of frequencies. The responses of most acoustically drivable cells (62%) depended on the location of the sound source with reference to the monkey's head so that the maximal response was elicited by sounds with a certain angle of incidence, usually on the contralateral side. The present results suggest that the area studied participates in the analysis of the temporal pattern of a sound, the location of the sound source and in spatial control of head movements.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237551
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  • 2
    Electronic Resource
    Electronic Resource
    I. Functional properties of neurons in lateral part of associative area 7 in awake monkeys (1979)
    Springer
    Experimental brain research 34 (1979), S. 299-320 
    Details
    ISSN: 1432-1106
    Keywords: Parietal lobe ; Association cortex ; Microelectrode recording ; Monkey ; Behavior
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The lateral part of area 7, area 7b, of alert, behaving macaque monkeys was investigated using transdural microelectrode recording technique. Two hundred twenty-eight cells from five hemispheres of four monkeys were isolated and studied. The functional properties of 2% of the cells isolated remained unidentified. Functions of the identified cells were prominently related to the spatial control of arm movements. Of the cells 70% responded to somatosensory (40%) or visual (16%) or both somatosensory and visual (14%) stimulation. The receptive fields of these passively drivable cells were large, covering, e.g., the arm or leg or chest or even the skin of the whole body. Most of the visually drivable cells responded to stimuli in both halves of the visual field. Of the cells responding to sensory stimulation 80% were activated by stimuli moving in a certain direction. Of the directionally selective cells 25% received information through more than one sensory channel. The complex stimulus-response relationships of these “convergence” cells revealed the existence of an integrative system which analyzes the direction of a stimulus moving in one sensory system using an other sensory system as a reference. Of all the cells isolated 28% discharged only during active movements of the arms (25%) or eyes (3%). Firing of these neurons was related to contraction of a functionally uniform group of muscles and not individual muscles. Some previous investigations of the parietal association cortex, conducted mainly in area 7a, have shown that most cells are active only when the monkey himself moves his eyes or arms. In our study on area 7b most cells responded to passive stimulation. The discrepancy between the results indicates functional differentiation within area 7.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235675
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  • 3
    Electronic Resource
    Electronic Resource
    Saccade and blinking evoked by microstimulation of the posterior parietal association cortex of the monkey (1984)
    Springer
    Experimental brain research 55 (1984), S. 1-8 
    Details
    ISSN: 1432-1106
    Keywords: Monkey ; Parietal cortex ; Microstimulation ; Saccade ; Blinking
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Electrical stimulation with microelectrodes of the posterior parietal association cortex in alert behaving monkeys elicited saccadic eye movements and blinking. The sites in which saccades were elicited by electrical stimulation were concentrated in the anteromedial part of area 7a, especially in the posterior bank of the intraparietal sulcus, in a region which sends efferent projections to the frontal eye field and the superior colliculus, but they were also found in the posterolateral part of area 7a. Compared with the frontal eye fields and the superior colliculus, the threshold current for eliciting saccades was relatively high, on the average 86 μA. Moreover, the elicitation of saccade was inconsistent even with suprathreshold stimulation and suppressed during visual fixation. Latencies of the saccades were relatively long, on the average 50 ms; they were longer in the posterolateral part than in the anteromedial part. Direction and amplitude of evoked saccades depended on the site of stimulation, but was independent of eye position in most cases. However, “goal-directed” saccades which depended on initial eye position were elicited in three penetrations in the posterolateral part of area 7a. Blinking was elicited mainly in the lateral part of area 7a. The threshold of blinking was 70 μA and the latency was 50 ms on the average. In contrast to saccades, blinking was elicited constantly with each stimulus even during attentive fixation. We occasionally recorded single unit activity at the site of stimulation with the same electrodes. More than half of the units recorded at the site of blinking responded to approaching visual stimulus. These results suggest that area 7a participates indirectly in the control of saccades by way of its connection to the frontal eye fields or the superior colliculus, and it may also play an important role in blinking in response to a visual threat.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00240493
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  • 4
    Electronic Resource
    Electronic Resource
    Modification of parietal association cortex and functional blindness after binocular deprivation in young monkeys (1981)
    Springer
    Experimental brain research 42 (1981), S. 1-8 
    Details
    ISSN: 1432-1106
    Keywords: Monkey ; Visual deprivation ; Blindness ; Brodmann's area 7 ; Microelectrode recording ; Plasticity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Clinical experience from humans deprived of vision at an early age indicates that recovery of vision is often rudimentary after late correction of the abnormalities in the eyes. Binocular deprivation in cats does not change the function of the visual cortex equally much as does monocular deprivation. Therefore, the behavioural blindness observed after binocular deprivation is probably caused by changes central to area 17. We studied four monkeys deprived of vision by binocular lid closure from shortly after birth until the ages of 7 to 11 months and three control animals of the same age. After opening, the eyes of the deprived animals were normal, optokinetic nystagmus could be elicited, and microelectrode recordings of multiple unit activity in areas 17 and 19 indicated brisk responses to visual stimulation. Behaviourally, all deprived animals were blind, however. They bumped into obstacles, fell from tables and used their somatic sense for exploration. Only minute recovery of visual orientation was observed during several months after the opening of the eyes. Approximately 400 multiple unit recording penetrations were made in Brodmann's area 7 in the deprived monkeys and a similar number in the control monkeys using the transdural recording technique in conscious, behaving animals. The results indicated a profound decrease in the representation of vision in this area: the representation of visual mechanisms was reduced by 92% and the combined visual and somatic representation was reduced by 97% in the deprived monkeys. On the other hand, the representation of active somatic movement had increased by 117% and that of passive somaesthesia by 53%. Also the proportion of cell groups that could not be activated (only spontaneously active) increased fourfold. These results show that early visual deprivation alters the associative systems of the brain by reducing the efficiency of transmission along pathways that mediate visual influences. Inputs from different sensory systems may compete for influence on the association cortex, disuse in one leading to its functional deterioration. Such changes may explain the lasting behavioural alterations that take place in man and monkeys after prolonged visual deprivation at an early age.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00235723
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  • 5
    Electronic Resource
    Electronic Resource
    BLINDNESS AND MODIFICATION OF ASSOCIATION CORTEX BY EARLY BINOCULAR DEPRIVATION IN MONKEYS (1979)
    Oxford, UK : Blackwell Publishing Ltd
    Child 5 (1979), S. 0 
    Details
    ISSN: 1365-2214
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Summary Cells in the parietal association area of stumptail monkeys did not respond to visual stimuli after binocular early deprivation. Although the monkeys responded to stimuli in the visual cortex, behaviourally they were blind. The importance of encouraging babies and infants to use all residual vision is stressed, so that the representation of visual input in the brain does not become permanently overtaken by other modalities
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2214.1979.tb00142.x
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  • 6
    Electronic Resource
    Electronic Resource
    An Arbitrary Lagrangian-Eulerian finite element method (1998)
    Springer
    Computational mechanics 21 (1998), S. 81-90 
    Details
    ISSN: 1432-0924
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract This paper describes an Arbitrary Lagrangian- Eulerian (ALE) finite element method for the simulation of fluid domains with moving structures. The fluid is viscous, incompressible and unsteady and the fluid motion is solved by a fractional step discretization of the Navier-Stokes equations. The emphasis is on convection dominated flows, and a three-step method is used for the convection term. The moving structure causes the mesh of the fluid domain to move, and a new algorithm is proposed to solve the important and crucial problem of the calculation of the mesh velocities. Numerical calculations of the added mass and added damping of a vibrating two-dimensional circular cylinder in the frequency Reynolds number range Re w =20−2000 are performed to evaluate the proposed ALE finite element method. The numerically calculated added mass and added damping are compared to both analytical and numerical results. To further demonstrate the generality of the method, a numerical simulation of flow past an oscillating schematic sports car is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004660050285
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  • 7
    Electronic Resource
    Electronic Resource
    Effect of air ionization on heart rate and perceived exertion during a bicycle exercise test (1979)
    Springer
    European journal of applied physiology 41 (1979), S. 285-291 
    Details
    ISSN: 1439-6327
    Keywords: Air ionization ; Physical exercise ; Perceived exertion ; Heart rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The influence of ionization of air on heart rate (HR) and ratings of perceived exertion (RPE) during bicycle exercise was studied in nine healthy medical students selected according to a randomized schedule from the class of 90 students. The exercise tests were performed both under negative and positive ionization. The study was made with a double-blind, cross-over design. The body surface exposed to ionic current was made large by reducing the clothing of the subject. A significant overall tendency to lower HR and RPE values under negative ionization was observed (p〈0.01, sign test). The RPE values were significantly lower (p〈0.01, paired t-test and the Wilcoxon test) under negative than under positive ionization at the maximal work load level but not at other relative load levels. However, when separately tested at each relative load level HR values did not differ significantly in negative and positive ionization. The results of this pilot study indicate that ionic composition of the air can modify the RPE and possibly also HR during exercise; negative air ionization seems to be beneficial compared with positive ionization. The mechanisms involved are obscure, but we suggest that negative ionization of air may increase oxidative metabolism through generation of a superoxide radical (O2 −) that is reduced to H2O2 by superoxide dismutases.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00429745
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