Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Electron microscope study of the rat brain with experimental sodium azide intoxication (1969)
    Springer
    Acta neuropathologica 14 (1969), S. 185-193 
    Details
    ISSN: 1432-0533
    Keywords: Hypoxia ; Sodium Azide ; Electron Microscopy ; Ferritin ; Capillary Permeability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Experimentelle histotoxische Hypoxämie wurde in Ratten durch Natriumacid-Vergiftung erzeugt. Die mikroskopische Untersuchung der Hirne ergab keine Veränderung, aber bei der elektronenmikroskopischen Untersuchung fanden sich als Frühveränderungen in der Hirnrinde und im Subcortex eine Erweiterung der intercellulären Räume und eine Anschwellung der pericapillären Astrocytenfortsätze. Ferritinalbumin-Mischung, die als Indicator des Eiweißtransportes benutzt wurde, zeigte keine Vermehrung der Capillarpermeabilität. Es wird vermutet, daß Natriumacid den Wasserstoffwechsel beeinträchtigt, wobei es eine osmotische Ausgleichstörung im Gehirn erzeugt.
    Notes: Summary Histotoxic hypoxia was experimentally produced in the rat brain by sodium azide intoxication. In spite of the absence of light microscopic alterations, electron micrographs showed the early changes in the cerebral cortex and subcortex which consisted of widening of the intercellular space and swelling of the pericapillary astrocytic end-feet. However, ferritin-albumin mixture, used for the tracer of protein transport, did not show any increase in the capillary permeability. Sodium azide was considered to disturb the water metabolism, producing osmotic unbalance in the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685298
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Temporal profile of visual evoked responses to pattern-reversal stimulation analyzed with a whole-head magnetometer (1999)
    Springer
    Experimental brain research 125 (1999), S. 375-382 
    Details
    ISSN: 1432-1106
    Keywords: Key words Equivalent current dipole (ECD) ; Magnetoencephalography (MEG) ; Pattern-reversal stimulation ; Stimulus contrast ; Visual evoked magnetic field (VEF)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Magnetoencephalography (MEG) has become accepted as a useful method for non-invasively studying brain functions, including visual perception. The present study used MEG to elucidate information processing following pattern-reversal stimulation by analyzing the origins and properties of visual evoked magnetic fields (VEFs). The VEFs of ten healthy adults were recorded in a magnetically shielded room using a 122-channel whole-head magnetometer. The visual stimulation of checkerboard-pattern reversal at 1.7 Hz was presented to the subject’s right hemifield. Visual evoked potentials (VEPs) were recorded simultaneously, and 150 responses were each averaged for VEFs and VEPs. For the contrast profile study, pattern-reversal stimuli at five different contrast levels from 96% to 8% were used. In all subjects, the VEFs showed three components with latencies of approximately 95, 120, and 160 ms. The equivalent current dipoles for the first and the third components were located and were oriented close to each other in the left occipital lobe, but these dipoles were separated from that of the second component, which showed an opposite direction. Stimuli at a moderate contrast level markedly reduced the first component, but not the third. These findings indicate that the first and the third components of VEFs appear to originate from anatomically closely situated, almost identical, sources, but that their physiological properties differ.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050693
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Somatosensory evoked potentials following proprioceptive stimulation of finger in man (1996)
    Springer
    Experimental brain research 111 (1996), S. 233-245 
    Details
    ISSN: 1432-1106
    Keywords: Proprioception ; Kinesthesia ; Somatosensory evoked potentials ; Muscle afferent ; Generator sources ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Brisk passive flexion of the proximal interphalangeal joint of the middle finger, produced by using a newly devised instrument, elicited evoked potentials on the scalp. The present study carefully excluded the possible contribution of sensory modalities other than proprioception. The initial part of cortical response was a positive deflexion at the contralateral central area (P1 at 34.6 ms after the stimulus). This was followed by a midfrontal negative wave (N1 at 44.8 ms) and a clear positivity at the contralateral centroparietal area (P2 at 48.0 ms). The evoked responses persisted in spite of the abolition of cutaneous and joint afferents of the finger caused by ischemic anesthesia, but they were lost by ischemic anesthesia of the forearm. Thus, the cortical evoked responses obtained in this study most probably reflect muscle afferent inputs. The scalp distribution of P1 suggested that its cortical generator source was different from that of the N20-P20 components of evoked potentials to electrical median nerve stimulation. Brodmann areas 2 and 3a of human brain, which are known to receive deep receptor inputs, are the most plausible generator sites for the early components of the proprioception-related evoked responses. The amplitude of P2 was related to the velocity but not to the magnitude of movement. In conclusion, the present study established a method for recording the evoked responses to the brisk passive movement of the finger joint, which mainly reflect the dynamic aspects of proprioception mediated through muscle afferent.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00227300
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Age-related changes in cerebral blood flow activation during a Card Sorting Test (1997)
    Springer
    Experimental brain research 114 (1997), S. 571-577 
    Details
    ISSN: 1432-1106
    Keywords: Key words Card Sorting Test ; Prefrontal ; Aging ; Perseveration ; Positron emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  To determine the age-related changes in the neural processing involved in the Modified Card Sorting Test (MCST), we measured cerebral blood flow (CBF) during performance of the MCST and of the number-matching task in young and elderly subjects using positron emission tomography. Compared with that during the number-matching task, CBF during the MCST was increased in the left dorsolateral prefrontal cortex (DLPFC), left inferior parietal lobule, and left striate and prestriate cortices in both age groups. However, CBF activation in these areas was significantly lower in the elderly subjects than the young subjects. Furthermore, CBF activation was reduced in the left DLPFC, right parahippocampal gyrus, and prestriate cortex in proportion to the increase in the number of perseverative errors with aging. These results suggest that the impaired MCST performance in elderly subjects may be due, in part, to dysfunction of the network involving certain cortical areas such as the prefrontal and parahippocampal cortices, although the essential neural circuits for MCST performance were still preserved even in the elderly subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/PL00005665
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Comparative study of event-related potentials and positron emission tomography activation during a paired-associate memory paradigm (1998)
    Springer
    Experimental brain research 119 (1998), S. 103-115 
    Details
    ISSN: 1432-1106
    Keywords: Key words Event-related potentials ; PET ; Paired association task ; Working memory ; Episodic memory ; Human
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Event-related potentials (ERP) and regional cerebral blood flow (rCBF) activation using 15O-labeled water associated with retrieval and retention of episodic memory were studied during a visual paired-association task with delayed response in eight healthy subjects. In both studies, the subjects memorized four pairs of figures during the learning period. They were presented with each cue (S1) and asked to judge whether the following figure (S2) formed one of the memorized pairs. In an attempt to identify brain activity related to memory function, a choice reaction task with delay was used as a behavioral control. The ERP study showed a posterior positive component in the difference waveform, which was obtained by subtracting responses in the choice reaction task from those in the paired association task, between 300 and 850 ms after S1 presentation. It was maximal at the parietal midline electrode and distributed predominantly over the left posterior quadrant of the scalp. The rCBF activation study showed a greater increase in rCBF in the right dorsolateral prefrontal cortex (Brodmann’s area 46), left inferior frontal cortex (Brodmann’s area 44/45), left thalamus, and bilateral cerebellar hemisphere during the paired association task as compared to the choice reaction task, which suggests a possible involvement of cerebello-thalamo-cortical circuit in the memory processing. Additionally, it is suggested that the scalp distribution of the ERP component may not necessarily represent regional cortical activation below the electrodes where such a component is observed and could indirectly represent activation in remote areas such as subcortical regions. It seems that ERP and rCBF activation may provide information about different aspects of higher brain function.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002210050324
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Presurgical identification of epileptic foci with iodine-123 iomazenil SPET: Comparison with brain perfusion SPET and FDG PET (1997)
    Springer
    European journal of nuclear medicine 24 (1997), S. 27-34 
    Details
    ISSN: 1619-7089
    Keywords: Iodine-123 iomazenil ; Benzodiazepine receptor ; Epilepsy ; Single-photon emission tomography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Iodine-123 iomazenil (IMZ) has excellent characteristics for the quantification of central benzodiazepine receptor (BZR) binding with single-photon emission tomography (SPET). In order to evaluate the clinical value of IMZ SPET for presurgical identification of epileptic foci in patients with medically intractable seizures, we measured the binding potential (BP) of BZR using two IMZ SPET scans and compared the results with brain perfusion SPET and fluorine-18 fluorodeoxyglucose (FDG) positron emission tomography (PET). A total of ten patients with intractable partial epilepsy were examined by electroencephalography, magnetic resonance imaging, FDG PET, brain perfusion SPET and IMZ SPET. After neuroimaging examinations, five patients underwent selective surgery, and all of them have since been free of seizures. Two SPET scans were performed at 15 min (early) and 3 h (late) after intravenous injection of123I-IMZ (167 MBq). Parametric images of the ligand transport (K 1) and binding potential (BP) were calculated by the table look-up method, which is based on a three-compartment two-parameter model, using the standard arterial input function obtained by averaging of six normal volunteers' input functions. BP images delineated the epileptic foci more precisely than either FDG PET or ictal perfusion SPET. FDG PET showed widespread reduction, including the area surrounding the focus, and ictal increase in the cerebral blood flow was seen in possibly activated areas spread from the focus. In four epilepsy cases which originated from the mesial temporal lobe without lateral temporal abnormality, there was no significant decrease in the BP images in the lateral temporal structures, which showed decreased uptake of FDG. It is concluded that parametric images of BP with IMZ are valuable for precise presurgical localization of epileptic foci.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01728305
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Clinical studies of the movement-related cortical potential (MP) and the relationship between the dentatorubrothalamic pathway and readiness potential (RP) (1978)
    Springer
    Journal of neurology 219 (1978), S. 15-25 
    Details
    ISSN: 1432-1459
    Keywords: Readiness potential ; Parkinson's disease ; Cerebellar ataxia ; Ramsay Hunt syndrome ; Benedikt's syndrome ; Vim thalamotomy ; Dentatorubrothalamic pathway
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Kortikale Potentiale vor der willkürlichen Fingerbewegung wurden bei 20 Patienten mit Parkinsonscher Krankheit und bei 20 mit cerebellärer Ataxie studiert, um den Effekt der Stammganglien- und Kleinhirnläsion auf den Bereitschaftszustand der Großhirnrinde für Willkürbewegungen zu untersuchen. Das Bereitschaftspotential war abnorm bei 90% der Parkinsonpatienten und bei 55% der Patienten mit Ataxie. Die häufigste Abnormität war eine Depression und ein früherer Anstieg des Bereitschaftspotentials bei beiden Patientengruppen. Der bemerkenswerteste Befund war ein vollständiges Fehlen des Bereitschaftspotentials bei Patienten mit wahrscheinlicher Dyssynergia cerebellaris myoclonica (Ramsay Hunt Syndrom), während ein normales Bereitschaftspotential bei Patienten mit cerebellärer kortikaler Degeneration gefunden wurde. Das Bereitschaftspotential fehlte oder war auffallend niedrig bei Patienten mit einseitiger vaskulärer Mittelhirnläsion (Benedikt Syndrom) und bei Patienten mit Parkinsonscher Krankheit nach einseitiger Thalamotomie (Nukleus ventralis intermedius). Diese Befunde weisen auf eine wichtige Rolle der dentato-rubro-thalamischen oder dentato-thalamischen Bahn in der Pathogenese des Bereitschaftspotentials hin.
    Notes: Summary In order to investigate the influence of basal ganglia and cerebellar involvement on the preparatory state of the cerebral cortex for voluntary movement, the cortical potential preceding finger movement was studied in 20 patients with Parkinson's disease and 20 patients with cerebellar ataxia. Readiness potential (RP) was abnormal in 90% of the Parkinson group and in 55% of the cerebellar ataxia group. The most frequent abnormality was a depressed amplitude and earlier onset of RP in both groups. The most remarkable finding in the present study was the complete absence of RP with dyssynergia cerebellaris myoclonica (presumed Ramsay Hunt syndrome) whereas normal RP was obtained with cerebellar cortical degeneration. In addition, RP was absent or severely depressed in patients with a unilateral vascular lesion of the midbrain (Benedikt's syndrome) and in patients with Parkinson's disease who underwent unilateral intermedioventral (Vim) thalamotomy. These facts suggest a possible important role of the dentatorubro-thalamic or dentatothalamic pathway in the physiogenesis of RP.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00313365
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Scalp topography of somatosensory evoked potentials following median and posterior tibial nerve stimulation in Down's syndrome (1993)
    Springer
    Brain topography 5 (1993), S. 253-261 
    Details
    ISSN: 1573-6792
    Keywords: Somatosensory evoked potentials ; Down's syndrome ; Scalp topography ; Mapping ; Significance probability mapping ; Gender difference
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The scalp topography of somatosensory evoked potentials (SEPs) following stimulation of the median and posterior tibial nerve of 39 patients with Down's syndrome was compared with that of age-matched normal controls using significance probability mapping (SPM). The maximal area of each potential in Down's syndrome was similar to that in normal controls, but the scalp distribution was wider. The amplitudes of all components, except the N45 and P59 potentials of the posterior tibial nerve SEPs, were greater in Down's syndrome, and the t values calculated by SPM were significantly greater. However, the difference of SEP maps between Down's patients and aged controls (over 65 years) was much smaller than that between Down's patients and age-matched controls. Therefore, we conclude that the generator sources and generating mechanisms of SEPs in Down's syndrome are not different from those of normal control, however SEP potentials in Down's syndrome are remarkably enhanced, resulting in a wider distribution, probably due to accelerated aging in Down's patients.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01128992
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Cortical magnetic and electric fields associated with voluntary finger movements (1994)
    Springer
    Brain topography 6 (1994), S. 175-183 
    Details
    ISSN: 1573-6792
    Keywords: Movement-related magnetic field ; Movement-related cortical potential ; Magnetoencephalography ; Readiness field ; Motor field ; Movement evoked field
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Multichannel recordings of both movement-related magnetic fields (MRMFs) and movement-related cortical potentials (MRCPs) were simultaneously recorded in association with voluntary unilateral self-paced index finger abduction movement in two normal volunteers. 1) Slow magnetic field (readiness field; RF) can be detected several hundred msec before the movement onset, and its field distribution indicates the existence of the largest generator source over the contralateral primary motor area. Taken together with the vertex-maximal Bereitschaftspotential which corresponds to the earlier part of the RF, the complexity of this magnetic field suggested by relatively low correlation value in single dipole model indicates the co-activation of other underlying generators besides this largest dipole. 2) The utilization of MRMF with MRCP facilitates the separation of two distinct electrophysiological events in proximity to the movement onset, which are difficult to be determined by the technique of MRCP only. Those are the motor field (MF) and the movement evoked field I (MEFI) in MRMF, and the parietal peak motor potential (ppMP) and the frontal peak motor potential (fpMP) in MRCP, which occur approximately 20 and 100 msec after EMG onset, respectively. These two subcomponents may imply the culmination of motor cortex and sensory feedback activation, respectively. Combined study of MRMF and MRCP will provide better definition of cortical events related to voluntary movement than the study of either modality alone.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01187707
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Assistant force compensation for hand movement of patients by using exogenous signals and/or neurophysiological signals (2000)
    Springer
    Artificial life and robotics 4 (2000), S. 227-232 
    Details
    ISSN: 1614-7456
    Keywords: Hand movement disability ; Compensation for hand movement control ; Visual target tracking ; Industrial articulated robot arm ; Equipment for generating assistant force
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract Because functional diseases of the brain can cause disabilities related to human movement control, a compensation method was developed for improving the performance of hand movements. The compensation for human hand movements can be carried out by adding an assistant force that is generated from artificial equipment attached to a human arm. From the experiment on visual target tracking, it was found that the tracking trajectory was adequately represented by a dynamic model of the motion of an articulated industrial robot arm, and the different abilities for movement control among healthy people and patients were classified by different model parameters as position loop gain, velocity loop gain, and response delay. Dynamic force compensation was approached by considering the different control features of the patients. The effectiveness of the proposed compensation method was verified in a simulation study on an actual industrial robot arm. A human-machine interface, e.g., a brain-computer interface (BCI), for realizing the control of artificial equipment to compensate for human hand movements is also presented and discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02481179
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...